All animals pose some risk of infection to people, to one degree or another, but the risk varies a lot between animal species. I guess I’ve always considered guinea pigs to be relatively benig, with a few zoonotic disease concerns but with bites probably being the biggest risk.
I still think that’s true, but a couple of recent studies show that there are a few other things to to keep in mind.
A paper coming out in January’s edition of Emerging Infectious Diseases (Gruszynski et al., Streptococcus equi subsp zooepidemicus infections associated with guinea pigs) describes infections caused by a bacterium, commonly known as Strep zoo, that is typically found in horses, and occasionally in other species like dogs.
The first case was an adult in Virginia who started off with flu-like disease and then deteriorated, developing a serious systemic infection, shock and necrotizing fasciitis (flesh eating disease). Strep zoo was isolated from the patient's wounds. He spent several months in hospital and a rehabilitation centre, but survived.
The second patient was an elderly man, also from Virginia, who was related to the first patient. He went to the hospital with vague, predominantly flu-like signs, and developed pneumonia, septic shock and multi-organ failure. Strep zoo was isolated from his bloodstream. He was hospitalized for 18 days but survived.
Two infections by the same bug in people who have contact with each other certainly suggests there’s a common source or one infected the other. But where do guinea pigs come into this story?
A relative of the first patient mentioned that he had recently purchased four guinea pigs, and that one had died shortly thereafter. The second patient had cleaned the guinea pig cage a couple of days before he became ill. So, it was logical to consider the guinea pigs as a possible source. Unfortunately the response was over-the-top. They euthanized all the guinea pigs and then tested them. Strep zoo was found in two of the guinea pigs, and the guinea pig and human isolates were indistinguishable. Presumably, the pigs were infected first and passed it to the two people through regular contact.
What does this mean, in the grand scheme of things?
- Probably nothing major.
- It’s a reminder that infections (including serious ones) can result from even normal contact with species we don’t often consider to be high risk.
- It shows the importance of physicians querying pet contact.
- It highlights the need for good basic infection control and hygiene practices around animals.
It also shows the common, but what I’d consider to be excessive, response that can occur when people finally do consider an animal source. It’s not clear whether the pigs were euthanized at the owner’s direction or whether public health pushed for it.
Euthanasia is the easy way out, since it removes any need to think about ongoing risk (euthanizing the animals before even testing them makes no sense at all to me). If the owner wasn’t going to take them back (or their interim caretaker wasn’t comfortable keeping them) and they were unwilling to re-home the pigs because of fear of infecting someone else, I can see how that decision would be made. It’s a stressful time when people are sick, and the fear of it happening again would be understandable.
- This bacterium is a rare cause of disease, and some people (e.g. horse owners) are exposed to it quite regularly.
- It might only be present in the guinea pigs for a short period of time. We don’t know if they can be long-term carriers, and it’s possible they would get rid of it after a short period of time in a household (versus a stressful breeding colony or pet store environment).
- Strep zoo-free guinea pigs would still pose some risk.
There’s never a simple answer for situations like this, and the full story would be interesting to know.
2014 was the worst year ever for Eastern Equine Encephalitis (EEE) in Ontario (though our numbers still pale in comparison to more endemic areas in the southern US, such as Florida). A recent article published in the Animal Health Lab (AHL) Newletter (December 2014) by Dr. Alison Moore from OMAFRA sums things up well:
"Twenty-two horses and 2 emus in the province died or were euthanized due to the disease with potentially as many deaths being suspected by attending veterinarians. Two horses were confirmed infected but survived. Counties in Eastern Ontario suffered the greatest casualties. Diagnosis in 21 horses was by serum IgM ELISA testing and 3 were diagnosed by RT-PCR on brain tissue. The affected horses were diagnosed between the end of July and the end of October. Ages of affected horses ranged from 2-20+ years, with no breed or sex predilection. Most of the infected horses were unvaccinated backyard horses and only a single horse per property was clinically affected. Most horses had an acute onset of disease with death or euthanasia performed within 24-48 hours. Common clinical signs included ataxia progressing to recumbency, with fever noted in some and blindness and head pressing noted in others. In the 2 horses that survived, the clinical signs were mild (ataxia and lethargy). The 2 emus were diagnosed with hemorrhagic enteritis and EEEV confirmed in the intestine and liver by RT-PCR.
The virus causing EEE is transmitted by mosquitoes. In Ontario, the most important species is Culiseta melanura, which feeds on birds. Bridge vectors, mosquitoes that feed on both birds and mammals, then complete the cycle to humans and horses. Outbreaks occur in hardwood, flooded areas with competent avian reservoirs and mammals present. Horses and humans are dead-end hosts as they do not produce sufficient viremia to infect mosquitoes.
So why was 2014 such a devastating year? Some speculate that eastern Ontario was relatively warmer this year than other parts of the province, others say it was due to the amount of spring precipitation. Others implicate the spring migration of wading birds such as herons from Florida. Herons are a preferred host for Culiseta sp. over winter in Florida, a major reservoir state for EEEV. The spring migration of herons and similar birds is thought to disseminate the virus to the northern USA and Canada. OMAFRA and Public Health Ontario will be working together over the winter to determine any associations between ecological and meteorological factors and disease occurrence."
Given the amount of activity we saw with this virus this past summer, vaccination of horses against EEE (particularly in hard-hit areas) will be important come spring to help avoid a repeat of this year's outbreak.
More information about the occurrence of EEE and other equine neurologic diseases in Ontario is available on the OMAFRA website: Equine Neurological Disease Surveillance 2014.
As I mentioned a few days ago, eliminating the risk of rabies in animal shelters is pretty much impossible. Another shelter-associated rabies exposure situation highlights the problems.
A cat at the Washington Area Humane Society was recently diagnosed with rabies, resulting in three people receiving post-exposure prophylaxis (i.e. rabies antibodies and a series of rabies vaccines). What’s quite interesting here is the fact that the cat had been in the shelter since May. So, unless the cat was exposed to rabies in the shelter (possible, but very unlikely), that means the incubation period was at least 6-7 months. That’s not unheard of, but it’s pretty long for a cat. We don’t know exactly how long the incubation period can be, except that it’s long. In humans, cases have been identified a few years after the presumed exposure. This situation shows how the 6 month quarantine that is used after exposure of unvaccinated animals is very reasonable, but still not a guarantee. It also shows how short-term isolation of animals in a shelter after arrival can’t guarantee there will be no rabies exposure (although it’s good for many other reasons).
Yes, that’s an "oops," but it’s also not completely preventable.
A stray dog and her 6 puppies were sent to a foster home recently by a South Boston, VA animal shelter. It’s a common and logical thing to do, to get the puppies into a lower risk environment until they are old enough to be adopted. However, any animal with an unknown history is a risk, and that was a problem here, because the dog started to act abnormally after being fostered. She was subsequently diagnosed with rabies, and seven people (including, not surprisingly, the foster family) had to receive post-exposure prophylaxis.
Here are some comments from the article:
It takes about 10 days for an animal to start showing signs of rabies. Staff at the pound had no clue that the dog had rabies because it only stayed there for two hours.
The first point is incorrect. It can take much longer for an animal to develop signs of rabies. The 10 day window is what is used after an animal has bitten a person, because an animal that is shedding the virus will become ill with rabies within 10 days. However, the incubation time (i.e. the time from when an animal is exposed to the time it develops disease) can be months. So, a 10 day quarantine of new arrivals is good for some things, but doesn’t mean that the dog won’t develop signs of rabies later.
Staff sanitized the area.
This isn't really needed for rabies, because the rabies virus isn’t spread through contact with the general environment. It is certainly a good practice for the shelter overall, though, since there are presumably many other bacteria and viruses lurking in the shelter environment.
When an animal is brought in now, it’s monitored for signs of any disease.
That’s a common (and common sense) measure. However, it only helps with some, but not all, diseases. In this particular case, it may have helped the staff to identify this dog as being rabid before it was sent to a foster home (because it developed signs in less than two day), but it won’t prevent all cases like this from occurring. It’s a tough balance between monitoring for signs of disease and wanting to get the animal out of the shelter ASAP (because of shelter space issues, and to reduce the chance of the animal being exposed to something in the shelter, etc.). There’s no perfect approach.
“People need to get their dogs and cats vaccinated. You’re playing Russian Roulette when you turn the cat out at night and it doesn’t have the vaccine,” said Dan Richardson, the Environmental Health Manager for Southern Virginia.
Amen to that.
A recent paper in Zoonoses and Public Health (Whitten et al, 2014) describes reptile-associated salmonellosis cases in Minnesota between 1996-2011. Like similar reports, the data underestimate the problem because it’s thought that for every documented case, approximately 30 cases go undiagnosed. Regardless, there are some useful findings.
Twelve to 30 cases of reptile-associated salmonellosis were identified in the state each year. That represented about 3.5% of all sporadic (non-outbreak-associated) cases.
- This is lower than is often reported, but Minnesota is also known to have one of the lowest pet ownership rates among states, which might account for this discrepancy, at least in part.
Kids bore the brunt of disease (as is normal), with the median age of victims being 11 years. 17% were less than one year of age, 31% were less than five years of age, and 67% were under 20.
- The very young kids presumably had little or no direct contact with reptiles. This highlights the fact that living in the house with a reptile is a risk factor, even if there’s no direct contact. That’s why reptiles shouldn’t be in the house if there are high risk people present (i.e. kids less than five years of age, elderly individuals, pregnant women, immunocompromised individuals). Just trying to keep the high risk people from having contact with the reptile isn’t enough.
23% of cases had to be hospitalized. Fifteen (5%) had invasive infections, where Salmonella made it out of the intestinal tract and into the rest of the body.
- These types of infection are a major concern, and the report included one case where the bacterium was found in the cerebrospinal fluid (indicating the person presumably had Salmonella meningitis).
Fortunately, none died.
Over half of the people who got sick and who were asked (i.e. not including the young kids) reported knowing that reptiles can be sources of Salmonella.
Almost half reported exposure to a lizard, with 20% reporting snake contact, 19% reporting turtle contact and some reporting contact with more than one type of reptile.
A quarter of those who reported turtle contact and indicated the size of the turtle said the turtle was less than four inches in length.
- That’s relevant because it’s illegal to sell turtles that small in the US. The rule was put in place due to the increased risk of kids handling small turtles and getting exposed to Salmonella. The finding isn't surprising, though, since this law is widely ignored.
Some people consented to having their reptile tested. 86% of the tested reptiles were shedding Salmonella at the time the follow-up was performed. 96% of those were the same strain that caused disease in the person.
Overall, not a lot has changed, which is concerning. There’s a risk of disease with any pet contact, but reptiles are undeniably high risk. We’ll never completely eliminate the problem, but logical pet ownership and animal management are needed to reduce the risk. A good start is getting young kids away from reptiles. Reptiles can make great pets… but not for young kids, and not without some risk.
I’ve written a lot lately about importation of pets and associated infectious disease issues. A recent paper in the journal Zoonoses and Public Health (Sinclair et al, Dogs entering the United States from rabies-endemic countries, 2011-2012) provides some interesting data on this topic.
Dogs entering the US from countries where rabies is present must be vaccinated against this disease. If they are not vaccinated, the importer must sign an agreement that says the dog will be confined until it is fully vaccinated, i.e. 30 days after it receives its first vaccine. Dogs have to be at least 3 months old to be vaccinated, so any dog under that age must be confined until it is 3 months old, vaccinated, and then confined for an additional 30 days post-vaccine.
The study focused on dogs that had to be confined due to lack of rabies vaccination on entry to the US.
- Over a 1 yr period, 2746 dogs were confined. That's a pretty impressive number of imported dogs considering this only accounts for unvaccinated dogs from countries where rabies is present.
- Dogs originated from 81 different countries. Canada (21%), Mexico (13%) and Europe (30%) were the most common sources. Dogs from Mexico would be the greatest concern of these because of the presence of canine rabies in that country. Europe is variable risk, with rabies in wildlife and dogs imported from higher risk regions. It’s not clear to me whether some of these "European" dogs might have actually originated elsewhere and been funneled through Europe, which would make them higher risk as well.
- 11.4% of the dogs came from South America, 8.5% from Asia and 1.2% from Africa. These are all higher risk regions.
- Most (67%) were puppies less than 3 months of age (so too young to have been vaccinated.)
- The nature of the movement of the dogs (e.g. how they arrived, where they arrived, from where they came) in comparison to human travel patterns led the authors to conclude that most were "entering the United States for increasing the dog supply", as opposed to people traveling with their own pets.
One of their other conclusions was “Dogs unimmunized against rabies and coming from rabies- endemic countries (i.e. DPCAs) continue to be imported into the United States in considerable numbers. These DPCAs pose a demonstrated risk for re-introduction of canine rabies virus variant and may also pose risks for entry of other animal and zoonotic diseases.“
If over 2700 unvaccinated dogs were brought into the country, how many dogs were brought in in total? How many of the "vaccinated" dogs were really vaccinated? (Since scrutiny is limited and faking a vaccine certificate doesn’t exactly take a lot of effort.) What other pathogens might those thousands of imported dogs been carrying? Finally, why import those dogs in the first place? There’s hardly a shortage of dogs looking for homes in the US...
No, not really. Just for the sake of training.
The ongoing Ebola epidemic in West Africa, along with a few "escapes" of the virus into other regions, has brought scrutiny on the potential role of animals (beyond the wildlife reservoirs) in Ebola virus transmission. Concerns have led to development of contingency practices in some regions for handling potentially exposed animals (just in case).
Today, we ran a trial retrieval of an Ebola-exposed dog (played by Merlin) from a household to evaluate and practice our retrieval, transportation and quarantine protocols. Things like this are typically more complex than they seem at first glance, which is one reason to do a dry-run, despite having spent a lot of time developing the protocols and talking through the entire procedure.
How did it go? Pretty well, overall. Merlin’s a pretty good practice-patient since he’s easy to handle. However, the trial run got us thinking about a few things we hadn't considered, helped identify some little points to improve, and gave us good practice with donning and doffing (i.e. putting on and taking off) personal protective equipment (PPE, one of the most complex and easy-to-screw-up aspects of high-risk patient management).
What are the odds we’ll ever do this for real? Very low. However, it we ever have to, we’ll be very glad we tried it in advance.
With regard to what we’re doing for animals (like this training exercise) and the broader Ebola-management training in human healthcare, one question I've been asked a lot is "Isn’t this a complete waste of time and effort?" It’s very unlikely that the overwhelming majority of healthcare centres in Ontario will encounter a case or Ebola, just like it’s very unlikely we’ll have to manage a potentially exposed pet. However, the time spent isn’t a waste. While Ebola may not make it here, we will continue to encounter emerging diseases. All this training, along with the communication networks and similar behind-the-scenes work that’s going on will better equip us for the next infectious disease challenge. We may not know what’s coming, but the main aspects of response to a lot of infectious diseases are the same.
How’d Merlin do? He didn’t really appreciate waiting around in the crate outside in the cold while we were donning and doffing PPE, and getting ourselves sorted out, but lots of treats were involved so he didn’t seem to mind too much.
Photos: A, B Loading Merlin into a crate and covering it for transport; C Merlin (in his crate) in the back of the transport truck; D Two response team members in full PPE at the quarantine site.
The cats were mainly indoor cats owned by one person - a pretty classical case of cat hoarding. All were in very poor condition. There were vaccination records for 15 of them, but there was no way to figure out which record corresponded to which cat (e.g. "black cat" doesn’t help much when you have 30 black cats in the group).
Since all of the cats had to be considered unvaccinated and they were exposed to a rabid animal, that left two options: euthanasia or 6 month quarantine. The logistics and cost of a 6 month quarantine, along with the poor condition of the cats themselves (and probably concerns about finding adequate homes after quarantine) led to the decision to euthanize the group.
Sometimes, these decisions have to be made despite knowing that the true risk of rabies exposure was very low. However, that’s not the case here. There was one confirmed rabid kitten, but other kittens in the litter had already died by the time that one was tested. The others may have also had rabies. The kittens had to get rabies from something, and if they were indoor (which is probably the case here given the primarily indoor nature of this group and their age), that means the virus probably came from one of the indoor-outdoor cats or from the mother (no word on her health status), which means there were multiple potential sources of exposure for the larger group than the one kitten that tested positive.
In some ways, they got lucky here. The kitten was taken to a veterinary clinic, where it bit a technician. The clinic fortunately did things right and reported the bite, and the kitten was tested. Otherwise, this would not have been picked up and there’s a much greater chance that the owner or someone else would have been exposed, and possibly died.
Inadequate rabies vaccination of this group led to the deaths of 50 cats, expensive post-exposure treatment of a few people (the veterinary technician, an animal control officer who was also bitten, and likely the owner), and presumably a lot of time and effort investigating this.
This case, and other recent rabies diagnoses, is plotted on wormsandgermsmap.com
More information about rabies is also available on the Worms & Germs Resources - Pets page.
It’s that time of year. No, not for snow (although it is snowing here at the moment). It’s time for the annual US rabies surveillance report in the Journal of the American Veterinary Medical Association (Dyer et al. Rabies surveillance in the United States during 2013).
- Over 5800 rabid animals were identified in the US. 92% of those were wildlife. That’s going to be a profound underestimation since most rabid wildlife aren’t caught and tested, but it shows that rabies is still alive and well in the US.
- Rabies was most commonly diagnosed in raccoons, followed by bats, skunks and foxes.
- Among domestic animals, there were 247 cats, 89 dogs, 86 cattle, 31 horses/mules, 9 sheep/goats, 3 pigs, 2 llamas, and a partridge in a pear tree. (Obviously the last one’s my lame attempt at early winter humour. Birds aren’t a rabies concern).
- Other species affected included mongooses (38; as always, just from Puerto Rico), groundhogs (37), bobcats (16), coyotes (5), deer (5), otters (3), opossums (2), wolves (2), marmots (2), a rabbit and a fisher. Most of those are fairly typical, both in terms of the species affected and the numbers.
- Pennsylvania had the most rabid cats, while Texas won for most rabid dogs.
- Vaccination history was not usually available for rabid dogs and cats. None of the rabid cats had been properly vaccinated against rabies. One of the rabid dogs had been vaccinated, a 10-month-old dog that developed rabies 7 months after receiving its first dose. This one’s a bit concerning, though. By being vaccinated at 3 months of age, it would have been considered "up-to-date" on rabies vaccination and this would therefore be a vaccine failure. No vaccine is 100% effective (although rabies vaccine is considered very effective as vaccines go) and the dog having only received only one dose because of its age was probably a key factor.
- The dominant rabies virus variants had a typical geographic distribution (see map above).
Three people were diagnosed with rabies during the year.
- The first was a person who died of raccoon rabies. There was no history of animal exposure, but he had received a kidney transplant 17 months earlier. The donor had been diagnosed with severe gastroenteritis, but also had some neurological abnormalities and when banked samples from the donor were tested, rabies virus was found. Three other organ recipients were then given post-exposure prophylaxis.
- The second person was a man from Guatemala who was detained trying to enter the US. While in custody, he developed neurological disease and died. Central American canine rabies variant was identified.
- I assume the third reported case was the organ donor from the first case, since the case was diagnosed in 2013 (even though the person died in a different year).
As per usual, there’s a little information about Canada and Mexico in the paper.
- 116 rabid animals were identified in Canada, 88% of those being wildlife. There were also 12 cats and dogs (combined) and 2 horses.
- In Mexico, an important finding was the fact that, for the first time since 1938, no people died of rabies. Eleven rabid dogs were identified. However, care must be taken in comparing data from different countries because of potential differences in testing (if you don’t look too hard, you don’t find).
Today, guidance documents coordinated by the US Centers for Disease Control and Prevention and the American Veterinary Medical Association were released. CDC descriptions of the two documents are below. Click on the title to get the document.
This document provides interim guidance based on the latest scientific evidence and recommendations from national organizations, for the management of pets, specifically dogs and cats, owned by Ebola virus disease (Ebola) contacts.
Interim Guidance for Dog or Cat Quarantine after Exposure to a Human with Confirmed Ebola Virus Disease
The intent of this interim guidance is to provide guidance for companion animals, specifically dogs and cats with exposure to a person with Ebola, based on the latest scientific evidence and recommendations from national organizations. This interim guidance describes the process for conducting a risk assessment for exposure of dogs or cats that had contact with a human with laboratory-confirmed evidence of Ebola, and it describes how to implement quarantine of dogs or cats if deemed appropriate by state and federal human and animal health officials.
Image: Scanning electron micrograph of Ebola virus particles budding from a cell. (Source: CDC Public Health Image Library #17775)
The latest Worms & Germs infosheet, all about Lyme disease and ticks, is now available on the Resources - Pets page. Although it's getting colder and occasionally snowy up in Ontario, there are lots of parts of North America where ticks are active all year round. It's particularly important for any "snowbirds" who may travel south with their pets over the winter to be aware of the potential for exposure to ticks and the diseases they transmit (not just Lyme disease!), and to make sure their pets (as well as they themselves) are properly protected. (The same goes for exposure to mosquitoes, which can transmit (among other things) heartworm.)
Remember that dogs (nor any other mammal for that matter) cannot transmit Borrelia burgorferi, the bacterium that causes Lyme disease, to people; however, this is a good example of a "one health" disease that clearly affects both people and animals. Finding the disease in one species is an indication that the other is at risk as well, when there is exposure to a common source (i.e. the ticks).
Thanks to University of Guelph professor and parasitologist Dr. Andrew Perigrine for his input on the infosheet as well.
Image: A female blacklegged tick, Ixodes scapularis, engorged with a host blood meal. (Source: CDC Public Health Image Library 15993)
The short story: a blind dog was imported from Iran. Upon arrival, it was found to have (probably among other things) leishmaniasis, a concerning parasitic disease that we’re seeing occasionally in imported dogs. Leishmaniasis is nasty, hard to treat, expensive to manage and there are concerns about whether these dogs could pose a risk to people (i.e. due to disease transmission). Dogs are the main reservoir of the parasite (Leishmania spp.) in many regions, and people become infected when sandflies bite an infected dog, then later bite a person. We don’t have those sandflies in Canada, but we can’t be certain that there are no other biting insects that could transmit Leishmania. It’s probably a low risk but it’s an unnecessary one.
Back to the dog from Iran: Now, the adoption fell through and the foster home won’t keep him because of his health problems, so there’s a search on for donations and someone willing to adopt a blind, sick dog that will require long-term and expensive veterinary care, probably with a poor prognosis.
I wonder how much time, effort and money was put into bringing this dog from Iran to Canada, and the stress that the dog endured through a very long trip (alone in the cargo hold of a plane), probably to ultimately be euthanized. Yes, in some ways it’s nice that the dog was given a chance, but it should have been pretty obvious that this wasn’t a good idea and wasn’t going to end well.There are finite resources to care for animals, and investments of time and money such as this don't make sense to me.
While these are approached with good intentions, the lack of health screening by some of these "rescue" groups, combined with our completely lax canine importation requirements allow situations like this to occur.
Check out the kijiji ad for more details.
Leptospirosis is a bacterial infection that’s been described as a re-emerging problem in dogs in North America. (It’s been described as that for many years now so maybe we should drop the "re-emerging" and just say it’s a problem). The causative agent, Leptospira interogans, is a widespread bug that’s carried by a variety of wildlife species, and it can cause disease in many different animals, including dogs and people.
In dogs, lepto is an important cause of kidney disease in some regions, and infected dogs pose some degree of risk to people who come in contact with their urine. While it used to be mainly associated with rural dogs here in Ontario, it’s increasingly being found in urban dogs because of the proliferation of raccoons (that can shed the bacterium in their urine) in cities.
A recent study from the University of California Davis (Hennebelle et al, Risk factors associated with leptospirosis in dogs from northern California: 2001-2010, Vector Borne and Zoonotic Diseases, 2014) looked at 67 dogs with lepto and 271 non-lepto controls. You can’t extrapolate all the results to other regions, because there are different animal reservoirs and other factors to consider, but the study provides some good information.
Here are the highlights:
- Vomiting, lethargy, increased white blood cell count and increased kidney values (azotemia) were the most common presenting problems. That’s not surprising but it’s a constant problem. Dogs don’t come in screaming “I have lepto!!!” They often have vague signs and it may be a little while (and a lot of handling) before lepto is considered or diagnosed. That in-between period poses a risk to handlers if good practices to avoid urine contact aren’t used, so practicing good general infection control and keeping lepto under consideration in any of these cases are important to reduce human risks.
- Dogs with lepto can be pretty sick and treatment can be pretty expensive. On average, affected dogs were hospitalized for 11 days at a cost of $5459 (USD). This doesn’t mean it’s always this expensive. This is a referral hospital that probably sees a caseload that’s sicker than average, but regardless, it’s a serious and often very expensive disease.
- 13% of affected dogs died. Again, that’s based on a biased caseload, but still shows it’s not to be taken lightly.
- The main serovar was Pomona. That’s different than we see here in Ontario, where Grippotyphosa (mainly from raccoons) predominates.
- There were regional differences even in California, with more cases from the central or south coast, Sierra Nevada foothills, San Francisco bay area or north coast compared to the distribution of control dogs.
- Owners of dogs with lepto were more likely to report that their dog had contact with water or wildlife, or visited a ranch. These are risk factors for lepto that have been found in other studies as well, and make sense biologically.
- Other risk factors included being 5-10 years of age or over 10 years of age, or being hound breeds.
Lepto’s a big problem in many regions, including around here. That’s why my dog Merlin’s vaccinated against the disease. Lepto vaccines have gotten a bad rap because the older ones were relatively ineffective and associated with increased risk of adverse reactions. However, today’s vaccines protect against the important strains (for most regions) and are quite safe. Discussing the risk of lepto and whether vaccination is indicated is something every dog owner should do with their veterinarian. Knowing regional trends in lepto help make that determination.
Some information about lepto distribution in dogs is available at http://www.wormsandgermsmap.com We don’t have a lot of cases entered yet, so more data would help. If you are a veterinarian or veterinary technician and would like to know how you can help contribute data, click here.
Spanish authorities have issued a statement through ProMED-mail about their decision to euthanize the dog owned by a nursing assistant with Ebola virus disease.
Regarding the news [that] appeared in the magazine "Veterinary Record", dated 18 Oct 2014, where it was questioning the scientific reasons on which euthanasia of the dog Excalibur were based, we are
sending a report based on the opinion of the leading Spanish and European renowned specialists on this subject, epidemiologists, virologists and experts in preventive medicine on animal health.
Case background: [On] 6 Oct 2014 afternoon, the 1st indigenous clinical case of Ebola virus (EBOV) disease was confirmed in a health worker in Spain. The health worker had been involved in the care of a severely diseased missionary who had contracted the virus in Sierra Leone and had died on 25 Sep 2014. The patient developed fever on 29 Sep 2014, and at the time of the confirmation of the diagnosis, she presented with high fever and other typical clinical signs like vomiting and diarrhea. The cohabitation between the patient and the animal was close and constant during some of the period of virus excretion, and therefore the potential for disease transmission could not be ruled out.
In the epidemiological investigation, it was noticed that the health worker was cohabiting with her dog Excalibur in their apartment during the acute phase of her infection and before admission to the hospital. She kept close contact with the dog during the 5 days previous to the confirmation. Thus, the exposure of Excalibur to the virus was very likely, as well as the risk of its contagion.
There are numerous knowledge gaps related to the infection of dogs with EBOV. Allela et al. (2005) studied the potential role of dogs in the epidemiology of EBOV disease. They observed specific antibodies against the virus in pet dogs living in Gabon during the 2001-2002 epidemics. In fact, the apparent seroprevalence reached up to 25 percent in villages with confirmed viral activity. Although the study failed to detect the virus, the authors hypothesized that dogs may carry the virus without showing any clinical sign. Also not determined is possible viral excretion from dogs, the viral loads in these excretions and the lapse of time between the infection of animals and the potential viral shedding. Thus, the risk of EBOV transmission from dogs to humans cannot be ruled out.
The desire of the Spanish authorities would have been to move the dog to quarantine and confirm its infection. Unfortunately, there are no veterinary medical means in Spain to do so respecting the biosafety level 4 (BSL4) requirements pertaining to this virus (CDC, 2009). These missing minimal needs include proper means to carry the dog alive, contrasted protocols for this situation, BSL4 facilities for its quarantine, and training of personnel handling the animal. In addition, the procedure followed the 'precautionary principle', due to the lack of sufficient evidence to eliminate the potential role of EBOV transmission from dogs or other pets to humans, as stressed by Dr. Bernard Vallat, Director General of the World Organization for Animal Health (OIE) to AFP [Agence France-Presse].
Due to these uncertainties and the highly possible risk of infection, the Madrid regional government authorized the euthanasia of Excalibur on 8 Oct 2014 through a court order due to the rejection of the
husband of the patient to allow the health operatives to enter the apartment. The procedure was performed by highly qualified staff of the Health Surveillance Centre of Madrid (VISAVET) and following the strictest animal welfare measures.
The Spanish episode has been repeatedly compared with another EBOV case in Dallas (Texas, United States), although epidemiological and logistic differences exist. The American case occurred in a nurse who had contact with Thomas Eric Duncan and was confirmed on 12 Oct 2014. This nurse also has a dog, which was living with her before the diagnosis confirmation. In contrast to the Spanish case, the period of contact between the patient and the dog comprised the 1st 2 days of clinical infection, in which the viral load in the excretions is lower, so the contagion was less likely than in the Spanish dog. In addition, the US government has sufficient means to maintain the animal in quarantine.
In conclusion, the euthanasia of Excalibur was not an automatic procedure, but a health measure carried out in the best available way and always aimed to protect public health.
Direccion General de Ordenacion e Inspeccion Consejeria de Sanidad
Comunidad de Madrid
c/ Aduana 29 - 4a
I go on periodic rants about people abusing service animal rules to take their pets places they cannot normally go (while potentially compromising the critically important need for true service animals to have unfettered access).
Sometimes, it's nice to know I'm not the only one.
A recent article (pointed out by a writer from the VIN News Service) in The New Yorker describes the exploits of the article's author, Patricia Marx, as she tested the ability to talk your way into various situations with over-the-top examples.
While I have some concerns about some of the scenarios (e.g. turtle bathing in a bowl of water in a deli, a stressed out turkey...) it showed how easy it is for people to manipulate the system. If you can get away with things like she did, it's easy to see how it's so easy for people with fake service dogs (complete with fake ID, vests and other paraphernalia) to do it.
A Brockton, MA dog was euthanized after being bitten by a rabid skunk, because of a combination of the skunk's rabies diagnosis, a relatively minor lapse in the dog's vaccinations, and regulatory inflexibility. The ten-year-old Schnauzer cross was bitten in its own yard, and the skunk was subsequently caught, tested and diagnosed as rabid.
Clearly, this needs to be considered rabies exposure. But, what needs to be done?
- If the dog was up-to-date on its vaccines, it would receive a booster vaccination and be subject to a 45 day observation period (typically at home).
- If unvaccinated, it would be boosted and quarantined for 6 months, or euthanized.
However, a dog doesn’t suddenly go from protected to unprotected immediately after the 1 year or 3 year vaccination duration passes. One year and 3 years are nice easy dates to remember and vaccines are known to provide that degree of protection because they've been tested at these intervals. However, since vaccine-induced antibodies aren’t programmed to self-destruct on a specific "best-before-date", there’s a grey area with animals whose vaccination has lapsed by only a short period. Here, the dog was two weeks overdue - immunologically probably almost identical to what its protection status was at the time its vaccination lapsed.
“It is really sad. My heart goes out to the animal’s owner,” Animal Inspector Megan Hanrahan said. “But those two weeks make the animal not covered.”
Yet, it’s not that clear-cut. NASPHV guidelines state “Animals overdue for a booster vaccination should be evaluated on a case-by-case basis based upon severity of exposure, time elapsed since last vaccination, number of previous vaccinations, current health status, and local rabies epidemiology to determine need for euthanasia or immediate revaccination and observation/isolation."
It’s definitely grey, and being bitten by a rabid skunk is concerning, but a ten-year-old dog that was two weeks overdue (and hopefully previously vaccinated many times over its life) certainly deserved some consideration of this grey area. I think a 45-day observation period would be entirely justifiable here.
Regardless, this is a good reminder of why people need to pay close attention to vaccination dates and ensure that their animals are properly covered at all times (and, no, testing antibody titres does not replace the need for vaccination).
OK…time to get back to work writing. A couple weeks of conference organizing and uncountable Ebola calls are hopefully winding down, so back to the neglected blog.
This bug is an obscure one that I write about regularly: Capnocytophaga canimorus. It’s found in the mouth of most dogs, so people are commonly exposed to it. It almost never causes a problem, but when it does, it’s bad. Capnocytophaga infections classically occur in people who don’t have a functional spleen, alcoholics or those who have a compromised immune system. We focus on education of these high-risk people in terms of avoiding exposure to dog saliva and good bite-management practices. But, as with most things in infectious diseases, there are very few true “nevers”, and there are sporadic reports of Capno infections in people who are (seemingly, at least) otherwise healthy.
Another report appeared in a recent volume of Infection, “A case of Capnocytophaga canimorsus sacral abscess in an immunocompetent patient “(Joswig et al. 2014). Long story short, this person developed an abscess in the sacrum (the bone at the base of your spine), with a pet dog being the presumed source. There was no obvious incident of exposure such as a bite, and the person had no apparent risk factors, so it’s an unusual case. The fact that it was an abscess and not an overwhelming systemic infection (as is often the case) is also unusual, and may relate to the fact that this person had a normal immune system that was able to prevent a rapid, life-threatening infection.
This report doesn’t really change anything, but it’s another example of how some of these potentially nasty infections that we associate mainly with high-risk people can also occur in healthy individuals. This doesn’t mean we should be paranoid of dog saliva, but we should be practically cautious. Avoiding contact with saliva, avoiding bites and proper bite first-aid are all basic measures that can presumably go a long way to helping prevent a wide range of infections.
Since I’ve spent most of my day answering questions about Ebola, here are some of the common Q&As.
Can dogs be infected with Ebola?
Yes, but what that really means is unclear. Most of the available information comes from a study in Gabon where they tested dogs in a community during an Ebola outbreak. They found antibodies against the virus in a large percentage of dogs. That’s not really surprising, as these dogs were apparently scavenging bodies of people and animals that had died from Ebola. So, it’s not hard to see how they’d be exposed.
Having antibodies against the virus means the virus got into their body and the body mounted an immune response. That doesn’t mean the dogs got sick or that they were shedding the virus. In that study, they could not find evidence of the virus in the dogs’ bodies. That doesn’t mean it was never there at relevant levels, but they couldn’t find it at the time.
Can dogs infect people with Ebola?
That’s the big question. Dogs can get infected (see above), but IF the virus can reproduce in a dogs and IF the virus is then present in adequate levels in blood and other secretions, THEN there would be the potential for dogs to be a source of human infection. That’s a lot of IFs for which we don’t have good information.
What do I think?
I think the risk of transmission of Ebola from dogs is very low. There’s currently no evidence that dogs have an important (or any) role in transmission of the virus in natural situations. It’s not zero risk (there aren’t many "it can never happen" situations with emerging diseases), and considering the how deadly the disease is the measures that can be used to mitigate that risk (small though it may be) are important.
So, how can we reduce the risk with an exposed dog?
Basically, treat the dog the same way you would treat a person with Ebola exposure or infection. An exposed person is quarantined and monitored for signs of disease. People are not infectious until they are sick. A sick person is handled with strict infection control precautions because of the potential that the virus is present in various body secretions.
With a dog, it’s probably warranted to err on the side of caution and treat an exposed dog like an infected person. Why? Because we don’t know that dogs are not infectious until they’re sick. So, it might be best to have them isolated and handled with strict biosafety practices, rather than just watch them at home (particularly given the potential for the dog to escape the house).
Is that degree of containment practical?
Maybe. It depends on the facility, personnel and motivation. Last week, I sketched out a containment plan for our facility in case we had a suspect case. It was done knowing there’s virtually no chance it would be needed, but it was a good mental exercise to consider what to do. The more you think about it, the more complex it can get. Containment is possible for a good facility with reliable personnel and a clear containment plan. However, you can’t just drop the dog off at any kennel, shelter or veterinary clinic and say "we’ll be back for it in 21 days." You need the right facility and personnel, and access to that will be variable.
There’s prudence and then there’s "let’s kill it so we don’t have to think about it."
The Spanish response to Ebola in a nursing assistant is a demonstration of the latter. Health Officials in Spain have obtained a court order to "euthanize and incinerate" the dog owned by a nursing assistant who was infected with Ebola virus while caring for a Spanish priest who acquired the infection in Sierra Leone. The case has received a lot of attention, as the first case of Ebola from this outbreak that was acquired outside of Africa.
There’s obviously cause for concern and prudence, and the woman’s husband is logically in quarantine. However, euthanasia of the dog seems like overkill. Yes, we have to be careful. But we don’t need to overreact.
The odds of this dog being infected are very, very slim. Even if the dog was infected, there is no evidence that dogs are a source of infection. The concern about dogs has been around dogs eating carcasses of other animals that have died of Ebola virus infection, and direct contact with people with active disease. In one study in a village in Gabon during an Ebola outbreak, a large percentage of dogs had antibodies against the virus, indicating exposure (Allela et al, Emerging Infectious Diseases 2005). But, exposure doesn’t mean the dogs were ever able to transmit the virus, and eating a body full of Ebola virus is very different from living in the house with one person in the early stage of infection.
I’m not saying transmission from a dog in some form or another is impossible, or that no precautions are required for pets that have been in contact with an infected person. In some ways, it’s good to see animals considered in this scenario. However, why not take the opportunity to quarantine and test the dog to see if it was infected? That would be better for the dog, for its owner, and for the next time the situation occurs. You can’t answer all the questions with one dog, but you can start to gather information. Euthanasia is the easy knee-jerk approach that removes all risk, but there are ways to house and monitor a dog for a few weeks with no contact. Since Ebola virus is spread by direct contact with infectious body fluids, it’s containable with good facilities and appropriate precautions. To me, that would have been a better approach from many aspects.
The salmonellosis outbreak in the US associated with hatching chicks continues to expand. The outbreak, ironically associated with Mt. Healthy Hatcheries in Ohio, has now sickened at least 344 people in 42 US states and Puerto Rico with a variety of Salmonella serotypes (S. Infants, S. Newport and S. Hadar). The outbreak shows no sign of abating, with another 42 cases identified in the past 6 weeks.
As is often the case, young people are more often affected, with 33% of sick individuals being 10 years of age or younger. Thirty-two percent of infected individuals have been hospitalized.
Unfortunately, the regulatory response in situations like this is most often to give places like the hatchery in question "guidance" as opposed to imposing mandatory measures. However, this is really a "buyer beware" situation, in which people purchasing hatching chicks need to be aware of the high risks associated with young poultry, and take appropriate precautions to manage them. While Salmonella-free eggs and chicks would be ideal, it’s not particularly realistic. People need to be more proactive themselves and listen to established infection control practices, which include keeping kids less than five years of age away from young poultry.
Hopefully schools will pay attention to these recommendations when they’re planning their annual (and often poorly managed) hatching chick activities in the spring.
Here’s a question that I get commonly: “What do I do to an outdoor area that might have been contaminated by a dog with parvovirus?”
There’s not a lot of research to back anything up, but understanding the virus and some basic principles helps us come up with some reasonable recommendations.
- Highly tolerant of environmental exposure, disinfectants and other things that kill most viruses.
- Shed in potentially massive amounts in the feces of sick animals, but also potentially by some healthy animals.
- The cause of a potentially fatal disease.
- A pathogen against which we have effective vaccines.
- Really only a concern for unvaccinated (or inadequately vaccinated) dogs.
There’s definitely cause for concern if a puppy with parvo infection has passed diarrhea outside. We can assume there’s lots of virus there, and that the virus is going to be able to survive there for some time. We don’t know how long, and it will certainly vary with environmental conditions (e.g. temperature, pH of the soil, humidity, sunlight), but it’s safe to assume that it will be a fairly long time in most situations.
So, what do we do?
- Disinfection of outdoor surfaces is pretty futile. Disinfectants don’t work well in the presence of organic debris (dirt), so pouring disinfectants on grass or gravel will not likely do much (except put a lot of disinfectant residue into the environment). Unless it’s happened on a surface like concrete or asphalt (both of which can still be hard to adequately disinfect because they are porous), leave the bleach bottle in the cupboard.
- Removing feces is a good first step. This actually removes the vast majority of virus that has been passed. It might require using a shovel to get rid of some of the diarrhea-soaked grass or soil, but removing as much of the visible contamination as possible is key.
- Restricting access to the area can’t hurt, when it’s feasible. That doesn’t mean cordoning it off and keeping everyone away. The focus should be to keep young, unvaccinated or incompletely vaccinated dogs (and dogs that have contact with those dogs) away from the area.
- Raking the site can help turn over the substrate (e.g. dirt, soil, gravel) and get more exposure to UV light. Sunlight is our best outdoor disinfectant, and raking can help expose virus particles that are hidden away.
As always, prevention is better than cure. Preventing these situations is ideal, but admittedly not always possible. Things that can help include:
- Making sure all puppies are properly vaccinated.
- Keeping unvaccinated puppies away from high dog-traffic areas.
- Keeping sick animals away from public areas.
- Promptly picking up feces from any dog, healthy or not.
Well, "news" perhaps isn’t the best description since we’ve been seeing it for a while, but a paper in an upcoming edition of the Journal of Clinical Microbiology (Gold et al. 2014) entitled "Amikacin resistance in Staphylococcus pseudintermedius isolated from dogs" provides published support for the trend we’ve been seeing.
Staphylococcus pseudintermedius is an important cause of infections in dogs, and a resistant form, MRSP (methicillin-resistant Staph pseud) is a major problem. MRSP also does a great job of becoming resistant to additional antibiotics, usually by picking up resistance genes from other bacteria. We’ve rapidly lost most of our typical antibiotic treatment options for many MRSP strains, and are left with only a couple of viable drugs. One of those is amikacin, an antibiotic we try not to use when we don’t have to because it has to be injected, and because it can be hard on the kidneys. However, it’s literally a lifesaver in some cases.
Over the past year or two (unsurprisingly, really), we’ve been seeing some amikacin resistance in MRSP strains. I say that’s unsurprising because, with bacteria in general (and MRSP in particular), we’re trapped in a game of "use it and lose it." Any time we use an antibiotic, there is some potential for resistance to develop.
The study by Gold et al looked at 422 Staph pseud from dogs, and found that MRSP were significantly more likely to be amikacin resistant, with a rather astounding 37% amikacin resistance rate in their MRSP collection. Amikacin-resistant strains were also more likely to be resistant to a range of other antibiotics, regardless of their methicillin-resistance.
What do we do?
Tough question. Bacteria eventually seem to outsmart us most of the time (or we seem to "out-dumb" them, since it’s often our poor use of antibiotics that leads to problems).
So, what can be done?
Prevention is better than cure: MRSP infections are almost invariably secondary problems. Preventing or limiting underlying disease (e.g. controlling allergic skin disease) can greatly reduce the number of infections and the amount of antibiotics used to treat them.
Infection control: MRSP surgical site infections are increasingly common, and using good infection control practices should help limit them.
Use them right: Making sure drugs are given as prescribed with proper dosing (amount and frequency), and limiting the use of the few remaining MRSP treatment options for cases that really need them are important.
Antibiotic alternatives: Antibiotics aren’t always needed to treat infections. Topical therapy with things like chlorhexidine shampoo can be highly effective for skin infections, and can save antibiotics for infections that can't be treated otherwise.
Will these steps stop the scourge of antibiotic resistance?
No. But they might buy us some more time to figure out how to better handle this and to save some of our limited remaining antibiotic options.
Orange County CA is currently experiencing a major outbreak of West Nile infection in people. Since January 94 cases have been confirmed, three of which were fatal, representing nearly a quarter of the 400 cases reported across the country so far this year. The number of cases of infection with a mosquito-borne virus like West Nile (or EEE, which we’ve been seeing over the last month in Ontario horses) can be affected by a lot of factors, including climate/weather, flooding or drought, bird populations and movements, mosquito populations and local mosquito species, and population density of those affected, be they people or animals.
Often we associated wet weather and flooding with increased incidence of diseases like West Nile, but this year California is experiencing a drought. How does that make sense? It’s been suggested that the dry weather is driving birds into more populated areas to look for water. More infected birds in the area provides more opportunity for mosquitoes to bite the birds and then transmit the virus to a person. The number of mosquito pools testing positive in Orange County (80%) is the highest its been since West Nile first hit California a decade ago, and 6.5 times more dead birds (260 total) have tested positive for WNV compared to 2013.
Most of the human cases in California included some signs of illness. When you consider that 80% of people infected with WNV show no signs of the disease, that means there has actually been an even larger number of people actually infected.
The impact on the local horse population has not been mentioned, but it is unlikely that horses will escape this outbreak unscathed. After a relatively slow year for WNV in 2013, I wonder how many horse owners in the area may have decided to forgo vaccinating their horses this year, and may now be regretting it. It’s easy for us to get complacent about infection control when things are going well. In the case of West Nile, people may stop taking precautions to avoid mosquitoes, to remove standing water from their property, and vaccinating their horses. It’s important to remain vigilant though, because there are so many different factors involved in the cycles of various diseases that predicting their resurgence can be extremely difficult, if not impossible. Taking some simple preventative steps, and making basic infection control practices habit can help reduce the impact of unexpected outbreaks, and help keep everyone (people and animals) healthier and safer.
While having nothing to do with my previous rants on the topic, the FDA has issued warning letters to the manufacturers of Angels' Eyes and similar products that are vaguely disguised antibiotics sold for purely cosmetic reasons, and without a veterinary prescription. These products have been widely available to decrease tear staining (hardly a life-threatening problem) in dogs, fully at odds with any concepts of prudent antibiotic use.
Here’s some of the FDA letter text:
“We have determined that your tear stain remover products containing tylosin tartrate are intended for use in the mitigation, treatment, or prevention of disease in animals, and/or to affect the structure or function of the body of animals, which makes them drugs under section 201(g)(1) of the Federal Food, Drug, and Cosmetic Act (the FD&C Act) [21 U.S.C. § 321(g)(1)]. Statements on your labeling, including your website and product labels, that establish these intended uses of your products include, but are not limited to, the following:
• "The active ingredient in Angels' Eyes®, Tylosin as Tartrate, will prevent your dog from contracting Ptyrosporin (Red Yeast) and bacterial infections which causes excess tearing and staining."
• "May help keep tear stains away by reducing oxidation released through tear ducts."
• "Angels' Eyes® is the first product specifically developed for BOTH DOGS & CATS to help eliminate unsightly tear stains from the inside out!"
• "Only ANGELS' EYES® helps give your pets tear stain free eyes and bright coats."
In addition, your tear stain remover products containing tylosin tartrate are new animal drugs, as defined by section 201(v) of the FD&C Act, [21 U.S.C. § 321(v)], because they are not generally recognized among experts qualified by scientific training and experience to evaluate the safety and effectiveness of animal drugs, as safe and effective for use under the conditions prescribed, recommended, or suggested in the labeling. You are using Tylovet Soluble (tylosin tartrate) as an ingredient in the formulation of your product. Although Tylovet Soluble is an approved drug, your use of Tylovet Soluble in your product is not a use covered by its approved application, and your products are not the subject of an approved new animal drug application, conditionally approved new animal drug application, or index listing under sections 512, 571, and 572 of the FD&C Act [21 U.S.C. §§ 360b, 360ccc, and 360ccc-1]. Therefore, the products are unsafe within the meaning of section 512(a) of the FD&C Act, [21 U.S.C. § 360b(a)], and adulterated under section 501(a)(5) of the FD&C Act [21 U.S.C. § 351(a)(5)]. Introduction of an adulterated drug into interstate commerce is prohibited under section 301(a) of the FD&C Act [21 U.S.C. § 331(a)].
We acknowledge the receipt of three written responses submitted after the inspection in December 2013. These responses discuss your facility's compliance with the Current Good Manufacturing Practices for Finished Pharmaceuticals (Title 21 Code of Federal Regulations Part 211 ). However, your responses do not adequately address our concerns regarding the approval status of your products and your use of tylosin tartrate in those products, as discussed above.
Failure to promptly correct the violations specified above may result in enforcement action without further notice. Enforcement action may include seizure of violative products and/or injunction against the manufacturers and distributors of violative products. “
Interestingly, there’s no mention of anything on the Angels' Eyes website. It will be interesting to see what happens, but it’s great to see some attention paid to this completely illogical use of antibiotics. Hopefully the FDA follows through with this and doesn’t leave it at the warning letter stage.
The credit (or blame) for the alliteration goes to colleague and frequent blog material supplier Dr. Stephen Page. It relates to an article in the prestigious medical journal Lancet (Kagihara et al. 2014) entitled “A fatal pasteurella empyema.”
The article describes the case of a 60-year-old man from Honolulu who was admitted to hospital in cardiac arrest. He had various health problems and had had a cough and body aches over the past four weeks, then suddenly deteriorated. He was resuscitated and fluid was found in his chest cavity. When they collected a sample of the fluid, it was full of bacteria that were subsequently identified as Pasteurella multocida. Unfortunately, he died shortly after admission.
Pasteurella multocida is a bacterium that can be found in many animal species but is classically associated with cats. It can be found in most (if not all) healthy cats, as well as in large percentages of other species such as dogs and rabbits. It’s an uncommon cause of infection in people, and is most often linked to cat bites or contact of cats with wounds or other breaks in body barriers. However, it can also be carried by people, and cats are certainly not the only source.
Here, the patient cared for several feral cats and they often slept in his bed (which to me, would make them more pets than feral cats, but that’s beside the point). The authors don’t specifically blame the cats, but it’s inferred. However, there was no investigation (for logical reasons, since it wouldn’t change anything).
Was the cat the source?
Probably, but not certainly.
Further, why the infection developed is a bigger, more interesting and more relevant question, since just being in the vicinity with a cat doesn’t mean you’re going to get an infection.
I often get asked about testing cats for Pasteurella multocida. My somewhat flippant (but still accurate) response is “Here’s the test: Does it look like a cat? If so, it’s carrying Pasteurella.” Cheap and highly accurate.
Seriously, though, it’s true. Most cats carry the bacterium so there’s no indication to test for it. If people are worried about Pasteurella infections (which is really uncalled for, since there are many greater risks in life), they should focus on good hygiene practices, bite avoidance and bite/scratch first aid, not determining whether their cat is carrying the bacterium.
The following question was posed to Dr. Patty Khuly in an article she writes for the Miami Herald.
"Our cats had to go to the vet hospital last week to have their teeth cleaned. The procedures went very well and, as predicted, both were back to normal that evening. Unfortunately, two days later they both started sneezing. First Patches and then Stumpy came down with the exact same cold. Patches got better but we had to take Stumpy back to the hospital. We actually had to pay more for his cold than for the teeth cleaning! Shouldn’t the vet have gone easy on us since our cats live safely indoors and they obviously caught the cold there?"
Here’s my take on the subject:
There are two main questions.
1) Did the cats likely get an infection at the clinic?
- That’s hard to say. Often, it’s straightforward. In a case like this, not so much. It’s possible the cats picked up a respiratory virus in the clinic from another cat that was sick, or from a healthy carrier. However, it’s also possible (and maybe more likely) that the cats had a recurrence of an underlying infection (or one did, then spread it to the other in the household).
- Feline herpesvirus is a common cause of upper respiratory tract disease in cats, and a large percentage of cats are infected when they are young. Herpesviruses often live dormant in the body after infections and can reactivate at any point, causing disease. Cold sores in people are caused by a human herpesvirus, and they behave this way too. Stress is a major cause of re-activation, and the stress of hospitalization, anesthesia and the procedure could easily have lead to recrudescence of herpevirus infection in these cats.
2) Did the clinic provide the required standard of care to reduce the risk of hospital-associated infection?
- Even if the cats acquired an infection at the clinic, it’s not necessarily the clinic’s ‘fault’, particularly if the infection came from a healthy cat that was shedding a virus, unbeknownst to anyone who would look at it. Infection is an inherent risk of hospitalization, and clinics have a duty to take reasonable measures to reduce the risk of disease transmission. That’s a bit of a moving target and it’s pretty subjective, but it’s a key point here. If the cat got the infection in the clinic, was it likely because of inadequate practices, such as failure to isolate a cat with respiratory tract disease, poor hygiene practices (e.g. poor handwashing), failure to use routine infection control measures (e.g. use of protective outerwear like a lab coat) and various other basic infection control concepts? If so, then the clinic’s liable (and should pay for the infection). If not, then it’s an unfortunate event but one that’s no one’s fault.
- We can’t prevent all infections, but we have a duty to try to prevent as many infections as possible. If the clinic had a reasonable infection control program, had this documented, and followed their policies, they’re unlikely to be liable. Beyond providing optimal patient care, this is why vet clinics need to improve infection control practices. Too often, infection control programs are very informal, undocumented and weak, creating risks to patients and staff, and creating liability risks for the clinic. It leaves the door open for someone to claim that a hospital-acquired infection occurred, and makes it hard for the clinic to convince anyone that the infection was non-preventable.
So, was it the clinic’s fault? I don’t know, and it’s hard to prove. It probably wasn’t, but only with a good infection control program could they state with confidence that they did their best to the prevent infection.
The Ontario Ministry of Agriculture Food and Rural Affairs (OMAFRA) has issued an Equine Health Advisory in response to diagnosis of Eastern Equine Encephalitis (EEE) in a horse in Stormont/Dundas/Glengarry, in eastern Ontario. The 12-year-old gelding died, which is the typically outcome with this disease in horses.
EEE is a devastating but fortunately rare (at least in Ontario) disease of horses, people and an assortment of other species (including emus, llamas and alpacas). Typically, a few equine cases are identified in Ontario every year, with human cases being rarer. However, since people and horses are infected in the same way - by the bite of an infected mosquito - finding the disease in a horse indicates risk to both horses and humans in the region.
More information about EEE cases in North America can be found at WormsAndGermsMap. Information for horse owners in Ontario, as well as Ontario-only equine neurological disease cases, can be found on the OMAFRA website.
The US Food and Drug Administration has released the 2011 NARMS (National Antimicrobial Resistances Monitoring System) executive report. It's a good-news/bad-news outcome, which may be as good as can be expected, but at least there's some good news.
- Eighty-five percent of non-typhoidal Salmonella collected from humans had no resistance to any of the antibiotics tested.
- In people, the five-drug resistance pattern “ACSSuT” (resistance to ampicillin, chloramphenicol, streptomycin, sulfonamide, and tetracycline) in Salmonella Typhimurium has declined to 19.5% in 2011, from its peak in 1997 at 35.1%.
- During its 16-year history, NARMS has found Salmonella resistance to ciprofloxacin, one of the most common antibiotics to treat Salmonella infections in humans, to be very low (less than 0.5% in humans, less than 3% in retail meat, and less than 1% in animals at slaughter).
- Multi-drug resistance in Salmonella from humans, slaughtered chickens and slaughtered swine was the lowest since NARMS testing began. However, multi-drug resistance in Salmonella from retail poultry meats generally increased, with slight fluctuations.
- Erythromycin resistance in Campylobacter jejuni (C. jejuni) has remained at less than 4% in isolates obtained from humans, retail chicken and slaughtered chicken since testing began. The antibiotic erythromycin is the drug of choice for treating Campylobacter infections, more than 90% of which are caused by C. jejuni.
- Campylobacter resistance to ciprofloxacin has increased slightly in isolates from humans since 2005. Ciprofloxacin is not approved for use in poultry, and the FDA withdrew approval for the use of enrofloxacin in poultry in 2005. Ciprofloxacin and enrofloxacin are both in the same class of drugs (fluoroquinolones).
- Resistance to third-generation cephalosporins, another important drug class for the treatment of Salmonella infections, rose among isolates from retail ground turkey between 2008 and 2011, and among certain Salmonella serotypes in cattle between 2009 and 2011. In April 2012, FDA prohibited certain uses of cephalosporin drugs in cattle, swine, chickens, and turkeys. NARMS will continue to monitor these trends over time.
Are some pangolins higher risk than others?
What infection control measures should be used?
I don’t know, and from a cursory review of the literature, I don’t think anyone really knows.
So, do we really want to be exposing them to some of our most susceptible individuals - kids who are patients in children's hospitals?
CBSnews.com posted an article earlier this year about exotic animals and hospitals (something that would be contrary to international pet therapy program guidelines published in the American Journal of Infection Control, and various other policies). The cover picture is of a child, presumably quite immunocompromised, touching a pangolin. She’s wearing a mask and gloves, but it looks like she’s also wearing her pajamas (which she is touching with her glove, that maybe just touched the animal).
In reality, the title and pictures don’t have a lot to do with the actual article. It focuses on a great initiative by a group of zoos to create videos about animals and animal care, and to make a TV network that will be provided to children’s hospitals across the US. That sounds like a great idea. The pictures of exotic animals in hospitals are not-so-great.
Pet therapy’s a wonderful thing. I work with pet therapy programs and have been involved in a few initiatives to produce guidelines to make these programs as safe and effective as possible. Part of that involves knowing what you’re dealing with.
Yes, pangolins (sometimes referred to as "walking artichokes") are cool looking critters. I’m sure the kids get a kick out of seeing them. But, is there any additional benefit beyond what the children would get from interacting with a well trained dog? Beyond the cool factor, there’s not a lot of personal connection with a pangolin, I suspect. A happy, friendly dog might actually provide a greater benefit, and since we know a lot about dogs, we are able to manage the risks much more effectively.
The zoo TV initiative sounds great.
Well-run pet therapy programs are similarly great.
Bringing pangolins and other exotic animals into hospitals… not so much.
Photo: Tree pangolin (Manis tricuspis) in central Democratic Republic of the Congo (credit: Valerius Tygart)(click image for source)
Oh, where to start...
- Why do people feel the need to have monkeys as pets? I realize that they’re fascinating critters, but is it in the best interests of the monkey and the public? (Generally no...)
- Why is a pet monkey in a restaurant? Actually, here, it was three monkeys. I have fewer issues with dogs in restaurants since a well trained dog would just sit quietly on the floor. I doubt that the average monkey is going to do the same. Add two more monkeys to the mix and there's not a chance. In this case, problems started when one of the monkeys took off and ran under a parked car.
- Why does a monkey that’s allowed out in public bite? I know that extreme circumstances occur and that you can’t 100% guarantee that bites won’t happen, but monkeys tend to bite more than the average pet. That’s just the way they are. As such, why are they out in public? In this case, after one of the monkeys took off, they were retrieved by another person, who was ultimately bitten when she returned to the runaway monkey to her owner.
- Why a six month quarantine? Someone definitely dropped the ball here. After an animal bites, there’s supposed to be a quarantine period to give the animal time to develop signs of rabies if it was indeed able to transmit rabies at the time of the bite. That takes a matter of days. A 10 day quarantine or observation period is the standard approach for dogs, cats and ferrets (since we know more about how rabies progresses in those species). For other species, where less is known, the default response on paper is often euthanasia and immediate testing for rabies, but in practice, a 10-30 day observation period is usually applied. California (where this incident occurred) guidelines are consistent with this and state “While isolation of biting animals other than dogs, cats, and ferrets is not recommended for the reasons given above, local health officers have the prerogative to forego euthanasia and testing in rare special circumstances. If the biting animal has a comprehensive and reliable history that precludes opportunity for exposure to rabies virus, and the risk of rabies in the biting animal is judged by the health officer to be acceptably low, the health officer may institute a prolonged (30-day) isolation of the biting animal."
Like many other aspects of this situation, a six month quarantine just doesn’t make sense. In contrast, if the monkey had been bitten by a potentially rabid animal (for example, a bat), then it would require a six month quarantine to ensure it had not become infected by being bitten. The difference between the two kinds of quarantine periods is frequently misunderstood.
Image: A 19th-century organ grinder and his capuchin monkey (click image for source)
Hopefully we can chalk this one up on the "weird and not-so-wonderful" list, and not have it emerge as a significant problem. However, there’s something new to pay attention to as St. Louis Encephalitis virus (SLEV) infection was recently identified in a Brazilian horse with neurological clinical signs.
In a recent paper (Rosa et al. 2013), SLEV was found in the brain of a horse from Minas Gerais, Brazil that had died of neurological disease. Fairly extensive testing was performed to rule out other causes, so the presence of the virus in the brain and the absence of other potential causes is quite suggestive that SLEV was the problem here. It’s an interesting finding because while this virus is widespread in North and South America, from Canada to Argentina, it rarely causes disease in mammals. It circulates between birds via mosquitoes and occasionally spills over into mammals, which are considered "accidental" and "dead end" hosts since they are not part of the virus's normal transmission cycle and once infected, they can’t pass the virus on to anyone/anything else. Most infections are reported in people and they tend to be mild, although serious neurological disease can occur, especially in elderly individuals.
So, this would be the first confirmed report of SLEV-associated disease in a horse. The signs of disease were pretty non-specific and included depression, incoordination and paralysis of the hind limbs. That’s something we can see with a few different neurological diseases in horses, including the much more common EHV-1 encephalomyelopathy (and in Ontario and other parts of North America, West Nile virus).
The infection was diagnosed in a horse that died in 2009 after 72 hours of neurological disease. That’s a long time from disease to diagnosis, but in this case it’s probably also a good sign. No other horses on the farm were affected at the time, and no one has reported changes in neurological disease patterns in the area (or beyond) since then; therefore, this presumably was not the start of a large, rapidly moving new disease, as we saw when West Nile virus hit North America in the early 2000s.
Hopefully this was just a strange one-off infection, but it shows the need for continued infectious disease surveillance and the ever-changing challenges of infectious diseases.
“Animal-loving grandmother died from rare infection after her pet dog licked her hand and bacteria spread into her bloodstream.” For me, the first thing I think of when I hear that is Capnocytophaga canimorsus (to which most people respond “Capno-whata cani-whatsis?”).
It’s a tragic but textbook example of what this common dog-associated bacterium rarely can do. In this case, 53-year-old Sheena Kavanagh developed septic shock from C. canimorsus infection, presumably after the bacterium got into her body when she was licked by her dog.
This bacterium is found in the mouth of virtually all dogs, but rarely causes human infections. The right set of circumstances are required: First, the bacterium has to make it past the body’s skin defenses (usually, it’s via a bite but in this case, the victim had a small cut on her hand and the thought is that saliva got into the cut), and then it has to evade the body’s immune system. Classically, the disease is primarily found in individuals who don’t’ have a functioning spleen (an organ that plays a key role in eliminating some microorganisms from the blood), and that was the case here. As is common, the woman's condition deteriorated very rapidly, and she died before anyone knew what was happening.
People shouldn’t fear their dogs and become germaphobes. However, people need to be aware of the risks, know some basic preventive measures and know when they are at increased risk of infection. Too often, people who are at increased risk because they have lost their spleen, have an immunocompromising disorder or have some other problem don’t know anything about this and similar issues. Communication with (and between) physicians and veterinarians about these risks is often rare to non-existent.
People like to talk about "one medicine," but we need to actually practice it more often.
More information about Capnocytophaga can be found on the Worms & Germs Resources - Pets page.
I’ll admit it - I don’t understand dogs. How is it that they have this incredibly well-developed sense of smell, but my dog feels it necessary to roll in the most disgusting smelling things he can find? I guess it’s not that he feels like he needs strong body odour, just that he has a poorly developed part of the brain that says “hey, that smells gross” (along with related parts of the brain that say “hey, that tastes gross,” “maybe I shouldn’t chase that skunk,” and “maybe body slamming the side of the bed to scratch my back at 4 AM doesn’t endear me to the people that feed me.”).
Anyway, that’s a pretty indirect introduction to a question of what animals can track back into the household and other unusual routes of zoonotic disease exposure. I won’t get into the whole issue, but I have had a rash of calls lately from people worried about indirect exposure to rabies virus. Questions have include:
- My dog was nosing raccoon roadkill. What if the raccoon had rabies?
- If I run over an animal and then touch the tire, could contract rabies?
- If someone who works removing bats from houses comes over, could they have rabies virus on their shoes and contaminate my house?
For someone to get rabies, the virus has to go from the infected animal’s body (saliva or nervous tissue) into the person’s body. Rabies virus isn’t airborne, it doesn’t survive long in the environment and it can’t infect through intact skin. Indirect transmission of rabies is exceedingly rare, with one of the only examples that comes to mind being rabies in a family of shepherds who cared for a sheep that was attacked by a rabid wolf. The attack occurred right before the people handled the sheep, and wolf saliva (containing rabies virus) was likely present on the sheep’s coat from the attack, and the handlers had cuts on their hands. Very rare.
That said, with infectious diseases we rarely say "never." That often causes angst because people want to hear “there’s absolutely, positively no way you could have gotten [insert disease here] from [insert event here].” Yet, there are situations that are so unlikely that we probably should take the plunge and just say "never."
For example, is there a theoretical chance that an animal run over by a car would be rabid, and that brain tissue would be splattered on the tire, and that it wouldn’t be killed right away by heat from the tire, and someone would touch the tire right after and that person touched a virus contaminated area of the tire and the virus had contact with an open wound?
Sure, I guess...
However, while rabies post-exposure treatment is very safe, the odds of an adverse effect of post-exposure treatment are probably infinitely higher than the odds of getting rabies in weird situations like those about which we are sometimes asked. Considering how well rabies cases are tracking in developed countries, and how many wild animals have rabies, if indirect exposure was a real concern, we’d know about.
It's not a coincidence that we see more equine infectious diseases during busy show seasons. Shows are a great way for infectious diseases to spread, with outcomes ranging from disease in single horses to widely disseminated outbreaks, even across international borders.
We can't eliminate all risk in life, and the risk of infection in horses is no different, but we can do many things to reduce the risk. A lot of these are what I call "low hanging fruit," meaning they are measures that are really quite easy and practical (but often not done regardless).
Friend and colleague Dr. Paul Morley and his team have put together a great 7-minute video entitled "Preventing infections in Horses Attending Shows and Traveling." It provides great information and is well presented, and anyone who travels with horses (or runs a farm that has horses that travel) should take a look.
Two recent papers have raised concerns about cats in households with cystic fibrosis (CF) patients. People with CF are at high risk for a range of complications because of their condition and the treatments that are required. Some complications can be life-threatening, so there’s lots of research into factors associated with disease in people with CF.
One of the recent studies (Morrow et al. Journal of Pediatrics 2014) looked at 703 kids with CF. As is fairly consistent with the general population, 47% lived with one or more dogs and 28% with one or more cats. Dog ownership was not associated with problems, but cat owners had an increased risk of developing nasal polyps. Nasal polyps are a common problem in people with CF, thought to be caused by allergy, infection and/or chronic nasal congestion. If there’s truly a link with cats, it’s logical that allergies would play a role. When analysis combined dogs and cats, pet owners were twice as likely to report wheezing compared to non-dog/cat owners; again, likely an allergic, not infectious, issue.
Fortunately, wheezing and polyps aren’t typically severe complications. A different situation is presented in a separate case report in Pediatric Respiratory Reviews (Pabary 2014). It describes a child with CF who had difficult-to-control symptoms that were thought to be exacerbated by a cat allergy. The child only improved when the cat was removed from the household.
Does this mean that pets should be removed from households with CF patients?
No, but it means that the cost-benefit balance needs to be considered. As the Morrow et al. paper states "Prospective studies are needed to confirm these associations and the potential psychosocial benefits of cat and/or dog ownership." Figuring out whether these relationships are real (i.e. causative) and determining what the risk of these complications means for an individual person compared to the potential benefits is the key. It’s not easy, and the cost-benefit will vary between households. That’s why there needs to be conversations between patients and their families, their healthcare provider(s) and their veterinarian. The Pabary case report indicates that pet removal is sometimes required, although that’s a rare situation - pet removal/surender needs to be very carefully considered and should not be a knee-jerk reaction (as it all too often is).
Photo credit: Tracy (click image for source)
West Nile virus (WNV) infection has been identified in a horse in Colorado. It's not really a surprise. West Nile virus is one of those pathogens that we know is coming back every year, we just don't know exactly when. The date of return varies a bit from year to year, but tends to be fairly consistent within a region (e.g. if West Nile cases started to crop up in a certain state in mid-August last year, they are likely to start again at roughly the same time this year).
The timing of onset of WNV cases depends on a few things, including WNV circulation in birds, climate and mosquito populations. The latter is quite important since only certain mosquitoes like to bite both birds and mammals. These particular mosquitoes species (called bridging vectors) are the concern, since they are more likely to bite an infected bird, and then possibly transmit the virus to a horse (or human) if they bite them next. Mosquito populations aren't the same all year and in all regions, which explains in part why WNV cases don't start earlier in the year, and why there are some major regional variations in disease despite the widespread presence of mosquitoes.
In Ontario, I suspect we have a few more weeks before we get the first reports of cases for 2014, but the WNV season is approaching here as well.
Photo credit: Rennett Stowe (click image for source)
MERS-CoV, the Middle Eastern Respiratory Syndrome coronavirus, continues to cause infections (often fatal) and confusion. For a while now, there's been speculation that camels are the source of this virus, based in part on how commonly antibodies against the virus (or a related virus) are found in healthy camels. It always seemed strange, though, for camels to be the ultimate source, leaving lingering questions about whether there is another source or where camels got exposed to the virus in the first place.
Some have focused their attention on bats (which were ultimately the source of the related SARS-coronavirus). A recent paper in the Journal of Virology (Corman et al 2014) helps answer some of those lingering questions questions. The researchers found a coronavirus in the feces of a South African Neoromicia capensis bat. When they looked at the sequence of the virus' genome, it was quite similar to that of MERS-CoV - close enough that the two viruses would be considered the same species. There were some differences, though, indicating there appears to be a "bat type" and a type that infects people and camels.
Relatedness is one thing, but figuring out how viruses are different and when they diverged is important (i.e. did the camels get the virus from the bats, or did the bats get it from the camels?). From an evolutionary standpoint, the bat virus "roots" the phylogenetic tree of human and camel MERS-CoV, meaning that when the different viruses are shown in their "family tree" based on their genetic makeup, the bat coronavirus is the one that comes up at the common ancestor. So, it appears that MERS-CoV originated from this bat virus.
The genetic relatedness of these viruses, the fact that the bat virus appears to be the ancestor, and the evidence for circulation of MERS-CoV in camels for at least 20 years suggests that:
- The virus jumped from bats to camels in the southern part of Africa a few decades ago,
- It was imported to the Arabian peninsula (since that is a common route of camel movement), and
- It recently started to infect people.
There was also the suggestion that camels may be a "mixing vessel" for different coronaviruses, like pigs are for influenza viruses, but I think that's pretty speculative.
For me, a few questions remain:
- Why is MERS not detected in southern Africa, if that's where the related virus is present in bats and where it presumably made the jump to camels?
- Why has MERS only recently been identified in people when its been present in camels for a few decades?
As is typically the case with infectious diseases, a few nice answers lead to many more questions. Presumably, lots of camels, bats and other species will continue to be tested in Africa and the Middle East to see what other information can be learmed.
Unfortunately, Naegleria fowleri, more popularly known as the "brain-eating amoeba," is in the news again. Sadly, the latest case is a 9-year-old Kansas girl that died recently from N. fowleri infection. It’s still an extremely rare disease but it’s still a significant concern because infection is almost always fatal.
Naegleria fowleri is a single-celled organism that lives in fresh water, and likes it warm. It grows fastest to 42C (~107F), but about 25C (77F) or higher is warm enough for the amoeba to reproduce. That’s why most cases have been identified in Florida and Texas, and there are concerns that climate change may help expand its range.
People are infected when water contaminated with the organism enters the nose. Not surprisingly, most people are infected while swimming or diving in lakes and rivers. After entering the nose, the amoeba makes its way to nerves and then migrates to the brain, where it essentially "eats" brain cells. Death usually occurs a few days after the onset of disease.
Since people aren’t the only ones exposed to water, a logical question is can other species be infected by Naegleria fowleri? More specifically, can dogs be infected? Many dogs spend a lot of time outdoors and in the water, and could therefore be exposed.
For example, a couple of weeks ago, we were at a cottage for vacation. Our dog Merlin is a pathetic excuse for a Labrador since he’s too chicken to swim, but he still likes to wade in the lake and stick his nose in the water. So, what’s the risk to him (ignoring the fact it’s still up in the air whether he has much of a brain to target)?
Can dogs be exposed?
Certainly, dogs can be exposed to the amoeba. If it’s in the water and people can be exposed, there’s no reason dogs would be any different in that respect. The risk of exposure varies greatly by geographical region. Around here, the risk would be exceptionally low given the water temperature. So, Merlin and his microscopic brain are presumably safe. Even in warmer waters, the risk of exposure would still likely be very low.
Can dogs get sick?
We don’t know. A few different animal species are known to be susceptible, but there are no reported canine cases (yet). The disease is very rare in people, and a person is much more likely to get diagnosed than a dog, in which testing would be less common. It’s also not an easy infection to diagnose and it would require testing of the brain after death. Most dogs that die of neurological disease don’t get tested for something like this. So, I don’t think we can rule it out, but I also don’t think it’s a high-risk situation.
Should anything be done?
It’s hard to say. It’s a rare to non-existent problem in dogs. My general line is that common sense must prevail, but you never want to be the first case of something. Thinking about the risk of disease, what can be done and whether those measures have a realistic chance of doing anything is the key.
Here’s what’s typically recommended for people:
- Use nose clips when in high-risk waters (not going to happen for dogs)
- Avoid putting your head under water in high-risk areas (ditto)
- Avoid stirring up sediment in the water (also probably not going to happen)
- Avoid going in the water during periods when water temperatures are high (this one’s practical)
Bottom line for me: life carries some degree of risk. We have to live with that and we can’t eliminate it all. The lack of evidence that this is a significant problem makes it hard to recommend any disruptive measures.
If Naegleria fowleri is known to be present in a water supply, stay away (for you, as much as the dog). Beyond that, enjoy the summer.
Plague… it’s a term that typically conjures up images of the devastating "Black Death", the pandemic that killed 75-200 million people in Europe back in the 14th century. Yet, it’s not just a historical disease. Plague is still present in a variety of small mammals in different regions worldwide (see map), including parts of the US, with periodic reports in Canada.
A recent case of plague in a Colorado man has attracted a lot of attention. The individual developed the pneumonic form of the infection after his dog died of the same disease. It’s suspected that he was infected from a flea that fed on the infected dog, and then bit the man. However, I don’t think you can really rule out the potential for direct transmission of the bacterium, Yersina pestis, from the dog. Fortunately, despite developing pneumonic plague (the form in which the bacterium infects the lungs, and the deadliest form of Y. pestis infection), it seems that he’s recovering. Plague is treatable with antibiotics, but it is critical that treatment be started as soon as possible or it can be fatal.
Transmission of plague from pets to people isn’t new. However, most often it involves cats that get infected while hunting rodents carrying infected fleas. Cats can develop plague, and then people caring for them (e.g. owners, veterinarians) can acquire the infection.
This case highlights a few important points:
- Plague is still around. People living in areas where plague is present need to be aware of the risk, even though it's very low.
- Pets get infected from contact with infected rodents, either directly or from their fleas. Keeping pets away from wildlife (e.g. keeping cats indoors, limiting free-roaming of dogs) can reduce the risk of exposure.
- Sometimes, knowing the cause of an animal’s illness is very important for human health. Knowing that a pet had plague would greatly speed up consideration of plague in anyone who became sick and had contact with the animal.
- Flea control can help reduce the risk of many diseases, including plague.
Issues about infectious disease risks from the pretty much totally unregulated importation of dogs continue to rise, and I’m dealing with them in one way or another almost daily at the moment. I’ll stay away from the discussion of what we are and aren’t (mostly the latter) doing in Canada, since I've covered that before.
What I want to write about now is a push in New Zealand to ban entry of dogs carrying methicillin-resistant (MR) staphylococci, including MRSA and MRSP.
The push makes sense at some levels:
- MR staph infections are a problem
- MR staph are currently rare in pets in New Zealand
- We can find the same strains of MR staph in animals multiple countries, suggesting they do travel from place to place
- Prevention is better than treatment
However, it’s not that clear cut. One issue relates to the standard line “all staph are not created alike”. Methicillin-resistance is common in a wide range of staph species carried by perfectly healthy animals. Many of those species are of little to no risk to people or animals.
A related issue is how MR staph get into a dog population. There are a few main ways. One is from humans - MRSA and other MR-staph are present in people, and most MRSA in pets is human-associated. So unless there’s a parallel extermination of these bugs in humans in New Zealand (a rather unlikely scenario), there’s an ongoing risk of exposure of native dogs.
Another snag is transmission of methicillin-resistance from common resident staph species to species that cause disease. While MR-staph infections may be very rarely identified in the country, it’s very unlikely that there are no MR-staph of any sort in New Zealand. I’d wager that I could find MR-staph of various sorts in New Zealand dogs, so this risk would remain even if dogs being imported were restricted.
Feasibility and practicality are other concerns. Yes, dogs could be tested and held at the border or in a quarantine facility awaiting results, but what would be tested, and how? How the testing is performed (e.g. what samples are collected and what lab methods are used) can have a major impact on the results. We don’t actually know how to confidently declare a dog to be free of MR-staph. If I had to make a recommendation now, it would be to take swabs of the nose, throat, rectum, skin and area around the hind end (perineum), and test each swab using an enrichment culture method. Since the two main staph of concern, MRSP and MRSA, behave differently in the lab, two different approaches would be required. Further, I wouldn’t have complete confidence in one round of testing, so I would probably want that done at least twice. It's possible but it wouldn't be cheap or easy… and you still won't get me to sign anything saying this will "guarantee" that a dog is free of MR-staph.
Ultimately, trying to prevent entry of MR-staph is rather futile, and it also doesn’t address the bigger issues, such as how antibiotics are used, infection control practices and other components of veterinary care that influence the spread of MR-staph. While I applaud the fact that they’re being proactive by thinking about ways to control these bugs, and that they're paying attention to importation, import controls aren’t going to be a great tool for MR-staph control. Paying attention to judicious use of antibiotics, use of common-sense hygiene practices in households, improvement in infection control practices in veterinary hospitals, and good basic veterinary care for pets would be much more effective.
Camels are getting a lot of bad press on the infectious disease front lately. There’s been the ongoing question of their role in the epidemiology of the very serious Middle Eastern Respiratory Syndrome coronavirus (MERS-CoV). This enigmatic virus (like the similarly deadly SARS coronavirus) is a tremendous public health concern, with high deaths rates in infected people, and its origins remain unclear. Recent studies have found the MERS-CoV virus in camels, and that, along with finding that a large percentage of healthy camels harbor antibodies against the virus, has lead to suggestions that camels might be the natural hosts for the virus. (They could still be innocent bystanders, infected from the same source(s) that infects people, but evidence implicating camels is increasing.)
On top of that, H3N8 equine influenza virus has recently been found in camels from Mongolia. The camels weren’t sick, but it raises some interesting questions. The H3N8 equine flu virus has been relatively stable for decades, with only minor changes compared to the degree of variability found in typical human influenza viruses. While there’s lots of concern about influenza viruses moving to humans, this particular one hasn’t raised much attention. It made the jump to dogs a few years back, resulting in emergence of H3N8 canine influenza, but not much remarkable has happened with it outside of horses. Presumably, the finding of H3N8 flu in camels is a result of transmission of the virus from infected horses. However, what remains to be seen if whether this virus can/will cause problems (e.g. illness) in camels, whether it frequently moves from horses to camels, and whether camels can then infect horses or other species.
Presumably, these two issues (particularly the MERS-CoV problem) will lead to more attention to various infectious diseases in camels. In general, the more you look, the more you find, so it’s likely that other potential infectious disease issues will be identified. Whether this means there are truly emerging issues in camels or whether some of these issues have been going on under the radar for some time remains to be seen.
Photo credit: S. Taheri (own work)(click image for source)
That’s a great title that I can’t take credit for. A colleague (and regular supplier of papers for blog posts) Dr. Stephen Page send me a paper from the Journal of Clinical Microbiology with a more convoluted title “The Capnocytophaga canimosus isolate that caused sepsis in an immunosufficient man was transmitted by the large pine weevil Hylobius abietis” (Tuuminen et al 2014).
I often talk about the bacterium C. canimorsus, and any mention of it is usually greeted with either blank stares or the "what the heck was that bacterium called?" look. It’s an obscure bacterium that’s found in the mouths of pretty much all dogs, as well as some other species. While it rarely causes disease, when it does, it can kill quickly.
This report is noteworthy from a few standpoints. One is the source of infection, as it was associated with a pine weevil, an insect. Insects have not been linked C. canimorsus infections in the past, although I’d wager that little is known about their normal mouth microbiotas. The affected person was a 44-year-old sawmill worker in Finland, with no remarkable health problems. That’s important because C. canimorsus infections almost always occur in people without a functional spleen, alcoholics or people with compromised immune systems. He seemed to have none of those risk factors. While this has been reported before, it’s quite rare.
So, should pine weevil bites be added to the list of things that indicate a need for high-risk people to seek medical care? Well, that seems extreme but it shows the unpredictable nature infectious diseases.
Another question, though: where did the insect get the bacterium (i.e. where did the bug get the bug)? Does C. canimorus actually have a much broader host range? Did this insect recently bite a dog in the mouth? Or, did the person have some other form of exposure? The paper’s title is probably more definitive about the source of infection than it should be. He didn’t own a dog or report being bitten, but could C. canimorsus have been inoculated into the bug bite lesion from some other source?
Who knows? Sounds like a good excuse for a field trip to Finland to look at the microbiota of the pine weevil.
Photo credit: http://en.wikipedia.org/wiki/Hylobius_abietis
A couple days ago, I was talking to a vet who's trying to manage a strangles outbreak on a farm. In many outbreaks, the biggest hassles are dealing with horse owners, not the disease itself. Strangles, infection by the bacterium Streptococcus equi subsp. equi, is a highly contagious disease but one that is relatively easy to control if things are done right.
The critical variable is whether people will do things right.
There are many issues that result in prolonged outbreaks at single facilities or spread of strangles from farm to farms, but two are quite common, recurrent problems.
1. Unwillingness of people to skip shows during the outbreak. I understand the desire to go to shows, since the show season may be short and shows are what people look forward to all year. However, despite the fact that it's clearly unethical for people to take a horse to a show from a barn where a strangles outbreak is underway, it happens all the time. That's probably one of the most important ways strangles is spread during the show season.
2. People moving horses to other barns. It's not uncommon for there to have already been one or more people flee the barn by the time I'm involved in an outbreak investigation, and I've seen multiple situations where one-farm outbreaks have turned into regional outbreaks because of this. This response is sometimes because individuals want to try to avoid the outbreak (although their horse may have already been exposed, making it too late), or to avoid any restrictions that might be put on the barn and movement of horses therefrom.
Both situations are common, but ethically are unacceptable. If a person knows that his/her horse is on a farm where strangles is present, the animal is considered infectious until proven otherwise.
How can these problems be prevented?
1) Boarding contracts that stipulate owners will stay on the farm in the event of an outbreak (maybe not easy to enforce, but at least addresses the issue up front).
2) The carrot: Emphasizing that with a good infection control response, if a particular horse has not been exposed, it probably won't be, and if it has been exposed, it's a risk to others. Either way, keeping it on the farm is the best for it and for others.
3) The stick: Reminding owners that they know their horses might have been exposed to strangles. If they take a horse somewhere and infect other horses, they might be (or should be) liable for any costs and losses associated with those subsequent cases. Infectious diseases are an inherent risk of life and are not always preventable, but when someone knowingly creates a high risk situation (and that situation was avoidable), legal consequences may ensue.
Rabies is a very serious disease. We're very lucky in Canada that in most parts of the country the prevalence of this disease is now quite low, in large part due to wildlife control and vaccination efforts. Unfortunately that also seems to make some people quite lax when it comes to (common sense) things like vaccinating their pets and avoiding direct contact with rabies vectors such as foxes, skunks, raccoons and bats. Here are some of the most common misconceptions (or lapses in judgement) that we encounter.
1. My cat never goes outside, so it doesn't need to be vaccinated for rabies.
FALSE. False false false. It seems to be very difficult to get this message across to pet owners. Your cat may live inside, but cats can escape. Even my own cat, who has lived indoors his entire life for more than a decade, one day suddenly decided to explore the great outdoors. Was I ever glad he was vaccinated at that point! Even more importantly, bats - currently the most common rabies vector in most parts of Canada - can get into your house. This happens even in the middle of large cities, and to people who live in apartments. If your cat is unvaccinated and happens to have contact with a bat that gets in your house, kitty could be facing a 6-month quarantine which is not easy or fun for anyone.
2. My cat had all its shots when it was a kitten, so it's protected.
FALSE. Cats (and dogs, and ferrets) need at least TWO rounds of rabies vaccination before they are considered fully protected. Generally they get one dose at 3 months of age (with their last set of puppy/kitten shots) - 30 days later they are considered "primarily vaccinated". The animal then needs a booster 1 year later (regardless of the type of vaccine used) at which point it is then considered fully vaccinated for 1 to 3 years, depending on which vaccine was used. As soon as that 1 to 3 year window expires, kitty once again faces a 6-month quarantine if it is potentially exposed to rabies, which is just what happened to a dog in North Carolina recently.
3. If I have a bat in my house, I should get rid of it as soon as possible.
MAYBE. If you see a bat fly into your house through a door or a window, you can definitely try to shoo it back out as soon as possible as long as you don't touch it (lots of people use things like tennis rackets or brooms for this, but remember you don't need to hit the bat). If you're not comfortable with that, trap the bat under a big bowl or bucket, or in a closed room with no animals or people, and call animal control (or a friendly neighbour) to help you with it.
BUT if the bat has touched any person or if there is a chance that your cat (or dog) may have touched the bat or been playing with it do not let the bat escape. A risk assessment needs to be performed in these cases to determine if the amount of contact with the bat could have been enough to transmit rabies virus. If the answer is no, the bat can then be released, but if the answer is yes, then it is very important to keep the bat so it can be tested for rabies.
Have your pets vaccinated for rabies by a veterinarian on a regular basis. Make sure they are up-to-date and that you (or your veterinarian) have the records to show it. It is by far the best insurance for preventing rabies in your pets, and avoiding unpleasant, long and difficult quarantine periods. It is now summer in Canada and wildlife (including bats) are active - don't wait, get your pets updated today.
Not surprisingly (since bacteria don't respect borders), the Salmonella Cotham outbreak in the US associated with bearded dragons has also affected people in Canada. Nine cases of human salmonellosis associated with this rare Salmonella strain have been identified, many with a link to bearded dragons.
It's not particularly remarkable, but should be yet another reminder of the need to take care with reptiles, because they are such common carriers of Salmonella. Remember that basic hygiene and common sense (like keeping reptiles away from any and all food preparation areas, like the kitchen) go a long way to reducing the risk of disease transmission from these critters. High-risk individuals (young children, elderly, pregnant or immunosuppressed) need to be extra careful, or ideally just stay away from reptiles and other high-risk animals.
I guess it’s not surprising but it’s sad when people are skirting the pathetically lax canine import regulations and falsifying rabies vaccination status. In the US, the CDC has issued a Health Alert because of an increasing number of dogs that are being imported with "questionable" documentation of rabies vaccination.
These dogs are destined for various sources, including on-line sales, pet stores and adoption agencies. Various breeds are involved and some dogs are falsely identified as being from the US.
Concerns were raised when it was noted that importers were providing inaccurate vaccination certificates. Currently, dogs that are 4 months of age or older and which are vaccinated against rabies at least 30 days prior are imported with essentially no restrictions. So, importers are either falsifying vaccination records (indicating dogs have been vaccinated when they have not) or lying about their age. Instances of falsifying birth location and breed have also been identified.
Because of these problems and the lack of any foreseeable effort to bring any form of import controls into play, the CDC is recommending that veterinarians "strongly recommend" vaccination against rabies if the owner of a new patient is unable to provide an original rabies certificate, if the certificate comes from an unknown source, or if the reported age does not match the appearance of the animal.
Too bad there’s not an effort to charge people with falsifying data pertaining to an almost invariably fatal disease...
Hint... if you like time off during the summer, don't get into equine infectious diseases.
Vesicular stomatitis (VS) has been identified in five (so far - probably more to come) horses in Kinney County, Texas. The case is shown on the Worms & Germs Map, and more details are available in the news release from the Texas Animal Health Commission.
Vesicular stomatitis is a viral disease that causes blistering and sores of the mouth/muzzle of infected animals, as well as on the udder and coronary band (around the hooves) in some cases. The disease is certainly uncomfortable, and can cause animals to stop eating, but the lesions gradually heal and the infection resolves on its own in a few weeks. Part of the reason VS is such a big deal is because it can also infect cattle, sheep, goats and pigs, and in these species the lesions look just like those caused by Foot and Mouth Disease, which is a very serious foreign animal disease to Canada and the US.
In some ways, it doesn’t surprise me because it’s happened many times before. However, you’d think that, at some point, things would start to improve.
The US CDC is reporting yet another outbreak of salmonellosis associated with contact with feeder mice, that is, mice produced commercially to feed to pet reptiles. Sadly, this outbreak is quite similar to previous outbreaks. Multiple people (37 confirmed so far) in multiple US states (18 so far) have become ill, and 15% of affected people were hospitalized.
As I mentioned a few days ago about a salmonellosis outbreak linked to a company that sells eggs for hatching chicks, there seems to be no ability or effort (not sure which one is the case) to do anything about the source of these outbreaks. The FDA has issued a notice that “In the absence of a voluntary recall from Reptile Industries, Inc, FDA issued a warning to pet owners who have purchased frozen rodents packaged by Reptile Industries, Inc since 11 Jan 2014 that they have the potential to be contaminated with salmonella. Reptile Industries, Inc packages frozen rodents for PetSmart stores nationwide and are sold under the brand name Arctic Mice.”
The issue may be that these mice are not being sold as human food, so there’s no ability to mandate a recall. Yet, people are clearly getting sick from them, so it makes no sense that a recall and careful investigation of the facility and its practices is not underway. People purchasing feeder rodents need to remember:
- Freezing doesn’t kill Salmonella.
- Frozen rodents can be (and often are) contaminated with Salmonella and presumably various other pathogens.
- All feeder rodents should be considered contaminated and basic hygiene practices should be used when handling them at all times. This includes storing them away from human food, thawing them in sealed containers in a manner that won’t contaminate human food or food-preparation surfaces (including the kitchen sink), and hand washing after contact with rodents or packaging.
Following the Canadian Food Inspection Agency's (rather mind-boggling) abandonment of the rabies response portfolio, there's been a scramble by provinces to figure out what to do. The CFIA will still perform testing, but will not have any role in sample collection, sample shipping or investigation. I'm not sure what most provinces are doing (and based on the calls I get from people in different provinces, I'm not alone) but in Ontario, a lot of effort has been put into working out a new system. Ontario's Ministries of Health and Long-Term Care (MOHLTC) and Agriculture and Food (OMAF) have taken on different components of the void left by CFIA. A lot of work has gone into this transition, but there's still a lot of confusion (and some misinformation).
Not many days go by when I don’t get a few calls about rabies. Here are a couple from yesterday that highlight some important issues.
An indoor cat tangled with a bat. The bat’s no longer around to test so this is considered a potential rabies exposure (bats being important rabies vectors, and catching and snacking on a bat being a potential way to encounter the virus). Unfortunately, the cat was not vaccinated against rabies, meaning it needs a strict 6 month quarantine, or euthanasia. A cheap and easy rabies vaccination would have significantly reduced the issue, changing that to a 45 day observation period, and greatly decreasing the risk that the cat would develop rabies. Indoor cats need to be vaccinated. Even if the cat never goes outside, rabies virus can find its way inside (and the number of indoor cats that get into fights with wildlife or hit by cars indicates that indoor cats aren’t always indoors!). I have personal experience with that.
A horse in Texas was diagnosed with rabies. Rabies is uncommon in horses but it certainly occurs. As above, rabies vaccination is cheap insurance. No vaccine guarantees protection but it’s a very effective vaccine, a fatal disease, and horses with rabies have attacked and killed people. Every horse (in or traveling to any rabies-endemic country) should be vaccinated against rabies.
Additionally, various (continuous) reports of rabies deaths in India also highlight the importance of controlling rabies at the population level, to reduce the risk of exposure by reducing the number of rabid animals. There is also an absolutely critical need for healthcare providers to properly handle potential rabies exposures.
The Texas rabies case can be found on Worms & Germs Map (www.wormsandgermsmap.ca), along with some other recent cases.
April showers bring May flowers.
…and I can’t come up with a good rhyme for salmonellosis.
Nonetheless, it’s Salmonella season, courtesy of cute but biohazardous baby poultry.
You can buy chicken, turkey and other bird eggs to hatch every spring. Our local feed mill had the order forms out a while ago, and you can also buy them over the internet. Some schools still buy them.
The problem is baby poultry are high risk for shedding Salmonella (and Campylobacter, another problematic bacterium). Every year, outbreaks of disease in people occur from contact with hatching chicks, so the message isn’t getting around or getting through to people.
In the latest CDC report, 60 people in 23 US states have been diagnosed with salmonellosis linked to a single hatchery that "has been associated with multiple outbreaks of salmonellosis linked to live poultry in past years, including in 2012 and 2013." (How many outbreaks does it take to tell you your company is probably doing something wrong, or in the wrong business?)
The figure of 60 infected people is probably an underestimate, since it’s expected that many people were probably sick but didn’t go to a doctor or submit a stool sample for testing. Of the 60 diagnosed cases, 31% ended up hospitalized, re-enforcing that fact that this is a serious problem.
While the hatchery said they are “working collaboratively with authorities at the Ohio Department of Agriculture and CDC as they proceed with their investigation,” the Ohio Deptartment of Agriculture tellingly stated “The more accurate description of our relationship with that company has been we have tried to provide guidance through the years, but I don't know how many of the recommendations that we have brought to them have actually been implemented.”
Sadly (and bizarrely, from my standpoint) the agiculture department doesn’t have any authority to require the hatchery to implement recommended changes. "We're trying to tell them what they need to do in order to keep this from happening every year." How many people does one company need to sicken before they are forced to do things right (or shut down)?
This report shows a few things.
- Some people just don’t learn (sellers and buyers alike)
- Regulation of animal production for sale to the general public is horribly lax
- Contact with young poultry is a major risk factor for salmonellosis.
- The industrial scale of production of eggs for hatching chicks (and some pet species) means that a problem with a single facility can lead to widespread disease.
- It’s a "buyer beware" world. Don’t trust that the critter you just bought is pathogen free, and take measures to protect yourself.
- High-risk individuals should not be around hatching chicks because of the risk of salmonellosis. This includes kids less than 5 years of age (a key target group for sellers), elderly individuals, pregnant women and people with compromised immune systems.
Photo copyright: piep600 / 123RF Stock Photo
Let’s put this one in the "smart people doing stupid things" file.
Some well-intentioned people at Washington University in St. Louis thought they'd help relieve stress during exam time by bringing in a petting zoo - that unfortunately included "Boo Boo" the biting bear. As you can likely guess, problems ensued.
18 students sustained skin-breaking bites from Boo Boo.
- You’d think someone would clue into there being an issue after, say, a few bites. Once it hit a dozen, I would have thought anyone with common sense would get concerned. But 18??? Did they even pull Boo Boo out of the petting zoo by then, or did he just get tired of biting people? (Or did he simply run out of willing victims?)
Local public health officials originally mandated euthanasia and rabies testing.
- Because Boo Boo is a wild animal species, there are no quarantine provisions after potential rabies exposure. Because of that, standard guidelines are to euthanize the animal for rabies testing. This didn’t go over well (not surprisingly), and they eventually relented. From a practical point, it’s reasonable since Boo Boo’s not likely rabid, he’s just not a good petting zoo critter. However, the decision was probably more PR than science and they’ve gone against standard rabies prevention practices. This is one reason why wild species aren’t supposed to be in petting zoos.
It was reported that "This year, without the university's prior knowledge, the petting zoo included in the experience a 2-month old bear cub,"
- Easy way to deflect blame but no excuse. The University brought in the animals. They had a duty to know what was happening.
Petting zoos can be fun and entertaining. Bear bites and rabies scares aren’t. A little common sense goes a long way. Unfortunately, common sense isn’t always very common.
A question about young puppies in the workplace came up the other day. Specifically, what’s the risk of a 4-week-old puppy coming to an office to visit?
There are two main considerations:
Risk to the puppy
- Not inconsequential. A 4-week-old puppy has a developing immune system, no vaccine protection, and the antibodies it received from its mother are waning.
- If older dogs are sometimes in the workplace (as was the case here) or if people wear clothing that has come into contact with other dogs, there’s a chance of exposure to various pathogens that could hurt the puppy.
- The real risk isn’t known and there’s an blurry line between the benefits of socializing the puppy by taking it to various places and risks to the puppy from pathogen exposure. Typically, we err on the side of protecting the puppy’s health at this young age.
Risks to people
- Not inconsequential either.
- Puppies (just like human children) are cute little pathogen machines. A relatively high proportion of puppies shed a variety of potentially harmful microorganisms (and have a much greater chance of depositing those bugs on the floor, hands and clothing since they’re not house-trained, and they may also have a greater chance of carrying these pathogens on their coats due to contamination).
- Contact with young puppies has been repeatedly shown to be a risk factor for diseases such as Campylobacter infection in people, especially kids.
- The overall risk is pretty low and concern is mostly focused on high-risk populations (i.e. kids less than 5 years of age, individuals over 65 years of age, pregnant women and individuals with compromised immune systems). The problem is, most workplaces have some of these people in them, even if others aren't fully aware it. Furthermore, people can carry pathogens home on their clothes and bodies and expose high risk people (e.g. infants) back at home.
It’s always hard to say how restrictive to be. Puppies are cute and entertaining, and people enjoy being around them. I don’t go running in the other direction when I see a puppy (except maybe if my daughter Amy is with me, since she’s lobbying for another dog) and I don’t keep my kids away from them (they’re all older than 5). At the same time, I realize that I’m accepting some risk.
Balancing the risk/reward is tough, and it’s not the same for everyone.
Ultimately, a few things need to be considered:
- Education: People need to know that there are risks.
- Mitigation: People need to know how to reduce those risks (e.g. hand washing).
- Choice: People who are high risk or have high-risk people at home need to be able to avoid exposure. That can be tough when a puppy is brought to a workplace, though, especially when you consider the potential for people to cross-contaminate common surfaces.
I’m not against animals in the workplace, although a lot of thought needs to go into things like allergies and safety. Young puppies are best kept out of workplaces because of risks to them and others. Establishing minimum age, vaccination and health status requirements should be part of a pet policy for any workplace that allows pets to come in.
The US CDC is reporting yet another multistate Salmonella outbreak linked to reptiles. This one is an outbreak of Salmonella Cotham that, as of April 21, has infected at least 132 people in 31 states.
The story is pretty similar to other reptile-associated Salmonella incidents.
58% of infected individuals are kids five years of age or younger.
- That’s presumably a result of both higher risk contact by young kids (especially kissing reptiles) and the fact that young kids are at increased risk of getting sick when exposed to the bacterium.
42% of infected people have been hospitalized.
- That’s a pretty high number compared to many other outbreaks. However, the actual overall hospitalization rate is probably lower, since it’s likely that many people had mild infections that were not diagnosed. Fortunately, no one died.
This Salmonella type is pretty rare, which makes it easier to trace it to a specific source. The investigation in this case traced it back to bearded dragons purchased as pets from a variety of stores in different states. Further investigation of the source is ongoing, and breeders that supplied the pet stores are being identified.
Of particular concern here was the presence of resistance to ceftriaxone, an important antibiotic, in a strain from at least one person. That’s something we don’t want spreading, since ceftriazone is often used to treat people with serious Salmonella infections.
Bearded dragons have a lot of personality (for reptiles), and are interesting little critters, so they’ve become popular pets. Like all other reptiles, they pose a risk of Salmonella exposure, and they shouldn’t be in households with high-risk individual (i.e. kids less than five years of age, elderly individuals, pregnant women, immunocompromised individuals). People who own "beardies" should use good hygiene practices and a solid dose of common sense to reduce the risk of salmonellosis.
More information about Salmonella and reptiles is available on the Worms & Germs Resources - Pets page.
It's hard to think about mosquito-borne disease season here at the moment, with temperatures in Ontario still going down to freezing, but the highly concerning disease eastern equine encephalitis (EEE) has been identified in a Marion County, Florida horse. This mosquito-borne virus causes highly fatal infection in both humans and horses. People don't get it from horses, though - rather, people are exposed the same way horses are, by a bite from an infected mosquito.
Mosquito borne diseases vary quite a bit geographically, both in terms of where and when they occur. EEE is fortunately very rare around here, but it's a bigger concern in other areas, particularly the southeastern US and US seaboard.
We won't likely see mosquito borne diseases like EEE and West Nile virus infection in Ontario for a few months, but in other areas, the risk period has already begun. Knowing what diseases occur in your area, what diseases occur in areas your horse may visit, and when those diseases occur is important. That's one of the reasons we recently launched the Worms & Germs Map. The location of the EEE case mentioned here can be found on that site.
Spring’s slow arrival has brought many things. Disappearing snow, a hint of green in the grass... and a greater risk of disease outbreaks in horses. Outbreaks can occur at any time of year but we often start to see certain infectious diseases ramp up as horses start moving around more at the start of training, racing and showing seasons.
A tentative diagnosis equine herpesvirus I (EHV-1) neurological disease in a horse has resulted in a precautionary quarantine of a barn at Aqueduct racetrack in New York. This virus is a concern because of the potential for serious disease (e.g. the affected horse died) and the potential for large outbreaks. However, concern needs to be tempered by awareness that this virus is widespread in the horse population and that single, sporadic infections are more common than outbreaks.
At Aqueduct, horses in the barn in which the affected horse was housed are not permitted to race, and may only train after the general horse population is off the track. Rectal temperatures of horses from that barn are being checked twice a day to help detect any new cases as soon as possible. Usually, this type of outbreak response goes on for 21-28 days after the last identified case, but the planned time frame hasn’t been stated here.
Too often, we see one of two things happen when EHV-1 is identified. Traditionally, little was done in the hope that nothing bad would happen. More recently, the pendulum has swung the other direction and people often completely freak out over it, panicking and implementing measures that are over the top.
Like most things, a happy medium is needed, with enough attention (and common sense practices) to reduce the risk of further cases, while no causing undue hardship to those affected. It’s not always an easy balance to find. As someone who is frequently involved in these situations, it’s tough to figure out where to draw that line, especially when you have multiple different agendas, perceptions and degrees of risk tolerance. Taking a draconian approach (lock all the horses in the barn until further notice) is the easy way out, but it rarely makes sense. Being more balanced and less restrictive creates some risk for people making those decisions (because if something bad happens, they’re probably going to be blamed) but the easy-way-out is rarely the best-way-out.
The response at Aqueduct seems to be well balanced.
- They’ve identified a potential problem.
- They’re trying to determine if there are more cases (although I’d take temperatures of all horses on the track, not just that barn. You need to know if it’s escaped from the index barn.)
- They’re communicating.
- They are taking reasonable measures with the highest risk group (horses from the affected barn).
- They’re not taking the easy, knee-jerk response of totally restricting horses in that barn, rather they are using common sense practices to limit the risk of further exposure should any other horses in the barn be affected.
Most often, these incidents end up being single cases. However, by the time you realize something is going on, it’s possible that multiple horses have already been infected and are getting ready to become sick and/or be able to transmit the virus further. A short period of relatively aggressive but reasonable precautions is usually the key in outbreak management, and hopefully nothing more will come from this.
The location of this outbreak can be seen on the Worms & Germs Map at http://www.wormsandgermsmap.com
Most of the time, when we talk about the parasite Dirofilaria in animals, we’re talking about Dirofilaria immitis - a.k.a. heartworm. However, it’s not the only member of this parasite family that is found in dogs and cats. Another one, Dirofilaria repens, is present in pets in many regions, and it can also spread to people via mosquitoes.
A recent report from Belarus, highlighted in ProMed-Mail, describes 21 cases of dirofilariasis caused by D. repens. Interestingly, this is a relatively new finding for the area, as the disease was not reported in Belarus before the mid-1990s.
This parasite naturally infects dogs, cats, and a variety of wild carnivores like wild canids (e.g. wolves, coyotes, foxes). Mature worms live in tissues under the skin of a suitable host, where they produce larvae (microfilaria). These larvae enter the bloodstream and can then be taken up by mosquitoes that bite the host. If a mosquito feeds on an infected animal and then a person, it’s possible to transfer the larvae to the person. People aren’t natural hosts, and the parasite almost never develops into its adult state. However, as the parasite undertakes its futile migration through a person’s tissues, trying to find a place to mature, the body mounts an immune response. This results in local inflammation, typically causing the development of little tissue nodules. Very rarely, more serious infections can occur, in which case surgical excision of the nodule, with or without antiparasitic drugs, is the typical treatment.
Heartworm prevention practices should also prevent establishment of D. repens infections in dogs. Control of the parasite in the dog population is an important control measure in areas where it exists, but if the parasite is also present at high levels in wild animals, that complicates things. Basic mosquito control and avoidance measures also make sense.
Image source: http://www.cdc.gov/dpdx/dirofilariasis/index.html
A recent rabies death in a Russian man highlights multiple screw-ups that led to the man’s death.
A 50-year-old man in Smolino Kovvrosko, Russia was bitten by his cat at the end of February.
- Problem #1. The cat was presumably not vaccinated against rabies. Vaccination is not 100% protective but it’s pretty likely this was an unvaccinated animal. If the cat was vaccinated, the chance of it having rabies would have been very low.
The man went to the local "medical assistant," but rabies prophylaxis was not given.
- Problem #2. Here was the opportunity to initiate the discussion about rabies. This would involve querying the health status of the animal and quarantining it for 10 days to see if it developed signs of rabies (which would indicate the need for post-exposure treatment). These things weren't done.
A few days later, the cat started acting strangely. A local vet euthanized the cat. Rabies was not discussed.
- Problem #3. Malpractice. Plain and simple. A cat with neurological disease needs to be considered a rabies suspect. Bite history must be queried before euthanizing an animal. If rabies testing had been performed or if rabies had been mentioned as a possibility, the man might have been treated.
At multiple time points, there were chances to identify the potential for rabies, but multiple people screwed up and the man died as a result. Rabies is virtually 100% preventable with proper post-exposure treatment, but virtually 100% fatal by the time someone develops disease.
Clinical guidelines are fairly new (and limited) in veterinary medicine, although they’re widespread in human medicine. Following up on recent guidelines for diagnosis of treatment of urinary tract infections in dogs and cats, a working group from the International Society for Companion Animal Infectious Diseases (ISCAID) has completed guidelines for the treatment of a common type of skin infection in dogs, superficial folliculitis (pyoderma).
No, not what I write (although I certainly get enough emails suggesting otherwise... and I'm sure another round of interesting emails is going to be coming at my way shortly).
In the past, and even sometimes still today, public health has had to deal with the phenomenon of having "chickenpox parties." These are events held by well-intentioned but grossly-uninformed parents who deliberately expose their kids to a child with chickenpox in order to "get it over with." Yes, the children will get chickenpox and yes, the children will become nicely immune to the disease thereafter. Most of the time, it’s not really a problem, but then there are the times when a child develops serious (and potentially fatal) complications from chickenpox. Or when one child picks up chickenpox and spreads it to a high-risk child who then develops complications. It went so far at one time that at least one person was selling lollipops laced with chickenpox over the internet (until it was pointed out that this was essentially a bioterrorism activity).
We now have the analogue being recommended in dogs. The basic idea is to take young puppies to an area where distemper virus or parvovirus is likely present, so the puppy will be exposed and vaccination won’t be required.
Sure, it might work.
- The puppy might get exposed to enough virus to develop an immune response but not cause disease.
- Or the puppy might get sick and require expensive veterinary care.
- Or the puppy might get sick and die.
- Or the puppy might do any one of the three above and also spread the virus to other susceptible dogs, whose owners didn’t make the conscious - and dumb - choice to purposefully expose their dogs to these potentially fatal viruses.
Do vaccine reactions occur?
- Of course.
Are animals vaccinated more often than needed?
- Probably. Vaccination intervals are increasing so progress is being made. However, confusing the debate about how long we can go between vaccines with whether dogs should be vaccinated at all is dangerous. There's no doubt that young animals need proper early-life vaccination to prevent these potentially fatal infections.
Does the benefit outweigh the costs?
- Absolutely. Vaccination has controlled some incredibly important infectious diseases.
- Choosing not to vaccinate in response to internet rumours isn’t logical and it puts lots of animals at risk.
- Also, decreasing population vaccination rates increases the disease risk to the dog and cat population overall, since fewer protected animals means more chance of disease circulating from animal to animal to animal before it can be stopped. It’s like the “Wakefield effect”: the surge in some vaccine-preventable diseases attributed to the now-discredited (and former doctor) Andrew Wakefield, whose flawed and unethical research fed the anti-vaccine movement with since-retracted data.
Vaccination of young animals is critical for the control of certain infectious diseases. Recommending otherwise is illogical, and when it’s done by people who should know better, it’s unethical. Hopefully this doesn't get to the point where we need to start tracking the animal equivalent of the Jenny McCarthy Body Count.
A cluster of Brucella canis infections has raised concerns in Calgary, Alberta, and hopefully will prompt more discussion about importation of dogs.
Brucella canis is a bacterium that can infect both dogs and people, although it’s natural host is dogs (more specifically, dogs that are not neutered or spayed). Human infections are quite rare but they can be nasty, and therefore need to be taken seriously. Infections are sporadically identified in dogs in Canada, but it seems to be a very rare disease overall, and most cases I’ve dealt with have been in dogs that were imported.
The latest incident involves identification of brucellosis in five dogs. The first case, not surprisingly, was imported, having come from somewhere in the southern US. Three other dogs also from the southern US had contact with the first dog. The fifth case, concerningly, was a local Alberta dog that had contact with the first dog. There seems to have also recently been another unrelated Brucella canis infection in a local dog that originated from Mexico.
The main human health risk associated with Brucella canis is contact with breeding animals, as the bacterium is shed mainly in vaginal discharge, placental and fetal fluids, semen and aborted fetuses. Contact with dogs that have given birth or aborted is the main concern. The bacterium can be shed in urine, but that seems to be less of a concern, particularly with otherwise healthy dogs. The risk to the general public is therefore quite low, but it’s important to try to control this bacterium because of the potential for serious human disease.
Brucellosis is just one of many potential disease risks with imported dogs. As I’ve discussed previously, there is little to no control over importation of dogs and little comprehensive guidance for people who are importing them. This is a big reason why we are seeing certain "foreign" diseases in dogs in Canada (e.g. leishmaniasis). We sorely need a comprehensive approach to dog importation to help reduce the risk of disease entry and help people who choose to import dogs do so safely.
This cluster of infections can also be found on our new disease tracking site, http://www.wormsandgermsmap.com.
A few questions were sent in by a reader regarding a recent post about rabies in a Texas animal shelter. They’re good ones so I thought I’d cover them here.
I'm a little confused by this. Weren't these shelter dogs vaccinated?
- Probably not. Many shelters don’t vaccinate against rabies. There are a few reasons for this:
- One reason is cost. From a shelter standpoint, rabies vaccination may even be considered of less importance compared to vaccination against diseases that are more common causes of illness in shelters (such as parvo).
- A big reason is that in most regions, rabies vaccines must be given by a veterinarian, and many shelters don’t have much veterinary involvement.
- Another consideration is that even if animals are vaccinated in the shelter, they are not considered protected until 28 days after vaccination.
- Yet another thing to consider is whether vaccination would have changed anything. Vaccinated dogs would still require a 45 day observation period. That’s much easier than a 6 month quarantine but still problematic and could lead to euthanasia for logistical reasons.
How exactly were these dogs exposed?
- Good question. It depends how the shelter was run and whether dogs were mixed together or socialized in groups. Sometimes, all dogs end up being considered exposed unless shelter personnel can definitively state that they know a particular dog didn’t have contact with the rabid dog. It’s often hard to say that with confidence, so by default they consider all dogs exposed.
What about vaccinated pets (dog and cat) that live in homes but go outside in suburban or rural environments? How do we know, for instance, that an indoor/outdoor cat hasn't come into contact with a rabid wild animal or feral cat? Do owners of indoor/outdoor cats really know where their cats go and what they do or who they associate with when they're out all day long? And, what about dogs that go out for their last potty break, unattended, in the fenced backyard at night when the wild critters come out? How do we know, really, that our pets haven't been exposed to rabies?
- We don’t. That’s an inherent risk in life, and a reason that we push for vaccination of all pets. Vaccination isn’t 100% but it will greatly reduce the risk of an animal developing rabies.
- This is also one of many reasons to make sure animals aren’t allowed to wander outside unsupervised.
A single rabid animal has lead to plans to euthanize 40 dogs at a Texas animal shelter. It’s very similar to a situation I discussed with vet students recently, and it’s one that raises a lot of emotions.
The brief version...one rabid dog was identified in the shelter.
- This means that consideration has to be given to who (people and animals) was exposed to the dog.
- If the shelter cannot state with confidence that a particular dog was not exposed to the affected dog (e.g. if they don’t strictly cohort groups and/or follow these practices), then it’s considered exposed. Fortunately, only 40 of the over 300 animals at this shelter were deemed potentially exposed. It’s not clear if this is because some dogs were considered unexposed or, more likely, that all dogs were considered exposed but cats were kept separately and therefore not exposed.
- A dog that’s been exposed to rabies needs a 45 day observation period (if properly vaccinated) or 6 month quarantine (if not known to be properly vaccinated) or euthanasia.
What are the odds that any other dogs were actually infected? Very low.
Is euthanasia, then, a reasonable response? Unfortunately, yes, in many situations.
This is where people start to get upset. Why euthanize these perfectly healthy dogs if none were likely going to get rabies and you can simply quarantine them?
At a basic level, I agree. But, when you think about it more, these actions make sense.
- Yes, the dogs could be quarantined, but how? That would involve keeping them in the shelter for 6 months, since fostering out rabies-exposed dogs would be hard to justify.
- If they quarantine them in the shelter, they essentially have to keep the shelter closed since it would make no sense to bring in more dogs (that would have to be strictly isolated from the others) and there’s probably little or no room for added dogs anyway.
- As a result, instead of being admitted to the shelter, the animals might be euthanized on the doorstep, since there’s often not a "plan B" for sheltering.
So, does it make sense to shut down the shelter for quarantine? That’s hard to justify. The net impact on dogs (both those in the shelter and those that would be admitted) plus considerations of shelter operations (e.g. lots of presumably unvaccinated people having to work with potentially exposed animals) need to be part of the discussion.
Unfortunate as it is, this is often the response. Ideally, there’d be a way to isolate these dogs and continue shelter operations (and pay for the extra costs associated with doing this). In the real world, this is rarely an option.
All of this could potentially have been prevented if the affected dog had been properly vaccinated by its original owners.
There have been a few reports of equine herpesvirus (EHV-1) neurological disease over the last couple of weeks and some other cases that have been less well publicized. Hopefully it’s all just been a blip on the radar and not a sign of things to come as equine events start to ramp up at this time of year. However, it would be good for racetracks to take these cases as reminders of the ever-present risk of EHV and the need to try to prevent problems.
Some tracks have taken this issue seriously and are working on infection control and outbreak response plans. In response to one outbreak, a Minnesota track is building an isolation area for infected horses and implementing a variety of infection control measures.
Too often, the response to EHV-1 is only reactive: when there's no immediate problem, people don’t do anything, and when there is a problem, people freak out (and it’s hard to do things right when people are freaking out).
We need a happy middle ground that includes a reasonable response plan (effective and realistic) and proactive measures to both reduce the risk of an outbreak and to facilitate response.
Racetracks are starting to understand the need, although the response is variable. The number of outbreaks and the potential implications of them (e.g. sick or dead horses, cancelled racing, horses banned from going to certain tracks) means that it is in the horse owners’ and tracks’ best interests to do things right. What constitutes "right" is a moving target, though, and some people just don’t want to bother.
You can virtually guarantee that there will be EHV-1 outbreaks at racetracks this summer. A limited number of horses will die but there will be massive disruption based on quarantines (sometimes reasonable, often excessive) and other fall-out.
While there’s no way to completely eliminate the risk of EHV in horses, there are many things that can be done to reduce the risk of an outbreak. Some are relatively cheap and easy, such as
- Ensuring that horses with signs consistent with EHV-1 are promptly examined and isolated
- Avoiding shipping horses from sales directly into racing barns
- Cohorting groups on tracks as much as possible to contain incidents to individual barns
- Fostering routine infection control practices by people who frequently move between barns like veterinarians, farriers and riders/drivers
Other measures may take more time, effort and planning, such as creation of isolation areas and development of clear outbreak response plans. One of the most important things that can be done, however, is improving communication and trust. Often the biggest challenges in outbreaks involve poor communications, such as unwillingness to report cases, egos and agendas that get in the way of effective and timely response, and various other related problems that can be fixed by people thinking and talking to each other.
Some tracks are doing a good job of thinking proactively. Many are taking the "head-in-the-sand" approach. Any track could run into a problem, but my money’s on bigger problems occurring at the tracks that don’t take this problem seriously.
Unfortunately, we’ll be talking more about EHV-1 outbreaks this summer.
“Seek and you shall find.”
That might be the simple explanation for why we’re hearing more about spillover of different types of flu viruses into dogs. Sporadic reports of dogs being infected by different flu viruses keep coming in these days, maybe we didn't get this reports in the past because people just often didn’t bother testing dogs when doing surveillance of flu outbreaks in other species.
The latest incident is a report of finding antibodies against the H5N8 avian flu virus in a dog on a South Korean farm. This H5N8 strain is different from the H3N8 canine flu strain that has become a true "dog-flu", having adapted to dogs following spillover from horses.
This potentially emerging H5N8 avian flu virus has caused a lot of concern in southeast Asia as it can be devastating to poultry farms. It doesn’t sound like the dog in this case was sick, but the suspicion is that the dog was infected by eating infected poultry.
Avian flu viruses are a concern because some avian flu types can infect people and cause very serious disease. They can also cause devastating outbreaks in birds. Mixing of avian (and other) flu viruses with human viruses is the biggest concern, as it could potentially create a new pandemic virus that retains its high mortality in people but spreads much more easily like regular human flu strains. Adding more species to the mix adds more potential routes for transmission and flu virus recombination. It's likely that dogs are of little to no concern here, and the dog was probably never infectious - it just got exposed, mounted an immune response and the virus died. However, it indicates the need to consider broader surveillance, involving various companion animal species, when investigation new influenza threats.
Actually, the title of this post should be “Obese cat attacks family after being booted in the rear as a disciplinary measure. Family freaks out but wants to keep cat.”
Oh, where to start.
1) A 22 lb cat is obese and there are obviously animal care issues.
2) Kicking a cat in the rear after it objects to having its tail yanked by a baby is hardly an appropriate training measure
3) A cat that will attack with enough vehemence to make a group of adults barricade themselves and call 911 has other behaviour issues.
4) A family that thinks a cat that has a history of aggression and that made them barricade themselves in a room and call 911 is still an appropriate family pet for a household with a seven-month-old child is delusional.
While there may well be more to this story than has been reported, it seems like the baby pulled the cat’s tail, the cat objected and scratched the child, the owner kicked the cat, the cat responded, and the owners ended up locking themselves in a bedroom and calling 911 saying "I kicked the cat in the rear, and it has gone over the edge, He's trying to attack us -- he's very hostile. He's at our door; he's charging us" as the cat screeched in the background.
Yet, after all that they apparently want to keep the cat, though they "definitely want to keep [the cat] away from the baby and keep an eye on his behavior."
Does this cat pose a major risk?
It’s hard to say. Probably not in most circumstances, but it can certainly be sent over the edge and respond very aggressively, something that has apparently happened more than once.
Should this cat be in this household?
Probably not. It’s in a household with a high-risk individual (the baby). Kids sometimes inappropriately handle animals, and this cat clearly doesn’t respond well to provocation. The owners don’t seem equipped to handle this properly. The cat might be perfectly fine in a household where it’s not provoked, but it doesn’t seem like a good fit for this household.
Can anything be done to prevent further problems?
A few things need to be considered. The first is a veterinary exam to make sure there’s not a physical reason for the cat’s response (e.g. is there a problem that made a little tail pull cause severe pain?). A consultation with a veterinary behaviourist (a veterinarian that specializes in behaviour as a result of extensive specialty training - not a self-proclaimed, untrained "pet psychologist" that the owners mentioned) would then be indicated to try to identify why this happened, and how (or whether) it can be prevented in the future.
While rarely (if ever) is there a situation where there should be no pets in households, there are situations where a combination of a certain pet and certain people doesn't fit. This is probably one of those.
Surprisingly (at least to me), I don't hear much about individuals suing other people because of infectious diseases in their horses (apart from sporadic situations involving veterinary hospitals). I'm not saying the increasingly litigious nature of society is a good thing, but I can see how lawsuits could happen given the costs associated with infectious diseases, the emotions that can be involved and the lack of a well-defined standard of care.
The potential for liability isn't necessarily a bad thing IF it motivates people to do what's right. While ideally it wouldn't take the threat of financial loss to properly motivate someone, it can be a useful argument. Our first strangles poster touched on social influences as a motivator (i.e. if you do something that causes other peoples' horses to get sick, you're not going to be popular). Our second poster (below) addresses the potential for liability, which I think is particularly real when people knowingly move horses from a farm with strangles, especially when they don't notify the new farm about the potential for strangles exposure and take appropriate precautions.
An outbreak of equine herpesvirus type 1 (EHV-1) neurological disease has occurred on an Oregon farm. At last report, five horses had tested positive for the virus (though it's not clear if all of them had neurological disease) and one had died.
EHV-1 outbreaks are not exactly rare these days. There's certainly more reporting of sporadic disease and outbreaks, but it also seems like there's been a true increase in outbreaks over the past 10-15 years. During my residency, we saw EHV-1 neuro cases not uncommonly, but almost always as single cases. Now, clusters like this are more common, for no clear reason.
Anyway, this outbreak appears to be contained, and it's good that there's been no movement on or off the farm in a while. This will likely end up being a sporadic, contained cluster on a farm with no broader implications. Since EHV-1 is very common, being found in the majority of horses, there's always some risk of disease occurring. That's one of the main challenges we have in understanding and controlling this virus.
Tracking of EHV-1, and other equine (and dog and cat) diseases will soon be available on Worms & Germs MAP. Stay tuned.
There's been a lot of press about strangles (Streptococcus equi) outbreaks in Ontario lately, including a biosecurity update from the Ontario Ministry of Agriculture and Food (OMAF). In some ways, it's surprising since this is an endemic disease and strangles is pretty much always causing trouble somewhere in the province. However, a little press is never a bad thing, if it can help get people to do what they need to do (but often don't do) to control this highly contagious equine disease.
A big problem with strangles control is the unwillingness of some people to admit they have cases and/or people knowingly taking exposed horses off the farm, thereby spreading the bacterium to other farms.
Along that line, here's our latest educational poster. As with all of our materials, feel free to print, copy, post or disseminate at will. A higher resolution version can be downloaded from the Worms & Germs Resources - Horses page.
There’s been some controversy in the past regarding allowing pets to sleep in or on the bed. I don’t get too worked up about it, since I think it’s very low-risk in terms of disease transmission for most pets and households, but a variety if reasons for prohibiting this practice have been given.
I haven’t previously heard the reason: “Don’t do it because you might think you’re petting your cat when you are actually mistakenly pissing off the rabid raccoon that’s dozing beside you.”
Maybe that should be added to at list.
A Massachusetts woman learned this one the hard way. The woman was asleep one night a few weeks ago and reached over to pet what she thought was her cat. Unbeknownst to her, the critter beside her was actually a rabid raccoon that had come into the house through a cat door. Unhappy at being disturbed (and with a less-than-functional brain from rabies), the raccoon attacked, jumping on the woman's face and biting her lip, refusing to let go. She managed to pry the creature off her face, whack it with her phone and call 911. Animal control caught the raccoon, which was subsequently euthanized and confirmed as rabid.
From a more serious standpoint, this case highlights one of the big drawbacks of having a cat door that allows entry and exit of any cat-sized animal. Keeping cats indoors is a good idea for the cat’s health, the family’s health and the wild bird population (and avoids the cat door issue entirely!).
I would have thought this would fall under the realm of common sense, but as the saying goes: Common sense is like deodorant, the people that need it the most don’t use it.
A recent report out of Scotland is warning people not to kiss their pet reptiles, in response to four people who were hospitalized with salmonellosis after kissing bearded dragons, and other reptiles.
Reptile-associated salmonellosis is a major concern, and while there are ways to make reptile ownership very safe for most people, some risk will always remain. Certain behaviours will increase that risk. A large percentage of healthy reptiles have Salmonella in their intestinal tracts, and anything that’s in the intestinal tract ends up in the animal’s habitat and on its skin. Kissing reptiles is an obvious way to be exposed to this bacterium, which can cause serious disease in some situations.
Among the report's recommendations are:
- Families that own a bearded dragon or similar reptiles are advised to consult their doctor if they become ill with symptoms of fever, vomiting, abdominal pain and/or diarrhoea.
- They should also inform their GP that they keep a reptile. Children are particularly at risk because they like to stroke and handle pets.
- NHS Forth Valley have also issued a guide for pet owners to reduce the risk of catching Salmonella from lizards, which includes supervising children to make sure they do not put the animal, or objects it has been in contact with, near their mouths.
- It also recommended washing hands with soap and water immediately after handling a reptile, its cage or any other equipment, keeping a reptile out of rooms where food it prepared or eaten, and disposing of droppings and waste water down a toilet, rather than in a sink or bath.
Just common sense.
More information about reptiles and Salmonella can be found on the Worms & Germs Resources - Pets page.
The University of Guelph’s Animal Health Laboratory recently published a summary of selected zoonotic disease diagnoses in its monthly newsletter. It’s an interesting summary of what’s gone through the lab in the last year. It also helps to remind us of the zoonotic potential of all of these pathogens, some of which are relatively common and can be found in a variety of species.
A couple months ago, I wrote about a family suing PetsMart over a case of rat bite fever in a child.
Now, a San Diego family is suing PetCo after their ten-year-old son died of the same infection. Rat bite fever is a bacterial infection caused by Streptobacillus moniliformis, and it is almost always associated with bites from rats.
The San Diego family’s situation is tragic. Fortunately fatal zoonotic diseases from pets are rare. But when they happen, who’s to blame?
Part of figuring that out is thinking about what has to happen for an infection to develop, and where that cascade can be interrupted.
What has to happen for rat bite fever to develop?
The rat has to be carrying the bacterium in its mouth.
- The bacterium is found in basically all rats, so you have to assume that every rat is infected. (So, it’s hard to blame the supplier.)
The bacterium has to get into the person's body, usually by a bite.
- Bite avoidance is therefore key, and involves proper handling of the rat and selecting a rat that has a good temperament.
When the bacterium gets into the body, it has to be able to cause disease.
- Most often, the immune system takes care of it. However, the number of bacteria that get into the body, the weakness of the immune system, and the whims of biology all play roles. In an otherwise healthy child, bite first aid is critical to help remove as many bacteria as possible from the wound before they invade the rest of the body.
To me, it all boils down to education.
- Pet stores need to inform purchasers about infectious disease risks and preventive measures.
- People need to take responsibility to learn about any pets they may purchase (before they get them), and take measures to reduce the risk of zoonotic pathogen exposure.
- Physicians need to be more aware of zoonotic diseases and ask about pet ownership and animal contact.
Would any of these have made a difference here? It’s hard to say. However, these are all relatively easy things to do and could probably prevent a lot of infections.
More information about Rat Bite Fever can be found on the Worms & Germs Resources - Pets page.
A female Corgi was presented to a Parker County, Texas veterinary clinic and subsequently diagnosed with rabies. Presumably, the dog was exhibiting neurological signs, died or was euthanized, and the veterinarian made sure the dog was tested for rabies (something that could become more complicated in Canada now that the CFIA has inexplicably dumped rabies investigation from their mandate).
Presumably, the dog contracted rabies from a skunk, since it brought a skunk carcass home with it a few weeks earlier, and that timeframe that fits with rabies' incubation period.
The dog's vaccination status wasn't reported, but it was probably not vaccinated against rabies. Rabies vaccination is not a 100% guarantee against contracting the disease (no vaccine is), but it's a very good vaccine, and failure of the owners to get the dog vaccinated is the most common contributing factor to rabies in dogs and cats. It's interesting that there were two other dogs in the family that were up-to-date, so it would be nice to get clarification of this dog's vaccination status.
Unfortunately, the dog was nursing a litter of five-week-old puppies at the time, and the puppies were euthanized. It's hard to say how likely it is that they had contracted rabies, but regardless, a six-month strict quarantine and hand-raising a litter of puppies don't exactly go hand-in-hand.
The report also says that two adults and a child are "currently under medical supervision and treatment as a precautionary measure," meaning they are getting a course of post-exposure prophylaxis, which consists of a shot of anti-rabies antibody and a series of four shots of rabies vaccine.
There's no guarantee, but effective vaccination might have prevented the death of the dog, euthanasia of five puppies, hassles with (presumably) a 45 day observation of the vaccinated dogs, and the angst and expense of post-exposure prophylaxis for three people. Rabies vaccination is well worth the investment!
I’ve written before about concerns I have with international rescue programs. We’ve been seeing various "foreign" diseases in dogs that have been imported to Ontario, and some of these could pose a risk to the broader dog population. I also have a hard time justifying someone spending a few thousand dollars to import a dog when we have lots of dogs right here in local shelters looking for homes. Often, people just want to be able to say they have an “[insert exotic sounding country here] rescue dog.”
There’s been a lot of discussion about stray dogs in Sochi, Russia, where there is a large stray population and reports of culls being undertaken by Russian authorities. Not surprisingly, even such a concerted effort isn’t going to get rid of all strays. More than a few people at the Sochi Olympics have bonded with local strays and are looking into bringing home a canine souvenir.
To me, this is a different situation than the one above, since these people have bonded with a specific dog (or dogs) and I can more easily justify the effort and cost to bring those dogs home.
However, disease risks remain the same.
Unfortunately, rules for importing dogs are very limited for most countries and don’t do much to protect the local dog population or public health. Typically, the only government concern is rabies, and even for that disease the rules are pretty lax.
- If it’s been vaccinated against rabies at least 30 days prior to entry, that’s all that's needed.
- If it has not been vaccinated, it can still be imported if the importer agrees to vaccinate the dog within 4 days of arrival and keep the animal confined for at least 30 days after vaccination.
- If the dog is less than 3 months of age (too young for rabies vaccination), it must be kept confined until 3 months of age, at which point it needs to be vaccinated and confined for 30 more days.
(I doubt anyone actually follows up to see if vaccination or confinement are done.)
Importing a dog into Canada
- This one’s even easier. If the dog is less than 3 months of age, it’s "welcome to Canada," since “Dogs do not require rabies vaccination or certification if they are less than three months of age at the time they are imported into Canada.”
- There is no quarantine or follow up.
So if you’re coming back from Sochi with a puppy, you’re not going to get a lot (or any) guidance from federal authorities. What should you do to protect the puppy, other animals and yourself?
- Take the dog to a veterinarian ASAP to identify any problems, and have it dewormed and vaccinated. Make sure it gets treated right away with praziquantel to eliminate any Echinococcus multilocularis (a highly concerning tapeworm) that might be present. (I have no idea what the prevalence of this parasite is in the Sochi area, but I’d err on the side of caution and assume the dog’s infected, particularly since a single dose of this very safe and inexpensive drug will eliminate it.)
- Keep the dog away from other dogs for at least a few weeks. That means staying away from parks and other areas where it may encounter local dogs. This helps to protect the other dogs AND the new arrival, since it takes time for vaccines to work and there may be some impact on the immune system from the stress of travel and adjusting to a new home.
- If the dog gets sick, get it to a veterinarian. Don't mess around.
- If the dog develops neurological disease, make sure rabies is considered. The incubation period can be months, and while we need to think about rabies in all neurological cases, it’s of particular concern in dogs imported from some other areas of the world.
If someone bonds with a dog while and Sochi and wants to bring it home, good for them. However, they should take some measures to reduce the health risks to their new furry friend, other animals and themselves.
It's a scary sounding headline: “Cat Bites Pose Risk Of Infection As 1 In 3 Patients Bitten Hospitalized; Teeth Inject Bacteria Into Joints, Tissue” and it cites a research article from the Mayo Clinic in the Journal of Hand Surgery (Babovic et al 2014).
Cat bites are nasty. The mouth of any cat harbours thousands of different bacteria and their needle-like teeth can inoculate bacteria deep into tissues. A variety of complications can occur after cat bites, and they are not something to dismiss as innocuous.
But hospitalization of 1/3 of people that are bitten? Not a chance.
Let’s see what the paper actually said:
The paper is entitled “Cat bite infections of the hand: assessment of morbidity and predictors of severe infection.” It was a review of 193 patients that were presented to one hospital with cat bite injuries to the hand.
- Point 1: The study population is people who went to the hospital for a cat bite, not all people who were bitten.
- Point 2: The study only looked at people bitten on the hand(s). That’s a common site to be bitten by a cat, but it’s also a high-risk site for complications because hands have lots of sensitive and fairly superficial structures (e.g. bones, joints, tendon sheaths, nerves) that are more likely to cause problems if they get infected.
So, it’s pretty clear that 1/3 of all bites don’t result in hospitalization. In reality it's a much smaller percentage, but you really don’t want to be part of that small group, so bite avoidance and proper post-bite first aid are still very important.
Some other highlights from the paper:
- Nineteen percent (19%) of patients were admitted to the hospital at presentation (i.e. they had to stay at least one night). A further 11% failed initial outpatient antibiotic treatment and were subsequently hospitalized.
- Sixty-nine percent (69%) of patients were women (not sure why - could be that more women own cats, more women get bitten by their cats, or more women are likely to seek medical care if they're bitten by a cat, or a number of other reasons).
- Risk factors for hospitalization (compared to people that presented to the hospital for a bite but did not require hospitalization) included smoking, having a compromised immune system and a bit over a tendon sheath or joint. Those are not surprising at all.
- Signs of inflammation (e.g. redness, swelling at the site of the bite) were associated with increased risk of hospitalization. Not too surprising either.
- The average time from bite to presentation was 27 hours. Interestingly, time from the bite to presentation was not a risk factor for complications, as this has been reported as a risk factor previously (and it makes sense that it would be). However, don’t take that as an indication that you can wait a long time to seek medical care after a high-risk bite.
- Complications were those that are typically encountered with cat bites (and good reasons to avoid them): abscesses, tendon infection and nerve involvement.
- Seven percent (7%) of all patients (not just the hospitalized ones) had loss of joint mobility after resolution of infection. Remember that cat bites can have long-term consequences.
- Cultures were only available for some patients, but Pasteurella multocida was the most commonly isolated bacterium. This bacterium is a notorious bite-associated bacterium and is commonly (if not always) found in the mouths of cats.
Crappy headline but an important topic.
Cat bites are bad, and it doesn’t matter if the hospitalization rate is 30% or 0.3%, they can still result in serious problems. They can also be largely avoided through proper cat handling, understanding some basic cat behaviour and proper first aid - things every cat owner should know.
More information about cats and about cat bites can be found on the Worms & Germs Resources - Pets page.
Photo credit: Moyogo (click image for source)
Antibiotic resistance is a big deal. Lots of people and animals die because of it every year. It costs the healthcare systems (human and veterinary) tremendous amounts of money and it’s not getting better.
It’s been clear for years that we have to do a better job of using antibiotics responsibly, in both animals and humans. It’s a complex area, and people often spend too much time complaining about the "other" side (human vs veterinary) rather than trying to address their own problems. However, there are issues with certain practices that seem so straightforward I’m amazed they're allowed to continue and that they haven't already been addressed.
One such issue is the ability to buy certain antibiotics in large volumes over the counter at feed stores in some countries (like Canada), with no veterinary involvement.
Another is the plethora of fish antibiotics you can buy all too easily in pet stores (and which often end up being used on dogs and cats).
And today’s rant is about a group of products that's ongoing use boggles my mind: tear stain prevention products like Angels' Eyes. These are over-the-counter products marketed to reduce tear staining, mostly in small, white dogs. Yes, tear staining - an entirely cosmetic problem that has absolutely no impact on health. The scary part is that products like Angels' Eyes contain tylosin, an antibiotic of the macrolide family. (How much it contains is a bit of a mystery since that information isn't even included on the label.)
Does it make any sense to treat animals for a purely cosmetic problem for long periods of time (or lifelong) with a (presumably) low dose of any antibiotic, let alone one in a drug class that includes many antibiotics that are important for treating infections in people and animals?
In some countries, irrational antibiotic use like this is banned. More countries need to follow suit.
Sometimes, people send me links to articles because they think I’d be interested in them. Sometimes, they do it to see what kind of response they can evoke. I’m not sure which one this was:
I was directed by a couple of people to a recent post of PLOS’s blog about snakes in classrooms. (I don’t really know why a scientific journal organization has a blog to which people who aren’t experts in a given field can submit posts. I would have thought a PLOS blog would relate to PLOS papers, but what do I know.)
I’m sure many people would agree with the sentiments in this blog, but (surprise, surprise), I don’t. It’s not that I’m anti-reptile, anti-pet-in-classroom, or think that the writer is clueless. Rather, he seems to be a passionate and well-meaning educator who just doesn’t see the issues with reptiles in classrooms. I’ve seen the issues and have my take on some of his points (in italics) below.
In this post I hope to give other educators a good foundation for keeping snakes in their classroom. A classroom pet is always a good way to teach responsibility. Administrators love any outside-the-box methods of teaching. Let them know students will be using this animal not just to learn science, but to learn important life skills like responsibility and compassion.
- True, but it has to be logical and safe. It also has to be educational. Animals can be used in classrooms for educational purposes, but they can also be distracting. The practice can be questionable from an animal welfare standpoint (especially for nocturnal species). They can be associated with disease. Reptiles are the leaders in that class, and reptile-associated salmonellosis has occurred from classroom snakes and other reptiles. Widespread Salmonella contamination of feeder rodents adds an extra level of concern.
- I also doubt administrators like outside-the-box ideas that pose a health risk to students (and therefore liability).
Your administrator may bring up questions about health risks. Salmonella is often associated with pet reptiles. This can be a bit misleading. Most animals, including pets like hamsters and guinea pigs can carry salmonella, but because turtles are wild caught, and often live in terrariums there is a better chance of salmonella living on their shell.
- No…(multiple no’s actually). While most animals can carry Salmonella, the prevalence of Salmonella shedding by pet mammals is very low. The rate of Salmonella shedding by captive reptiles is, in contrast, very high. Studies looking at snakes over time have shown that virtually all captive snakes are shedding Salmonella.
- It’s not just wild caught turtles that are the issue. Captive turtles are also a big concern (the bigger concern, actually).
Most snakes are kept in the same cage setup as hamsters and have little risk of ever having salmonella on their skin.
- Not a chance. Most do. As mentioned above, studies have shown high (to ubiquitous) carriage of Salmonella by snakes.
I have been handling snakes for 25 years and admittedly have poor hand washing skills and have never had an issue.
- That’s similar to saying “Gee officer, I drive drunk all the time and I’ve never killed anyone, so you have to let me go.” Yeah, that’s an extreme analogy but you hopefully get the point. Reptile contact causes thousands of cases of salmonellosis in people every year. There might be no infections in this classroom over the next ten years - or a child could die next week. It’s more likely that the former will happen, the the latter is possible.
I do keep multiple bottles of hand sanitizer in the classroom and make sure the students properly sanitize after handling and/or cleaning.
- That’s great. It’s an important risk reduction tool, but it’s not perfect and doesn’t compensate for the risk.
I would wager students are more likely to salmonella in the lunch line than they are from snakes in a classroom.
- I doubt it. Even if it was true, eating is a required event. Having a snake in the classroom is not.
Once bitten, the students lose most of their fear and wear it as a badge of honor.
- Multiple issues with this one...
Some issues are often overlooked:
- Do teachers always know if they have any high-risk (immunocompromised) kids in the class?
- Do teachers always know if there will be any high-risk kids visiting the class?
- What if a student is very afraid of snakes? How is that managed? (Is it managed? Might a child be afraid to say anything and instead work in a very stressful situation in silence?)
- Are students eating in the same area as the snake (a high risk activity to be sure)?
Here's my standard disclaimer: I actually like reptiles. Now that our kids are beyond the high-risk ages, Heather would be the main barrier to a request from them for a reptile, not me. However, while I like reptiles, I don’t like them in all situations. When the Salmonella risk can’t be contained and assurances can’t be made that only low-risk people will be exposed, reptiles shouldn’t be kept around. A classroom is a perfect example of just such a situation.
More information about Salmonella and safe management of different pets can be found on the Worms & Germs Resources - Pets page.
A few news articles have reported infection of two cats with the H1N1 flu virus. These are the first feline cases reported in Canada, but similar cases have been reported elsewhere, so it’s reasonable to assume that there have been previous undiagnosed feline cases in Canada. Nevertheless, it’s useful information.
Unfortunately, the new reports are very minimalistic in their details - not quite "cat-flu-dead" but pretty close. Information like what clinical signs the cats had, whether there were infected people in the household first, how infection was diagnosed and how the virus strain was confirmed would be useful.
Cases like this always raise a few questions:
What’s the risk to people in the household?
- Pretty limited. We don’t know if infected cats are able to spread the H1N1 virus (though we know that cats experimentally infected with the H5N1 flu shed enough virus that they could pose a risk).
- Nonetheless, it’s important to consider the household disease dynamics. From where did the cat get H1N1? From a person. With what people do most cats almost exclusively have contact? People in the household. So, if the cat was infected, it was probably infected by someone in the household or someone who visited the household, both of which pose a greater risk to other people in the household than the cat.
What’s the risk to the cat population?
- Pretty limited for a few reasons. Most cats don’t tend to have contact with that many cats outside of the household, and the flu virus is shed for a short period of time.
- Cats are also not very susceptible to the virus, so an infected cat would have to be shedding appreciable amounts of virus, have an encounter with a susceptible cat during the short time it’s shedding virus, and then this low-likelihood scenario would have to repeat itself in order for the virus to establish itself in the cat population.
Can cats be a source of new flu viruses?
- In the big picture, this is the main concern. Any species that can be a host for a human flu virus and other flu viruses is a concern because of the potential that infection with multiple viruses at the same time could lead to creation of a new virus - one that is still able to infect people, but is different enough that people don’t have any immunity and current vaccines don’t work (which means it could potentially make a lot of people sick very rapidly).
- However, the risk of this scenario is exceedingly low in cats since H1N1 infection in this species is very rare, and infection of cats by other flu viruses is ever more rare. Therefore, the odds of concurrent infection AND reassortment of the viruses AND transmission to a susceptible host that can further spread the virus is are extremely remote.
An outbreak of equine herpesvirus type 1 (EHV-1) neurological disease (also known as equine herpes myeloencephalopathy (EHM)) is underway in a currently undisclosed location in New Zealand. It appears that at least 12 horses have been affected with 6 deaths, all on one farm.
This is being described as the first outbreak of the neurological form of EHV-1 in New Zealand. That's pretty surprising to me, since this virus in endemic in the horse population throughout the world, and although the neurological form of disease is sporadic it's certainly not a rare occurrence. I imagine there have been periodic cases and maybe small clusters, but perhaps they mean that this is the first large outbreak to be identified (but that’s a guess). We do seem to be seeing more large EHV-1 neurological outbreaks in recent years, and I don't think it’s just because we're recognizing them more.
Fortunately, there is now much more willingness amongst most sectors of the equine industry to take these outbreaks seriously and act much more quickly and comprehensively than in the past (when getting people to admit to an outbreak was a challenge, let alone getting any action).
Hopefully this one's been contained on the farm and no further spread will be encountered.
Stay tuned for the launch of WormsAndGermsMap, a real-time disease mapping site to track cases like this. Coming soon.
The American Heartworm Society (AHS) recently issued a release emphasizing that "Contrary to what owners may think, heartworm disease is a year-round threat" and encouraging people to use heartworm preventive medications year round.
I’m in Canada, not the US, but some US regions have a similar climate and similar issues to us. Also, some people try to directly apply US recommendations to Canada, so I’ve critiqued their reasoning below, from an Ontario context.
The AHS based the release on 3 "facts":
Fact #1: Pesky pests pay no attention to the calendar.
- Mosquitos and heartworm don’t pay attention to the calendar, but they do pay attention to the weather. The picture to the right is the view of our deck (prior to the last couple rounds of snow). I don’t think there are many mosquitoes hanging around out there. Yes, they are somewhere, since they don’t become extinct over the winter, but is mosquito exposure a reasonable concern now? No.
- Furthermore, development of Dirofilaria immitis (the heartworm parasite) in mosquitoes ceases at temperatures below 57F, a level we haven’t seen in a while (and likely won’t for a couple of more months). So, even if there are mosquitoes hanging around at the beginning and end of the "heartworm season" in temperate areas, if the parasite can’t develop, it doesn’t matter much.
Fact #2: Mosquitoes know when to come in from the cold. When weather changes prompt pets to spend more time inside, mosquitoes follow, keeping the possibility of heartworm transmission alive. This means that so-called “indoor” pets are as much at risk as their more outdoorsy counterparts.
- I’d like to see some data backing that up. I haven’t had a mosquito bite in a while.
Fact #3: Staying on schedule with heartworm prevention keeps pets safe.
- Potentially, but assuming every pet owner is forgetful and unable to figure out how to treat their animal once a month over a prescribed part of the year isn’t really a reasonable justification for a treatment regimen that uses more drug and costs more money.
- There is no evidence that 12-months-a-year treatment results in any better compliance than targeted seasonal treatment. (If I can’t remember to give it 6 months of the year, does adding 6 more months really help?)
- Around here, the vast majority of heartworm cases are in dogs that are not on heartworm prevention medications, not in dogs in which treatment failed, potentially because of compliance problems. Is it possible that some people would be more reliable with monthly treatment? Sure. It’s also possible that some people would be as bad (or worse) with year round treatment. It’s also possible that some dogs would go untreated altogether if their owners balked at the cost of year-round treatment.
The bottom line for me:
Heartworm’s a nasty disease and one that we need to prevent.
There are effective preventive medications.
Ontario isn’t Louisiana. In some areas of North America, year round treatment is absolutely needed. In others, the risk period is much shorter.
Decisions about the approach to prevention need to be based on the risk in the area, the duration of likely mosquito exposure, the outdoor temperature and the owner’s ability to comply with treatment. This is a discussion that needs to take place between pet owner and veterinarian on an individual basis.
There is no one-size-fits-all approach to heartworm prevention.
Merlin and I will each get hundreds of mosquito bites this year (surrounded by wetland as we are). He'll get his monthly heartworm prophylaxis during what I feel to be the "at-risk" time of year. That doesn't include today, when it was -21C this morning!
For the third time in the past year, Macon-Bill Animal Welfare in Georgia (USA) has a problem with canine parvovirus. The shelter is closed for two weeks in response to a puppy testing positive for this highly contagious virus that can cause serious disease in dogs (almost exclusively in unvaccinated puppies). At first glance, it may seem like an overly-aggressive response. A single parvo case isn’t too surprising in a shelter, and if appropriate routine precautions are followed, there are sound protocols to isolate parvo suspects and a good vaccination program, the risk to other animals can be contained.
In this outbreak, 14 puppies have been euthanized (though some reports differ). Again, the news reports are pretty crappy and it’s unclear whether all the puppies were sick or whether they were euthanized because they were exposed. The statement that parvovirus infection is "most times fatal for dogs" is wrong, since it’s usually treatable, but it certainly takes time, effort and money - things that may be of limited availability in a shelter. Also, if the shelter has inadequate facilities or personnel to properly treat and contain parvo, euthanasia gets considered more readily that in better equipped facilities.
The first report also says that the shelter refunded adoption fees of people who adopted puppies that subsequently died from parvo, so it does sound like there was probably a real (and possibly large) outbreak.
Closing a shelter is an extreme move but it’s sometimes required. It helps reduce the number of animals in the facility in order to make isolation of sick animals, separation of groups, management of exposed and infected animals and many other aspects of the infection control response easier. It also stops adding fuel to the fire, by halting admission of new susceptible animals that can get sick and thereby propagate the outbreak.
Some shelter outbreaks are the result of poor routine management (and some incompetence). Some are the result of inadequate response to an infectious animal. Some are an over-reaction to a limited and containable problem. Some will occur despite the best practices in the best facility. That’s the nature of infectious diseases. Any time there’s an outbreak, a shelter needs to figure out which of the above categories they fit in so that they can reduce the risk of future problems.
(For tracking of selected infectious diseases and outbreaks, stay tuned for the launch of WormsAndGermsMap. More information to come!)
Rabies in horses is pretty rare but far from unheard of, and each case should be a reminder of the need for proper vaccination. The latest US case was a horse in Newport, New York, but I haven’t yet been able to track down more details. Presumably, human and animal contacts are being investigated, with assessment being made as to whether there was potential exposure to rabies virus. For people, that would mean a course of post-exposure prophylaxis. For animals, that would mean a quarantine, observation period or euthanasia, depending on the species and vaccination status.
The risk to people is quite low. The biggest human health risk is from being attacked or otherwise physically injured by a neurological horse, as opposed to getting rabies from an infected horse. But rabies is something with which we don’t play around, so anyone deemed to have been exposed will presumably be treated.
Rabies isn’t common in horses but it kills. Vaccinate your horses (and other animals).
Although at times it may seem that winter is never-ending in parts of Canada, spring is actually only a couple of months away. Along with spring comes insect season, and along with insects comes more than a few viruses. One of these is the virus that causes equine infectious anemia (EIA). This pathogen is a retrovirus like the human immunodeficiency virus (HIV), but EIA only affects equids (e.g. horses, donkeys, mules). It's a very serious concern in the horse world, because horses become infected for life, and in Canada we have strict control measures to help prevent the spread of EIA into and within the country. Nonetheless, in 2013 cases were detected on numerous premises in BC, Alberta and Saskatchewan. Maps of the areas affected are available of the website of the Canadian Food Inspection Agency (CFIA).
To help horse owners understand more about this disease, the existing control program and the reasons behind it, as well as how they can help prevent the spread of EIA, we've created two new info sheets in collaboration with Equine Guelph and Equine Canada: a full-length version complete with references (9 pages) and a shorter summary version (4 pages). Both versions are now freely available for download from the Worms & Germs Resources - Horses page, along with our many other equine infectious disease info sheets.
The first North American case of H5N1 avian influenza ("bird flu") was confirmed in an Alberta resident last night, causing much concern but posing little true risk. The affected person had just returned from a trip to China and began showing signs of illness during the flight from Beijing to Vancouver. After spending a few hours in the Vancouver airport, the person continued on a flight to Edmonton. The person's condition continued to deteriorate after returning home, and the patient was admitted to hospital on January 1, dying two days later.
H5N1 flu is a big deal. This bird-origin virus has only been identified in 648 people, mainly in Asia. However, 384 of those have died. Fortunately, it’s not transmitted very easily to people, and almost all human cases have occurred following close contact with infected poultry.
So, the risk posed by the Alberta case is very low, even to people who shared the long plane ride.
There are some strange aspects of this case though. The affected person didn’t have any known contact with live poultry, which is unusual. It’s even more unusual that the person reportedly only visited Beijing, where no cases of H5N1 have been detected, and did not travel to other areas of China where the virus has been found before.
As reported by the CBC, “China is going to be very interested in this,” said Dr. Gregory Taylor, deputy chief public health officer for Canada.
True. I think Canada should be interested in this too.
A case that’s unusual is a concern. Most often, things that appear to be strange or new don’t end up being anything remarkable. However, a disease that was potentially acquired in an area where it has not been found before, and not necessarily from the known main source means that you have to think about other sources (including humans). If this came from another source, maybe there is more risk. It’s very unlikely though, and chances are it will be eventually be explained (e.g. perhaps the person was in a restaurant that kept live poultry on hand which came from an area where the virus has been present).
I assume this H5N1 virus will be sequenced in the next day or so to see how it compares with other known H5N1 viruses. That will answer some questions.
Despite its high mortality rate, the H5N1 virus isn’t really the major concern here, because it’s rare and poorly transmissible between people. The concerning situation is if H5N1 gets together with human seasonal flu and ends up becoming a virus that is both highly transmissible between people (like seasonal flu) and highly fatal (like H5N1). The odds of this are limited, but the pandemic potential of a new virus of this kind is why there’s a lot of flu surveillance.
A recent high profile dog-bite death in the US has refocused discussion on bites and their causes. Co-incidentally, a paper in a recent edition of the Journal of the American Veterinary Medical Association (Patronek et al 2013, Co-occurrence of potentially preventable factors in 256 dog bite-related fatalities in the United States (2000-2009)) also addresses this topic.
The authors of the study looked at 256 dog bite fatalities and, primarily using investigation reports from law enforcement agencies, looked at potential preventable factors. This was a pretty intensive effort compared to other studies, involving review of all available documentation and interviews with investigators and animal control officers whenever possible.
Here is a synopsis of some of their interesting results:
- The overall dog bite fatality rate was approximately 0.087 fatal bites per million person years (or 8.7 fatal bites per 100 million people per year) and 0.38 fatal bites per million dogs. That’s low, but that's small comfort if you’re one of the 0.087.
- Almost half of the victims were less than 5 years of age, with slightly more males than females.
- Few victims (6.6%) were the dogs’ owners, and owners were present at the time of the bite in only 4.7% of cases. In 74% of cases, there was no relationship to the dog (i.e. the animal was not owned by the victim, a friend or relative, or some other situation in which the person knew the dog).
- In slightly over half of the cases, the victim was deemed "unable to interact appropriately," mainly due to young age. In another 22%, the victim was deemed "possibly" unable to interact appropriately, due to being 5-12 years of age, or having cognitive impairment because of age, mental disability, intoxication or seizures.
- 87% of the time, there was no able-bodied adult present who could have intervened.
- 58% of the time, only a single dog was involved. However, 87% of infant deaths were from a single dog.
- 74% of bites occurred on the owner’s property.
Obviously, dog factors get a lot of attention when it comes to fatal attacks. Here are a few:
- Most dogs were 23-45 kg.
- 88% were male.
- 84% of dogs were not spayed or neutered.
- 38% of the time, the owner or caretaker was aware of prior dangerous behaviour by the dog, or had repeatedly allowed the dog to roam freely.
- In 21% of cases, there was evidence that the dog had been neglected or abused.
- Breed reporting, which is important because it’s such a high profile subject, was pretty poor. Media often reported different breed info, and media and animal control reports often differed.
Dog bites cannot be eliminated entirely but they certainly can be reduced. A variety of approaches are needed, including measures directed at dogs, dog owners, the public and authorities. Understanding potentially preventable or modifiable factors (e.g. neutering, supervision, addressing previous aggressive behaviour) is an important step to developing optimal preventive approaches.
A Colorado family is suing PetsMart and a rat supplier after their son developed rat bite fever (RBF), following a bite from a newly acquired rat. Lawsuits seem to be increasingly common after zoonotic infections, which is probably more of a reflection of an increasing tendency for people to sue, not an increasing occurrence of zoonotic diseases. However, questions of liability, and the responsibility of both the purchaser and the seller are interesting to consider. Here are some statements in a report about the lawsuit, with my comments:
They claim the pet store had ample evidence that the rat was sick, but sold it anyway.
- Firstly, it wasn’t sick from Streptobacillus moniliformis, the bacterium that causes RBF. I don’t doubt that the rat was sick but that really doesn’t have anything to do with the risk of RBF.
- Secondly, if it was so obvious, why did they buy the rat? Buyers have a responsibility to learn about pets they are considering buying, to pay attention to animals they are purchasing and take measures to protect themselves. If they put even a minimal amount of effort into researching pet rats, they would have hopefully learned about RBF, things to consider when selecting a rat, and how to manage bites.
"The rat originally sold to [the father] Robert and Steiner was ill and died," the complaint states. "This rat became aggressive and at the same time sneezed a lot as if it was ill. Robert was then given a substitute rat which was also ill and infected with rat bite fever. It displayed the same behavior as the first rat about one week after it was given as a substitute for the first rat.”
- Same issues as above. It wasn’t sick from the bacterium that causes RBF. I doubt they actually confirmed that the rat was carrying the bacterium (as is suggested here) but it presumably was, since that bacterium is found in pretty much every rat.
- Also, if they bought a sick and aggressive rat, did they really think a rat from the same store at around the same time would be any different?
The family claims the rats "were not inoculated carefully," but were subjected to a shoddy batch immunization.
- I wonder what they were actually "inoculated" against. There are no standard vaccines for rats, and no vaccine against RBF exists.
Rainbow, upon information and belief, is known by members of the public including P.E.T.A. [People for the Ethical Treatment of Animals] to negligently and carelessly maintain the animals it sells to PetsMart and this fact is known to PetsMart at all times relevant including before the sale of the rat."
- That wouldn’t surprise me. Mass producers of pets, be it rodent warehouses or puppy mills, aren’t known for their quality of care. However, that’s a separate issue. It needs to be addressed more broadly but isn’t related to the risk of RBF in this case.
This isn’t meant to blame the victim. It’s unfortunate that the child got RBF. Pet stores and suppliers need to do a much better job of providing only healthy animals. However, at the same time, there’s no way to completely eliminate the risk of disease transmission and people have to learn what to do to reduce the risk, and then actually use those basic, common sense practices. There are certainly situations in which pet stores are negligent, but it’s hard to argue that this is the case here, when they’re dealing with an infection from a bacterium that is present in all rats.
As we were heading into our 5th day without power as a result of a nasty ice storm, the power came back on. It’s been a pain, but with the generator, fireplace and family to visit in unaffected areas, it’s more disruptive than anything.
Not everyone’s that lucky.
If you don’t have a generator or someone with power with whom to stay, what do you do (especially when the temperature dipped to -18C last night)?
Also, what do you do if you have pets?
You might be able to find someone with power to take them or you might find a kennel (if there is one with power and space, and if you can afford it). If not, what then? Warming centres have been opened up, but what would happen if we showed up at one with two dogs, two rabbits and a cat? (The sheep would have to get by on hay and snow, and the fish... well... they’d be screwed.) I doubt our menagerie would be welcomed.
So, you’re left with deciding whether to leave the animals at home with a big pile of food and hoping for the best, or staying behind with them.
It is a serious issue, and I can virtually guarantee there are people toughing it out in freezing houses because they didn’t have any place to put their pets.
When large-scale natural disasters occur, animal care can be an even bigger issue. I heard a figure once about the number of people who died in Hurricane Katrina, having refused to evacuate as it approached because their pets couldn’t be evacuated with them. I’m hesitant to repeat the number since I haven’t been able to find it in a well-documented source, but even if it’s a gross over-estimate, it’s still huge.
It’s also relevant on a smaller scale, on many fronts, such as homeless people staying out of shelters because they can’t take their pets (commonly dogs) with them.
Making plans for management of pets is important for situations such as these. Some people dismiss it as “why would you want me to waste time, energy and money saving a few dogs and cats when people are at risk”? Those individuals are missing the point. The goal isn’t to save the dogs and cats (though that’s a nice side-effect) - it’s to remove barriers to assistance that may be in place when people are unwilling to leave their animals behind. It’s not simple, since you have to consider a lot of things like feeding and housing animals, keeping them controlled, making sure there are no problems with bites or people who are fearful or allergic to animals, and taking precautions to prevent zoonotic diseases.
It’s not easy and it needs to be planned in advance - not during a crisis - but it’s something that needs to be done.
I write about Capnocytophaga canimorsus regularly... disproportionately so, since it’s a rare cause of disease in people. However, though rare, when disease does happen it’s usually serious, and cases illustrate some important basic concepts that apply more broadly to other zoonotic diseases from pets.
The title of this post is from the latest edition of the Canadian Journal of Infectious Diseases and Medical Microbiology, which includes a report describing a single case of Capnocytophaga infection in a person (Popiel et al 2013). In that respect, it’s not particularly remarkable, but some common themes and a few interesting statements that appear are worth considering.
The case report is about a 56-year-old male who presented with fever, headache, joint pain and nausea. He had some other health problems and was a heavy drinker (a major risk factor for Capnocytophaga infection). He developed Capnocytophaga meningitis and deteriorated quickly, but fortunately responded to treatment. The family dog had bitten the man on a finger a week earlier. As is common, it was a minor bite and one that was likely dismissed as inconsequential. However, a minor bite is all that’s needed to drive Capnocytophaga into the body.
The paper starts with the sentence “In 1976, Bobo and Newton (1) described a syndrome that would forever change mankind’s relationships with their canines.”
I think that’s completely false. I’d wager that >99.99% of people have never heard of this bacterium. Most veterinarians haven’t either, and I suspect the same could be said about most physicians. So, I don’t see how it could have had a major impact on how people interact with dogs.
In some ways, I’d like this statement to be true, if it meant that people paid more attention to zoonotic diseases and improved basic disease prevention practices (e.g. hand hygiene, having high risk individuals avoid contact with saliva, good bite prevention and bite care). In other ways, I’m glad it’s not true, were it to result in people being paranoid of this bacterium (that’s found in the mouth of pretty much every dog) and limiting the positive aspects of pet ownership and contact.
More information about Capnocytophaga can be found on the Worms & Germs Resources - Pets page.
Here's another one of my favourites from the archive (largely because it didn't happen to me) that was worth re-posting (original post date 11-Oct-2009).
I was talking with a colleague the other day and somehow norovirus came up. He explained how once, his wife had viral gastroenteritis and ended up vomiting on their cat. Weirdly enough, his wife told my wife the same story (they work together). My wife got a better version of the story which included a nice image of her chasing the cat around the house in her sickened state because the cat was splattering vomit all over the place. (Yuck!)
Anyway, beyond being an entertaining story (as long as it's not you doing the puking and chasing), it raises the question: if you've turned your cat into a biohazardous (and stinky) norovirus vector, what do you do to clean it up?
Dogs and cats cannot become infected with norovirus. However, they could potentially act as a source of infection for people if their coats are contaminated with the pathogen. Usually, I think about this in the context of someone having a little contamination of their hands and subsequently touching a pet (not a vomit-soaked animal, although evidently that can happen too).
So, what should you do? I don't really know. The CDC recommends using bleach or another approved disinfectant on contaminated surfaces, but that's obviously not an option for a cat. Heating contaminated objects to 60C is another recommendation, but again, not for a live animal.
I guess giving the cat a bath would be a good start, and it would presumably greatly reduce the amount of norovirus on the coat. However, if you have viral gastroenteritis already you're probably not in much of a state to do that. Another family member that is not flat-out sick in bed could do the job. However, anyone bathing a heavily contaminated animal should wear a mask and gloves, change their clothes after, clean any surface that gets contaminated in the process with bleach or another disinfectant, and (of course) wash their hands. Unfortunately, I suspect if you had to bath a cat covered in norovirus that you would probably end up getting infected, either from the cat or the contaminated environment. Leaving the animal covered in vomit is not a good alternative either, since it would continue to contaminate the household as well as look and smell really bad. We don't know how long norovirus can survive on an animal's coat, but it's reasonable to suspect that it could survive a couple of days. Keeping the pet away from uninfected individuals for a week or so wouldn't be a bad idea.
The easiest way to handle this is to avoid vomiting on your pets.
From the archives...Why should I vaccinate Fluffy, he's an indoor cat? (aka Why I'm glad I vaccinated Finnegan, my indoor cat)
Over the past few years, I've written a lot of posts on this blog. Hopefully the odd one's been interesting and/or informative, and in the spirit of recycling (not laziness!) I'm going to re-post some that I thought were memorable or of particular interest.
The first one is actually the second post ever on this site (original post date: April 11, 2008).
Picture this. I’m driving home from the airport and get a call from my wife who’s locked in the bedroom with our kids because a bat is flying around the house. It’s not necessarily a big deal, except for the fact I thought I might have seen a bat in the house a couple days earlier, and a bat in a house with access to sleeping people = rabies exposure! [2013 addition: Not all jurisdictions consider this to be exposure now.]
I’ll save you the long but somewhat funny saga, and just say I eventually caught the bat. Our sigh of relief was short-lived, however, because it came back rabies positive. That meant we all needed rabies post-exposure prophylaxis (2 shots for Heather and I who have been vaccinated, but 6 shots for each of the kids). We also have a dog and cat, and they had to be considered exposed as well (the cat almost caught the bat). The cat, Finnegan, is an indoor cat but was vaccinated. The repercussions on the animals were much less than on us. However, if they had not been vaccinated, we would have had a problem.
Protocols for rabies exposure in non-vaccinated animals vary between jurisdictions, but long quarantines are the norm, and euthanasia often is chosen.
The take home message is if you care about yourself, your family and your pets, vaccinate your pets against rabies - even with indoor-only animals. In most places it’s the law. It’s also good sense.
It’s flu season so I’ll take advantage of the time to talk about flu of a different type… canine flu.
Canine flu is different from seasonal flu in people. It’s caused by canine influenza A H3N8, and has spread around the US is a rather meandering and unpredictable manner. It’s caused major problems in dogs in some areas, while other areas have been completely unscathed.
Influenza in animals is a concern for animal health, but there are also human health concerns because of the ability of many influenza viruses to cross species barriers.
The human health risk posed by canine flu has been unclear, but it’s been assumed to be low. One reason is that there have been no credible reports of disease in people working with infected dogs (although that’s a far-from-convincing degree of evidence). More importantly, from my standpoint, is that canine influenza originated from, and is still closely related to, equine influenza H3N8. This virus is widespread in horses internationally (and has been for a long time) and it’s not of much zoonotic concern.
However, it’s always good to have more information, and a recently published study (Krueger et al, Influenza and Other Respiratory Viruses 2013) explored this area further. The researchers looked at 304 people who were regularly exposed to dogs and 101 people who did not have canine exposure, and they looked for antibodies against H3N8 influenza in the subjects’ blood.
There were no differences in antibody levels between the two groups, suggesting no evidence of flu transmission from dogs to people.
The study would be more informative if they knew whether any of the people had been exposed to dogs with influenza (or respiratory disease, in general), so conclusions from the study are somewhat limited. The study targeted people at higher risk for exposure to dogs with flu, such as show dog owners, racing greyhound caretakers and similar groups, which is good. More useful would be a study looking at owners or caretakers of dogs with canine flu and comparing them to other dog owners and people with no dog contact (although that’s not easy to do).
So, we’re still left with some questions but no convincing evidence that canine flu is a human health risk. That being said, it would be better not to have it circulating in the dog population where a co-infection of an animal (or person) with H3N8 and a common human flu virus could result in a new virus that is more easily able to infect people and to which there’s little resistance in the human population. New flu viruses are potentially a big problem, as the bird/pig/human pandemic H1N1 flu virus showed a few years ago.
A rabies exposure incident in New Jersey provides another example of some common good and bad points that come up in these situations.
Fifteen people from four families, along with a veterinarian, are receiving post-exposure treatment after contact with a rabid kitten. In the all-too-familiar scenario, a kitten was found in a cat colony outside a workplace and taken home by a well-intentioned individual. A couple of weeks later, the kitten became sick, ultimately showing signs of neurological disease. It was euthanized at a local veterinary clinic, and subsequently identified as rabid.
A sibling of the rabid kitten that was adopted by a different family is under a strict six month quarantine. As opposed to most rabies exposure quarantines, the odds of this kitten being infected are reasonable high, so the little critter is certainly a concern.
The good points:
The kitten was taken to a vet.
- This may sound simplistic but it’s critical. If the kitten had died before being taken to the clinic, would testing have been performed? It’s hard to say but it’s much less likely. While people don’t tend to think about diagnostic testing after their pet has died, it’s important to consider what might have killed the animal and whether there are any risks to people that need to be evaluated.
Rabies testing was performed.
- Again, maybe this seems straightforward but this is a critical step. The veterinarian has to identify the potential for rabies (pretty easy here) and explain the need for testing to the owner (or alternatively, get public health personnel involved to seize the carcass and mandate testing… a much messier approach).
The bad points:
Lots of people were exposed to the rabid kitten - a total of 15 people from four families.
- That’s hard to prevent, in reality. Kittens attract attention. Whether all 15 individuals actually had contact worthy of calling them exposed to the virus itself isn’t clear. There’s no mention of anyone being bitten. However, given the sharp teeth and playful behaviour that can easily result in little bites (or saliva-contaminated scratches), it is much better to err on the side of calling someone exposed.
All 15 people went to an emergency room for treatment on a weekend.
- That’s a waste of resources and ER time. Rabies exposure is a medical urgency, but not an emergency. Rarely do you need to get treatment started immediately, especially if it wasn’t a large bite to the head or neck. They could have waited until regular hours and gone to their physician or public health. Often, there’s poor communication and lack of understanding regarding the time frame for post-exposure treatment, which can lead to this.
The veterinarian was exposed.
- That may have been unavoidable. However, a young, unvaccinated kitten adopted from a feral colony that has neurological disease is rabid until proven otherwise. Basic infection control practices can reduce the risk of rabies exposure. Maybe those were used and exposure still occurred; that’s possible, but it’s a reminder that prompt identification of rabies suspects and using good infection control practices is important.
These days, there’s more and more doom-and-gloom information about multidrug-resistant bacteria. They’re in our hospitals, medical tourists, people on the street, our pets, our food, and pretty much anywhere else you can think of. We can now add crow poop to the list too.
It’s almost to be expected, really. We know that birds can carry various resistant bacteria, and the more contact birds have with human environments and food animal environments, the greater the chance these bacteria are going to be transmitted between them (in one direction or another). It's important to remember that resistant bacteria are also present in nature, independent of human activities.
A recent report of a pretty high profile multidrug-resistant bacterium - vancomycin-resistant Enterococcus (VRE) - in birds wasn’t all that surprising. The study (Oravcova et al, Environmental Microbiology 2013) reported finding enterococci carrying the vanA resistance gene in 2.5% of 590 crows sampled in multiple US states. It was quite interesting though, because VRE is (in North America) a human-associated bacterium. It’s a little more muddled in Europe where VRE was an issue in food animals, in part due to former use of a drug related to vancomycin (avoparacin) in some food animal species. Here though, we rarely see VRE in anything species but humans. This raises some interesting questions about where these crows picked up VRE, if they are able to carry the bacterium for long periods of time, and if they can act as a source of human or animal infection.
Does this bother me? No. It’s of academic interest, but not something that’s going to pose a real risk to me. I tend not to walk under trees full of crows with my mouth open, and I’m pretty sure I’d wash my hands if a crow pooped on them. Yes, there’s the chance that I could have unnoticed contact with contaminated crow poop remnants on an outdoor surface, but the odds of it containing viable VRE are pretty low, and there are lots of other things that I’m more likely to pick up in my daily activities. In terms of VRE, I’m presumably more likely to be exposed in other ways than from crows. However, the study is still important in that it shows how widespread antimicrobial resistance is, how complex the issue is and how we need to do more to understand the ecology and epidemiology of various resistant bugs.
There's no need to go exterminating crows, but Johnny Depp may want to consider an alternative style of hat.
Pet aquatic turtles have been implicated in three outbreaks of salmonellosis involving 43 US states over the past year and a half. Disappointing, but not surprising.
Disappointing, obviously, because people are getting sick. Disappointing also because these outbreaks have occurred over and over, despite availability of good information on how to reduce the risks.
It’s not surprising, though, because it’s happened so often.
Why? It’s a combination of people not researching these animals properly before buying them, pet stores not providing information, turtle farmers in denial that there is a problem, people flouting the small turtle ban, and poor overall awareness (and application) of basic infection control measures (more on that in a minute).
The Michigan Department of Community Health (MDCH) has reported that 5 people from Michigan have become ill as part of these outbreaks. As is typical, most were kids.
So, if you own a pet turtle, what do you do?
“We don’t recommend that they release them into the wild. Instead, we recommend that you contact a pet retailer, a pet store, to talk to them about it. Also, you can speak with a local animal shelter or a veterinarian for other options as well.” said MDCH spokesperson Angela Minicuci.
That’s not bad advice. However, the pet store and vet probably aren’t going to take the turtle. The humane society might (and those that do might try to find it a home or might just euthanize it right away). There’s another step here that’s forgotten: doing a risk assessment.
Are there high-risk people in the household (kids less than five years of age, elderly, pregnant women, people with compromised immune systems)?
- If yes, the turtle should be re-homed.
- If no…
Are you willing to accept some degree of risk, risk that can be mitigated with some basic practices?
- If no, the turtle needs a new home. (There’s always some degree of risk with turtle (and any animal) ownership).
- If yes…
Are you willing/able to take some basic measures to reduce the risk of Salmonella exposure, on the assumption that your turtle is Salmonella positive?
- If no… (take a guess here) the turtle needs a new home.
- If yes...
A little knowledge can be a bad thing. We see that with zoonotic diseases. Awareness is great. However, a little bit of awareness can be a problem if it’s enough make people paranoid but not enough to help them understand the real risks. This can lead to excessive and illogical responses (often ending with "...get rid of the cat").
Sound guidelines for preventing infections written by authoritative groups help a lot. An example of that is the recently updated Guidelines for the prevention and treatment of opportunistic infections in HIV-infected adults and adolescents. As a collaborative set of guidelines from the US Centers for Disease Control and Prevention (CDC), the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America, it carries a lot of weight - as it should.
It’s a monster of a document of 416 pages. Pet contact gets a little bit of room and probably just the right amount. Enough to say "it’s something to think about," "we’ve considered the issues" and "here are some basic things to consider.”
Here are their specific recommendations:
Hand-washing also should be recommended in association with the following activities: after handling pets or other animals, gardening or having other contact with soil; before preparing food or eating; and before and after sex (BIII).
HIV-infected individuals—particularly those with CD4 counts <200 cells/μL [i.e. people who have advanced disease]—should avoid direct contact with diarrhea or stool from pets (BIII).
Gloves should be worn when handling feces or cleaning areas that might have been contaminated by feces from pets (BIII).
HIV-infected individuals also should avoid other sources of Cryptosporidium oocysts as much as possible (BIII). These include working directly with people with diarrhea; with farm animals such as cattle and sheep; and with domestic pets that are very young or have diarrhea. If exposure is unavoidable, gloves should be used and practices for good hand hygiene observed.
The letters and numbers indicate the strength of evidence. B means there’s moderate evidence supporting the recommendation and III means it’s based mainly or exclusively on expert opinion, not research trials.
Note that nowhere does it say "get rid of the pet" or "avoid contact with animals altogether." Rather, it endorses the use of basic hygiene practices and common sense. In reality, all these recommendations could apply to any individual, not just people with HIV infection.
The preamble to the pet section includes a great statement:
Health-care providers should advise HIV-infected persons of the potential risk posed by pet ownership. However, they should be sensitive to the psychological benefits of pet ownership and should not routinely advise HIV-infected persons to part with their pets. Specifically, providers should advise HIV-infected patients of the following precautions.
…and those precautions are:
HIV-infected persons should avoid direct contact with stool from pets or stray animals. Veterinary care should be sought when a pet develops diarrheal illness. If possible, HIV-infected persons should avoid contact with animals that have diarrhea.
When obtaining a new pet, HIV-infected patients should avoid animals aged <6 months (or <1 year for cats) and specifically animals with diarrhea. Because the hygienic and sanitary conditions in pet-breeding facilities, pet stores, and animal shelters vary, patients should be cautious when obtaining pets from these sources. Stray animals should also be avoided, and specifically those with diarrhea.
Gloves should always be worn when handling feces or cleaning areas that might have been contaminated by feces from pets. Patients should wash their hands after handling pets and also before eating. Patients, especially those with CD4 cell counts < 200 cells/μL should avoid direct contact with all animal feces to reduce the risk for toxoplasmosis, cryptosporidiosis, salmonellosis, campylobacteriosis, E. coli infection, and other infectious illnesses. HIV-infected persons should limit or avoid direct exposure to calves and lambs (e.g., farms, petting zoos). Paying attention to hand hygiene (i.e., washing hands with soap and water, or alcohol-based hand sanitizers if soap and water are unavailable) and avoiding direct contact with stool are important when visiting premises where these animals are housed or exhibited.
Patients should not allow pets, particularly cats, to lick patients’ open cuts or wounds and should take care to avoid any animal bites. Patients should wash all animal bites, animal scratches, or wounds licked by animals promptly with soap and water and seek medical attention. A course of antimicrobial therapy might be recommended if the wounds are moderate or severe, demonstrate crush injury and edema, involve the bones of a joint, involve a puncture of the skin near a joint, or involve a puncture of a joint directly.
Patients should be aware that cat ownership may under some circumstances increase their risk for toxoplasmosis and Bartonella infection, and enteric infections [although I’d argue data supporting a broad statement of cat ownership increasing those risks that are largely lacking]. Patients who elect to obtain a cat should adopt or purchase an animal aged >1 year and in good health to reduce the risk for cryptosporidiosis, Bartonella infection, salmonellosis, campylobacteriosis, and E. coli infection.
Litter boxes should be cleaned daily, preferably by an HIV-negative, non-pregnant person; if HIV-infected patients perform this task, they should wear gloves and wash their hands thoroughly afterward to reduce the risk for toxoplasmosis. To further reduce the risk for toxoplasmosis, HIV-infected patients should keep cats indoors, not allow them to hunt, and not feed them raw or undercooked meat. Although declawing is not usually advised, patients should avoid activities that might result in cat scratches or bites to reduce the risk for Bartonella infection. Patients should also wash sites of cat scratches or bites promptly and should not allow cats to lick patients’ open cuts or wounds. Care of cats should include flea control to reduce the risk for Bartonella infection. Testing cats for toxoplasmosis or Bartonella infection is not recommended, as such tests cannot accurately identify animals that pose a current risk for human infection.
Screening healthy birds for Cryptococcus neoformans, Mycobacterium avium, or Histoplasma capsulatum is not recommended.
HIV-infected persons should avoid or limit contact with reptiles (e.g., snakes, lizards, iguanas, and turtles) and chicks and ducklings because of the high risk for exposure to Salmonella spp. Gloves should be used during aquarium cleaning to reduce the risk for infection with Mycobacterium marinum. Contact with exotic pets (e.g., nonhuman primates) should be avoided.
I'm getting ready for next week's ASM/ESCMID conference on methicillin-resistant staphylococci in animals, for which I'm involved in a plenary session about critically important antibiotics in companion animals. The whole area of antibiotics and animals in complex and controversial (and made worse by political agendas, lack of evidence and confusion about different issues).
Anyway, one thing that often gets overlooked is the difference between companion animals and food animals in how antibiotics are used, what regulations are in place, and what differences should be present between species. Just discussing antibiotics "in animals" isn't adequate, because a pet dog is very different from a feedlot steer in many respects, and many of the issues around antimicrobial use are different as well.
One question that's going to be up for debate is "should antibiotics that are used in serious resistant infections in people be used in animals?"
My answer to this important question has evolved a bit over the years. It's "yes, but..."
The but is the important part.
- As a veterinary clinician, I see the need to treat my patients (or the patients I'm providing advice on).
- As someone who works in the field of antimicrobial resistance, I see the issues with drug use and resistance.
- As a parent, I don't want my kids to develop a serious infection that I may have played a role in fostering.
- As a pet owner, I understand the desire to try to save the life of a pet.
That doesn't even cover all the issues, but it shows the variety of standpoints that need to be considered.
Back to the question at hand. As I said, my answer is yes, but with disclaimers:
- We need to use antimicrobials only when required.
- We need to use antimicrobials properly.
- We need to take measures to reduce infections overall (so that less antimicrobial use is required).
At our veterinary teaching hospital, we have a restriction policy for vancomycin, an important human drug. For it to be used in an animal, the following criteria must be met:
- The offending bacterium must be susceptible to vancomycin (duh!).
- There must be no other reasonable antibiotic options that are likely to work.
- There must be a reasonable chance of survival with treatment.
- Systemic treatment of the infection is needed (i.e. it can't just be treated with local therapy).
- The clinician must get approval from infection control (i.e. me).
That has happened twice in the past 12 years. Both cases were dogs with life-threatening abdominal infections; they were each treated with a short course of vancomycin and survived.
That's probably 10-14 days of vancomycin use per ~200 000 patients. I don't know what the comparable numbers would be for people in Guelph General Hospital down the road, but their use would be staggering compared to ours. Also, the risk of resistance with each use is presumably much higher for each human patient since they are in an environment where vancomycin resistant bugs are present (and therefore can be selected for with treatment). Vancomycin resistance is exceedingly rare in our hospital population, further decreasing the risk.
Is there some risk? Certainly. Use inevitably carries some risk.
Does our 2 / 200 000 use constitute a reasonable human health risk? I can't see how it does.
So, is antibiotic use in animals something we can just ignore? Absolutely not. It's a big problem, just like antibiotic use in people. However, just as all animal species issues aren't the same, all types of antibiotic use aren't the same.
Are there other things we can focus on to reduce resistance? Absolutely.
- A 1% improvement (i.e. decrease) in use of fluoroquinolones in animals would probably have a dramatically greater effect on resistance in human and animal pathogens than a complete ban on vancomycin. Fluoroquuinolones are a commonly used drug class in animals that is also important in people, and one in which resistance is certainly an issue.
- A 1% improvement (i.e. decrease) in use of of fluoroquinolones in humans would probably have an even greater effect.
- Better infection control, preventive medicine and other practices could potentially have an even greater impact by reducing infections and therefore the need for any drug therapy, and delaying the treat-resistance-more treatment-more resistance cascade.
Some people would say that any drug that's of any relevance in humans should not be used in animals. Some veterinarians would say no one should control their prescribing practices. Like most things, I think there's a happy (and more effective and practical) middle ground. It's not the status quo, though. We need to have discussions about how to control antimicrobial use in all species, including humans, and not just pointing fingers at the other side. We also need to discuss how to improve infection control to reduce the need for antimicrobials, and how to improve the way we use antimicrobials when they are required. In order to have good discussions, we also need proper data (something that's still lacking).
Different opinion? Feel free to comment (or show up in Copenhagen next week).
In my line of work, I deal with feces from a lot of different species. Never once, however, have I thought to model defecation pressure and distances.
Maybe I’m just strange.
A few years ago, German researchers felt the need to model the defecation habits of penguins. The title of the paper, published in Polar Biology, was “Pressures produced when penguins pooh - calculations on avian defaecation" (Meyer-Rochow et al 2003).
The authors considered the fact that penguins don’t leave their nests to defecate (probably preferring not to freeze every time they need to poop). Rather, they observed that penguins move to the edge, “stand up, turn their back nest-outward, bend forward, lift their tail, and shoot. The expelled material hits the ground maximally 40±12 cm away from the bird and then leaves behind a whitish or pinkish streak that can end a few centimetres from the nest’s periphery and may be up to 1 cm wide.”
That observation lead (perhaps fostered by some alcohol?) to questions about the exit velocity of the feces.
Given their protected status, you can’t run around poking and prodding penguins, so much of the research is done from a distance. The researchers in this case used pictures to estimate the "aperture" and determined it to have a "maximal diameter of 8 mm at the moment of "firing"."
Using the size of the "exit" and an estimate of average penguin poop viscosity, along with the angle and distance of firing, they used mathematical models to determine the "penguin-generated pressures" associated with defecation.
I won’t get into all the of the calculations. Suffice it to say, the image at right will probably not been seen in too many other scientific papers.
They concluded that "fully grown chinstrap and Adelie penguins generate pressures between 10 kPa (77 mmHg) and 60 kPa (450 mmHg) during the evacuation of their faeces on land. The process of defaecation commences with the highest pressure initially and then rapidly drops to zero, hence the production of faecal streaks (and not ‘‘blobs’’). In water, different parameters would apply, although (as in air) the smaller the cloacal diameter, the higher the pressure."
And to wrap it up…
"All birds, penguins included, spend a considerable time preening and cleaning their feathers. It seems therefore that these birds propel their faeces as far away as possible (with a minimum amount of effort) lest they soil their plumage. Birds could theoretically increase their projectile defaecation range by squirting 45° up-wards. However, their upright posture and position of the vent prohibit this in penguins, but in eagles and other birds-of-prey the squirt is, indeed, directed upward by ca. 15–30° (unpublished observation). The forces involved apparently do not lead to an energetically wasteful turbulent flow. It is interesting to note that the streaks of the faecal material radiate from the edge of the nest into all directions (no preference is noticeable). Whether the bird deliberately chooses the direction into which it decides to expel its faeces or whether this depends on the direction from which the wind blows at the time of evacuation are questions that need to be addressed on another expedition to Antarctica."
Photo: Adelie penguins, Antarctica (credit: JHB Anderson)
A few days ago, I received a question about whether bathing a young child and a dog together in the bathtub is a bad idea.
It’s not really something I had considered before because, despite having 3 kids and 2 dogs, it’s never crossed my mind to toss them in the tub together. Anyway, I guess it’s a reasonable question since apparently some people are doing it. So, here’s my thought proces:
Is there a risk?
Sure. We know there’s always some risk of disease transmission when interacting with an animal. Generally, the risk is quite low and therefore the pet contact is still worth it because of all the other positive aspects, but in some situations, the risk goes up. We know that risks are higher with young children, and that bacteria present in the intestinal tract of dogs are probably the most common issue.
Is the risk a realistic concern?
Yes I think so. When a dog is bathed, presumably there’s going to be some contamination of the water with fecal-origin bacteria from the animal’s rear end and/or haircoat. There’s also a pretty good chance that contaminated water would be ingested by the child, considering how often toddlers put bath toys in their mouths or drink the water.
What’s the benefit?
Of bathing a child and dog together? None that I can think of.
Is it an avoidable risk?
This one’s easy. Yes. Don’t bathe pets and children together. That’s the best way to avoid the risk and seems like a common sense recommendation to me.
A local county newspaper had a front page headline about a zoning amendment that was approved to allow for a feeder rodent facility that will produce about 10 000 rodents a week (I know, apparently there aren't a lot of big things happen around here). Co-incidentally, a couple days later, I received an alert and fact sheet from the Ontario Ministry of Health and Longterm Care and the Office of the Chief Veterinarian of Ontario about Salmonella and feeder rodents because of an increase in human Salmonella Typhimurium infections in people in Ontario and a link to feeder rodents in some cases.
It’s not really a surprise. Large and sustained outbreaks of salmonellosis associated with feeder rodents have been reported for a while. These rodents are often produced at large facilities with hundreds of thousands of rodents, and if Salmonella gets in the facility, thousands (or millions) of biohazardous small-and-fuzzy snake snacks can get shipped around the world.
The fact sheet is attached here, and it contains good information about the standard reptile and rodent handling practices that I always keep coming back too: wash your hands, keep high risk people away, prevent cross-contamination of snake food with people food (e.g. don’t thaw frozen rodents in an open container in the fridge (yuck… but it happens) or cross contaminate kitchen surfaces) and other basic hygiene practices.
Infection control isn’t complicated, it’s often just ignored.
Cat hoarding has been in the news in the Toronto area a few times lately. Multiple incidents of serious cat hoarding have been identified in the past month, involving large numbers of cats being kept in horrible conditions. It’s not hard to see how cat hoarding can create infectious disease challenges. I can’t see how anyone could keep a large number of cats in a house without problems, even if they worked very hard to keep things under control. Add together the issues of keeping massive numbers of cats in a confined space, no veterinary care, poor nutrition and limited hygiene, and you can see how the cats and the building would quickly become biohazardous. Add in mental health issues and hoarding of other objects (both or which are also common in such situations), and you get a house that’s a cesspool, fire hazard and no place for humane housing of any animal or person.
When cat hoarders are investigated, there are often dead cats found in or around the house. There are also often cats that end up being euthanized promptly because of severe disease. A wide range of diseases can be encountered in such cat-dense and hygiene-deficient situations. Mostly, the typical feline diseases are found, including vaccine-preventable illness and a whole range of opportunistic bacterial infections. However, these cats can be very compromised and therefore prone to rare infections as well. A recent report describes one of these unusual infections. The report (Brooks et al, Veterinary Microbiology 2013) describes extraintestinal pathogenic E. coli (ExPEC) infection in one of about 60 cats from a hoarding situation. The cat died and the bacterium was found to be the cause of pneumonia and kidney abscesses.
Is this a major concern for feline health? Not really. This is presumably a rare infection that occurred in a highly compromised cat, and not the crux of a new problem. However, it shows the wide range of diseases that can occur and, probably most importantly, that some of these infections are zoonotic: ExPEC is actually a significant human health concern, since it can cause similarly severe disease in people. It’s been previously shown that people and pets can share the same strains of ExPEC within households, and pets have been suggested as being a potential source of some human E. coli urinary tract infections (another form of ExPEC infection).
In the hoarding situation with the ExPEC-infected cat, there was concern not only for people who had contact with the cat, but a wide range of emergency responders, public health personnel and probably many other people who entered the house (since one cat with disease probably means many cats shedding the bacterium in their feces, which means lots of contamination in the hoarder’s house).
Dealing with hoarding is a complex problem because of typically weak laws, reluctance to enforce laws, mental health issues and a range of other challenges. Early identification of hoarders with proactive intervention - before the place becomes a disaster - is important, but easier said than done.
Australian Elmer Fudds beware… there are concerns that feral pig hunting is a risk factor for brucellosis in New South Wales. Brucellosis is a rare disease, but a report like this raises concern because it can be nasty, and it can also be hard to diagnose (or it's not considered right away).
We don’t have feral pigs in Ontario, but they are common in many areas, including parts of the US. In Australia, it’s been estimated that there are over 13 million feral pigs ranging over approximately 38% of the country. Any contact with animals carries some degree of infectious disease risk, and hunting is no exception. In fact, some risks are higher because of the close contact with the target animal and its bodily fluids after its been killed.
The brucellosis story is a bit old, and relates to a NSW Public Health Bulletin from a few years ago (Irwin et al. 2009) of four cases of this bacterial infection detected between December 2006 and September 2009. The infected individuals, all men, reported having hunted feral pigs before the onset of disease, and they all butchered the pigs without any protective gear (e.g. gloves). They didn’t have any of the common risk factors for brucellosis, such as overseas travel or consumption of unpasteurized milk from areas where the disease is endemic in dairy animals, so it was likely that the pigs were the source. Public health authorities trapped and tested 200 pigs, all of which were negative. However, 200 negative pigs from a multimillion population certainly doesn’t mean the pigs are Brucella- free, as was shown when Brucella suis was found in testicular samples of pigs from southern Queensland in a separate investigation.
All of the men reported typical symptoms including fever, sweating, abdominal pain, vomiting, back pain and "loin" pain (a term that’s not typically used since it’s not very descriptive - brucellosis often causes testicular swelling so maybe that’s what it means. Either way, it doesn’t sound pleasant).
Brucellosis is a disease that warrants some attention because it can be nasty and it can take a while to diagnose. Fortunately, it’s rare in most developed countries, although the same link between brucellosis cases and hunting feral swine has been seen in the US as well. Hunters need to be aware of a wide range of potential zoonotic diseases. Additionally, brucellosis is a concern for pet owners since sporadic human cases associated with transmission from pets have been reported, and this may be an emerging or previously overlooked problem.
It doesn’t. (Just like monkeypox doesn’t come from monkeys.)
Cowpox is a viral infection and the natural reservoirs are actually rodents. Humans, cats and cows are amongst the more common "accidental hosts" - species that get infected sporadically but are not reservoirs. Contact with an infected rodent can result in transmission of cowpox to people. The virus can also come from an animal that gets cowpox from a rodent and then passes it on to a person, as a Dutch teenager found out...
A 17-year-old girl found a kitten in the ditch and picked it up. It was sick and ultimately died (probably not from cowpox). She later developed a skin lesion on her wrist, which progressed to red lumps over her arm. Not surprisingly, cowpox didn’t jump to mind when she saw her doctor, so it took a while before a diagnosis was made, but they figured it out eventually. Since cowpox infection is usually self-limiting in individuals with a normal immune system, the girl eventually got better without any specific treatment. It took a couple months, though, and left a scar.
Presumably the girl got cowpox from the kitten, which probably got cowpox from contact with an infected rodent. This is an unusual series of events, certainly, but far from unprecedented. Cats are one of the main non-reservoir species that are implicated in cowpox transmission to people, presumably because they get infected while hunting wildlife (e.g. rodents). Cowpox is a pretty rare infection in people and usually not very severe, so it’s nothing to be paranoid about, but it’s another reason to use good hygiene practices and keep cats from going outside and hunting.
FYI Cowpox got its name because infected cows often develop lesions on their udders, and it was a common infection of dairymaids in times when cows were milked by hand. This virus also features prominently in the development of the world's first vaccine in the late 1700s, as the cowpox virus itself was used as a vaccine against the deadly smallpox virus.
It's that time of year again… time for the US annual rabies surveillance report in the Journal of the American Veterinary Medical Association (Dyer et al 2013).
- There were 6162 cases of rabies diagnosed in animals in 2012. (This is a 2.1% increase from 2011, but I don't put much stock into changes like that when the tested cases only represent a minority of the animals with rabies.)
- The vast majority (92%) of rabid animals were wildlife, with raccoons "winning" at 32% of all animals diagnosed. They were followed by bats (27%), skunks (25%), foxes (5.5%), cats (4.2%), cattle (1.9%) and dogs (1.4%)
- A variety of other animal species were also diagnosed as rabid, including bison, llamas, bobcats, deer, a cougar, a mink, groundhogs, opossums and beavers. That just shows how any mammal is at risk. I was surprised at the number of rabid groundhogs (42 in 10 states).
- While dogs accounted for only 1.4% of cases (84 animals), a disproportionate number were found in Puerto Rico (18), with relatively large numbers also in Texas (16), North Carolina (9), Georgia (7) and Oklahoma (7). Presumably this relates to a combination of lower vaccination rates and a higher level of endemic rabies in the wildlife population in these areas. It appears that none of the rabid dogs were properly vaccinated against rabies, although vaccination history was not known for many.
- Rabid cats were mainly found in areas where raccoon rabies was common. Pennsylvania had the most rabid cats (15.6%). Other commonly affected areas were Virginia, North Carolina, New Jersey and Georgia.
- The distribution of rabies virus types was pretty much as expected. Raccoon rabies virus predominated on the east coast. Skunk rabies covered the central US, overlapping with fox rabies in the southern regions. Fox rabies was also dominant in the Nevada and Arizona area, while skunk rabies predominated in central to northern California. Fox rabies dominated in Alaska and the mongoose rabies virus strain was found in (not surprisingly) Puerto Rico.
Some Canadian data were also reported:
- There were 142 confirmed rabies cases in animals, 84% of which were wildlife.
- There were 18 rabid cats and dogs, 4 livestock and one person. The person was infected with rabies while abroad, in Haiti.
- No rabid raccoons were found - something that has been the case since 2008.
And in Mexico…
- There were 12 cases of rabies in dogs, and those involved the canine rabies virus variant which is not present in Canada or the US.
Take home messages:
- Rabies... still here (and not going away any time soon).
- Vaccinate your animals.
- Stay away from wildlife.
Image: Distribution of major rabies virus variants among mesocarnivore reservoirs in the United States and Puerto Rico, 2008 to 2012. (click for source: Dyer et al. J Am Vet Med Assoc 2013)
I had an interesting question today about the cat-associated parasite Toxoplasma gondii. It can cause serious infection in people that ingest it, particularly in immunocompromised individuals and pregnant women, but disease is rare. Since cats can pass one form of the parasite in their feces, the question was whether using flushable kitty litter is a bad idea, since it would result in Toxoplasma being discharged into the sewage system.
On one hand…
- Water is a source of Toxoplasma exposure.
- Food contaminated by Toxoplasma-contaminated water is a also a source of exposure.
- Municipal water was determined to be a possible source of exposure in at least one Toxoplasma outbreak (Bowie et al. 1997).
- The form of Toxoplasma in cat feces is hard to kill, so it could survive routine water treatment measures.
On the other hand….
- Cats rarely shed Toxoplasma. They typically do so only for a short period of time after their first exposure (usually when they're quite young), so the vast, vast majority of household cats are not shedding the parasite.
- There’s a massive dilutional effect when something goes down the drain. To constitute a risk, the parasite would have to come out of the cat, survive waste water treatment and be discharged into the environment, then either make it into a drinking water source (with more dilution and more treatment) or reach someone’s mouth through other routes such as on food or from contaminating the general environment (e.g. soil, recreational water bodies). Even if some Toxoplasma were present in cat feces in flushable litter, the odds that someone susceptible would encounter enough Toxoplasma from this source to cause disease is exceedingly remote.
I don’t think using flushable litter constitutes a public health risk.
I’m not a big fan of the title of a paper in the latest edition of the Canadian Journal of Infectious Diseases and Medical Microbiology…”Pets are ‘risky business’ for patients undergoing continuous ambulatory peritoneal dialysis” (Yahya et al 2013), even though it’s an interesting paper that actually takes a reasonable approach to zoonotic disease risk from pets. I get a little concerned with titles like this that might reinforce certain excessive fears that some physicians have (usually from lack of understanding) regarding pets and zoonoses.
The paper is a case report of a 49-year-old man with kidney failure who was undergoing peritoneal dialysis at home. Peritoneal dialysis involves infusing fluid into the abdomen and then draining it, to help flush toxins out of the body. This requires an indwelling abdominal catheter that is placed through a small hole in the body wall. Any time a tube gets stuck into the body, there’s some risk of it acting as a pathway for infectious organisms to also get in. Good management practices are essential to reduce the risk of infection in these cases, but good practices are not always used.
In this case, the person had a dog and a cat in the household. Over the course of about eight months, the man developed four different infections. One was caused by Pasteurella multocida, a bacterium that is very common in the mouths of cats. Another was caused by Enterobacter cloacae, a bacterium that is found in the intestinal tract of a variety of species, so it may or may not have been a pet-associated infection. The last two were both Capnocytophaga infections. This bacterium is ubiquitous in the mouths of dogs, and to a lesser extent cats.
How did these bacteria cause the infections?
The patient was adamant that the pets didn’t have contact with the dialysis tubing and that they were not present when he performed dialysis. However, he admitted that his hand hygiene practices weren’t always great, so presumably he contaminated his dialysis tubing with bacteria on his hands that came from the pets (either directly or from contaminated household surfaces).
Did the infections really come from the pets?
There was no testing of the pets to confirm it, but Pasteurella multocida and Capnocytophaga canimorsus are clearly pet-associated bugs, so I don’t have much doubt that pets were the source.
So, are pets risky in situations like this?
Yes, but so are lots of things. The key is whether we can effectively manage the risk.
Does the presence of pets in the house increase the risk of a person undergoing peritoneal dialysis getting an infection?
We don’t know. I’m not aware of anyone looking at this specifically. However, since people are still able to publish single case reports of pet-associated infections, it’s fair to assume that pet-associated infections in these patients are relatively rare (and therefore make interesting case reports).
Should people undergoing peritoneal dialysis at home get rid of their pets?
I can’t support that (unless no onein the household really has any affection for the pet, in which case why not eliminate the risk by finding it a new home). Infections seem to be rare and basic practices (especially good hand hygiene) can presumably reduce the risk even further.
The authors conclude with some nice, balanced recommendations. “Our data support the recommendations by Rondon-Berrios and Trevejo-Nunez (2), Weiss and Panesar (12), Pers et al (10), Schiller et al (6) and Sol et al (3) that PD patients who own pets be made aware of the need for proper hand hygiene before PD bag changes and the risk of zoonotic infection if these precautions are not taken. The need to ensure pet oral secretions do not come into contact with PD equipment and the threat of these infections should be clearly communicated to PD patients. We recommend strict hygiene guidelines be emphasized and periodically reviewed with PD patients who have pets.”
I’ve been holding off on writing about this one for a while since it’s been unclear what’s happening, but a strange disease situation appears to be ongoing in Ohio dogs.
There’s old adage in medicine: an uncommon presentation of a common disease is much more likely than presentation of an uncommon (or new) disease.
- aka common things happen commonly.
While this is certainly true, emerging diseases continue to just that. This one seems like it really is something new, and something to which we need to pay attention.
Reports have been coming in for a few weeks about severe and sometimes fatal gastrointestinal disease (e.g. vomiting and diarrhea), and deaths were occurring, particularly in dogs that were not treated early in disease. The usual suspects were ruled out, and eventually there was suspicion that the cause might be a circovirus.
Until recently, circovirus was only known to be a problem in pigs (where it’s a very big problem). Then, in 2012, a canine circovirus was reported in dogs in California with severe gastrointestinal disease, as well as some healthy dogs. Circovirus wasn’t proven to be the cause of illness, but it was quite suspicious that this could be a canine pathogen.
Because of the similarity in disease signs in the Ohio dogs and the ones from California, circovirus testing was done and apparently the virus has been detected.
This doesn’t mean that the virus is what's making the dogs sick. Since the virus can also be found in some healthy dogs, its role in disease is unclear. Certainly, it’s not a virus that causes disease in every dog that is exposed. So, at this point, we’re still a bit (or more than a bit) in the dark. Yet, there’s enough evidence to indicate that we need to investigate this virus, see where it is, where it’s going and figure out how to control it.
How can you protect your dog?
It’s not really clear, but basic infection control practices are probably the key at this point in time. The virus is spread through contact with feces of infected dogs.
- If your dog is sick, keep it away from other dogs and places where other dogs go (e.g. the dog park).
- If your dog is sick, take it to the vet. (Make sure they know why you’re coming in so that they can take appropriate precautions to isolate your dog, rather than having you hang out in the waiting room with other dogs while waiting to see the vet.)
- Keep your dog away from sick dogs.
- Pick up your dog’s feces. Always. Even if it’s healthy.
Nothing fancy or really anything beyond what people should normally be doing, but this situation is a good reminder of why we should use basic infection control practices routinely.
I haven’t heard of any concerns about this disease in Canada, but rapid investigation and communication are important, so any concerns about possible cases will hopefully be sent my way.
I've had the occasional debate with people about the public health risks of rabies in horses.
On one hand...
- Rabies is rare in horses.
- I've never seen a report of rabies transmission from a horse to a person.
On the other hand...
- Rabid horses have attacked (and killed people).
- It doesn't matter whether the horse gave you rabies or stomped on you. Dead is dead.
A Carroll County, Georgia horse owner learned the risk of rabid horses the hard way, but fortunately doesn't appear to have been seriously injured. .
One day, the owner was bitten while getting the horse out of the pasture.
The next day, the horse attacked him....and according to the owner, tried to kill him. That night, the horse was in the pasture chewing on its leg and periodically nosing the electric fence.
While rabies is rare, these are some of the hallmarks...aggression and strange behavior. The horse was euthanized and tested positive for rabies. Presumably, the owner is undergoing rabies post-exposure prophylaxis.
Rabies is nothing to play around with. It's very rare in horses but endemic in wildlife so there's always a chance for exposure in most regions. Rabies vaccination is a cheap and highly effective way to reduce the risk.
This is an increasingly common question, as methicillin-resistant Staphylococcus pseudintermedius (MRSP - essentially the canine version of the high-profile human "superbug" MRSA) has expanded greatly in the canine population. As more dogs get MRSP infections and even more become inapparent carriers of this bug, more dogs that are carriers will need surgery (both elective and non-elective). Since MRSP is now a leading cause of surgical site infections in dogs, there's concern about what to do with these carriers, particularly when it comes to elective surgeries like spays and neuters.
My answer to the question is... maybe.
If the dog has an active MRSP infection (e.g. skin infection), I'd say "hold off for a while" if possible. I don't like elective surgeries being done on animals with active infections (this applies to almost any kind of infection, not just MRSP). If an animal has an active MRSP infection, it might increase the risk of the surgical site becoming infected because of the greater overall burden of MRSP on the skin and elsewhere.
If the dog doesn't have an active infection (e.g. is a healthy carrier after having gotten over a previous MRSP infection), I'd say "go ahead."
- Spay-associated infections are quite rare.
- We don't use antibiotics prophylactically (i.e preventatively) for spays (or at least, they shouldn't be used for this kind of low-risk procedure - unfortunately some people still use them inappropriately).
- MRSP is no more likely to cause a spay infection than methicillin-susceptible S. pseudintermedius. It's just harder to kill when an infection occurs.
- Methicillin-susceptible S. pseudintermedius can be found on almost all dogs.
So, if infections are rare, despite the fact that S. pseudintermedius is present on pretty much all dogs and that we don't use drugs to kill S. pseudintermedius during (or after) spays, there should be no added risk of infection by the antibiotic-resistant version of this bug.
Every dog is carrying lots of different bacteria that can cause an infection at any time. That's why we use a variety of surgical antisepsis practices (e.g. clipping, scrubbing, sterile instruments, proper operating room) to help prevent a critical number of bacteria from getting into the sterile surgical site where they can start to cause problems.
This strategy doesn't necessarily apply to surgeries where antibiotics are used prophylactically and where staph are the main causes of infection, especially in situations like orthopedic procedures where MRSP infections are common and can be very hard to treat. What to do in those cases with an MRSP-positive animal is a tougher question, and we're working on an answer to it at the moment.
'Tis the season...
Eastern equine encephalitis (EEE) is a very serious disease that's fortunately rare in Ontario, but when it happens, it's bad news. It's a viral disease transmitted by mosquitoes (similar to West Nile virus), and we often see a couple of horses affected every year, usually starting around now (late August) and extending into the fall.
The Ontario Ministry of Agriculture and Food has issued an alert after diagnosis of EEE in a 11 year old horse in Simcoe county (other cases have been reported in this area in previous years as well). They say the horse is recovering, which is a bit of a surprise because mortality rates with EEE are very high, and most affected horses die quickly.
What does this mean for horses in Ontario?
Not a lot, since we know EEE crops up every fall, and there's always some degree of risk, but it's a good reminder that this disease is a concern particularly at this time of year. The risk here isn't anywhere near the level it is in some US states, and with only a handful of cases every year (4 last year), the disease's overall impact in Ontario is low. However, infection is typically fatal and therefore not something to be ignored. A vaccine against EEE is available for horses, and it's been debated whether it should be a core vaccine for horses in Ontario. On one hand, the disease is typically deadly. On the other hand, it affects between 0 and a few horses every year, which is not many in the grand scheme of things (but if it's your horse, you don't really care about the "grand scheme" at that point).
What does it mean for people in Ontario?
Despite the name, EEE can affect people too. It's rare, but like in horses, it's devastating. There has never been a confirmed human case in the province, but they do happen Earlier this month an elderly woman in Norfolk County, Massachusetts was diagnosed with and died from EEE (like Ontario, Massachusetts typically sees a few cases in horses every year as well). Humans and horses get infected the same way (a bite from an infected mosquito), so cases in horses mean there is EEE in mosquitoes in the area. There's no vaccine for people, so we're left with mosquito avoidance.
This is one of those "pay attention but don't panic" diseases.
This one's not very surprising since it's the typical fake service dog scam, but it made me laugh. While on a completely unrelated website, I saw an ad on the page that said something like "Trouble walking on the beach with your service dog? Check us out." Unfortunately, I did.
The website sells the typical "service dog" paraphernalia - at a pretty high price. To start off, the site takes you through a series of questions.
1) Do you currently have a physical impairment?
2) Do you currently have a mental impairment?
- No (although my kids might have a different opinion on that one).
3) Do you have a record of a physical impairment or mental illness in the past that substantially limits one or more of your major life activities?
4) Are you regarded as having a physical impairment of mental impairment in the past that substantially limits one or more of your major life activities?
- "No, you probably do not quality"
So far, so good. That's the right answer.
But... (I love the rest...)
"However, this is a self-assessment and reasonable minds can come to different conclusions. You may wish to take our Disability Self-Assessment Test again. Alternatively, you may wish to visit our Products page and see whether it nonetheless may be helpful to you."
In other words, try again and make up a fake answer, or just go ahead and give us money for something like the $200 "Deluxe [fake] Service Animal ID Kit".
Alberta Health Services Medical Officer Dr. David Strong has urged the public to take precautions after a Calgary-area puppy was diagnosed with rabies. The five-month-old puppy came from Nunavut and had not been vaccinated against rabies. All those with whom the puppy had contact have been assessed and it doesn't sound like anyone required post-exposure treatment.
Since rabies is endemic in wildlife in the region, finding rabies in a puppy (especially when the puppy was presumably exposed elsewhere) doesn't mean that there's any greater risk to the public than there was before the case was identified. The imminent concern is the presumably limited number of people and animals with which the puppy had contact while it may have been infectious, but it's always useful to remind people about rabies and precautions they should take to prevent rabies exposure. In the infectious disease world, we often have to take advantage of high profile incidents to drive home some basic principles that we'd like people to pay attention to all the time.
Key rabies prevention points include:
- Avoid contact with wildlife.
- Keep your pets away from wildlife.
- Ensure your pets are up-to-date with their rabies vaccination.
- Make sure any bites from wild or domestic mammals are reported to public health so that it can be determined whether rabies post-exposure treatment is required.
Pretty basic. Common sense goes a long way with infectious disease prevention.
We've just posted a new info sheet about Capnocytophaga. One member of this bacterial group in particular, Capnocytophaga canimorsus, makes the news periodically because it can cause devastating infection in some individuals, like the Ottawa woman who lost three limbs after one of her own dogs accidentally bit her. This kind of severe infection, which is also sometimes called dog bite septicemia, is actually quite rare, but people with certain risk factors such as diabetes, alcoholism, and particularly lack of a functional spleen are at much higher risk. The bacterium very commonly lives in the mouths of dogs and cats, and is considered a part of the normal oral microflora in these animals. People are therefore commonly exposed to Capnocytophaga, yet infection is rare, but because it can be so catastrophic it's important to know the facts, especially if you or someone you know may be at higher risk.
You can read more about Capnocytophaga on the new info sheet, which you can find along with all our other info sheets on the Worms & Germs Resources - Pets page. You can also read about Capnocytophaga in the posts in our archives.
One of our most frequent pieces of advice on W&GB when it comes to kids is to always make sure they are supervised when they are around pets. This is important for at least two major reasons, one being avoiding potential high-risk contacts when it comes to infectious disease transmission (e.g. face-to-mouth, hand-to-bum), and the other being reducing the risk of injury (and subsequent infection) from bites and scratches. Children often don't know or aren't aware of the signs that a pet is stressed or uncomfortable, essentially forcing the pet to take progressively more drastic measures to get its message across, potentially ending in a snap or a bite. The problem is a lot of the time the supervising adult also doesn't know these signs, and thus many a bite or scratch may happen even when a parent is watching carefully from only a few feet away.
Yesterday I came across an excellent post on this very topic on another blog written by Robin Bennett, a certified professional dog trainer (CPDT-KA) in Virginia. Her post was very aptly entitled "Why Supervising Dogs and Kids Doesn't Work." Click on the title to see the entire post, but here are a few of the great points she makes:
- Watch for inappropriate child behaviour. In Robin's words, "Don’t marvel that your dog has the patience of Job if he is willing to tolerate [being poked, prodded, yanked, pulled, pushed, etc]. And please don’t videotape it for YouTube! Be thankful your dog has good bite inhibition and intervene before it’s too late."
- Intervene early. If the dog loses that loose, wiggly body posture and starts to stiffen up, don't wait until the animal has to escalate its message to growling or snapping to step in.
- Support the dog's good choices. If the dog chooses to move away from a child because it is uncomfortable, support that choice and don't let the child continue to follow the animal. If the pet can't get away, it may scratch or bite to try to make the child go away instead. Don't force the dog to make that choice. (This applies equally to cats or any other pet!)
It's very important for pet owners to educate themselves about basic pet behaviour, whether they have dogs, cats or other animals, and to teach that same information to their children. Another great program that teaches kids how to behave around dogs, and unfamiliar dogs in particular, is the "Be a tree" program, details of which can be found on the Doggone Safe dog bite prevention website.
As fall fair season starts, concerns about petting zoo outbreaks rise. While deficiencies are still common, petting zoos seem to be getting better with their infection control measures. People too are starting to get better at doing what their asked to do - namely washing their hands after visiting these exhibits. However, as we’ve shown through a few different studies, compliance with handwashing after being in a petting zoo is far from perfect. People also often fail to recognize the need to wash hands after being in a petting zoo even if they don’t touch an animal. It’s not uncommon to see a family come out of a petting zoo and the parents direct the kids to wash their hands, while the parents themselves just stand back and watch. Yes, if you touch the animals you’re more likely to have contaminated your hands. However, it’s been shown in a few studies and outbreaks that just being in the petting zoo area is a potential risk, and that disease-causing bacteria can be spread to a variety of hand contact surfaces. In short, the bugs aren't just on the animals.
A recent study in Zoonoses and Public Health (Pabilonia et al 2013) provides more evidence. Researchers visited poultry exhibits at agricultural fairs in Colorado and collected samples from areas like cages, feed, floors and tables, i.e. areas where there was direct contact with birds and areas that visitors might touch. They were able to grow Salmonella from 10 of 11 fairs that they visited. Overall, greater than 50% of surfaces that they tested were contaminated with Salmonella. It wasn’t surprising that finding Salmonella was fairly easy, but that number is pretty high.
Does this mean that poultry exhibits should be banned? No. But it indicates that there is some risk, presumably with any poultry exhibit anywhere.
How can you reduce the risk?
- Don’t eat or drink in poultry exhibit areas.
- Wash your hands after leaving (even if you don’t touch anything).
- Don’t take in items that might go into a child's (or anyone's) mouth (e.g. sippy cups, pacifiers).
Particular care must be taken with kids less than five years of age, elderly individuals and people with compromised immune systems. That could mean staying out of the exhibit altogether, or just being extra diligent about the basic measures listed above - it really depends on the scenario, the ability to follow these practices, and the level of risk aversion.
What should fairs do?
- Take measures to reduce environmental contamination, such as housing birds in such a way that bedding doesn’t get spread everywhere.
- Regularly clean environmental hand contact surfaces (e.g. railings, arms on seating/benches).
- Provide signs to make sure that people know what to do (e.g. wash their hands, don't eat and drink).
- Supervise exhibits.
- Provide good hand hygiene facilities.
These measures aren’t too hard to implement and they’re much better than dealing with an outbreak.
So, Amy and I get home from soccer practice, and she gets in the house and yells “The dog pooped on the floor."
My thought: “That’s annoying.”
Amy: “..and it’s EVERYWHERE!”
My thought: “Great. One of the dogs has diarrhea.”
My next thought: “Oh crap… the Roomba.”
In case there was any doubt, it was made very clear that Roomba, the robotic vacuum, very effectively covers the entire floor surface. At least it was set up only to clean part of the house and not any carpeted areas.
My next thought: “What do I do now?”
I’m far from a germaphobe, but I really don’t want a lot of dog poop residue all over the floor. So, I picked up the chunks and did a couple rounds of mopping with a general household cleaner. Cleaning is the key aspect of disinfection. Physically removing debris gets rid of the vast majority of bugs that are present, and that greatly reduces any risk of pathogen transmission. Fortunately we don’t have any infants crawling around the floor or any high-risk individuals in the household, so that also reduces the concerns. If we did have a baby crawling around, I’d probably be more diligent and thoroughly disinfect any potentially contaminated areas with a good environmental disinfectant. As it is, I’ll probably stick with a few rounds of thorough cleaning with a good general cleaner/sanitizer.
How to disinfect a Roomba though... that's a different story.
The latest Worms & Germs infosheets are all about some common and not-so-common members of a particular group of parasites: tapeworms. There are a number of different groups and species of tapeworms that can infect pets, people, and other domestic animals, and sorting through which is which can be tricky, so we created a Tapeworms infosheet to help sort out the details.
There is one group of tapeworms in pets that is a particular concern from a zoonotic disease perspective. These parasites belong to the genus Echinococcus. Normally these tapeworms circulate in the wildlife population, mostly in wild canids such as foxes and various prey species, but they can also affect domestic dogs (and sometimes cats) that scavenge or hunt the same prey. In most cases the pet does not become sick, but people who are exposed to the tapeworm eggs in the pet’s feces can develop slow-growing cysts known as hydatid cysts or alveolar hydatid cysts. Over time these cysts can become very large and difficult to treat. There is also now evidence that one Echinococcus species (E. multilocularis) may be spreading - in 2012 a dog in Ontario was found to be infected with the cystic form of E. multilocularis (which is unusual in itself), but the animal had no history of travel outside of the province, therefore it was most likely infected via local wildlife.
Because echinococcosis can be such a severe disease in people, we created an additional infosheet focused on just Echinococcus. Both infosheets can be found on the Worms & Germs Resources - Pets page.
Image: Dozens of Echinococcus granulosus tapeworms from the small intestine of a dog. Although these adult tapeworms are tiny compared to some other species, this species can cause significant problems in people through the formation of hydatid cysts. (Photo credit: Ontario Veterinary College)
The word "ironic” gets used a lot, often incorrectly.
Alanis Morrissette’s hit song “Ironic” is a great example of this since she (ironically?) describes situations that aren’t really ironic, they just suck (i.e. winning the lottery and dying the next day isn’t ironic, it’s just bad luck).
Anyway, irony doesn’t have much to do with the topic at hand, apart from picking on the title of a news report “In ironic twist, dogs of local rabies survivor Jeanna Giese are exposed to bat that tested positive for the disease.” It’s not really ironic, but it’s an interesting story.
If anyone knows about the implications of rabies, it’s Jeanna Giese. She will forever be remembered in the medical world as the first person to be successfully treated after developing rabies. When she was 15, she picked up a (rabid) bat and was bitten. Not knowing any better, the family cleaned the bite wound but did not take her to a doctor. A little over a month later, she developed neurological disease. At that point in time, rabies was still called "invariably fatal," but she was treated with an experimental protocol that involved, among other things, putting her in a coma and treating her with antiviral drugs. Remarkably, she survived. More remarkably, she didn’t just survive, she was able to go back to school, learn to drive and function normally. (As a result of her miraculous recovery, rabies is now termed "almost invariably fatal.")
Jeanna has become an advocate for both animals and rabies awareness, using her personal experience to get her message across. Well, now she has one more personal experience to add to her repertoire.
Recently, she found a bat in the enclosure that houses two of her dogs. The bat was dead and covered in dog bite marks. Presumably in no small part because of her heightened awareness of rabies, she submitted the bat for rabies testing - and it was positive. So, her dogs were considered exposed. “How many people in the entire world can honestly say that a rabid bat has affected their lives twice in nine years?” she asks. Fortunately, her dogs were vaccinated against rabies and therefore they only have a relatively short observation period at home to go through, as opposed to a strict six month quarantine or euthanasia.
Awareness of rabies is the key, whether you’re trying prevent exposure of yourself, your family or pets. It’s also an area that needs improvement. As Ms. Giese said, "It's not surprising people know little about rabies... I didn't. You can't walk into a counselor's office and just pick up a pamphlet about rabies. I'm teaching kids that it's out there and what to do. Had I known what I know now, I would have made a different decision (about picking up the bat in 2004)."
Ironic? No, but a good story nonetheless.
I've written (whined, lamented, and complained) about this before, but it's rearing its ugly head again: fake service dogs. Essentially, it comes down to self-centred people who think they should be able to do whatever they want, and the inevitable fallout that can occur for people that truly rely on service animals.
It goes like this:
- I want to take my pet anywhere I go.
- I am the Centre of the Universe, so what I want must be provided.
- I pay some other selfish/greedy/unethical person to provide me with a badge, tag or other identifier that says my dog is a service dog.
- I take my pet wherever I go and if anyone questions me, I say "SERVICE DOG" as my get-of-out-jail-free card.
It's been going on for a while.
It's stupid and selfish.
It compromises real service dogs.
How? Service dogs are very well-trained animals that do an important job. They should have widespread access to places where regular pets are banned. However, when any idiot with $50 can get some form of service dog ID, there are going to be problems with some of these animals (e.g. disruption, bites) and the public, business owners and legislators may not realize the difference between a real and a fake service dog. Accordingly, if there is enough disruption (or a high profile event), there's the potential for problems (e.g. banning) for service animals that are truly needed.
A recent New York Post article highlights the issues with fake service dogs and shows an astounding degree of selfish behaviour. I always assumed that people who got fake service dog IDs would be quiet about it, because deep-down they know it's wrong or to avoid facing any negative public opinion.
Not Brett David, who enlightens us with comments such as
"I was sick of tying up my dog outside."
"He's been to most movie theaters in the city, more nightclubs than most of my friends."
"I don't care who you are, a teacup Yorkie will trump a black [American Express] card when you're trying to pick up a girl."
Or Kate Vlasovskaya, who isn't worried about people checking up on her fake service dog ID because "With all of that effort [required to find out anything], they will probably just let you in."
I'll bite my tongue here because anything else I have to say won't be good.
This isn't a zoonotic disease issue, but certainly relates to ongoing discussions about keeping exotic pets.
A python from an exotic animal store in New Brunswick apparently escaped its enclosure and found its way into an apartment above the store. There, the python killed two boys, 5 and 7 years of age, possibly while they were sleeping. The snake is in the possession of the police. This is bound to provide more fuel to the fire of recent discussions pertaining to exotic pet ownership, unfortunately from a much more tragic incident that the comical (and somewhat annoying) ongoing saga of Darwin the monkey.
A colleague recently let me know about an article in the journal Infection Ecology and Epidemiology entitled “Human wound infectious caused by Nesseria animaloris and Neisseria zoodegmatis, former CDC Group EF-4a and EF-4b" (Heydecke et al 2013).
These are new bugs to me…
The article outlines an effort to characterize these bacteria from people with wound infections, most from dog bites. Thirteen bacterial isolates were studied - 11 were determined to be N. animaloris and 2 the related bacterium N. zoodegmatis. The authors concluded that localized infections occur most often, but severe complications can sometimes develop and that recovery is often slow (probably because of suboptimal treatment).
The true role of these bacteria in disease is unclear, since they might be missed by diagnostic labs or misinterpreted as being contaminants (and therefore not tested further or reported). These bugs tend to be resistant to quite a few antibiotics, so identifying them promptly is important to get the right treatment started.
There’s never a dull moment in infectious diseases. We’re constantly hearing about new pathogens. Sometimes, it’s because people just rename bugs about which we already know a lot. Sometimes, it’s because we realize that what we thought was one bacterial species is actually more than one. Sometimes, it’s because we realize that something we’ve dismissed as innocuous is truly a potential problem (so we start paying attention to it). Finally, sometimes truly new microorganisms are identified. With bacteria, the latter usually happens when someone first figures out how to identify an organism that’s been around for a while, but true emergence of new microorganisms can occur.
Anyway, whenever a new bug is found, it’s important to figure out how relevant it is. In this case, in the end, we’re still left with the main point being that the mouths of our domestic pets are cesspools of bacterial badness. Most often, our skin and immune system are able to prevent this from being a problem. However, when bites occur (or in other situations, such as licking wounds or when people have compromised immune systems), the potential for disease increases. Yet, it doesn’t really matter what the bug is - the key prevention points are the same:
- Reduce the risk of bites by good animal training, good animal handling and common sense.
- Promptly and thoroughly wash any bite wounds.
- If you have a compromised immune system, make sure you talk to your physician about any risks of pet contact and what to do in the event of a bite.
This report doesn’t mean that dogs are any higher risk to people than they were before. It just means we have a new name for a risk that’s been present for a while.
ProMed-mail usually posts a monthly recap of rabies cases in the US. The most recent one (like most of them) doesn't have anything too astounding, but it provides some good reminders.
Skunk attacks baby
A five-month-old baby that was outside in a car seat was bitten in the face several times by a skunk. The skunk was killed and tested positive for rabies. This is a high risk situation because it involves a young child and bites to the face. Because of that, the incubation period would potentially be very short so prompt treatment of the baby would be needed (and presumably post-exposure treatment was started right away).
Rabid family dog attacks
Five people were bitten by their pet dog, which was subsequently identified as being rabid. This should be a reminder that rabies exposure is still a concern with pets, that pets should be vaccinated, and that rabies exposure must be considered after any bite.
Fox + bite + electric hedge clippers = ...
A Virginia man was bitten by a fox, and he then killed the fox with hedge clippers (probably not a pretty sight). The bite did not break the skin (although the man did pass out afterward... not sure whether that was from fear of the bite or the aftermath). Anyway, the fox is only being reported as "presumed" rabid. Given the time frame of the encounter and the press release, I would have thought they'd know the rabies status of the animal, if it was tested. In the absence of knowing that the fox was not rabid, they'd have to assume that it was and take appropriate measures. Since the bite didn't break the skin, the bite shouldn't be considered rabies exposure; however, depending on how gory the subsequent fox-clipping was, there might have been exposure to infectious tissues by other means, and post-exposure treatment might have been indicated anyway.
Calf bites, animal health personnel screw up
Rhode Island health officials are trying to track down anyone that might have been exposed to a calf that lived next door to a popular ice cream shop. The calf bit someone and was quarantined. However, it died the next day and in a pretty major screw-up, local animal health officials didn't notify the state until 3 days later. By that time, the calf's body was too decomposed to be tested for rabies. So, it must be assumed that the calf was rabid.
A few take home messages:
- Rabies is still around... think about it.
- Vaccinate your pets.
- Avoid contact with wildlife, and if wildlife is behaving abnormally (e.g. attacking), rabies must considered.
- Make sure all bites from mammals are reported so that the need (if any) for rabies post-exposure treatment can be determined.
- Hedge clippers are not the best euthanasia tools.
Dogs have had some bad PR lately because of some high-profile bites and bite infections in people. So, in the spirit of fairness, I’ll write about a dog as a victim of an attack… from a cat.
Any infection characterized as "necrotizing" is bad. Necrotizing essentially means "dying," and any time you put "dying" in front of the name of a tissue or body part, you can assume the condition is pretty high on the "badness" scale.
In this case, the dog was a three-year-old Whippet that was bitten on the chest by a neighbour’s cat. The dog developed necrotizing cellulitis due to Pasteurella multocida, a bacterium that is commonly found in the mouths of cats, and one that not uncommonly causes cat bite infections in people as well. Within 24 hours of the incident, there was redness, swelling and pain over the area of the bite. The skin lesion progressed rapidly, with death of the skin over the affected area and development of large, deep skin ulcers, similar to what can happen in people with this kind of infection. Fortunately, the dog was successfully treated with intravenous antibiotics and survived.
Why did this dog develop necrotizing disease?
The reason one infection with P. multocida becomes necrotizing while another infection with the same bacterium does not is unknown The same is true for most cases of necrotizing fasciitis (aka flesh eating disease) in people, which is usually caused by Group A Streptococcus or by Staphylococcus aureus. While saying it's "bad luck" is highly unscientific, it’s about all we can say in most cases, since there are often no obvious factors that would predispose the affected individual to severe disease, and the bacterial strains that cause necrotizing infection are usually the same as those that cause mild disease and that are found in healthy individuals. So the "bad luck" explanation is about all we have to offer at this point.
Hastings Racecourse cancelled racing last Saturday because of an outbreak of equine influenza in horses at the track. A recent CBC news report indicates that things started a week and a half earlier, with 150 horses affected when the race cancellations were announced. That's a pretty impressive outbreak.
There's no information about the response, beyond cancelling racing. In some ways, flu is quite easy to control because animals do not become long-term carriers of the virus and infected horses only shed the virus for a short period of time. This makes it easier to contain an outbreak with good infection control precautions, since you only need to implement them over a fairly short period of time. However, the downside is flu is highly infectious and can spread easily and quickly.
I have no first hand knowledge of this outbreak so I can't say anything about what was done or what was missed. However, from a generic standpoint, these are the main problems I see with this kind of outbreak.
There's no response.
- This is too often the problem. This can occur because people don't realize something is happening or the snow-balling of issues that can result. Education is needed to help prevent this.
- Lack of response can also occur because people don't want to tell anyone about an infectious case or don't trust the authorities. This sometimes happens if horsemen are worried about being stigmatized or prevented from racing or showing. Again, education is needed.
- Sometimes, there's mistrust of track or regulatory personnel. If people are worried that the other group doesn't understand or care about their situation, or they don't realize the benefit of communicating, they might try to hide a problem.
There's a late response.
- Another common problem. This usually occurs because people try the "I hope it will go away" approach to infection control first. This rarely works.
- If you get infection control measures in place early, you can contain things much more easily. You're much more likely to contain an outbreak if you only have one horse, or a few horses, affected. It's also easier to contain the disease if you can keep it localized to one barn. Once it spreads to many horses and gets into multiple barns, it can be tough to stop.
- This is why protocols that require reporting of fevers other other basic, early signs of infectious disease (and how to respond to them) should be commonplace.
The response is half-hearted.
- Yet another common problem. Even when people get moving and try to contain an outbreak, it's often not done effectively.
- One reason for this lack of efficacy is people often don't want to do what's recommended. Infection control measures always make life more difficult, and they take time, no doubt. They're important though. Skipping important measures and just trying to do the more convenient ones isn't a good response.
- Another reason for an inffective response is not knowing what to do. Sometimes, I get involved in outbreaks after there's been an initial response and see lots of effort being put into relatively (or completely) useless activities, while the key control measures are ignored. Getting the input of experts as early as possible is critical.
There's inconsistent response.
- This may be similar to 'half-hearted," but by this I mean an outbreak where some people do everything right, and some do little or nothing. Sometimes this is a result of poor communication, and therefore everyone doesn't understand what's happening. Better communication and education can help.
- Other times, this can be caused by simple belligerence: "I don't want to do it so I'm not going to do it!" Sometimes good communication and education can help with this too, by showing people that it's to their own benefit. However, willful neglect is not uncommon and it's hard to handle.
The common themes to preventing these issues are communication and education.
The title gives it away: "Single, uninsured Ottawa mom loses three limbs to rare illness."
My first thought? Another Capnocytophaga canimorsus infection.
That's what is was - another rare but devastating infection cause by this bacterium, which can be found in the mouth of pretty much any dog.
People get exposed to C. canimorsus very commonly, but rarely does disease develop. The news article doesn't provide a lot of information from a medical standpoint. There's no mention of whether the woman in this case had any of the common risk factors for C. canimorsus infection, but it's highly likely. The big risk group is people who don't have a working spleen, as the spleen is an important immune organ that helps fight off infections by certain microorganisms, such as this one.
One notable statement from the article is "Since 1976 only about 200 septic shock cases caused by Capnocytophaga canimorsus have been reported worldwide, Health Canada says." I'm not sure from where that information came, and it might be something that is written on a Health Canada site, but you have to take statements like this with a grain of salt. Specifically, what does "reported" mean? Usually, they're talking about published case reports. However, most infections don't end up in the medical literature. This one presumably won't either, since (devastating though it was for the patient) it's probably a rather typical C. canimorsus infection. Considering how often there are news reports about these infections and the number of calls and emails I get about them, 200 cases over the past 20-30 years is a massive underestimation. That's not to say that C. canimorsus is common, a serious threat to the average person or something that's on the rise. It's just not as rare as some people may think.
Pet owners who don't have a spleen (or whose spleen isn't functional), have a compromised immune system or are alcoholics are the big risk group for serious infections by this bacterium. These individuals should:
- Know about C. canimosus
- Make sure their physician knows they own a pet
- Avoid contact with dog saliva, and
- Make sure that they seek medical care after any bite (not matter how minor it may seem)
Antibiotic use in animals, and the impact on humans is a controversial area. At a conference a few years ago, one of the organizers posed the question, "What percentage of resistance in human pathogens is attributable to antibiotic use in animals?" They had people write their answers on cards, and later in the day they gave a synopsis of the results. Basically, the responses ranged from 0-96% (or something like that). That's not surprising really, as there are a lot of opinions but there's been a lack of good data. Clearly, use of certain antibiotics in animals in certain situations can lead to increased resistance in some human pathogens. Sorting out the "certains" and "somes" is the problem. It's also clear that there's massive overuse (and abuse) of antibiotics in human medicine that leads to lots of resistance.
The biggest problem is our current lack of data. It's not for lack of trying, but it's an extremely complex area. A study in the upcoming issue of Emerging Infectious Diseases (Collignon et al. 2013) starts to put some more solid numbers behind the concerns. The study took data from a variety of sources and attempted to figure out the number of human deaths from resistant E. coli (just one of the bugs we're concerned about, but a big one) that is attributable to antibiotic use in animals. Their conclusion was that infections with E. coli resistant to 3rd generation cephalosporins (an antibiotic group which is used in some animals and is also important in humans), in which resistance was attributable to antibiotic use in poultry, accounted for 21 deaths and 908 hospital bed-days in the Netherlands in 2007. If this is extrapolated to Europe (which can only be done loosely because of differences in antibiotic use and infection trends between the vastly different EU countries), it would mean 1518 deaths and 67 236 hospital admissions. That's a very small percentage of people in Europe overall, and a small percentage of all the people in Europe who die of resistant infections, but it's still a lot and it's therefor still a concern.
What does this mean more broadly for other countries, other bugs, other drugs? It's hard to say. To quote the authors, "To more accurately estimate the associated increased deaths among persons resulting from third-generation cephalosporin use in poultry, detailed data from more countries is essential." I'd substitute "third-generation cephalosporin use" with "antibiotic use," since we also need to know about other drugs. It's always amazed me how hard it is to get even a basic idea of how much antibiotic use occurs in people and animals, with profoundly different estimates by different groups (often driven by different agendas).
Antibiotic use is a necessity in some situations. We have a moral obligation to keep animals healthy, and healthy animals help make healthy food. However, at the same time, we need to think about standard practices and make sure antibiotics are truly being used wisely in both people and animals. Stopping all antibiotic use isn't practical at this time, nor will it eliminate resistance. Knee-jerk reactions like simply banning antibiotics might actually make some things worse, if they result in other practices that also drive resistance (e.g. adding heavy metals like zinc to animal feed to help prevent diarrhea, resulting in the same pressure for antibiotic resistance, or replacing prophylactic treatment using drugs that are of limited concern in people with later use of therapeutic drugs that are important in humans). However, the use of antibiotics as a replacement for good management practices needs to end, and more thought needs to be given to how to use antibiotics wisely, effectively and sparingly - in all cases (animals and people).
I grew up with cats, and they were all indoor/outdoor. I never really thought about it since that was just the way things were done. Yet, as much as he’d like to convince us otherwise, our current cat Finnegan is an indoor cat. There are a lot of reasons for this.
One reason for keeping Finnegan in the house is zoonotic disease prevention. I was recently giving a talk about "Pets and immunocompromised owners" at the American College of Veterinary Internal Medicine forum, and a recurring theme for reducing the risks associated with cats was keeping them inside. (Want to reduce the risk of the cat being exposed to Toxoplasma? Keep it inside. Want to reduce the risk of Salmonella exposure? Keep the cat inside...).
Another important reason is the animal's own health:
- Cat vs car rarely ends well for the cat, and untold thousands of cats meet their ends on roads every year.
- Cat vs cat isn’t as bad but can lead to cat bite abscesses and transmission of a few different pathogens such as feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV).
- When outside, cats can also be exposed to various insect borne pathogens that can be of concern. This kind of risk varies between regions, with areas such as those where there are ticks carrying Cytauxzoon felis (a parasite normally carried by bobcats) perhaps being the biggest concern.
Wildlife is another concern, in two ways. Just like with cars, cat vs larger critter such as a coyote rarely ends well for the cat. From an ecological standpoint though, greater problems occur from cats killing smaller wildlife. It’s been estimated that free-roaming domestic cats kill billions (yes, Billions) of birds and small mammals every year. I won’t go into all the details here, but there’s a good article on the Canadian Cooperative Wildlife Health Centre’s website healthywildlife.ca about the impact such avid feline predators can have on local ecology.
Some people would argue that cats are better off going outside. Looking back at the cats with which I grew up, a lot died early because they were allowed to go outside. It’s hard for me to justify the risk to the cat, wildlife and public health for some anthropomorphic “he’d really enjoy being outside” argument.
Ok, I had to Google that one…”Moggy” not being a typical Canadian term. Apparently, it’s British slang for "cat." Anyway, the "Death by moggy” article in the UK paper The Sun is pretty basic, mentioning the death of a 59-year-old woman who would probably be considered a classic cat hoarder. She was single and slept with 15 cats in her room, and as described by the coroner “hygiene was not what it could have been due to so many animals.”
I actually don’t buy the "number of animals" excuse. Fifteen cats is a lot, but cats are pretty clean and with some effort, it’s not hard to maintain a hygienic environment. It’s a lot of litter to clean, but it can be done. If there were hygiene issues, it probably went beyond a problem of sheer cat numbers.
Regardless, the report is pretty brief but it appears that the woman died of sepsis (overwhelming bloodstream infection) that was somehow linked to the cats. There’s no mention of whether the cats were actually the source, or if it was a matter of "lots of cats…big mess…must be from the cats." However, the woman was apparently often scratched, so it makes sense that the cats could have been the source of infection or a scratch could have allowed a bacterium from the woman’s skin to cause an infection that ultimately killed her.
Something I often discuss when doing infection control talks is needlestick injuries. The contrast between the approach to needlestick injuries (and blood exposure in general) in veterinary and human medicine is pretty astounding. In humans, there are strong educational campaigns, careful reporting, testing and treatment protocols, and increasing use of "safety engineered sharps devices" like retractable or guarded needles. In veterinary medicine, getting stuck with a needle is often considered "part of the job" and "no big deal". A study we did of veterinary technicians a few years ago found that 74% of techs had suffered a needlestick injury in the past year (Weese & Faires, Canadian Veterinary Journal 2009). I’ve had many such injuries during my career, pretty much all before I started to focus on infection control, and I honestly didn’t put much though into them (beyond ”oh crap, that hurt!”).
There are some valid reasons for the differences between human and veterinary medicine when it comes to needlestick injury prevention, not the least of which is the risk of HIV and hepatitis B virus transmission. In some ways, getting people to pay attention to needlesticks in veterinary medicine is tough because we don’t have viruses such as these in our patients. Needlesticks can cause pain, significant trauma and rarely severe (including fatal) problems (e.g. from drug reactions or infections), but the vast majority are rather inconsequential. However, a line that I frequently use is: “We don’t have an analogue of HIV or hepatitis B… at the moment. New diseases continue to emerge and you never want to be the index case.”
Is this really a risk? Well, yes. Beyond some new disease that could emerge and be a serious problem, we also have new issues being identified from bugs that we’ve known about for a while. Recent concern has been expressed about transmission of Bartonella species. This is a strange group of bacteria that are commonly found in cats and dogs. Bartonella henselae is the cause of cat scratch disease, a well-known problem, but Bartonella are attracting a lot more attention these days because they are being implicated in a range of often vague human diseases. Bartonella can be found in the blood of healthy cats (and to a lesser degree dogs), raising questions about whether a needlestick could result in transmission of these bacteria to people.
Two case reports highlight these concerns.
The first one (Lin et al, Vector Borne and Zoonotic Diseases 2011) tells the story of a veterinarian who developed a fever of unknown origin and back pain. Ultimately, he was diagnosed with Bartonella henselae infection which they speculated may have been transmitted following a needlestick injury. The needlestick link is weak here though. As a veterinarian, there are lots of other opportunities to be exposed to Bartonella henselae. It’s not uncommonly present in the blood of healthy cats and the main route of exposure is through fleas. Fleas feed on the cat, pick up the bacterium, then shed it in their feces. Cat scratches are a common route of transmission as the contaminated flea feces may be driven into the body. The veterinarian in the report didn’t recall having been bitten or scratched recently, but recall bias is an issue since scratches are common and often forgotten if not severe. Flea exposure wasn’t queried. Also, the needle with which he was stuck was a clean needle that had not been used yet. It still could have been the source of infection if it acted like a scratch, driving infected flea dirt on his skin into the wound, but I don't think this report is very strong.
The second article (Oliveira et al, Journal of Veterinary Internal Medicine 2010) describes infection by a different Bartonella speces, B. vinsonii berkhoffii, also in a veterinarian. The person was taking an aspirate from a mass with a needle and syringe and was poked in the finger as the dog was struggling. Five days after the needlestick, the person was still healthy. A blood sample was taken from the person and Bartonella was not found. However, by day 34 after the incident, the veterinarian reported having had frequent headaches for the past week, fatigue and some intermittent numbness in one arm. Bartonella vinsonii berkhoffii was detected in the person’s blood at that time. There was also an increase in anti-Bartonella antibodies between the two blood samples, which supports an active infection. The bacterium was not found in the tumour aspirate, but as a dog-associated bacterium and one that is rarely identified in people, and with the timing of exposure and disease, it’s quite suggestive that the needlestick was the source.
These may just be two reports, but they may just be the tip of the iceberg, because disease caused by Bartonella infections is often vague and probably routinely gets missed. There’s also increasing evidence of wide-ranging types of infection that may be overlooked, so people (and particularly veterinary staff) need to be aware and pay attention to the potential risk.
Needlestick injuries shouldn’t be considered part of the job. There are risks, but a little common sense goes a long way.
Information sheets on both cat scratch disease and needlestick injuries (and how to avoid them) are available on the Worms & Germs Resources - Pets page.
A few weeks ago, I did a talk about Schmallenberg virus for a government group. It was an unusual talk for me since it was about a disease that I’ve never seen, and a virus that as far as we know is not even present in North America. While I’ve been monitoring the issues with Schmallenberg virus in Europe, it was a good opportunity for me to look into the subject more thoroughly. One reason to do so is just academic interest, as someone who deals with infectious diseases. Another is because foreign diseases have a habit of becoming non-foreign, and that’s a serious concern with Schmallenberg.
Schmallenberg virus was first identified in 2011 along the Dutch-German border, so it’s a "new kid on the block." The virus is spread by insects called biting midges, and the disease affects ruminants (mainly cattle, sheep and goats). It causes two main problems: 1. diarrhea and decreased milk production in adults, and 2. adverse effects on the developing fetus in pregnant animals (causing abortion, stillbirths, and deformed calves/lambs/kids). The virus has rapidly spread across all of Europe and is now a major issue in some regions.
One important question about this virus is from where did it come? The answer is not clear. It’s important to figure this out to help determine where the virus might go. A midge hitch-hiking on a plane could be one way for the virus to make it to North America. However, a recent report from Sweden raises a few interesting questions.
Researchers at the Swedish Institute of Agricultural Sciences tested blood samples from 100 dogs. They found antibodies against Schmallenberg virus in 2 of them, and both positive samples were from the same dog that lived in an area where the virus has been found in ruminants.
What does this mean? It’s not clear yet.
- It might be of no consequence at all. It could just mean that an infected midge bit the dog and the dog’s immune system mounted an immune response to kill the virus.
- It can’t be dismissed that it could cause similar disease in dogs as in ruminants. I think that’s unlikely but it’s possible.
- Another concern is if, after being bitten, the virus can reproduce and reach reasonable levels in the dog’s blood (like it does in ruminants), then the dog could be another source of virus for more midges. It might not mean much in endemic areas where there are already lots of infected ruminants harbouring lots of virus. However, dogs travel more than ruminants, and if the virus can live in this species (whether or not it causes disease), then an infected dog could carry the virus to another country or continent. That’s my concern.
It’s incredibly easy to get a dog into Canada. That’s why we’re seeing various imported diseases in dogs, such as leishmaniasis. There’s not even a basic requirement (as in some countries) to mandate treatment for the concerning parasite Echinococcus multilocularis. So, there’s certainly going to be no testing for Schmallenberg virus (nor would this be practical). If European dogs can become infected and be infectious for a period of time, it’s quite plausible that dogs could be a source of international transmission. Fortunately, infected ruminants only shed the virus for a short period of time, so if dogs can be infectious, they’d hopefully following the same course. However, ever if they only shed for a few days, it’s still possible that they could be shipped across the ocean and find a waiting midge. Stranger things have happened with infectious diseases.
The New York Times has a nice article on hospitals that allow patient's pets to visit. This is a controversial area, with policies (when they are actually present) that range from wide-open access to complete prohibition. Like most things in life, there's a middle ground that's the most reasonable.
The positive aspects of people being allowed to have their animals come visit are pretty obvious, since people may have close bonds with their own pets and having a chance to see their pets might make a big difference to their mental state/well-being, particularly for someone who is chronically ill.
The negative aspects are less clear. We certainly know that pathogens can be transmitted from animals to people (and in the other direction too), and people in hospitals are often at higher risk of infection and complications thereof. There's a list of pathogens we worry about, but there's a serious lack of data to help determine the severity of the risk - and how to reduce it. Organized pet therapy programs are great because they are structured and there can be a lot of scrutiny and training of the pet and handler. Visits by patients' own animals are inherently less controlled, since the individual animal and handler don't undergo the same degree of assessment and training.
I get asked to review visitation guidelines frequently, and a reasonable middle-ground can usually be found. These are some snippets from the NYT article that highlight common points.
A doctor’s order allowing the family pet to visit is typically necessary...
That's a good approach, although it's not often used. This lets the doctor decide if it is reasonably safe to have the pet visit, i.e. the patient is not at a very high risk of infection. The weak link here is sometimes the doctor, because sometimes the doctor doesn't understand the risks associated with pet contact and may not identify a concern. Other times, the doctor may not understand the relatively low risk and the potential benefits, and therefore default to banning visitation without giving it much thought. I think that's less common these days but still an issue.
...as is an attestation from a veterinarian that the animal is healthy and up to date on all its shots.
The first part is great: making sure there are no health or behavioural issues with the animal that would pose an increased risk. The second part is very common but largely represents a lack of understanding of the issues. Too often, "has he had his shots?" is the main question that's asked about the animal, despite the fact that it's largely irrelevant from a zoonotic disease standpoint. Yes, we want to make sure the pet's rabies vaccination is up-to-date, but the other core vaccines are irrelevant from a human health standpoint (although they're very important for keeping the animal healthy overall).
Most institutions require that dogs — the most common visitors, by far — be groomed within a day or so of a visit and on a leash when they walk through hospital corridors.
Standard and logical policy. Grooming might help reduce the burden of bacteria, fungi and parasites on the haircoat, as well as a lot of loose fur and dander that could otherwise contaminate the hospital environment.
Cats must be taken in and out of the institution in a carrier.
Logical. Some cats do well on leashes but it's better to have a cat in a carrier when taking it through a strange area. It also helps prevent other people from coming into contact with it.
If a dog or cat wants to get up on a patient’s bed, a covering is laid down first.
Good policy, and it protects both the patient and the animal.
If an animal seems agitated or distressed when it comes into the hospital, staff members who meet the family and escort them to the patient’s room have the right to turn it away.
This has two important components. One is that the visitation is supervised, which is great. The other is that staff are given the ability to intervene in the unlikely even that there are problems.
If the patient shares a room with someone, that person must agree before a pet may visit.
This is often overlooked. Roommates might be afraid or allergic, and in those situations, visitation shouldn't happen in a shared room. There might be a way to do the visit in another room, so it doesn't necessarily preclude the visit from happening. This has to be broached in advance and in a manner that the roommate doesn't feel pressured into consenting. It's best done by having the patient's healthcare providers approach the other patient and/or the other patient's family.
There's always some risk with animal hospital visitation. That's never going to be eliminated, but a lot of common sense practices can reduce the risk to a very low level, hopefully to the point that the risk is overwhelmed by the benefits. A little structure and a lot of common sense go a long way.
It's maybe a sad statement that reading about someone whose diseased toes were gnawed off by their dog doesn't shock me anymore. It's not an everyday event but it's far from rare. An Indiana man learned about this the hard way when he woke up thinking his dog was licking his toes, when in fact, the dog had eaten them.
As is typical in cases like this, the person is a diabetic and had a foot infection, which contributed to the dog being attracted to the toes and the person not feeling the midnight snacking. Presumably, the person will be fine with some wound care and antibiotics. In fact, the dog may have just altered the manner of amputation if the toes were that severely affected. They may have been coming off one way on the other in the near future, but this is still not the desired approach.
A couple of questions come up sometimes in cases like this.
Is the man at risk of any infections from the dog?
- Certainly, there are concerns. This should be treated just like a bite since there was obviously contact between dog saliva and broken skin. Antibiotics were presumably already being used because of the toe infection, so that might have been enough, but antibiotic treatment would be needed in a situation like this given the type of exposure and the person's compromised state.
- Rabies is unlikely but it still has to be considered. This is just like a bite, so a 10 day observation period of the dog would be indicated. There's almost zero risk of rabies here, but when we're talking about rabies, "almost" isn't good enough.
Is the dog at risk of catching anything from the owner?
- This is perhaps the more likely of the two concerns. The dog was licking and eating infected tissue. Many of the bacteria that cause this type of infection can also infect dogs. The odds of the dog developing disease from this are pretty low. It's more likely the dog would become a carrier of the bacterium for a while (e.g. in its mouth, nose, or intestinal tract). If the dog is otherwise healthy, it's probably not going to suffer any consequences, but knowing what bacterium was causing the toe infection would help with that risk assessment.
While dogs amputating toes is rare, it's surprising how often I hear about people who let their dogs lick diabetic ulcers. As well, I've heard of people who have looked down and realized their dog or cat was gnawing on their toes (not amputating - at least not yet - but chewing away nonetheless). Usually, these are diabetics. Usually, nothing bad will happen. However, a dog's mouth contains many different bacteria that can cause severe illness given the right situation, and chewing on a toe of a diabetic patient in particular would fit into that "in the right situation" category.
An outbreak of equine herpesvirus type 1 (EHV-1) has resulted in implementation of a quarantine at Woodbine, a major Thoroughbred track in Toronto. This outbreak is unrelated to the recent outbreak at an Ontario Standardbred training facility.
The Ontario Racing Commission has issued the following release:
The Ontario Racing Commission (ORC) announced that there have been five confirmed reports of the neurotrophic form of EHV-1 in thoroughbreds residing in Barn 1 at Woodbine Racetrack. One horse was euthanized on June 10 after becoming recumbent with a fever. A second horse in the same barn (Barn 1) also had a fever and showed neurological signs. The second horse was transported to the Ontario Veterinary College for further evaluation and treatment.
Thoroughbred racing will continue at Woodbine. However, due to the infectious nature of this disease, the ORC has ordered the implementation of various infectious disease protocols to protect our equine athletes.
In order to determine any further spread of the disease to horses in other barns, no horses are to exit Woodbine Racetrack without ORC approval for the next 7 days (June 19). This restriction may be reviewed based on the progression of the disease.
In addition, no horse is allowed in or out of Barn 1 or Barn 3 for the next 7 days, including training. This restriction may be reviewed, based on the progression of the disease.
All horses stabled at Woodbine must have their temperatures taken and recorded visibly on the horse’s stall door for inspection. Trainers with horses that have clinical signs consistent with EHV-1 infection (including fever (101.5 F/38.5 C or above), respiratory signs (cough, nasal discharge and/or neurological signs) must report these findings to their veterinarian immediately.
Horse people who had horses at Woodbine Racetrack within the last 7 days should monitor their horses for any signs of illness. Standardbred horses are not stabled at Woodbine Racetrack. As well, the standardbred racing meet concluded at Woodbine on May 20, 2013 and moved to Mohawk Raceway on May 23. Therefore the June 15 North American Cup at Mohawk will not be impacted by these measures.
As with most outbreaks, the next few days are critical to see how far the virus has spread. Early on, you never know whether it's confined to a specific barn or group, or whether it's widely disseminated across the facility. An outbreak that just affects one barn is still a problem, but it's much easier to contain than one that's already moved beyond the initial group. Without knowing how the first horse was infected (something that's rarely identifiable), time and testing are needed to determine the extent of the spread and how hard it will be to contain it.
Several dogs at a Miami humane society were quarantined last week because of concerns (or possibly panic/over-reaction) about methicillin-resistant Staphylococcus aureus (MRSA). MRSA in dogs is a concern because it's an important cause of infection in both people and animals. However, it's an opportunist, meaning it typically doesn't cause disease when it encounters a normal, healthy person or animal. In fact, a small percentage (~1-3% probably) of the human and pet populations carry this bacterium in their nose without knowing it, and the vast majority never suffer any consequences.
It's often tough to strike the right balance when dealing with an MRSA issue. We want people to realize that it's an important cause of disease and that it needs to be taken seriously, but we also want people to keep it in perspective and not freak out.
The Miami shelter report seems to be on the "freak out" side, particularly on the part of the local media.
It's not really clear what's happening based on this fairly poor article. The shelter's Chief Medical Officer, Dr. Maureen Swan, is quoted as saying there's a routine respiratory disease cluster in the shelter, but MRSA rarely causes respiratory disease in dogs. The article then adds Dr. Swan said it was "not the highly contagious MRSA virus." I have no idea what that means, and MRSA is not a virus.
My suspicion is that they have respiratory disease caused by the typical bacterial and/or viral pathogens that are commonly found in shelter dogs, and that they isolated a methicillin-resistant staph that just happened to be hanging around in that particular dog (since such bacteria normally live in the mouth, nose and skin). It's also not really clear whether this is MRSA. The article says MRSA, but the first thing I ask when I get an advice call about MRSA is "what staph species does the report say was isolated?". Most often, it's Staphylococcus pseudintermedius or another staph. These bugs can still be relevant, but they don't carry the same human health risk as MRSA, so it's important to know exactly what's been found.
Finding MR staph, including MRSA, isn't unheard of in a shelter. It's just one of many reasons that good general infection control practices are needed in these facilities. When MRSA is found, taking some extra precautions is reasonable because of the potential for disease and transmission to people, but too often people panic. It's understandable based on concern about MRSA and the scary stories people can find with a quick Google search. Not uncommonly, there's a combination of an short-term overly aggressive response while at the same time failing to improve basic infection control practices, which are the most important.
More information about MRSA can be found on the Worms & Germs Resources - Pets page.
The latest edition of the University of Guelph Animal Health Laboratory's newsletter contains an interesting report about 4 horses that died over the past few years from what was suspected to be contaminated intravenous fluid solutions. These cases were dead horses that were submitted for post-mortem examination from three different farms, so if anything, this could be an underestimation of the problem.
The first two horses were from the same farm. They were young Thoroughbreds that were routinely treated with intravenous electrolytes, vitamins and minerals (whether by the trainer or veterinarian is unknown). The first horse was found with its head hanging low after treatment. It later developed seizures and died. The second horse showed similar signs. The bacterium Klebsiella pneumoniae was isolated from a few different tissues of the first horse, as well as one of the "jugs" used to administer the fluids. The second horse had the same general lesions as the first, but Klebsiella wasn't isolated; however, this may have been because the body wasn't in great shape by the time it was submitted to the lab, and various other bacteria had overgrown the Klebsiella, making it difficult to isolate.
Another case was a young Standardbred that died after receiving intravenous fluids with vitamins, and a glyceryl guaiacolate jug. It had signs of bloodstream infection (septicemia) and Klebsiella oxytoca was isolated from multiple organs. Various bacteria were isolated from remnants of fluid in treatment bottles.
The final case was a five-year-old Standardbred that died after receiving a home-mixed vitamin jug. It had lesions similar to the other horses and consistent with a bloodstream infection. Klebsiella oxytoca was isolated from multiple organs.
Contamination of multidose drug vials or fluid solutions can occur if bacteria are inoculated into the bottle with a needle when a dose if withdrawn. We've shown this happens with multidose vials in a hospital situation, and of the farm it's even more likely to occur because it's a dirtier environment and, in the case of farm personnel, individuals have less experience with sterile technique. Fluid solutions can be contaminated in the same manner or when something is added to the fluids (e.g. vitamins). Contamination of reused fluid administration sets (i.e. fluid jugs/bags and the IV tubing) is quite likely, and that's why use of sterlie, single-use administration sets is recommended. Adverse events from a little bit of contamination are uncommon, but as shown here, they can happen and they can be severe. There's no information about what contributed to the contamination in these cases, but it's almost certain that poor infection control practices were at the root of the problem. Trying to save money by skimping on sterilization, reusing items without proper care, and using poor hygiene practices in general can end up costing much more.
Darwin's back in the news. He’s a young macaque who is often called the "Ikea Monkey" since he was found wandering around a Toronto Ikea parking lot one day last winter in a designer winter coat. He was seized because of a Toronto bylaw prohibiting monkeys as pets, and transferred to a local primate sanctuary. His owner, Yasmin Nakhuda, has been waging a high profile battle to get him back. There are numerous Facebook pages dedicated to freeing Darwin, and she apparently sent him a birthday greeting (perhaps not realizing it's unlikely that he had internet access at the sanctuary... or can read).
Anyway, Ms. Nakhuda is suing for custody and the trial is currently underway. Needless to say there's a lot of drama in the courtroom as Ms. Nakhuda tries to regain custody of the animal she calls her "son." Much of the trial has centred around issues of property, which I guess makes sense since that’s the main legal avenue.
However, what’s not been mentioned are the greater concerns, namely does Darwin pose a risk to the public and does Ms. Nakhuda pose a risk to Darwin? I think the answer to part 1 is certainly yes, and the answer to part 2 is maybe.
The first question (does Darwin pose a risk to the public) is easy. There are a variety of issues with keeping non-human primates as pets. They can be destructive, they are surprisingly strong for their size, and macaques are notorious for being aggressive, so the risk of trauma alone is a major issue. Disease is another concern, and the big problem in this case is herpes B virus. This virus can be found in most healthy captive macaques and can cause fatal infection in people. The fact that it’s been reported that Darwin was prone to biting makes me cringe, since that’s a huge risk for herpes B transmission. Among the trial testimony was an email Ms. Nakhuda sent to a US primate trainer in November documenting her struggles. Among the problems was aggression that Darwin had towards her son and co-workers.
It’s bad enough that she’s exposing herself and her family (including her human chldren) to Darwin. Exposing people with whom she works (and perhaps people who work for her, and would have a hard time raising any concerns they had) is completely inappropriate, as is taking Darwin out in public (apparently "everywhere," including the gym, grocery store, and obviously Ikea). Ms. Nakhuda either doesn’t understand the issues or doesn’t care. Either way, it’s not good.
I don't doubt that Ms. Nakhuda cares for Darwin. However, as the primate sanctuary lawyer Kevin Toyne said "This is not about who loves Darwin the most." For me, it should be about protecting the best interests of the public and Darwin, neither of which would result in him being returned to his previous owner.
An abstract for the upcoming CSTE (Council of State and Territorial Epidemiologists) conference in California describes a rare but concerning case of Brucella canis infection in a child. All I have to go by is the abstract (since the meeting hasn’t happened yet and I won’t be there anyway), but it provides an interesting outline.
Brucella canis is a bacterium that is (not surprisingly, given the name) associated with dogs. It’s present in dogs internationally, with higher rates of infection in strays and shelter dogs. It can cause a variety of problems in dogs, most often abortion, stillbirth and birth of weak puppies, but also things like reproductive failure and genital inflammation in males, and diskospondylitis (a kind of back problem). After a dog gets infected, the bacterium can localize to genital tissues, where it tends to hang out, resulting in intermittent shedding of B. canis in urine, vaginal discharge, fetal fluids, semen and, to a lesser extent, some other tissues. Humans can then be exposed via contact with these fluids. The main risk to humans comes from handling breeding dogs, particularly female dogs that have aborted puppies. However, people seem to be relatively resistant to B. canis infection, and there are actually only a small number of reports of human infections with this bacterium.
The risk to average pet owners is very low, but as this report shows, low doesn’t mean zero. This abstract deals with an infection in a 3-year-old child from New York city. The family had acquired a Yorkshire terrier puppy from a local store in March 2012. As is expected, there was close contact between the child and the puppy.
Near the end of April, the child was taken to an emergency room because of fever and difficulty breathing. Bacterial infection wasn’t the main suspect and he was discharged without antibiotics (presumably having improved from how he was at the time of admission). However, a blood culture was collected and it came back positive for Brucella canis. While the boy had been doing well, he was treated with 45 days of antibiotics to try to make sure the bacterium was eliminated, since it can cause chronic problems.
In a step that’s too often overlooked in zoonotic disease occurrences, there was an investigation of the source. That’s not surprising since this is a rare and concerning bacterium, and it’s pretty clear that pet contact tracing is required. The puppy was healthy but the bacterium was isolated from its blood. Because of the test result, the puppy was euthanized. (There’s no mention of whether this was at the owner’s request or based on the recommendation of public health personnel.)
The source of the puppy was a major concern, since it’s important to make sure that there aren’t other infected puppies around. The puppy came from a "commercial breeding facility" in Iowa - yet another instance of the potential for widespread national and international distribution of pathogens from large commercial pet operations. The facility was quarantined but there’s no more information in the abstract about whether other positive animals were found, whether infected puppies may have been sent elsewhere in the country, and what measures were taken to correct the problem.
A littermate of the New York puppy was sold by the same store. It also tested positive for B. canis and was treated.
This is a rare incident, but it highlights some points for me:
- Large commercial breeding facilities for dogs are unnecessary and create increased risk of disease in animals and by extension people. Yes, this could occur with a small private breeder, but the more animals, the more risk of infectious disease, and the larger the facility, the larger the potential impact should a disease issue develop.
- Proper counseling of people whose pets are diagnosed with a zoonotic pathogen is needed. I don’t know the story at all about why the first puppy was euthanized, but it might have been avoidable. What to do with animals that are healthy but shedding potentially concerning pathogens is a tough area to address. That’s particularly true for a bug like B. canis, since it can be hard to eliminate.
- Good communication is needed between the medical field, public health, veterinary medicine and the public. It’s hard to say how smoothly this investigation actually went, but it shows a good response to a rare but potentially serious problem.
- People that sell animals need to keep accurate contact information from purchasers. It’s good to see that they were able to track down the owners of the original puppy's infected littermate. Contact tracing is important with infectious diseases and it can be exceedingly difficult at times.
- There’s an inherent risk in pet ownership. We know that and have to accept it. The child was high risk because of his age. That doesn’t mean we don’t let kids have pets, but we have to understand the risk and use some basic hygiene practices to reduce that risk. Would it have had any impact on this case? Who knows, but it never hurts to improve.
I’ve written about the African dwarf frog and Salmonella issue before, but it’s worth a recap since an overview of the 2008-2011 outbreak was recently published in the journal Pediatrics (Mettee Zarecki et al 2013). The fact that reptiles and amphibians can carry Salmonella is nothing new, nor is the fact that outbreaks of disease can occur in people who have contact with them. However, the scale of outbreaks associated with pets can be impressive.
Here are some highlights from the paper:
- Between January 1, 2008 and December 31, 2011, 376 people were diagnosed with salmonellosis caused by the outbreak strain, a type of Salmonella Typhimurium.
- As is common in pet-associated outbreaks, kids bore the brunt of this one. The mean age of infected individuals was 5 years, and 69% were children under the age of 10.
- Severe disease wasn’t uncommon - 29% of people were hospitalized, half of those being kids less than 5 years of age. Fortunately, no one died.
- During a preliminary study, when they compared people who got sick with a group of healthy controls, they found that people who reported exposure to any aquatic pet were almost 5 times as likely to have salmonellosis. When that was narrowed down to exposure to just frogs, the risk went up to 12.4 times higher than healthy controls.
- When they looked at people who were sick and reported exposure to frogs, only 27% reported having touched a frog, with 46% reporting having fed a frog, 59% having had contact with a frog’s habitat and 60% having had contact with water from a frog’s habitat. Twenty-three percent (23%) reported cleaning the frog’s habitat in the kitchen sink, and 35% in the bathroom sink. This tells us some very important information. It tells us that direct contact with frogs or their environment is a high risk behaviour. However, direct contact isn’t required to get sick. While the frog may stay in its habitat, Salmonella may not. Cleaning habitats in kitchen or bathroom sinks is a high risk activity, because it can result in contamination of common human-touch surfaces and items that go into peoples’ mouths (e.g. toothbrushes, cups).
- Often, disease occurred not long after a new frog was obtained. The median time from purchase of a frog to disease was 30 days (range 5-2310 days).
- Only 17% of people interviewed reported knowing that frogs can carry Salmonella. Over twice as many knew there was a risk from reptiles. This shows there needs to be more education of people who buy animals such as frogs. Pet stores should be required to provide some basic public health information. Pet owners should also take initiative and research potential new pets, including how to care for them and how to reduce the risk of zoonotic infection.
- The outbreak Salmonella strain was found in the environment of some patient homes (not surprisingly), an African dwarf frog vendor (potential source of infection), a large-scale African dwarf frog distributor (a great way to spread an outbreak across the continent) and a daycare centre (that never should have had an amphibian in the first place!).
- One breeding facility in California was the likely source. With centralized, large-scale breeding and warehouse-style distribution of pets (of various species, not just frogs), we’re seeing more large-scale outbreaks like this.
More information about African dwarf frogs can be found on the Worms & Germs Resources - Pets page.
Studies that look at risk factors can be pretty variable in terms of what they tell you, the impact they have and how accurate they are.
Some findings are pretty logical, clear and indicate something that should be done.
- Smoking is a risk factor for [insert many diseases here], so to reduce the risk of [whatever disease], stop smoking.
Others make sense but don’t necessarily lend themselves to an effective intervention.
- Being male is a risk factor for cardiovascular disease... not much I can do about that.
Sometimes, you have to remember that a risk factor for one thing doesn’t provide a clear answer when a broader context is considered.
- Moderate consumption of red wine can reduce the risk of various conditions, but alcohol consumption can also increase the risk of other conditions.
Sometimes, how the study is designed and performed can really affect the results.
- If I did a large study of the general population in Guelph, I could presumably show that going to a hospital greatly increases your risk of death. Does that mean you shouldn’t go to the hospital? No, because I could presumably also show that if you have chest pain and go to a hospital, you’re more likely to live. Knowing the study population and what question is really being asked are critical.
Sometimes, something that’s found to be a risk factor isn’t really the risk factor, but it’s associated with something else that is.
Sometimes, something can be "statistically significant," but of limited consequence.
- If doing something increases the risk significantly, but only by 0.0001%, does that mean anything?
Why do I write this? Because these are some of the things that we have to think about when assessing risk factor studies. While one Toronto radio station loves to give 10 second snippets on some new risk factor medical study, you can’t determine much about the study itself from a sound-bite (or internet post). You need to think about the details regarding how the study was done. Nevertheless, risk factor studies can provide useful information, but consider the results carefully, whether they are relevant, whether they indicate changes need to be made or whether they indicate that we need to look at the issue further.
The first study compared dogs from northern California that had or didn’t have leptospirosis. They found a few things:
- There were differences in geographic distribution of the lepto cases and controls. That makes sense since we know lepto varies regionally, but living in different areas might also be associated with different behaviours and contacts (e.g. wildlife contacts).
- There was a temporal cluster, with more cases occurring between May 2003 and May 2004, compared to the rest of the 2001-2010 study period. That makes sense too since we see variation in cases within and between years.
- These results don’t change anything, but are an indication of what work needs to be done next. Looking at why things vary geographically and temporally might be important for figuring out how to reduce the risk of disease. It also indicates regions where more efforts to educate pet owners (and veterinarians) are indicated, and where vaccination is more important.
The second study looked at dogs from Kansas and Nebraska, with and without leptospirosis. They also found a few risk factors.
- Lepto was more common in houses lacking complete plumbing facilities. Presumably, this is a proxy for something else. Poor plumbing doesn’t likely result in lepto in dogs. Rather, it presumably means that a dog living in a house with poor plumbing has some other factor that increases its risk. For example, incomplete plumbing may be more likely in lower socioeconomic (i.e. lower income) households, which might then correspond to other more direct risk factors for the dog (e.g. poorer nutrition, less veterinary care). It could also be that houses lacking complete plumbing tend to be in a different area where there’s more exposure to wildlife reservoirs. A couple of other indicators of poverty status were also significant, highlighting the potential impact of owner poverty on pet health.
- Dogs that lived within 2500 m of a university or college, or a park, were also at increased risk. The park risk factor makes sense since they could be exposed to sites infected by wildlife reservoirs (e.g. raccoons). Living close to a university or college is tougher to figure out. Maybe it’s associated with economy, as students are typically at lower income levels. Maybe it’s because colleges and universities usually have lots of green space that might harbor wildlife.
So, these studies tell us some new information, reinforce some previous knowledge (or perceptions) and raise some new questions that we need to answer. By themselves, they won’t result in major changes in how we try to prevent lepto in dogs, but little steps is typically how science progresses.
Horse show season is upon us, and with it comes the questions from concerned horse owners who want to protect their animals from the infectious diseases they may encounter at these events. In this case, the specific question is:
What protocol would go into place if a horse with a highly contagious disease such as EHV-1 were to be found at a competition in Canada?
The short answer (to the surprise of many) is that there is no pre-established nation-wide protocol for most equine disease outbreaks. Every outbreak is managed differently, based on the disease, the types of horses, where exposure might have occurred and a range of other factors. Typically, a disease like EHV isn't going to be noted during the show, since it takes some time for illness to develop after exposure. Therefore, the response is more of an investigation of what happened at the show, why and how it can be prevented in the future, and of course trying to prevent further transmission in the community (e.g. identifying exposed horses, communicating with people who have been to the show with recommendations to quarantine and test exposed horses and potentially all horses, surveillance for ongoing transmission from horses that have left the show).
With horses, there's no regulatory body with a mandate to oversee (and fund) this type of investigation unless it's a federally reportable disease like rabies (and even then, assistance may not be forthcoming). Some provinces have more authority and interest (e.g. the Animal Health Act in Ontario gives the province a mandate and powers to intervene) but often investigation is not a priority for regulatory bodies and it's left to whoever is around and interested. There are some good outbreak management guidelines from different institutions or groups (e.g. the ACVIM consensus statements on EHV and strangles) but there is no standard approach. Because testing costs are placed on the owners, responses can be quite variable since getting people to test when indicated can be a challenge. Additionally, getting people to follow quarantine recommendations is a challenge because of inability to effectively quarantine on their farm or unwillingness to do so (usually more the latter). So, each outbreak ends up being managed quite differently.
In general, the key points to outbreak investigation and management are:
- Identification of a problem
- Diagnosis of the problem
- Communication to let people know what's happening
- Identify potentially exposed and infected horses
- Quarantine, if appropriate (usually some form of quarantine is indicated, but not necessarily for all diseases)
- Develop testing recommendations
- Develop and communicate a plan to maximize compliance with quarantine and testing
- Create a way to centralize data collection and communications, so that a clear picture of what is happening is obtained
- Keep people in the loop as the investigation ensues to maximize compliance and decrease loss of compliance because of boredom or fatigue with the recommendations
As if horse owners and veterinarians in Queensland need another infectious disease challenge.....
Recently, a horse in southwest Queensland was diagnosed with Australian bat lyssavirus infection. This virus, which is similar to rabies, is present in some bats in Australia. It can be transmitted to people from bats, causing fatal disease, but human infections are very rare. Even though it's rare, it warrants attention because the disease is so severe.
Finding an infected horse is surprising in some ways, because the virus has never been detected in this species before. However, a virus that's present in bats can certainly find its way into a horse, and we already knew that a closely related virus (rabies) can infect horses. So, maybe it's not that surprising afterall.
In this case, the horse was suspected of being infected with Hendra virus initially. While Australian bat lyssavirus can kill people, this diagnosis was actually much better than Hendra virus infection, because horse-human transmission of Hendra is a major concern. Hendra virus infections have high fatality rates and, perhaps most importantly, there are no effective preventative measures that can be taken after Hendra virus exposure. Since Australian bat lyssavirus is so closely related to rabies virus, rabies post-exposure treatment can be used in this case (and is probably effective).
It's unclear whether an infected horse poses much risk to people. The very small number of human Australian bat lyssavirus cases have occured in people who were bitten or scratched by bats. Since this is the first equine case, it's not known if affected horses shed large amounts of (or any) virus. People who had contact with the horse were identified and offered post-exposure treatment. It's reasonable to consider this situation like rabies exposure in the absence of more evidence, and treat people who were bitten or otherwise may have gotten virus-contaminated saliva into their tissues via broken skin or mucous membranes.
Is this the start of yet another new problem?
Most likely, this is just an example of the rare scenario of a virus infecting an atypical host, not the start of a new, common problem. However, it's worthy of attention in case the virus has changed or there is now a specific virus type that can more easily infect horses (both very unlikely). This case also shows the importance of thorough diagnostic testing, particularly when an animal has severe disease.
If you don't look, you don't find.
If you don't find, you can't act.
I've been bitten lots of times, some on the job (including the last dog I saw when I was in general practice) and some off (including a dog down the road a couple of years ago). Fortunately, I haven't suffered any serious consequences. That's what happens most of the time. However, bad things can and do occur after bites.
A paper in BMJ Case Reports (Tumram et al 2012) describes a rather unusual and unfortunate situation. It's about a fatal infection in a 55-year-old Indian woman who was bitten by a mongoose. She was bitten (unprovoked, it seems) on the leg by the mongoose while washing dishes. She went to the hospital a couple of hours later because of pain and swelling in her leg. It's not clear what happened there, but she went back to hospital the next day, and then received antibiotics. However, that same day, she suffered cardiac arrest (a heart attack) and died a few days later. The bacterium Streptococcus pyogenes (Group A Streptococcus) was isolated from some lesions on her legs, leading to a suspicion that she developed a severe and rapidly progressive infection from the mongoose bite.
Various aspects of this case are unusual. Fatal bite infections occur, but they are rare. Involvement of streptococci is rarer still.
Why did this woman develop a fatal infection, especially when she sought prompt medical care? It's hard to say, and there is a "bad luck" component of infectious diseases. She had diabetes and high blood pressure, which probably increased her susceptibility to infection (but lots of other people who get bitten also have these conditions and suffer no consequences). It doesn't appear that she received antibiotics when she went to the hospital originally, but a bite over the leg isn't one that would always be treated prophylactically with antibiotics.
Why did the mongoose bite? That's another good question. Unless you're a snake, mongooses are typically not aggressive.
Where did the bacteria come from? We don't know much about the oral bacterial population of mongooses, but Streptococcus pyogenes is a human-associated bacterium. It's rarely found in animals and I suspect that the strep didn't come from the mongoose. Rather, it was probably already on the woman's skin and introduced into her body by the bite, or she contaminated the wound after being bitten. It's just a guess, and it doesn't change anything, but it makes sense.
This report shouldn't make people freak out over a bite. However, it should serve as a reminder that bad things can happen. More information about dealing with bites can be found on the Worms & Germs Resources - Pets page.
Image: Dwarf mongoose (Helogale parvula) in Korkeasaari zoo (photo credit: Miika Silfverberg, click image for source)
We've just posted a new info sheet about cat scratch disease (CSD), which is caused by a bacterium (Bartonella henselae) commonly carried in the bloodstream of healthy cats. Signs of CSD in people can be quite non-specific, so (as always) it's important to let your physician know if you've been bitten or scratched by a cat if you're feeling ill, so that CSD is considered. Other than proper training and handling of cats to avoid bites and scratches, the next most important component of CSD prevention is flea control.
You can read more about CSD and B. henselae on the new info sheet, which you can find along with all our other info sheets on the Worms & Germs Resources - Pets page. You can also read about CSD in the posts in our archives.
As someone who works with zoonotic diseases, I often find myself fighting battles on both sides of the issue. One side is trying to increase awareness about zoonotic diseases (i.e. those caused by microorganisms that are transmitted between animals and humans) and getting people to think about the potential role of animals in human infection. However, I often also have to deal with trying to keep things in perspective, and prevent people from over-reacting to disease risks. Part of this is helping people understand that disease transmission is typically a two-way street. While animal-to-human transmission is usually the greatest concern, human-to-animal transmission of a variety of bugs also occurs, and this can cause problems for the animals, and for people who subsequently have contact with those animals.
A recent paper in the journal Mycoses (Van Rooij et al 2013) highlights one such scenario. The paper describes ringworm in a dog that was associated with the fungus Trichophyton rubrum, which is not the typical ringworm species (Microsporum canis) that we find in dogs. Trichophyton rubrum is a common cause of infection in people, particularly tinea pedis (athlete’s foot) and onychomycosis (fungal infection of finger and toe nails). The authors did something that’s often lacking in reports of animal-human transmission: they actually tested both the person and the pet. Here, they found that the owner was a carrier of this fungus. They were able to isolate the fungus from his skin and determined that he likely had an asymptomatic infection that was subsequently transmitted to his dog. (He’d previously had untreated and self-resolving athlete’s foot, and presumably remained a carrier after that). Since this ringworm species is predominantly found in humans, it’s a reasonable assumption that it started with the person and the problem was only identified when the dog developed disease. In this case, the dog was old and had been treated with corticosteroids, both of which probably affected it’s immune system and made it more susceptible to this uncommon cause of canine disease.
It’s important to remember that while zoonoses are important, pathogens go both ways.
In the end, we’re all animals.
I have three kids that are all now (thankfully) past the diaper stage. I have no idea how many diapers I changed, but I don't have a huge desire to start doing it again, especially for chickens.
I understand the whole urban chicken concept. I don't actually have many issues with it if it's done right - but that's a big IF, unfortunately. Keep your chickens on your property, don't do it if you have young kids or other high risk individuals in the household, use good basic hygiene practices, feed them right, don't get roosters, and don't run screaming to the newspapers or local politicians if some get eaten by carnivorous urban wildlife. The nuisance and risk of backyard poultry can be limited.
Live chickens inside the house... that's another story.
Chickens aren't house pets in my world. I'm not sure if the chickens benefit at all from living in a house with people, and it's probably actually detrimental in many ways. I'm not sure what the benefit is to people either. Although I haven't seen any studies on this specific topic, it stands to reason that keeping a chicken indoors would be associated with a fairly high risk of widespread contamination of the household with bacteria like Salmonella and Campylobacter, two bugs that cause millions of infections in humans every year.
I'm all for risk mitigation, including using creative (and sometimes off-the-wall) measures - but diapers for chickens? Not so much.
Yet, Pampered Poultry makes diapers for your indoor chickens, and not just run-of-the-mill diapers: they're (allegedly) both functional and fashionable. This isn't the only company that sells chicken diapers either, much to my surprise.
One website states "Our chicken diapers are not just for the fashion obsessed hen. They offer your and your home protection against the inevitable! Our diapers fit comfortably and allow you to enjoy your birds in the house or car [car?] without worry."
Does using chicken diapers make sense?
I have a hard time believing these diapers are very useful. They probably do reduce the burden of pathogens that are deposited in the environment, but they are presumably far from 100% effective at containing all of a bird's droppings. It's also likely that chickens are contaminated with these bacteria on other parts of their bodies. Thinking you've eliminated the risk of household contamination from your pet poultry by using diapers isn't logical. The diapers also need to be changed (risk of more contamination) and disposed (don't we have enough waste already?) or washed (risk of cross-contaminating other items).
If you want fashionable chickens, go ahead and dress them up in diapers. Nothing says haute couture like a chicken walking around the living room in pink floral undies. Just don't convince yourself that you're reducing the infectious disease risk for other animals and people in the house. Better yet, let the chickens be chickens and keep them in a proper coop outside. I've seen too many indoor goats, pigs, miniature horses and other species with profound health problems from owners thinking they're just like people.
Apart from diapers, the store also sells "saddles" for the chickens. I'm not even going to start on that one.
I’ve received a lot of emails over the past 24 hours about the recent report of equine herpesvirus type 1 (EHV-1) neurological disease in an Ontario horse. The two main questions are whether there’s an outbreak and whether horse owners in Ontario should be concerned.
I don’t have any firsthand knowledge about this case (or any information beyond what’s been written elsewhere), but as far as I know, this is just a single sporadic case. That doesn’t mean an outbreak can’t occur, but most often, these just occur singly.
Whether there’s cause for concern is a tough question to answer. Yes, EHV-1 can be a serious problem, causing neurological disease in adult horses, abortion in pregnant mares, and severe disease in neonatal foals. Yet, at the same time, it’s an endemic disease that most often occurs as sporadic cases rather than large outbreaks (people just don’t hear about single cases as often, although they are now reported a lot more than they were a few years ago). The EHV-1 virus is very common and can be found in its dormant form in a large percentage of horses, so it’s not like some pathogens with which an unexposed population can suddenly be threatened when a single case is identified. In general I pay close attention to EHV-1 cases, but they are not a cause for panic. If a case occurs, we need to see if some broader issue is at play, and put steps in place to limit the problem, but we don’t need to cause massive disruption. In short, we want to ensure that good surveillance and infection control measures are in place, but not freak out in the process.
People have really taken a 180 degree turn in how they handle EHV-1 over the past 10 years or so. I don’t think we see EHV-1 neurological disease any more than when I was a resident. Back then, we saw sporadic cases and the odd small cluster, and people didn’t get too worked up about it in terms of the risk of transmission. Outbreaks, such as one I can remember associated with a large Ontario Standardbred yearling sale, certainly got lots of attention, but it was short-lived. Things changed (for good reason) based on some large, high-profile outbreaks in the last decade. It’s not known why such outbreaks now seem to be more common.
Anyway, if you live in Ontario and have a horse, don’t panic. Your horse is probably at no greater risk today than it was last month, assuming it wasn't in contact with the affected horse (which was diagnosed in early April). Virtually every horse is at some degree of EHV risk every day, but the odds of disease occurring are very low.
Some key prevention tips include:
- Use good general infection control practices to reduce exposure of horses to pathogens brought in by newly arrived horses.
- Observe your horses regularly and if there are any problems, isolate the horse and have a veterinarian examine it ASAP.
- When travelling to shows, races or other events, take measures to reduce direct and indirect contact between horses.
The first true confirmed canine influenza virus (CIV) was the H3N8 canine flu that evloved from H3N8 equine flu. That's the virus that spread to and amongst dogs in various parts of North America. The general consensus has been that only this strain should be called CIV, since it's been the only true dog-adapted influenza virus that's developed the ability to stay and circulate in the dog population.
More recently, another canine flu virus has emerged in dogs, this time a type H3N2 in Asia. H3N2 is a common human flu type, but birds are the ultimate reservoirs of all flu viruses, and based on the genetic relationship of H3N2 from dogs and birds, it's thought that this virus came to dogs from birds.
Anytime a new infectious disease is encountered, it's important to figure out who/what it can infect. When H3N8 CIV emerged, it was shown that even though it came from horses, it was no longer adapted to readily infect horses. So, knowing a virus' origin or typical infection trends can be useful but it doesn't necessarily tell you the whole story.
Cats and ferrets are susceptible to many different types of influenza viruses, and are good species to look at when figuring out if a virus can spread to other domestic animals. A study in the recent edition of Influenza and Other Respiratory Viruses (Kim et al, May 2013) looked at transmission of H3N2 CIV between dogs, cats and ferrets.
In that study, researchers infected dogs with CIV and kept them in close proximity to cats and ferrets, but without direct contact. They also infected cats and ferrets to see whether they could transmit the virus to other cats or ferrets.
Here are some highlights from the study:
- All directly infected animals developed some degree of illness, with cats and dogs typically developing sneezing, coughing, increased respiratory effort and nasal discharge, and ferrets only developing sneezing.
- Cats could become infected by being in proximity to both infected dogs or infected cats.
- Ferrets didn't get infected when exposed to infected dogs.
- Ferrets did not develop disease after exposure to an infected ferret but 2/3 developed antibodies against CIV, meaning the virus had been transmitted, but not able to cause disease.
- Cats shed higher amounts of virus than ferrets.
- Dogs stopped shedding the virus by day 8 after infection. That's not surprising since influenza shedding is short-term with H3N8 CIV. It shows that use of good infection control measures, particularly isolation, can be a key component of canine flu control.
- Dogs with H3N2 CIV are potential sources of infection for cats and ferrets.
- Cats that are exposed to the virus can get sick and be sources of infection for other animals, presumably including dogs. Cats may be another truly susceptible host for this virus.
- Ferrets seem pretty resistant to the virus. It probably takes fairly high level exposure for them to get infected and they are less likely to be of concern for subsequent transmission.
Interspecies transmission of flu viruses, and other viruses, is obviously an issue. Most of the attention is paid to the bird-pig-human cycle, for good reason. Birds are the reservoirs of all influenza virus variants, pigs are susceptible to both human and bird flu viruses and can act as a "mixing vessel," and humans are the species we're ultimately most concerned about. However, the potential for disease in pets and for pets to be reservoirs of influenza for people or other animals shouldn't be neglected. I've frequently had discussions with colleagues in the medical and public health fields about the need for parallel companion animal surveillance when plans are made for emerging infectious disease surveillance and response (e.g. SARS, H1N1 flu, novel coronavirus). They typically respond with general enthusiasm, but interest and application aren't the same, and actually getting plans in place to perform coordinated parallel surveillance hasn't happened. Studies like this are just one more piece in the puzzle that indicate the need for broader surveillance and consideration of pets.
Surprise, surprise - Meg has a hot spot.
"Hot spots" (aka focal bacterial pyoderma) are common skin infections in some dogs. Meg has underlying skin issues and lately has spent a lot of time wallowing around in ponds (because that's what she likes to do). With her skin issues, potentially weaker immune system because of her advanced age, and frequent wetness, she's a bacterial skin infection waiting to happen.
The latest hot spot is under her neck, and was evident by some colour change in the area (picture #1) and a bit of scratching, along with an odour if you get really close. These signs can easily be missed, especially early on, as the infected site is a bit hidden. Often, people only notice when it gets really wet and stinky, or when the dog scratches at it incessantly. Clipping the area revealed a more extensively affected area (picture #2) and a couple of focal spots with some pussy discharge. (It's quite amazing what can be hiding under an animal's fur!)
A hot spot is caused by a bacterial infection, and it's almost guaranteed that it's a staph infection (most likely Staphylococcus pseudintermedius). I took a swab from the affected area for culture. That's probably not critical in a case like this, especially when I'm going to treat it topically and without antibiotics, but since I can do it myself, it never hurts to have the information with regard to what bug is responsible (particularly if the infection comes back again).
The approach to treating hot spots is pretty straightforward, and owner compliance is key. Here's the plan:
Clip the area
- This helps identify the extent of the problem. It also (very importantly) helps keep the area dry and facilitates topical treatment.
Keep the animal from traumatizing the site
- That's been easy so far with Meg since she's not really scratching at it. If she was scratching, we'd need to put on an Elizabethan collar or use some other form of protection. In some cases, corticosteroid anti-inflammatories are needed to control the itch (and thereby the scratch).
Keep it dry
- Easier said than done. Despite being old and lazy, Meg is very motivated when it comes to lounging around in whatever water she can find (including the other night at 3:00 am... don't get me started on that one). Other than that, since the site is clipped now, keeping it dry is not a major problem.
- This is a bacterial infection, but the advantage of skin infections is that skin's on the outside. We can treat it topically and avoid using oral or injectable antibiotics. There are various things that can be done this way, usually involving bathing, wiping or spraying the area with topical antiseptics. We're using an antiseptic spray on Meg.
- Nothing major. It's unlikely that the cause is something zoonotic (and if it's MRSA, she presumably got it from someone in the family!). The staph that typically cause these infections are common inhabitants of canine skin. They rarely, if ever, cause infections in the absence of some inciting cause so Merlin (the other dog) and Finnegan (the cat) are unlikely to get an infection from Meg in this situation.
- A little handwashing goes a long way.
Hopefully I don't get to write about the massively increasing hot spot next week.
Cranimals Organic Pet Supplements has launched an at-home urinary test kit for dogs and cats that lets you "Monitor and track your pets health in an accurate and economical way, avoiding costly, unnecessary trips to the vet" (while not avoiding costly, unnecessary supplements, I assume).
The test claims to diagnose urinary tract infections (UTIs) by "detecting blood, leukocytes (AKA white blood cells) and nitrite in animal urine." Unfortunately, it cant.
- Blood in the urine does not necessarily mean there is an infection (i.e. this is a non-specific sign). In fact, a minority of cats with blood in their urine have an infection. They are much more likely have another problem like idiopathic cystitis that needs to be treated differently than an infection.
- Urine test strips for white blood cells are notoriously useless in animals. Maybe they have a better, more useful version, but I doubt it. The best way to detect these cells in the urine is to look for them using a microscope.
- Nitrite can be produced by bacteria in the urine but it has little to no diagnostic value in dogs and cats.
There's no mention about any specific evaluation of the test (i.e. they haven't checked to see if the test actually does what it's supposed to). By the look of the picture, it seems to simply be a urine dipstick in a fancy holder marked up a couple thousand percent to make money. Actually, it seems to be an inferior type of dipstick since it only tests for 3 things, two of which are useless.
Not surprisingly, the test is to be used in conjunction with their supplements (which probably explains why a supplement company decided to enter the diagnostic testing business).
The test isn't exactly cheap either: $39.95 for dogs and $49.95 for cats (the only difference to me being the cat kit comes with a bit of non-absorbent litter to put in the litterbox to collect urine, with a nice markup there too). While marketed as a way to save money on veterinary bills, think hard about what it will really do. Beyond potentially providing misleading information that could impact proper care, it will probably end up costing owners more:
- If the test is negative and the pet has urinary tract issues, it needs to be seen by a veterinarian to find out what's going on.
- If the test is positive, the pet needs to be seen by a veterinarian to get treated. No competent veterinarian is going to prescribe a treatment based on an at-home test like this. So, the full range of testing will be done anyway.
Ultimately, if the pet is sick, it needs to see a veterinarian. If it's not sick, there's no indication for testing like this.
If you want to know some real facts about diagnosing UTIs in dogs and cats, check out the International Society for Companion Animal Infectious Diseases Guidelines for diagnosis and management of UTIs in dogs and cats.
If you still think this test is worth the money, I've got some great oceanfront property in Saskatoon that I'll sell you (see photo). The water skiing is particularly good in January.
This is an increasingly common question, because MRSP is increasingly common. I've had two calls about it this week, and it's only Wednesday.
It's a good question to ask because MRSP (methicillin-resistant Staphylococcus pseudintermedius) is a highly drug-resistant bacterium that causes a lot of problems in dogs, and because of the high profile of its relatively distant relative, MRSA (methicillin-resistant Staphylococcus aureus), in people.
The short answer is: Yes, MRSP can infect people
BUT... (and it's a big and important but):
It's exceedingly rare and the overall risk is very low.
Here's my reasoning behind this answer:
1) Reports of MRSP infections in people are very rare.
- I think there are only two such published reports at the moment. There have probably been more infections than the number that are published, and there's the potential for MRSP to be misdiagnosed by some human diagnostic labs (meaning some MRSP infections may be mistaken for something else), but I think it's fair to sayl this a very rare infection in humans.
2) MRSP is not well adapted to infect people.
- MRSP is not inherently any more likely to cause infection than methicillin-susceptible strains of S. pseudintermedius (MSSP).
- MSSP can be found on basically every dog.
- A large percentage of the human population has contact with dogs every day.
- So, a large percentage of people encounter MSSP every day. Yet, reports of MSSP infection in people are very rare. To me, that indicates that this bacterium is poorly adapted to be a human pathogen.
3) Veterinary dermatologists are not extinct.
- MRSP is very common in dogs with skin infections. In some practices, it's the main cause of these infections.
- That means veterinary dermatologists encounter a lot of MRSP every day.
- I have yet to hear a report of a veterinary dermatologist getting an MRSP infection (carriers yes, disease no). I wouldn't be surprised if there actually have been some infections, but dermatologists can be considered the canaries in the mine when it comes to human MRSP risk, and I'm not aware of any real issues.
4) All dogs are biohazardous
- While this may not comfort the people calling me who are worried about the health of their families, it's important to put things into perspective. All dogs are carrying multiple microorganisms that could cause disease in people under the right circumstances (and the same goes for all cats, horses, people etc. for that matter).
- If you screened the average dog, you'd find things that are of greater concern that MRSP. In fact, MRSP probably barely cracks my "Top 10 List" of things I'm worried about the average dog spreading.
So, yes, there's a risk of MRSP infection when a person has contact with a dog infected with or carrying MRSP. There's also a risk of infection from methicillin-susceptible S. pseudintermedius, the version of the bug that basically all dogs carry, and a whole range of other bugs.
There will never be a zero-risk pet when it comes to zoonotic diseases. It's impossible. The risks may be very low but we can never eliminate all risk, just like we can never eliminate all risk from walking down the street. For some people, that slight degree of uncontrollable risk might be too much to handle, and they probably shouldn't own a pet. For most, the positive aspects of pet ownership outweigh the risks, and some basic hygiene practices (e.g. handwashing, avoiding licking, avoiding contact with the dog's mouth, nose and bum) can reduce that already low risk even further.
Merlin’s been a great dog so far, but despite that, there’s no need to propagate his genes. So, Monday was the big day… neuter time! As expected, since returning home he’s been feeling sorry for himself, but otherwise so far, so good.
Being someone who deals exclusively with infectious diseases and does surgical site infection (SSI) research, I have to think about his risk of developing an infection and how to prevent that.
Infection rates after neuters are very low. Actually, I can’t say that with confidence since we don’t have good data to back it up. We just finished one of the largest surgical site infection surveillance studies in dogs and cats, but being based at a tertiary care referral hospital, we didn’t get any data on neuters. I’m not aware of any private-practice-based studies that have assessed SSIs in dogs and cats, so my initial statement is just based on the fact that I don’t hear much about SSIs after neuters, and when I talk to people in primary care practices, they don’t report many of these infections. They occur, but they probably are truly rare.
However, rare doesn’t mean it will never happen, so pet owners need to be aware of what they can do to reduce the risk of post-operative infections (and then actually do it).
It’s been said in human medicine that the most critical time for preventing (or causing) SSIs begins and ends in the operating room. I think that’s true for animals as well, so there’s not much that the pet owner can do about that part except choose a good veterinarian, and not be afraid to ask pointed questions about the clinic's infection control measures. The pet owner’s major role is taking care of the animal after surgery. Here are a few things that I need to do for Merlin:
- Restrict his exercise for a few days. Trauma to the incision site will increase inflammation and the chance of an opportunistic infection developing.
- Keep him from swimming (or more accurately, wallowing in the swampy areas and ponds around home). Keeping the incision dry is important for good wound healing.
- Keep him from licking the wound. This a huge factor and one that people often mess up. Yes, he hates his Elizabethan collar (i.e. the head cone). However, it’s important that he wears it to keep him from damaging the incision site and seeding it with bacteria from his mouth. It’s a matter of short-term pain (annoyance, actually) for long-term gain.
- Keep an eye on the incision. A little inflammation (e.g. redness, swelling) is normal. If it increases or any discharge develops, that might indicate a developing infection. If that occurs, getting him re-evaluated ASAP is important.
- Make sure he goes in for his recheck, and that it’s done on time. This is important to detect problems in a timely fashion and to remove his sutures. (Merlin will presumably get his "recheck" at home, since the two DVM degrees Heather and I have hopefully give us the collective ability to remove a few stitches ourselves and determine if the incision is healing okay.)
None of this guarantees Merlin won’t get an infection, but these measures are all important. There is a non-preventable fraction of infections - meaning some will occur despite everything you do. However, a large percentage of SSIs are preventable and these basic practices can help.
While this morning's -7C temperature and snow don't exactly make me think about sandboxes or wandering around barefoot, warmer weather will presumably occur someday and the risk of outdoor exposure to parasites will start up again.
Since nothing says summer like hookworms, here's a new info sheet all about hookworms, including information on cutaneous larva migrans. The sheet can also be found on the Worms & Germs Resources - Pets page, along with info sheets on many other topics.
Business Mirror, a Philippine news website, had a recent article entitled "Rabies: deadlier than ever". That's a bit like saying Decapitation: now an even worse idea. Rabies isn't 'deadlier than ever,' since it's hard to get deadlier when the disease is already almost invariably fatal.
Anyway, beyond quibbling about the title, there are some interesting parts to the tragic story.
The article describes the death of a young boy. He was attacked by a dog while playing in his front yard in the Philippines. After the attack, he was taken to the hospital where, while he treated for some large scratches, he was not treated for rabies exposure because there were no bites.
This isn't too surprising, since it's an area in which there are some education gaps and misconceptions. The main risk for rabies transmission from dogs is from bites, since the virus is present in high levels in saliva, and bites directly inoculate saliva into the body. Rabies contaminated saliva deposited on intact skin isn't a risk. Rabies virus shouldn't be hanging out on a dogs paws, so it's easy to see how the transmission risk from scratches might be overlooked. However, during an attack, saliva contamination of the skin and a scratch that breaks the skin can both occur, thereby inoculating rabies virus into the body just like a bite.
Presumably that's what happened here, because 2 months after the attack, the boy developed rabies. It started with severe itchiness over the site of the scratch, and he was dead two days later.
We can't play around with rabies. If there's potential that an animal interaction led to rabies exposure:
- The animal must be identified and either euthanized so its brain can be tested, or (if a dog or cat) quarantined for 10 days to ensure that it does not exhibit any signs of rabies.
- If the animal can't be identified and quarantined or tested (or if it's positive for rabies), proper post-exposure treatment is required.
More information about rabies can be found on the Worms & Germs Resources - Pets page.
“Is MRSP zoonotic?” That’s a question I get all the time. MRSP (methicillin-resistant Staphylococcus pseudintermedius) is a canine staph (a bacterium) to which people are exposed all the time. Yes, it can infect people, but only very rarely, particularly when you consider how often they’re exposed. Nonetheless, human MRSP infections can occur.
My typical answer to the question is “Yes, but…” followed by an explanation of the overall low risk. My general line is:
- It can be transmitted to people.
- Human infections are very rare
- There’s no use panicking over MRSP or being draconian when you have an infected animal.
- At the same time, no one wants a highly resistant infection, so some basic measures should be used to reduce the risk of transmission.
Issues are also greater when people with compromised immune systems are involved, and a recent paper highlights this.
The paper (Savini et al, Journal of Clinical Microbiology 2013) describes MRSP infection in a 65-year-old man who was immunocompromised because of a bone marrow transplant. He developed a wound infection, and his physicians and the diagnostic lab did a pretty comprehensive study of the bacterium they isolated from the wound, ultimately determining it to be MRSP.
The man lived “close to a pet dog and farm cows," whatever that means. The dog was probably the source, but unfortunately (as is common) no efforts were made to see if the dog was carrying MRSP, to see if the cows were positive for MRSP (since this bug can rarely be found in cattle), or to type the isolate to see how it compares to strains that are typically found in animals.
Will this report change my answer to the first question? No. It gives me another example of a human MRSP infection, but such events are still exceedingly rare and this individual was highly immunocompromised, having graft-vs-host disease after his bone marrow transplant.
We don’t need to be afraid of MRSP, but we need to realize there is some risk, and the risk is presumably higher for certain people (e.g. very young, very old, people with compromised immune systems). We therefore need to use some basic infection control and hygiene practices to reduce the incidence of transmission of MRSP and other potentially harmful microorganisms from animals to people.
More information about MRSP can be found on the Worms & Germs Resources - Pets page.
Allegedly, spring is here. The foot of snow on the ground and minus double-digit temperatures don’t really convince me, but the calendar can't lie, I guess.
Anyway, spring brings with it many things, one of which is hatching chicks. I saw signs for them at a local farm supply store a couple of days ago, and perhaps not coincidentally, this week’s edition of CDC’s Morbidity and Mortality Weekly Reports provides an update on the 2012 human Salmonella outbreak that was linked to contact with chicks and ducklings from a single supplier.
This outbreak has been talked about before, but this report gives some final numbers.
- Ultimately, 195 people infected with the outbreak strain of Salmonella Infantis were identified. (That’s probably a major underestimation too, since in outbreaks like this lots of people get sick but don’t have fecal cultures for Salmonella performed.)
- 33% of affected individuals were children 10 years of age or less.
- 79% of people who got sick reported contact with poultry in the week before illness started.
- Birds were obtained from various feed stores or directly from hatcheries, and 87% of people that provided information about chick or duckling sources reported getting them from a single mail-order hatchery in Ohio.
Chicks and Salmonella go hand-in-hard. Chicks are high-risk for shedding the bacterium, and people can get infected by handling chicks or having contact with their environment. Children are at high risk for infection since they tend to have closer contact with chicks and because they are more susceptible to Salmonella. That’s why it’s recommended that kids less than 5 years of age not have contact with young poultry. Day cares and kindergartens planning on their annual hatching chick programs… please take note.
The article includes some more recommendations.
- Feed stores should use physical barriers (e.g., a wall or fence) between customers and poultry displays to prevent direct contact with poultry.
- Educational materials warning customers of and advising them on how to reduce the risk for Salmonella infection from live poultry should be distributed with all live poultry purchases
Part of the last point is keeping young kids away from chicks and stressing good hand hygiene practices. Like most things in infection control, a little common sense goes a long way.
Following outbreaks of campylobacteriosis in a Canberra, Australia nursing home, health officials have recommended banning puppies from aged care facilities. Two outbreaks that involved at least 15 people occurred in one such facility last year, and a healthy puppy was identified as the cause. Unlike many reports in which people try to blame an animal source without any evidence, they isolated Campylobacter jejuni from the puppy and people. That, along with ample previous evidence of a role of puppies in this disease, is pretty strong evidence that the puppy was the problem.
They concluded that puppies shouldn't be aged care companions because of "high rates of Campylobacter carriage and shedding, their social immaturity, susceptibility of elderly residents to infection and poor outcomes." Such a conclusion is not really that surprising or novel, actually. The 2008 international guidelines for animal visitation in hospitals recommend that only adult dogs and cats should be used for these activities, for several good reasons:
- Puppies are biohazardous. It's just biology. Young animals are at much greater risk of shedding various bacteria that can cause disease in people, such as Campylobacter.
- Contact with puppies and kittens has been clearly demonstrated as a risk factor for diseases like campylobacteriosis.
- Compared to adult animals, puppies and kittens are more likely to poop on the floor.
- Puppies and kittens are also more likely to nip or scratch through playful behaviour.
This is not to say that everyone should avoid puppies and kittens, after all they are cute and entertaining, and a great pet in many situations. The risk is higher in certain populations, such as people living in nursing homes, and while puppies are fun, similar positive impacts can be obtained by well-run visitation programs using older animals. That's the approach that being taken in Canberra, as trained adult dogs will still be allowed to visit aged care homes (hopefully as part of a structured program).
Today, we went to the University of Guelph's annual open house, College Royal. As per usual, we only covered a fraction of the events, but had to do the traditional visits with the animals and get some of the Food Science milkshakes (even thought it was -2C outside). Animals are a big part of College Royal. In most cases, you can look but not touch (e.g. Old MacDonald's barn, livestock shows), but there is a petting zoo.
The petting zoo has evolved a lot over the years. I was in charge of it for a couple of years when I was a veterinary student, but what we do now is very different from what we did then (in the mid 1990s).
- We've stopped using certain kinds of animals. Most notably, the calves (i.e. baby cows) are gone, since they're considered high risk for transmitting a few important microorganisms. The thing that triggered that was the year we decided to test fecal samples from the calves and found out (not too surprisingly, really) that all of them were shedding Cryptosporidium.
- We've changed the location, for a few reasons. The old location was in a ward in the large animal hospital, which therefore had the potential to impact patient care. The current setup is outside of patient care areas, and makes it easier to contain activities and visitors, and to organize overall.
- Signage has been improved. We used to have many signs, but they mainly provided just basic information about the animals (e.g. "Hi, my name's Betsy. I'm a Holstein cow.") I don't remember having many signs (if any) about hand washing, no food or drink, and other public health measures, but thankfully they do now.
- Hand hygiene is a priority. We didn't really do anything in terms of promoting hand hygiene at the event in the 1990s. Now, we have multiple hand hygiene stations, signs to tell people to wash their hands, people reminding visitors to wash their hands, and a structured flow of traffic through the petting zoo that leads people out past the hand hygiene stations.
Big changes, and for the better.
Has anyone ever gotten sick from the College Royal Petting Zoo? Not that I know of, but it's certainly possible.
Have we eliminated all risk? No. That's not possible. What we try to do is to reduce it as much as we can.
Are all petting zoos like this? Unfortunately no, they are not. Things at other petting zoos are much better overall than they were even five years ago, but there's still lots of room for improvement and still an unnecessarily high risk of infectious diseases.
A lawsuit filed recently in North Carolina highlights some of the issues around petting zoos. The suit was filed in response to a 2011 E. coli outbreak associated with the NC State Fair that sickened more than 100 visitors and killed a two-year-old boy. Among the claims in the suit are:
- animal areas were cleaned in such a manner that E. coli was spread around
- eating and drinking were encouraged in the animal area (presumably, the actual issue is that eating and drinking were not prohibited. I doubt the fair said "please eat and drink in this area")
- there were inadequate hand hygiene stations
- they failed to follow the State Fair's own guidelines
If these claims are true, that's a pretty big "oops" and someone is probably going to be writing a very large cheque.
On a similar note, a UK petting farm was recently found liable for a 2009 E. coli outbreak that sickened 93 people.
Petting zoo design and operation aren't foolproof, but it's not rocket science either - it's largely common sense. There are clear guidelines covering the basics, and adhering to them should greatly reduce any risk of illness or injury. Failing to do so leads to trouble, of both the infectious disease and legal kind.
I write a lot about reptiles, and while it's usually in the context of their biohazardous nature, I actually like them. I've owned some before and it's not outside of the realm of possibility that we'll get more in the future (I might be safe with that statement since Heather doesn't read this blog. However, her co-workers that do will likely rat me out).
Reptiles can be good pets in some situations. The key is understanding and accepting the risk. That involves understanding the risks associated with reptiles, understanding the types of households where the risk is high, and knowing what to do to reduce the risk.
Denial isn't an effective infection control measure.
- Uh...no. Reptiles are clearly higher risk when it comes to Salmonella. Reptile contact has been clearly and repeatedly shown to be a risk factor for human salmonellosis. Dogs and cats (and various other animals) are potential sources of salmonellosis, but while many more people have contact with dogs and cats, reptile contact is much more likely to result in Salmonella transmission. It only makes sense. Reptiles are at very high risk for shedding the bacterium. Dogs and cats rarely do (especially when they're not fed raw meat).
"She’s never seen a case in the 30-plus years she’s been working with reptiles."
- Ok. So, since I've never actually seen influenza virus, I'll never get the flu?
- I know a lot of infectious disease physicians who have had a very different experience. In fact, it's rare for me to talk to an infectious diseases physician without him/her providing details of various reptile-associated salmonellosis cases.
Talking about the risk of Salmonella shouldn't be taken as insulting or a threat to reptile enthusiasts. People should accept that the risk is present and try to minimize it. The article actually has some useful information along those line. "Just use common sense - wash hands thoroughly after handling the animal or its cage. A good rule of thumb is to keep hand sanitizer nearby. While children under age 5 should avoid any contact with reptiles, Hart doesn’t advise snakes for children under age 7 or 8 for fear they could unwittingly harm the creature."
Reducing the risk is common sense. Keep reptiles out of high risk environments and use basic hygiene and infection control practices.
However, any semblance of common sense goes out the door when a rescue like this offers programs where you can pay them to bring reptiles to daycares, pre-schools and grade schools. So much for young kids avoiding contact with reptiles.
Reptiles aren't bad, they're just bad in certain situations. Common sense needs to be more common.
Lately there has been a run of pet treat recalls due to Salmonella contamination (with the latest one courtesy of "Diggin' Your Dog"), but it shouldn't come as much of a surprise. Salmonella contamination of raw animal-based pet treats has been reported for years. It's not just a risk to dogs, since outbreaks of salmonellosis in people from handling treats have also been reported. Despite some good moves by the industry to improve the situation (e.g. better manufacturing practices, more products being irradiated), treats still need to be considered high-risk for being contaminated with Salmonella and other bacteria.
So, what can be done to reduce the risk?
- Buy individually wrapped or pre-packaged treats. Treats from bulk bins are higher risk because one contaminated item can cross-contaminate many others. Also, bins are often continually topped up without cleaning or disinfection so contamination can persist.
- Choose products that have been irradiated. There are still some baseless fears about irradiation, but there is absolutely no evidence that irradiation of food is harmful and it can effectively kill pathogenic microorganisms.
- Avoid feeding raw animal-based treats that have not been irradiated to animals at higher risk of becoming sick or having a serious infection. This includes elderly animals, puppies, pregnant and nursing dogs, dogs that are immunocompromised (e.g. undergoing chemotherapy) or dogs that have chronic intestinal disease. Also, they should not be fed to dogs that have contact with high risk people, such as those that live in households with infants, elderly individuals, pregnant women or immunocompromised individuals. Also, they shouldn't be fed to dogs that visit human hospitals. One study showed that dogs fed raw animal-based treats had a 12-times greater likelihood of shedding Salmonella (Lefebvre et al 2008).
- Wash your hands after handing pet treats.
If in doubt, or if your dog or family fits into one of those high risk groups, stick with processed treats that have been cooked or make your own cooked treats.
Some people like to send me links to internet sites to see if they can get a rise out of me. There are a few usual suspects (both senders of information and places I get sent to) but a new one for me was tlcpetfood.com
For some reason, this site has a series of FAQ's completely unrelated to pet food. Some are rather bizarre, such as "My dog keeps getting pneumonia, and we just found out her internal organs are on the wrong side. Help? "
Many of the answers are fine. That's because they're plagiarized... verbatim text taken from reputable sites (mainly AAHA's Healthy Pet site) without attribution. Besides the whole violation of intellectual property aspect, it's at least good that the advice is sound.
Some of the other answers they provide (likely the ones that aren't plagiarized) are considerably less sound.
The one that got sent to me was "Is it okay for my dog to lick my son's face?"
This is actually a common question and a reasonable one. There's no perfect answer to it, but there are definitely some imperfect answers, such as this one:
(It starts out okay...)
Yes, it probably is.
- I'd agree with that statement.
(Then goes downhill quickly...)
The only disease that dogs and humans can pass back and forth through saliva is beta strep throat, which is relatively rare.
- This is a myth that just won't go away. There's no evidence that pets are relevant sources of strep throat. Furthermore, there are many other pathogens that can be transmitted from dogs' saliva to people. Disease isn't common but it does occur and it can be fatal in some situations.
And if your son has a weakened immune system, you may want to be careful about exposing him to the normal bacteria that's present in the saliva of healthy dogs.
- Good advice. (However, if their statement that strep is the only thing that can come from dogs was actually true, this one wouldn't make any sense.)
My response to this common question is that I don't particularly like being licked by my dog. It's a personal thing and not a germaphobic response. It's unlikely to harm me as an adult with a (hopefully) functional immune system. I don't hover around my kid to make sure they don't get licked, but I don't encourage it either.
Licks to young kids (especially around the face), licks that have contact with skin lesions or mucous membranes (e.g. mouth, nose) or licks to people with compromised immune systems (including people that do not have a functioning spleen) are higher risk. Strep throat isn't a concern, but many other things are. There's a cost-benefit. If it's an important part of someone's bond with his/her animal, that's fine. Individuals just need to understand the risks, and be aware of when the risks are higher. Part of that is getting good advice, which can be a challenge on the internet.
Don't get me wrong. I'm all for pet therapy and animal visitation in hospitals - when it's done logically. I've been involved in research in the area, helped develop international guidelines and am chair of the medical advisory board of one of the largest pet therapy groups in the US. Animals can do great things in hospitals and we need to support good visitation programs. But that doesn't mean I check my brain at the door and think that all animals in all hospital situations are a good idea.
A colleague sent me a link to a Medscape News article entitled Woof! Does Fido Belong in the Hospital Delivery Room?
- My first thought was... not a chance. (My second, third and fourth thoughts were no better.)
The situation in the article isn't that clear cut though, since the English woman who wanted her dog in the delivery room had a trained therapy dog that helped her with an anxiety disorder. So, if this was truly a trained therapy dog (some people unfortunately make that claim just as an excuse to take their dog everywhere, and compromise people that truly need these animals), it would be justifiable since this is a service dog, not a companion, and we need to support access of service dogs.
However, it raises questions about whether this will open the door to requests for pets to join in the birthing process, now that we've moved from the era when dad paced outside the room to a time when half the family may be present, live-streaming the event to the internet and posting on Twitter.
What are some issues here?
A delivery room is a busy environment. Things can be nice and happy and relaxed. There can also be yelling (personal experience there), lots of activity and other things that might scare or upset the dog. I'm not worried about the dog's feelings here, but what a startled or upset dog might do (e.g jump, bark, bite, pee, try to run away).
Not all deliveries are smooth and things can go from good to bad quickly. The last thing that's needed is another distraction (e.g. the aforementioned dog jumping, growling, barking, peeing, etc.) when medical personnel are dealing with a life-threatening delivery complication.
A newborn is a high risk person for infectious diseases. Every dog is shedding multiple microorganisms that can cause disease. Usually, the risk is low. However, when you have a highly susceptible person (or persons, including the mother here to a lesser degree since post-partum infections are a concern), we don't want them exposed to pathogenic bacteria if we can avoid it. Yes, it's an ever-present risk in a hospital, but why add to the potential risks? It would seem illogical to have delivery personnel in full protective gear (e.g. gowns and gloves) with a dog potentially aerosolizing bacteria nearby through breathing, coughing, barking, shaking, and tail-wagging. People would also likely contaminate their hands often by touching the dog. Yes, medical staff can be to told to avoid contact with the animal and wash their hands, but we know from previous research that hand hygiene by medical personnel after animal contact is very (very!) uncommon.
Also, we know that a baby's first bacterial encounters have a major impact on its developing bacterial microbiome (that is, the composition of normal bacterial populations at various body sites, something that's important for good health and development). Babies born by C-section have much different microbiomes for a long period of time compared to those born by vaginal delivery. Do we really want to confuse the picture more by having some of the first bacteria encountered being Fido's bacterial flora? It's not going to make the baby start barking, but I'd rather the baby not be exposed to various bacteria from a dog seconds after it's born.
In my opinion, visitation is more important the longer the person is in hospital, the more lonely they are and the more upsetting or depressing the situation is. Delivery is typically a short-term, happy hospital stay. What's the real benefit here for your average dog owner?
Personal pets in any hospital situation is a controversial area. Unlike dogs that are part of proper visitation programs, these dogs tend not to have any health screening, behaviour screening or other type of assessment. There's also no handler training. You might say "well, the dog's just visiting its owner so that's not a big deal." However, the dog has to go from the parking lot to the room and back again. What are the odds that the dog's not going to encounter lots of other people in the process, let alone potentially distracting or scary situations. Do you want your elderly immunocompromised relative to ride (or be stuck in!) a hospital elevator with an aggressive or otherwise high risk dog? Or to have you child that just had surgery step on a pile of dog poop? There are clear screening, training and supervision criteria for hospital visitation dogs, and they are there for a reason.
Back to the article. Dr. Arthur Kaplan, the author, sums things up nicely:
"I think there are risks, and I think the risks are pretty significant. I am not sure that we should open the door to every barnyard creature we could think of to be present at birth, even when the mom-to-be says that she would like to have her pet there. But at the same time, I think there are arguments that, for some people, such as the woman in England who has a special relationship with her pet, or perhaps a woman who is blind, a case can be made."
In Canada (like most places), there's no semblance of a formal surveillance program for infectious diseases of companion animals. We're left with anecdotes and whatever short-term research projects we can put together to try to figure out what's happening in our companion animal populations. Not ideal, but better than nothing.
Over the past month or two, I've been hearing more rumblings about canine parvovirus infections in dogs in Ontario. Nothing too dramatic, just a spike in calls and emails about cases, mainly typical parvo cases (e.g. disease in young and un- or inadequately-vaccinated puppies, outbreaks in groups like shelters and breeding kennels) with some cases that seem more severe and some in dogs that seem to have appropriate vaccination history or in older dogs. It doesn't seem to be due to a focal outbreak, since these may be occurring in a few different regions in Ontario. This type of anecdotal information is far from definitive but enough to start asking questions.
I'm not the only one who's been hearing this. The Ontario Veterinary Medical Association has had enquiries and has been receiving more information from Ontario vets, so they have put out a press release indicating that something might be going on with regard to parvovirus in the province, and emphasizing the need for proper vaccination and preventive medical care for dogs.
So is something happening in Ontario? I'm still not sure. Sometimes situations like these are just because people are talking and we're hearing more about little clusters that go on all the time under the radar. However, this could be real and caused by a variety of factors such as decreasing vaccination rates, increased parvovirus circulation in some regions or a change in parvovirus strains.
The only way to truly figure out what's happening is to get more data. That's not an easy proposition since surveillance networks aren't established and there's no money to do any disease surveillance like this. However, Ontario veterinarians who are seeing parvo cases can feel free to provide more info and to send samples for typing.
A call to arms from guest blogger and University of Guelph professor, Dr. John Prescott:
Watching the global emergence and spread of multi-drug resistant bacteria is like seeing a train wreck in slow motion. There’s a sense of both inexorability and powerlessness. In the March 2013 issue of the Equine Veterinary Journal, Mark Bowen of the School of Veterinary Medicine and Science, University of Nottingham, writes that there is clear evidence of the need for change in our relationship with antimicrobials. Change is what many bacteria do for a living; of course the problem is not that bacteria change to resistance, but also that people are so resistant to change.
The excellent editorial (“Antimicrobial stewardship: Time for change”) describes the sensible steps taken by the British Equine Veterinary Association (BEVA) in 2012 to promote the stewardship of antimicrobial drugs in horses. These steps are summarized on the BEVA website: http://www.beva.org.uk/useful-info/Vets/Guidance/AMR. They provide an excellent approach to stewardship of antimicrobials in horses. BEVA has developed neat and simple promotional material to help equine veterinarians using these drugs do their part to help preserve them.
The BEVA project is summarized by the acronym PROTECT ME, which encompasses 9 steps to promote stewardship. PROTECT comes from for Practice policy; Reduce prophylaxis; Other options; Types of drugs and bacteria; Culture and sensitivity; Treat effectively, and ME come from Monitor and Educate. The brilliance and perhaps even contrariness of the BEVA approach is that it believes that policies should be created at the local level, and should be both dynamic and follow simple key concepts, rather than be national guidelines developed by people working in ivory towers.
The BEVA website provides the templates and forms for equine practitioners everywhere to develop simple and local policies that commit to stewardship. An important element in the PROTECT ME documents is to try to protect the drugs classified by the World Health Organization as the “Critically Important Antimicrobials” (3rd and 4th generation cephalosporins, fluoroquinolones). These drugs are categorized as “protected”. Drugs such as vancomycin and imipenem are categorized as “avoided”. The PROTECT ME approach promotes the use of “first line” antimicrobials as first choice for treatment of common conditions as part of the practice policy, and link this to the British “cascade” approach to antimicrobial drug choice. The BEVA approach is refreshing because it takes an intelligent, long-term approach that embraces the responsibility that users share to preserve the miracle while our scientists work feverishly to develop the next generation of antimicrobials. These are however going to be extremely expensive and perhaps also unavailable for animal use, except perhaps through the black market.
The antimicrobial “miracle drugs” revolutionized medicine and came into widespread use long before there was any science behind their optimal use. We’re still discovering how best to use them but we need to continue to develop strategies and approaches that optimize their use and minimize resistance and other side effects. The easily followed BEVA approach encourages user engagement with and responsibility for stewardship. Change is painful, but we have no choice. Let’s embrace it.
I tend not to write about recalls but the recent, large and expanding pet treat recall has lead to a lot of questions that are worth discussing. At last report, treats manufactured by Kasel Associates Industries Inc from April 20-Sept 19, 2012 were potentially contaminated with Salmonella and recalled. Not surprisingly, most of the recalled treats are things like pig ears, bully sticks and jerky strips made from raw animal products. The impact on pets isn't clear beyond a vague statement about "a small number of complaints of illness in dogs who were exposed to the treats." Anyway, here are some common questions I've been hearing:
My dog ate a recalled treat, will it get sick? Maybe, but probably not. It's not clear how many treats were really contaminated, so it's quite possible that most products weren't contaminated. Furthermore, the dose of Salmonella that a dog ingests is important. Low-level contamination is less of a concern, particularly in otherwise healthy dogs. The strain of Salmonella itself also plays a role since some strains seem to cause more serious disease or cause disease at lower doses than others. I haven't seen much information about the strain (or strains) involved here.
If my dog gets sick, what will happen? That's highly variable. Salmonella can cause disease ranging from vague (e.g. a little depressed and decreased appetite) to classical intestinal disease (e.g. diarrhea +/- vomiting) to rare but severe systemic disease (e.g. sudden death, bloodstream infection with subsequent overwhelming body-wide infection or focal infection of different body sites like joints).
Should my dog be tested for Salmonella? Not if it's healthy. The main question is what would be done with the result. If positive, it wouldn't mean that anything needs to be done or even that disease is likely to occur. A negative isn't very helpful either since a single sample is far from 100% sensitive. The key point is that we treat disease, not culture results. If the dog looks healthy, it's not going to be treated, regardless of the culture result. You'd also need to have the isolate tested to see if it's the same as the strain in the recalled treats if you wanted to determine whether treats were the source, and that testing is not readily available.
Should my dog be treated with antibiotics? As you can guess from the paragraph above - no. There's no evidence that antibiotic treatment of an exposed dog or a healthy carrier reduces the risk of disease or shortens the shedding time. In fact, it might even make things worse by disrupting the normal protective intestinal bacterial population, which might make disease more likely or make it harder for the body to eliminate Salmonella. Treatment might also encourage development of antibiotic resistance, something we don't need any more of with Salmonella.
What can I do to reduce the risk of disease? Not much. If a dog has eaten a Salmonella-contaminated treat, there's not really anything that can be done after the fact beyond watching for signs of disease.
So... what should I do? Relax and watch. The odds of a problem are low. If a problem develops, odds are it will be mild. That's not to say that severe disease can't or won't happen, it's just that it's unlikely and there's nothing that you can do after exposure anyway. Identifying signs consistent with early disease (e.g. lethargy, decreased appetite, diarrhea) and getting prompt veterinary care should help reduce the risk of complications or serious disease.
A proposed Florida bill would require shelter operators to produce monthly and annual euthanasia reports. The reported goal of the effort is to "reduce euthanasia of unwanted animals." But how? The idea has various pros and cons.
Potential good points
More transparency: Euthanasia rates are often considered the "dirty secret" of the shelter world. In reality, it's not the shelters' fault that animals are being euthanized. It's society's fault because of overpopulation. Shelters should be reporting these numbers (and ensuring they are accurate), not as part of a "we kill fewer than you do" competition, but to highlight the challenges, increase public awareness and to work toward improving the shelter system.
More data: The more we understand the epidemiology of adoption, euthanasia, disease and other events in shelters, the better. Knowledge helps us figure out better ways to run things.
Potential bad points
Animal welfare: Will shelters resist euthanizing sick or injured animals that would otherwise be euthanized to keep their rates lower? If an animal is very sick, will there be the temptation to let it die rather than euthanize it, if deaths are not reportable but euthanasias are?
Overpopulation in shelters: If shelters try to avoid euthanising animals because the rates are reportable, there will be more animals in the shelters - likely more than they can actually handle. More animals in a shelter does not mean more adoptions. Overcrowding leads to many problems such as increased disease risk, deceased quality of care, decreased human contact and increased shelter operation costs.
Outbreak potential: Yet another issue related to overcrowding is when you cram in as many animals as possible (often using carriers and other temporary housing stashed anywhere there's spare space) and decrease the time you spend with each animal, you create great potential for a disease outbreak. The more animals are present, the more likely the outbreak will take hold and the harder it will be to control.
Needless transfers: Will shelters try to transfer animals that are unadoptable to areas where this law is not in effect, simply to be euthanized outside of the recording system? Beyond the humane aspects of putting the animal through the stress of a transfer for no real reason, shipping shelter animals is notoriously high risk for shipping diseases along with them.
Cherry-picking: This already happens with some shelters, but one way to keep euthanasia rates low is to refuse to admit animals that are not likely to be adopted. Turning them away doesn't help the animal or society (and may result in more animal suffering, among other things, if the animals are simply abandoned), but it keeps euthanasia numbers low.
Will this work?
Shelters don't euthanize for fun. They do it because there is a finite number of homes available and the number of animals coming into shelters (especially cats) is way beyond that. This bill will not magically create millions of new homes for shelter animals. So, how will it "reduce euthanasia of unwanted animals"?
A representative of a group working to reduce shelter euthanasias added "We do not believe that it is the conscious will of the people of the state of Florida to kill over 50% of the lost and homeless shelter pets each year." It's not their conscious will but what can/will they do about it? Euthanasia numbers might help spur interest in adopting from shelters, and if so, that would be great. But the fact is that if 50% of animals in shelters are being euthanized, it's because they don't have homes.
Probably a well-intentioned but poorly thought-out approach to the pet overpopulation problem.
It's not hard to find news articles about animal bites. That's because they are very common, sometimes incite controversy (e.g. to euthanize the offending animal or not) and occasionally cause severe injury or death.
Here's a sampling of some recent reports:
- The University of Arizona Medical Center is reporting a steady increase in dog bites, with an almost doubling of bite numbers between 2008 and 2012. Three-hundred and twenty-eight (328) people were admitted with bites last year, including both children and adults. Most were bitten on the hands and fingers, and most were bitten by their own dogs. There were no deaths reported in 2012, but there was one in 2011, a man that was bitten in the neck and arm by his own pit bull cross.
- Sixty-three dog bite deaths were reported in Mumbai, India, over the past 5 years, out of a total of at least 90 000 people who are bitten annually.
- A Stoney Creek, Ontario mother is lobbying to have her neighbour's two German shepherds euthanized after they attached her 10-year-old son. The dogs were on leashes and being held by a friend of the owner's 14-year-old son when "The dogs became startled" and the boy was bitten on the arm and face. The dogs' owner argues that only one dog was involved, but figuring that out will be next to impossible. This raises a few different issues. One is the fact that a child, and not even a child of the owner, was responsible for the control of two large dogs in a public place. Another is what lead to the bite. The owner accuses the boy of taunting the dogs in the past, but even if that were true, previous taunting (what did he do? accuse the dogs of having a chihuahua for a mother?) isn't an excuse for biting.
While we often focus on dog bites, pretty much any animal with a mouth can bite. Records from a New South Wales, Australia, ambulance service reveal some more unusual calls for help in response to animal interactions. These include:
- A call because of a "deep bite on the hand" with "serious bleeding" after a woman was bitten by a Guinea pig. They were also called for a Guinea pig bite to a 4-year-old boy. The fact that Guinea pigs would bite isn't surprising, but the fact that the bite would lead to an ambulance call is.
- A call for a cat bite that severed an unnamed artery of an 80-year-old man. Hopefully it was a small artery.
- While not a bite (although cattle can bite), ambulances were called when a cow hit a 83-year-old man in the stomach, lifting him 3 feet in the air, and when a water buffalo tossed another man.
- Other animal associated calls included incidents caused by critters including a blue-ringed octopus, a catfish (would love to have the story about that one) and a goanna (a type of Australian monitor lizard - had to look that one up).
- And (not surprisingly, for Australia) there were shark bites, including a spear fisher who was "nudged" by a grey nurse shark attracted to the fish he had caught, and a more serious attack by a bull shark that resulted in loss of a finger and a serious leg laceration.
- Snake and spider bites weren't even listed in the report for some reason.
Understanding why bites occur is important to preventing them, and it's different in different areas. In North America, where most dog bites are from family pets, better training of the dog and people in the household is critical. In a place like Mumbai, where there are tens of thousands of stray dogs living in close confines with people and where many bites are from strays, a different approach is needed. Bites from pocket pets usually result from improper handling or trying to break up a fight. Shark bites are also another story. Ultimately, a lot of prevention is common sense, which unfortunately is not always that common.
I'm just back from vacation (luckily, with no infectious disease stories to write), but now I have to catch up on a few posts. One easy one that was waiting for me in my inbox was about Salmonella and hedgehogs.
I've written before about biohazardous hedgehogs, and more details about the US 2011-2013 multi-state Salmonella outbreak were reported in a recent edition of CDC's Morbidity and Mortality Weekly Reports. The outbreak was identified through recognition of a cluster of infections in people caused by the same, historically rare strain of Salmonella Typhimurium. Finding a cluster of the same strain, especially a rare one, suggests that there might be a common source, so an investigation ensued. Here are some highlights:
- Twenty people from 8 states (Alabama, Illinois, Indiana, Michigan, Minnesota, Ohio, Oregon and Washington) were affected, although (as is typical) it's almost guaranteed that many more people were affected but not tested.
- Young people were more often affected, with the average age being 13. The age range spanned from less than 1 year to 91 years of age.
- Four people were hospitalized and one died.
- 14/15 (93%) people interviewed reported direct or indirect contact with a hedgehog. That's a pretty strong indication that hedgehogs might be involved, since that number is wildly disproportionate to the percentage of people in the general population that have contact with hedgehogs.
- Hedgehogs were obtained from various breeders, not from a single source.That's not uncommon since breeders often get animals from other breeders or suppliers and a point-source of infection further up the supply chain is likely.
For some reason, hedgehogs are high risk pets when it comes to Salmonella. High Salmonella shedding rates have been identified in studies of healthy hedgehogs and it's clear that contact with healthy carriers can lead to human infection. Hedgehogs should be considered alongside reptiles in terms of pets that should not be present in high risk households (households with kids less than 5 years of age, elderly individuals, pregnant women or people with compromised immune systems). Hedgehog owners should take care to avoid direct and indirect contact with feces and use good hygiene practices to reduce the risk of infection.
It's been quite a while since the last post about MRSA in horses, but rest assured, it's still out there! Not too surprisingly it's also spreading (or at least starting to be found) in new places. A recent report in Veterinary Microbiology (Schwaber et al, 2013) describes an MRSA outbreak at a large animal teaching hospital in Israel. It is the first report of MRSA colonization in horses in the Middle East, although it's possible (and quite likely) that there's more to be found.
The discovery of the problem had a pretty typical progression: there were two horses in the hospital with post-operative wound infections from which Staphylococcus aureus was cultured, and the isolates from both horses had similar antimicrobial resistance patterns, including resistance to all beta-lactam antimicrobials (= MRSA). Validly concerned about the potential for the MRSA to spread among horses and people in the hospital, an investigation ensued - in this case the National Center for Infection Control (NCIC) was actually called in to coordinate the operation.
- They found MRSA in 12/84 (14.3%) horses, of which 11 were in the hospital at the time of sampling, and 1 had recently been discharged from the hospital. Consider though that 44 of the horses sampled were simply from farms from which an MRSA-positive horse had come - so 11/40 horses in the hospital were positive - that's 27.5%!
- 16/139 (11.5%) of personnel at the teaching hospital were positive for MRSA. Fortunately there were no clinical MRSA infections reported in people.
- The MRSA strain that was found in all the horses and most of the people was a very rare type - not the usual sequence type 8 (ST8) we're used to finding in horses in various other parts of the world. This one was an ST5, spa-type t535, SCCmec type V, which is even rare in the human population.
- The primary action taken to get the outbreak under control: increased infection control measures, including isolation of infected and colonized horses which were then handled with contact precautions (e.g. gloves, gowns), discharging horses from hospital as soon as medically possible to decrease transmission pressure, and having a nurse from the NCIC come in to instruct personnel on the measures to be taken, including emphasis on hand hygiene and increased use of alcohol-based hand sanitizer.
- In this outbreak, decolonization therapy was prescribed for all colonized personnel.
The report does not mention whether or not personnel at the hospital were required to submit to being tested and undergoing decolonization therapy. This can be a very tricky issue to handle, and it depends on what the local laws are. In Canada, employees cannot be forced to undergo testing or treatment, but in some other countries MRSA-positive healthcare workers may not be allowed to even work until their carrier status is cleared.
Interestingly enough, just a year or two before this outbreak occurred a study (as yet unpublished) had been carried out in the same region, during which they found MRSA in 7.2% (6/83) of hospitalized horses and none in horses from local farms. There is no mention regarding whether or not the hospital had taken measures to eradicate MRSA from the facility before the clinical infections that triggered the outbreak investigation occurred.
This was a typical MRSA "iceberg" - a couple of clinical cases were triggers for an investigation that found a lot more horses and people were actually carriers. This is exactly why it's important to remain diligent about infection control measures like hand hygiene at all times, so that pathogens like MRSA don't move in "under the radar." The authors of the paper summed it up nicely (although I'd leave out the part about decolonization):
"Strict implementation of hand hygiene, isolation of colonized and infected horses, decolonization
of colonized personnel and above all, constant education of veterinary students and personnel about the importance of infection control measures are required in order to decrease the risk for colonization and infection of both horses and personnel by MRSA and other pathogens."
More information about MRSA in horses is available on the Worms & Germs Resource - Horses page.
ProMed Mail's monthly US rabies update often contains some interesting cases, and the last one is no exception.
A llama in Georgia became aggressive, started biting itself and was spitting at one of its caretakers. A spitting llama certainly doesn't mean rabies (I have dodged enough llama spitballs to know that) but any sudden change in behaviour, especially with aggression, should raise some major red flags. Here, the llama was diagnosed as rabid and the person that was spat on is receiving post-exposure treatment.
A bobcat attacked a man and boy in Massachusetts, and not surprisingly, was diagnosed with rabies. In this case, the bobcat pounced on the man, bit his face, clawed his back and held him in something akin to a bear hug, before moving on to the man's nephew. Wild animals don't typically attack except under extenuating circumstances (e.g. being cornered, protecting offspring), so this type of event should be considered a rabies exposure until proven otherwise. The man shot the bobcat and it was confirmed as rabid.
In an all-too-common scenario, a family that took in a stray kitten ended up needing post-exposure treatment because the kitten was rabid. They found the sick kitten and tried to nurse it back to health, but it died the next day. Fortunately, animal control arranged for rabies testing, something that could have easily been overlooked if no one thought about rabies and just assumed the kitten was sick for some other reason. Two dogs in the household were also considered exposed, but fortunately had been properly vaccinated, so typical recommendations would be for a 45-day observation period versus 6 months strict quarantine or immediate euthanasia had they not been vaccinated.
In a similar scenario, two women are undergoing post-exposure treatment after being bitten by a stray kitten they were trying to catch. After they caught the kitten, they took it to a local Humane Society, where it was euthanized because of the bite. This ended up being an efficient approach, but more often there would be a 10 day observation period of an animal that had bitten someone, to see if it developed signs of rabies. If signs occurred the animal would be euthanized and tested for rabies, but if not then (theoretically) the animal would not have been shedding rabies virus at the time the bite occurred. Immediate euthanasia after a bite is not the typical recommendation, so I wonder whether the kitten was already showing some signs of disease. Otherwise, it wasn't a textbook approach to bite management but it ultimately resulted in the right outcome.
These cases have a few recurring themes:
- Changes in animal behaviour should lead to consideration of rabies.
- Be wary of stray animals. It's best to stay away from them. If you end up taking in a stray, if it gets sick and dies, ensure that it is tested for rabies.
- Vaccinate your pets because you never know when you'll encounter rabies.
When I was in general practice, I remember going into an appointment and being introduced by an owner to his cat named "Big Screen TV." Upon seeing my surprise at the name, the owner explained that the medical emergency the cat had the year before cost as much as the big screen TV he wanted, so he renamed the cat.
If that's the case, then L.A. Times columnist David Lazarus might want to call his cat "SUV." Lararus developed an infection after a cat bite that required surgery and extensive medical care. His hand was saved, at a cost of about $55 000. The article describing the ordeal it is focused on the financial aspect and the bizarre approach to hospital billing in the US, so there's not much information on the bite or the infection itself, but it's yet another example of why preventing bites and good bite care is important, regardless of how serious the bite may appear at first.
One on the things we try to do with the blog approach to getting zoonotic disease and infectious disease information out is to put a personal spin on stories. Whether it's new puppy issues, a rabid bat in my house, zoonotic disease issues at my kid's daycare or something more mundane, that personal touch sometimes helps keep things in perspective.
Knowing more about what we do and why might also help with understanding how our thoughts and opinions come about. An article posted on atGuelph details our own Dr. Maureen Anderson's ascent in the veterinary world from undergrad to infection control researcher, including her groundbreaking infection control surveillance in veterinary clinics. I'll let you read the story yourselves through the link highlighted above...
1) Do you know what a bully stick actually is?
2) Do you know what's in it?
A recent study headed up by Dr. Lisa Freeman, published in this month's Canadian Veterinary Journal (Freeman et al., CVJ 2013;54:50-54), looked into this by asking people what they thought bully sticks were made of, and testing the treats for calorie count and bacterial contamination.
The answer to question 1 is: bully sticks are raw, dried bull penis (which explains the need for a cuter name).
- Only 44% of people surveyed knew that.
Also, bull penis is considered a by-product, yet 71% of people that fed bully sticks to their dogs said they avoid by-products in food.
- This just shows a lack of understanding about what by-products are and their nutritional value. Many people classified things that are prohibited from by-products as being by-products, such as hooves, horns, road kill and euthanized pets. By-products aren't always bad and can, in fact, have good nutritional value. Also, they can be environmentally friendly and ethical since they are often made from nutritionally valuable parts of the animal that might otherwise be thrown out, thereby providing food for pets without taking anything out of the human food supply chain.
"What's in it?" was approached from 2 standpoints:
Firstly, caloric content was assessed.
- Treats often get ignored when thinking about a pet's caloric intake, but calorie-dense treats can certainly contribute to obesity. Fifty percent of people surveyed underestimated the calorie counts of bully sticks. The average caloric density was 3 calories/gram, and given the variation in size of bully sticks, total calorie counts for a single stick ranged from 45-133 calories (9-22 calories/inch). So, yes, size matters.
Secondly (my bit part in this study), we looked at contamination by a select group of bacteria.
- Salmonella wasn't found, which was encouraging since high Salmonella contamination rates have previously been found in some treats (mainly pig ears), and contact with pet treats has been implicated in some outbreaks of salmonellosis in people. We found Clostridium difficile in 1 treat (4% overall). That doesn't worry me too much since it's increasingly clear that we encounter this bacterium regularly. With common sense and handwashing, it's probably of little risk, but in some people (e.g. elderly, people on antibiotics, people with compromised immune systems) it might be more of a concern. We also found methicillin-resistant Staphylococcus aureus (MRSA) in one sample. This was a "livestock-associated" MRSA strain that can cause infections in people, but the risk is unclear. Theoretically, it's a potential source of exposure. If someone got MRSA on their hands from the treat then touched their nose (where MRSA likes to live) or a skin lesion (where it can cause an infection), then it could potentially cause a problem. Overall, the risk is probably quite low, but it's another reason to wash your hands after handling treats.
None of this means dog owners need to avoid bully sticks. It does mean that you should pay attention to what you feed your pet, think about treats when considering your pet's caloric intake (especially if your dog is overweight), keep treats away from high risk people (e.g. don't use a bully stick as a teething toy) and wash your hands after handling dog treats (of any kind).
Photo: A variety of bully sticks (also known as pizzle treats) often fed to dogs as chew treats (photo credit: Gergely Vaas 2006 (click for source))
I seem to write about this bug a lot - disproportionately for a rare cause of infection - but it just keeps getting attention. Reading the title of a recent article "Woman loses legs, fingers to rare infection from dog bite," it was an easy guess that the infection was caused by Capnocytophaga canimorsus. That's the type of dramatic disease this bug can cause, and as hard as it is to say "lucky" about someone that loses digits or limbs, they are lucky since death rates are very high with this infection.
Capnocytophaga canimorsus is a strange little bacterium. It's found in the mouth of pretty much every dog, so people get exposed to it quite commonly, yet it rarely causes disease. However, when it does cause disease (often after an otherwise inconsequential bite), it's bad.
In the most recent report, a 48 year old woman received some minor bites breaking up a fight between two family dogs. The next night, she had a fever and was vomiting, and things went downhill from there (click here to read the full story). An unusual aspect of this case was that the woman didn't have any of the risk factors that are typically present in a person who gets a Capno infection, such as not having a spleen, being an alcoholic or having an immunosuppressive disease. It is unclear why this bug, which is normally quite innocuous to an otherwise healthy person, almost killed her.
An infectious disease physician at the hospital made a few recommendations:
"If a person experiences a dog or cat bite it’s reasonable to have it examined, especially if it’s swollen, painful or red."
- Pretty good advice. It's never a bad idea to get a bite examined, and in some situations, it should be mandatory (e.g. bites over the hands or face, bites to immunocompromised individuals).
"It’s important for the public to not only closely watch animal bites but also to make sure pets are current on their shots and that the owners are up-to-date on tetanus shots."
- Good general advice, but not really related to Capno.
"Dog owners should use caution when trying to break up a fight between animals, she said. Instead of reaching near a dog’s mouth, pull the tail, she advised."
- I'm not so sure about this one. Grabbing a tail of a fighting dog sounds like a good way to get bitten, although reaching near the mouth of a fighting dog would be just as bad or worse.
"Animals that are the source of such infections don’t need to be euthanized, Mondy said, but the dog that bit Sullins was put down for various reasons, including increasing aggressiveness and concerns about exposing babies in the family to the animal."
- Capnocytophaga should never be a reason to euthanize a dog since basically every dog is a carrier. It doesn't matter if there's a baby in the house or not. If the dog's dangerous because of its biting, that's a different story.
This article, along with various other recent reports, makes me ask a couple of questions:
Are Capnocytophaga canimorsus infections getting more common?
- I don't know. It's possible, as disease trends can change. It could also be that reporters are picking up these cases more often since they tend to be dramatic.
Are more low-risk people becoming infected?
- This one concerns me a bit. Traditionally, when I saw a report of Capnocytophaga in the literature or lay press, I could guarantee I'd eventually come across a statement about the person not having a spleen, or less commonly being an alcoholic or having some other immunocompromising problem. Again, it may just be my impression but I'm seeing more reports where a risk factor isn't apparent. It could be that an immunocompromising problem is there but is not known, but this report, along with some other recent news articles and a published case report, raise concern about the potential for this bug to cause disease in the absence of traditional risk factors.
This doesn't mean owners should fear their dogs, since it's still a very rare problem. However, it re-inforces the need to:
- Reduce the risk of bites through proper training (of both the dog and people who interact with it).
- Use prompt and proper first aid measures after any bite.
- Ensure that people who are at high risk for infection, particularly people without a spleen and those with compromised immune systems, always seek medical attention promptly after a bite.
Santa gives the reindeer a few months off every year, so inevitably they're going to cause trouble.
A health board inquiry is under way after a young reindeer was taken into a Glasgow Children's Hospital and allowed to interact with patients. The reindeer fawn, from a local reindeer farm, was paraded around the hospital grounds as part of an organized event. That's great. The kids could see something unique. However, the problem occurred when a staff member decided to take the fawn inside so more young patients could see it. By doing that, the fawn was turned into a "therapy animal," meaning all the various recommended precautions for a therapy pet should apply (including a prohibition on bringing farm animals into a hospital).
It essence, good intentions + lack of critical thought + lack of clear local guidelines lead to this situation, which has caused an outcry amongst some groups (and probably a similar "so what?" amongst others).
Here are some interesting bits from the article:
"It had been checked by a vet..."
- Okay, good start, but for what was is checked? You can't tell what infectious agents an animal carries by looking at it. We know that young animals are more likely to shed various potentially harmful microorganisms, and deer can be sources of very harmful bacteria like E. coli O157.
"It is understood that the patients who did pet the fawn were later given antiseptic wipes with which to clean their hands."
- I wonder what "later" means. I suspect it wasn't right after animal contact.
“I don’t suppose any animal, no matter how well shampooed and clean it was, should be allowed into a hospital without prior knowledge and the correct arrangements made,” [Dr. Jean Turner of the Scotland Patients' Association] said.
- A reasonable statement. She's not saying "no animals," she's saying "no animals without a proper plan."
"I think it was well-intentioned, but I don’t think anyone was thinking about the consequences of taking a live animal like that to a hospital.”
- That sums it up nicely.
Every animal (and person) is carrying multiple microorganisms that could make someone else sick. Usually that doesn't happen, and we need to live life, not stay locked up in our bedrooms. However, some animals are at higher risk of shedding pathogens (e.g. young animals, farm animals), some situations make it more likely that an individual animal will contaminate the environment of patients (e.g. interacting with a farm animal, taking a non-house-trained animal inside) and some people are at much higher risk of serious disease when they encounter various bugs (e.g. hospitalized kids).
I'm sure some kids had a great time, and the overall risk was probably low. However, was there really any benefit here beyond a properly run pet visitation program with appropriate animals, established protocols, good hygiene practices and proper handler training?
Pet therapy programs are too important to be compromised by illogical events like this that sometimes cause a knee-jerk "no animals in the hospital" response. That's why there are good international pet visitation guidelines and why people need to follow them.
The fact that Salmonella and reptiles go together is old news. I often get questions about testing reptiles to see if they are Salmonella carriers and I tell people not to bother since even with a negative result, I'd consider the animal to be positive. A recent study in the Journal of Zoo and Wildlife Medicine (Goupil et al 2012) provides more evidence for this.
This study involved testing 12 snakes used in a public educational program, by sampling them weekly for 10 weeks. Here are the highlights:
- 11/12 snakes were positive at least once.
- 58% of snakes were positive on 5 or more weeks.
- On a weekly basis, between 25-66% of snakes were positive.
- Fifteen (!) different types of Salmonella were identified. Nine snakes shed 2 or more different Salmonella types over the study period.
- Two samples from feeder rodents were also positive.
This shows nicely how a single negative sample doesn't guarantee that a snake is truly negative. It also shows how common Salmonella is in snakes. The positive cultures from the feeder mice aren't surprising either, but shows that even if a snake was truly Salmonella negative, it could be exposed at any time through its food, and that there is potential public health risk from contact with feeder mice (something that large international outbreaks of human infection from infected feeder mice have shown).
This study just reinforces some key concepts:
- Assume all snakes are Salmonella carriers.
- Use good hygiene practices around snakes and feeder rodents.
- Keep snakes away from high risk individuals (e.g. the very young, elderly, pregnant, immunocompromised).
- Don't waste your money testing your snake for Salmonella. Focus your efforts on smart and practical management practices.
More information about reptiles and Salmonella can be found on the Worms & Germs Resources - Pets page.
Yes, the title's a bit misleading. Equine herpesvirus (EHV) is everywhere, since the virus circulates widely in the horse population internationally and lies dormant in the bodies of a large percentage of healthy horses. However, cases of EHV-1 neurological disease get attention because of the severity of disease and the potential for outbreaks (for reasons we really don't fully understand). Seeing a report of a new case isn't surprising, since they are always occurring somewhere, but it's worthy of note for horse owners in the area or those who might have visited the area recently.
The latest incident, reported by TheHorse.com, involves a Standardbred horse that raced at Sports Creek Raceway, a small track in Michigan. The animal raced on December 22nd and started showing signs of neurological disease on December 23rd. It presumably didn't pick up the virus at the track, because 24 hours is on the very low end of the potential incubation period, so the main concern is that the horse might have been shedding the virus while at the track. It's possible that EHV could have been transmitted to other horses via aerosols (virus on small particles released when the horse was breathing, shorting or coughing), contaminated items that were used for multiple horses (e.g. buckets), or on the hands or clothes of people. That's why good general infection control practices are needed at tracks and other horse competitions at all times - to reduce the risk of transmission when an infectious but currently healthy animal is present (and there's room for a lot of improvement).
Typically, the incubation period of EHV-1 in a neurological disease outbreak isn't very long: about 4-6 days or so. If anyone had a horse at the track on the 22nd and it's still healthy today (January 4th), odds are it won't be affected. However, there are some instances when the incubation period can be longer, particularly with abortions in pregnant mares. Also, horses could have been infected and not gotten sick, but still be able to spread the virus to other horses with which they subsequently have contact. For this reason, several racetracks have imposed temporary entry restrictions on horses that were at Sports Creek in December. It's probably a low risk situation, but you can never put an outbreak "back in the bottle," and a little short term inconvenience is much better than the major hassles (and deaths) that can come with an outbreak.
The affected horse was in pretty rough shape neurologically but ultimately recovered, as can occur with EHV-1 neurological disease. If your horse has to have a neurological disease, this is probably one you want since full recovery is possible. EHV-1 will probably live within this horse's body for a while, if not lifelong, but that's true of a large percentage of other horses as well, so after a few weeks (when the likelihood of him shedding the virus decreases), he probably poses no more risk than any other horse.
A recent article in the Toronto Star detailed an "underground railroad" that helped get stray dogs out of Afghanistan and into homes in North America and the UK. While it's a nice heartwarming Christmas story, the Scrooge side of me starts asking questions about whether this is a good thing. To me, there are two different scenarios here:
One is the military person who befriends a stray dog while on deployment and wants to bring it home with him/her. I get that. A bond has developed between the specific person and dog, and I completely understand the rationale.
The other scenario, which is the one that raises my concerns, is when this type of action expands to groups that start "rescuing" random Afghan dogs that are then shipped back to Canada for adoption. This is an ongoing issue which has come up with dogs coming from a variety of countries under various circumstances (e.g. Hurricane Katrina dogs). This is very different than the first scenario above. While it's certainly great for most of the adopted dogs, I have a harder time justifying it. Here's why:
Cost: Thousands of dollars are spent on each dog. Is that a wise investment? Could these funds be used differently to help more animals?
Local shelters: It's not like we need to encourage immigration of stray dogs because our shelters are lacking in dogs. I don't know of any shelters that complain about a shortage of dogs for adoption. How can we justify spending thousands to import dogs when we already have an oversupply here? Does adoption of an imported dog (that cost thousands) result in euthanasia of an additional local dog, since there's a finite owner population?
Disease: Thanks to Canada's basically non-existent control over canine importation, this creates disease risks. If I wanted to do a study of Salmonella shedding by dogs in Afghanistan and have fecal samples from healthy dogs sent to me, I'd have to: A) Get an import permit from the Canadian Food Inspection Agency (CFIA); B) Have a facility inspection performed to confirm that my lab fulfills containment level 2 practices; and C) Get an import permit from the Public Health Agency of Canada. To import the whole dog, poop and all, I just need to produce a rabies vaccination certificate. If the dog is less than 3 months of age, I don't even need that. We've seen leishmaniasis in Ontario recently from dogs imported from Greece. There were major concerns about heartworm from "hurricane Katrina" dogs that were imported from Louisiana. A dog incubating rabies was imported by a US military person a few years ago. This is more than just a theoretical risk.
I'm not saying don't do this, I'm saying let's think about the costs and the benefits, and if it's to continue, let's make sure we have some logical and practical control measures in place.
Are the overall benefits worth the risks? Do people really want those dogs, or do they just want to say they own an Afghan rescue dog? What's the infectious pathogen burden in imported dogs? What diseases occur in imported dogs? Who's tracking these issues? (Answer: no one.) Should any regulations be put in place to reduce the risks?
Heartwarming story, but one that should at least raise some questions.
The 15 cm of snow that fell last night is as good of an indicator as any that agricultural fair season is over in this region. But, planning ahead is important (and often not done well with fair petting zoos), so it's never to early to make a plan for next season. Petting zoos can be fun and educational, but are also associated with infectious disease risk. There's always some inherent risk with any kind of animal contact, since all animals (and people) carry a multitude of infectious agents. However, understanding pathogen shedding patterns is useful to help determine the best control measures.
A recent study in Comparative Immunology, Microbiology and Infectious Diseases (Roug et al 2012) looked at shedding of selected pathogens by cattle, sheep, goats, pigs, poultry, rabbits and horses at a California county fair. Here are some of the highlights:
- E. coli O157 was found in one animal. This is the main outbreak concern when it comes to petting zoos, because very low numbers of bacteria are required to cause disease and human infections can be very severe. Surprisingly, the positive animal was a pig, not a ruminant, as would be typical.
- Salmonella was isolated from feces of 3 animals: 2 pigs and 1 chicken.
- Campylobacter jejuni, another potential cause of diarrhea in people, was found in 3 animals: 2 cattle and 1 sheep. The 2 positive cattle were adult dairy cattle and they represented 17% of all tested cattle. That's a surprisingly high rate for adult dairy cattle, in my experience.
- Other Campylobacter species were found in 2 cattle, 3 goats (30% of all goats tested) and 1 chicken.
- Antibiotic-resistant E. coli were common, particularly in pigs.
- The parasites Cryptosporidium and Giardia, and the bacterium Vibrio, were not found.
The study didn't look at other aspects of the petting zoo, such as the types of contacts that were allowed, but based on the pictures that were included with the paper, they weren't optimal. Given the results, the picture of two children in the pen with the pigs (including one child who was sitting on the ground leaning against a pig) should raise some concern.
Does this study change anything? Not really, but more information can't hurt. We know that petting zoo animals can carry pathogens, and we have to assume that every animal in a petting zoo is carrying something that could cause an infection given the "right" circumstances. That's why there's a focus on good general hygiene and infection control practices (especially hand hygiene), along with excluding animals that are at particularly high risk. As the authors say "The study findings should not be interpreted as a deterrent to visit agricultural fairs, but as a reminder that good hygiene and sanitation are critical in these settings."
Following up on my recent post about MRSP in rats, here’s a story about MRSA in an alpaca (Stull et al, Can Vet J 2012). As far as we know, it’s the first report of MRSA in an alpaca (or any camelid).
The report relates to our large animal hospital, where we perform MRSA screening of all horses at admission, weekly during hospitalization and at the time of discharge. It's all part of our infection control program, and the screening is designed to help reduce the risk to horses and our hospital personnel, since this multidrug-resistant bacterium is endemic in the Ontario (and broader) horse population, and outbreaks can occur in equine hospitals.
While alpaca’s aren’t horses, and we don’t see that many of them here, they sometimes get screened anyway since screening is being done on most of the other patients.
This case involved a neonatal alpaca that was admitted with its mother because of severe respiratory disease. The cria (baby alpaca) was very sick and was ultimately euthanized about 36 hours after admission.
Surprisingly, the admission MRSA sample from the cria was positive. In this case, MRSA wasn’t involved in the animal's illness. The cria didn’t have any evidence of bacterial infection, so this was an incidental (but interesting) finding.
When the bacterium was tested further, it was classified as CMRSA-5 (Canadian epidemic MRSA-5), a human strain that also predominates in horses in North America. The mother alpaca was MRSA negative. Presumably, the cria picked up MRSA from the farm environment or a person shortly after birth. MRSA (especially CMRSA-5) carriage rates are high amongst horse owners and horse vets compared to the general public, and it would have been nice to have determined if there were any horses on the alpaca’s home farm, but we couldn’t get any follow-up information.
This single case is probably of limited concern in the grand scheme of things. It’s likely an "oddball" infection rather than an indication that MRSA is a serious threat to alpacas, or that alpacas are a relevant source of human MRSA infection. However, that’s largely what was said when MRSA was first found in horses in the late 1990's and early 2000's, and it has since become a significant issue in that species, so the potential for MRSA to become a problem in alpacas can’t be completely dismissed.
If nothing else, the occurrence of this case is an indication of the need think broadly when it comes to infectious diseases, since many pathogens don’t have species boundaries. CMRSA-5 is a human-origin MRSA strain, but it’s worked its way outside of its natural host. It’s not the first and certainly won't be the last bug to make its way from people to animals.
This story's a couple of weeks old, but Sonoma County (California) residents have been warned about an outbreak of salmonellosis in songbirds. Outbreaks of salmonellosis occur occasionally in songbirds such as finches, and can result is lots of sick and dead birds. There are also risks to other species, including cats and people.
Why cats? Cats can be exposed to Salmonella from eating infected songbirds, and sick birds are typically a lot easier to catch than healthy ones.
Why people? People can be exposed to Salmonella from areas the birds have contaminated, particularly bird feeders and their vicinity. People have been advised to remove bird feeders or clean them regularly, and to promptly remove dead birds from under feeders.
- Removing bird feeders temporarily might help keep birds (including sick birds) farther away from people. It's not going to hurt the birds since other food supplies are typically abundant.
- Washing feeders can reduce the Salmonella burden but it could also increase the risk to people if they contaminate themselves while washing them. Certainly, people should not wash bird feeders inside the house, especially not in the kitchen sink. They should also take care to avoid contaminating their clothing and make sure they wash their hands thoroughly after finishing with the feeder.
"Songbird fever" is a colloquial name for salmonellosis in cats - a testament to the potential for feline infection. It's uncommon but can be severe, and cats can act as a bridge between sick birds and people by bringing Salmonella into the household. This is just one of many reasons why domestic cats are better off living indoors.
A year or two ago, I received an email from Dr. Chelsea Himsworth, who was doing some interesting work looking at different bacteria found in rats in Vancouver's Downtown Eastside. This is an impoverished urban neighbourhood with lots of homeless people, IV drug users and HIV-infected individuals... and lots of rats. Dr. Himsworth, a veterinary pathologist working on a PhD at the University of British Columbia, is assessing potential health risks posed by rats to this type of population. The reason she got ahold of me was to see if I was interested in looking for some different bacteria, like methicillin-resistant staphylococci, in these rodents.
If you look, you often find, and that was the case here with methicillin-resistant Staphylococcus pseudintermedius (MRSP). This multidrug resistant bacterium was found in nasal or oral swabs from 2.1% of rats (Himsworth et al, Emerging Infectious Diseases 2013). So it was relatively uncommon but certainly present.
One question: from where did it come? Most MRSP isolates found were the same as the most common strain found in dogs, so presumably the rats picked it up directly or indirectly from pets or stray dogs. However, there was also a type we've never run across before. That could mean that there is a separate rat-associated MRSP strain, but more likely it means this strain is present in dogs in Vancouver and we just haven't found in dogs elsewhere yet (there aren't many of us typing MRSP, and we find new strains not uncommonly). While dogs and rats presumably don't spend time lounging around together, there is certainly potential for direct or indirect contact between dogs and rats, and rats have been found to harbour dog-associated oral bacteria in the past.
Another question: what's the risk to people? The risk of infection is probably limited, but not zero. MRSP can cause infections in people but doesn't do so very often. MRSP is unfortunately becoming fairly common in dogs, so people are commonly exposed, yet human infections are still rarely diagnosed. So, the risk to humans from these rats carrying MRSP is pretty low overall, although we'd rather not see new reservoirs for this bug.
What about the rats? Rats may be the innocent bystander here, having been infected by dogs. We don't know whether MRSP causes infections in rats. It probably can in certain circumstances.
Can rats spread this to dogs? I guess it's possible. Rats are probably not contaminating the environment too heavily with this bug from their noses or mouths (compared to dogs), but direct transmission if a dog caught a carrier rat could certainly be possible. The risk to the dog population is pretty low since this pathogen is well established in dogs already and there's a lot more dog-dog than rat-dog contact.
Why does an antibiotic-resistant bacterium live in these rats when they're not receiving antibiotics? Good question. Antibiotics certainly help when it comes to selecting for resistant bacteria, but they're not absolutely required. There are a lot of other factors that can also play a role, so rats don't need direct or indirect exposure to antibiotics to acquire MRSP (or other multidrug-resistant bacteria). It could be that they are just commonly exposed and the bacterium only hangs around for a short period of time, or that there are some other factors in the rats, their food or their environment that select for these resistant bacteria.
If you're in Toronto (or probably anywhere in Canada), you've probably heard a lot about Darwin, also known as the "Ikea Monkey". Darwin is a seven-month-old rhesus macaque (Macaca mulatta) that was found wandering around an Ikea parking lot on December 9 in a designer winter coat. He was seized by Toronto Animal Services since non-human primates aren't legal pets in Toronto, and the owner has been fighting to get him back ever since. She has organized protests. She's filed lawsuits. She's planning on moving to a neighbouring region that currently does not prohibit non-human primates as pets. Of course, not wanting to be known as the home for wayward monkeys and their wayward owners, that very region is in the process of enacting a bylaw banning such pets. Darwin's owner is trying to get him back and move ASAP because the bylaw will not apply to existing pets already living in the region when it comes into effect.
For this post, I'll stay away from some of the stranger aspects of this fight and the exotic pet issue in general, and address one basic question: are rhesus macaques good pets?
That one's easy. No.
Why? There are a variety of reasons.
Number one on the list is Cercopithecine herpesvirus (also known as herpes B, herpesvirus simiae or simply B-virus). This is the macaque version of the herpesvirus that causes cold sores in people. It's very common in macaques, and the vast majority of captive macaques are infected. A problem with herpesviruses is that they hang around for life, being shed intermittently and unpredictably. While this virus doesn't cause a major problem in the monkeys, it can cause fatal encephalitis (brain swelling) in people, most commonly after being transmitted by a monkey bite.
Other infectious diseases are also of concern. Bites are a major issue, both from the trauma associated with them and bite infections from the range of bacteria present in the animal's mouth.
Other injuries can be a problem too. While macaques aren't very big, they're strong and they can be aggressive. Injuries to people can happen from aggressive behaviour or over-exuberant play.
The animal welfare aspect can't be ignored either. These animals have complex care requirements. You can't just lock them in a room, toss in some monkey chow every once in a while, and take off for the weekend leaving the neighbour's kid in charge. These animals need a proper diet and care, and that's not something everyone provide. Stress-associated health and behavioural problems are quite common in pet macaques.
The lifespan of these monkeys also needs to be considered. If properly cared for, they can live up to 25 years. That's a long time to deal with a high maintenance animal. What happens if the owner gets sick or dies, moves somewhere that the animal's not allowed, or for whatever reason can't take care of it anymore? That's true for all pets, but the longer the lifespan, the greater the chance of one of these things happening, and harder it is to get someone to take the animal. It's not too hard for someone to adopt Aunt Edna's 15-year-old cat that rarely leaves the couch and isn't going to be around that long. It's different with a young macaque that's going to live many years and require intensive effort for that entire time.
Similarly, a paper co-authored by people from CDC (Ostrowski et al, Emerging Infectious Diseases 1998) states clearly "The extremely high prevalence of B-virus along with their behavioral characteristics make the macaque species unsuitable as pets."
Darwin needs to go to a good sanctuary or zoo, where he can be a monkey, interact with other monkeys, and have a happy, healthy and species-appropriate lifestyle.
Zoo Atlanta has closed its parakeet exhibit after one of the birds died of Chlamydophila psittaci infection. The concern is that this bacterium can cause infection in people (sometimes called parrot fever). Infection of humans is uncommon and usually just causes flu-like disease, but it can be very serious, especially if not diagnosed properly in a timely manner.
The zoo is going to test the flock and decontaminate the facility. The question is, "what will happen if other birds are positive?" Actually, the question probably should be "what will happen when other birds are identified as being positive?"
Chlamydophila psittaci gets the "psittaci" component of its name because it is commonly found in psittacine birds (e.g. parrots, parakeets and other related birds). The dead bird got the bacterium from somewhere, and living communally with other psittacines means that the odds are very good that multiple birds are now carrying it, since birds can carry this bacterium without any signs of disease. Varying carriage rates in psittacines have been reported in different studies, but in some groups (e.g. breeding colonies) rates can be very high.
Concern about the aviary is reasonable, since this bacterium can be spread through the air, mainly through inhalation of contaminated material that's been aerosolized (e.g. dried feces that end up in dust in the air). If there's no direct contact with birds, through, the risk to the public is probably very low. Some management practices can be used to reduce the risk of aerosolization of the bacterium and reduce the risk of exposure of the public. These could include using cage litter that isn't dusty, regular and thorough cleaning of the area and cleaning in a manner that reduces the risk of aerosolizing the bacterium (e.g. wetting things down before cleaning, not using a vacuum unless it has a HEPA filter).
So, what about testing? One of my standard lines is "never do a diagnostic test without a plan to use the results." Hopefully, the zoo has thought about what they'll do with positive results, since it's likely they'll have many.
Testing is a somewhat controversial area. It's been recommended that birds in areas where they will be exposed to a lot of people be tested. That could apply here, depending on how the birds are managed. One issue with testing is it's far from 100% accurate, so it's only one part of the control program and testing limitations need to be understood. Testing makes the most sense in a population of birds that is closed, meaning there are no new birds coming in. That way, a couple of rounds of negative tests can give you pretty good assurance that the group is negative. Positive birds can be quarantined and treated to try to eliminate the bacterium. If most of the group is positive, it makes it pretty difficult to eliminate. A single round of testing or testing and then bringing in new birds doesn't help too much.
Overall, the risk is greatest for zoo personnel who work with the birds and their environment. Good infection control protocols should already have been in place to reduce the risk of disease transmission, but presumably those are being revisited. It's often a controversial subject since use of barriers such as eye protection and an N95 mask are often recommended when cleaning cages, but this is rarely done and there's (reasonable) reluctance to do so because of the rarity of disease, the commonness of the procedures and the fact that people have been doing this for years without these extra precautions. It's a tough area to address and it requires careful consideration of the costs and benefits. Other important points for psittacosis control include avoiding bringing in new birds, avoiding mixing of different groups of birds, checking new birds for signs consistent with C. psittaci infection before bringing them to the facility, quarantining new arrivals and educating people who work with the birds.
One key factor, regardless of what's done, is that people who work with psittacines need to know that they are at increased risk of psittacosis. Their physicians also need to know that they work with psittacines (and that psittacosis is a potential concern). In this situation, people who have worked with the affected bird (and any other bird that might be a carrier) should know to see a doctor if they develop respiratory or flu-like illness.
About 500 people have sent me this article over the past week, so I guess I should get around to making some comments. The article entitled "Using a dog’s superior olfactory sensitivity to identify Clostridium difficile in stools and patients: proof of principle study" (Bomers et al 2012) is in the Christmas edition of BMJ, an edition in which they typically publish something fun or light. The study describes the use of a dog trained to sniff out C. difficile, an important cause of diarrhea people, especially hospital patients. The premise is that dogs could be used as a rapid and cheap way to diagnose C. difficile infection, and therefore allow for earlier treatment and implementation of enhanced infection control measures.
There were 3 components of the study:
1) Detection of C. difficile on a culture plate
The dog was trained using culture plates containing C. difficile. That's how they have to start, but detecting C. diff on a culture plates is pretty easy. I can do that, and my nose is nowhere near as good as a dog's. Clostridium difficile has a very characteristic odour on a culture plate and odour is one of the methods that's commonly used to determine whether C. difficile might be present on the plate.
2) Detection of C. difficile in stool
For this, the researchers set the bar pretty low. A positive fecal sample was considered one that was culture-positive positive on a test to detect the C. diff toxins. We know toxin tests are pretty insensitive (they give a lot of false-negatives), which is why there's a major movement to replace them with molecular tests. By requiring the sample be positive on both culture and toxin test, it means that the samples had to have been quite positive to be considered (i.e. they didn't test the dog with "weaker" positive samples that may have had less C. diff and C. diff toxin in them). That weakens the results a bit, but they're still interesting.
They presented the dog with 50 positive and 50 negative samples. The dog gave a positive response to all 50 positive and a negative response to 47/50 negative samples.
3) Detection of C. difficile in patients
Here's where it gets more interesting and potentially more relevant, since the real value in a sniffer dog would be to detect C. diff directly from patients, as a rapid and cheap screening tool.
For this part, they enrolled 30 patients with C. difficile infection and 270 controls. One problem I have is that 94% of their controls were non-diarrheic. It raises questions about whether the dog is detecting C. difficile or just diarrhea, since the groups don't just differ by their C. diff status, as would be most appropriate for a control group. The more differences there are between the groups, the greater the potential that a difference other than the one of interest (i.e. C. diff status) is actually the thing that's being detected. There' a big difference between a dog that can detect C. difficile and a dog that just detects diarrhea.
Another issue is that some C. difficile strains don't produce toxins and are not able to cause disease, but they'd presumably be detected the in the same way based on odour, in contrast to tests that are based on detection of the bacterial toxin or genes that encode toxin production.
Anyway, the dog correctly identified 25/30 (83%) cases and 265 (98%) controls. Not as good as current molecular tests but pretty remarkable, nonetheless.
Overall, it's an interesting story and shows how good a dog's nose can be, how smart (some) dogs are, and how thinking outside the box can result in some interesting ideas. Though I don't think diagnostic testing companies have much to worry about at this time in terms of competition from sniffer dogs.
Cool concept. Fun paper. Not coming to a hospital near you in the near future, but not something to completely dismiss.
My youngest daughter Erin is in every-other-day kindergarten and goes to a child care centre on her non-school days. Overall, it's a great place - excellent people, great learning environment and she enjoys herself.
During the initial interview at the centre, what I do for a living came up and we got into a discussion about pets. The person doing the interview talked about how they had policies against bringing in animals because of potential risks and the difficulty in doing it right (e.g. right animals, right supervision, adequate hygiene, informed consent, knowing fears and allergies). In reality, their policies are not quite as strict as they say. I didn't get too worked up about the parent who was apparently bringing a young puppy in for visits. Erin's getting outside the high-risk window now (she turned five this year), she's not afraid or allergic, and she knows how to interact with dogs. Odds were pretty low that anything bad would happen, but it still wasn't right because I doubt there was much supervision or understanding of the dog's health status. As a puppy, he/she was at higher risk for shedding various infectious agents, as well as more likely to bite, scratch and poop on the floor. It's also a risk for high risk dogs owned by people who visit the daycare (e.g. if the puppy happened to be shedding parvovirus and the kids transferred it on their hands or clothes to puppies in their households, like our puppy Merlin). Anyway, like I said, not a great idea but nothing to get too worked up about.
The next issue was a bigger deal. As I was picking Erin up yesterday I saw a bulletin board display that highlighted a recent trip to a pet store by the younger kids. On it was (predictably) pictures of these young kids handling reptiles, including turtles. As I've said before, reptiles can be good pets. But, they are clearly high risk pets and high risk people, including kids less than five years of age, shouldn't have contact with them.
I assume the parents of these kids had to sign a consent form. It probably said something like:
"We will be visiting ___ Pet Store to see and learn about animals."
It probably didn't say....
"We will be visiting ___ Pet Store, where your child may be handling high risk animals."
It definitely didn't say...
"We will be visiting ___ Pet Store, where, contrary to recommendations from the CDC as well as virtually every other public health organization that has put pen to paper, your child will be handling animals that have a high likelihood of being covered in Salmonella. Someone might try to ensure that she washes his/her hands after... maybe... We are optimistic that your child will not join the tens of thousands of people that develop reptile-associated salmonellosis every year and we really hope he/she isn't one of the handful of small children who die from it. Good luck! Please sign here."
There's a difference between a consent form and informed consent.
There's an educational value of interacting with animals and there are animal encounters where the risk exceeds the benefits.
I have no doubt that the field trip was arranged with the best of intentions; however, this shows that there is still a need for education of child care providers about pets and zoonoses. The pet store needs to be considered too, since they probably do this regularly. They should know better, and every pet store employee should know basic information about zoonotic disease risks and preventive measures associated with the pets they sell. Pet store visits aren't inherently bad, but they're "pet stores," not "petting stores," and it should be a look-but-don't-touch interaction.
People sometimes accuse me of being a kill-joy, but they miss the point. My girls would have more fun if we let them roll around in the van while driving rather than restraining them in car seats and booster seats (as often happened when I was growing up). I want my kids to have fun, but I'm not going to let them do things that are that dangerous. I want my kids to have pets and interact with animals, but I want it to be as safe as possible. There will always be a risk of infection or injury, and as someone who's informed and as their parent, I can define the degree of risk that I am willing to accept for them. Child care agencies have to look out for the welfare of the children they supervise. Zoonotic disease exposure prevention is part of that. It's not a matter of taking the fun out of life, it's making sure that we provide safe fun.
BMJ Case Reports has a recent paper entitled “Cirrhosis, cellulitis and cats: a ‘purrfect’ combination for life-threatening spontaneous bacterial peritonitis from Pasteurella multocida” (Hey et al 2012). (I don’t think we'd be able to use a title like that in a veterinary journal, but they often get away with titles playing on the animal side in medical journals.)
The case report describes a man who had liver cirrhosis from hepatitis C infection and alcoholism. He went into hospital with a chronic infection of his leg. He’d been seen various times for this problem and various bacteria had been isolated (leading to treatment with various antibiotics). This time, he had severe swelling of his leg that went from his calf to his groin, along with significant accumulation of fluid in his abdomen. Shortly after admission, he deteriorated and became septic (he developed an overwhelming bloodstream infection) and went into liver failure. Blood samples and samples of fluid from his abdomen were tested and the bacterium Pasteurella multocida was isolated. Fortunately, he responded to aggressive treatment.
Upon subsequent investigation, they found out that the patient had a cat, and that cat "had a disturbing habit of regularly licking the serous exudate [leaking fluid] from the patient’s chronic left leg leg cellulitis." (This probably occurs much more commonly than most people think.)
Pasteurella multocida is a bacterium that’s commonly linked to cats, and it’s a frequent inhabitant of the mouth of healthy cats. The cat wasn’t tested but it’s a reasonable assumption that this infection came from the pet. The patient was given “the appropriate advice with regard to the safe cohabitation with domestic animals” but unfortunately they don’t say what that advice was.
This is just one more in a series of reports that show the importance of asking people about pet ownership and pet contact. Asking that question initially can potentially help identify zoonotic disease risks, as opposed to asking the question after the zoonotic pathogen is eventually found when they’re trying to round out the story.
The authors list some ‘learning points’. I’ve copied two important ones below.
- Domestic animals can, under the appropriate clinical circumstances, pose a risk to an immunocompromised host, particularly if adequate hygienic practices are not adhered to.
- Questioning regarding exposure to domestic animals should form part of the clinical history when assessing immunocompromised hosts, allowing early institution of empiric antimicrobial therapy in the appropriate clinical scenario.
They’re both good points, although I’d remove "immunocompromised." While the risk is lower in people with normal immune systems, some risk still remains and pet contact should be queried all the time.
A recent report in the journal Infection (Chean et al. 2012) describes rat bite fever in a patient with AIDS. I’ve written about rat bite fever before, and it’s not really a surprising case report. Streptobacillus moniliformis, the bug that causes the disease, is found in the mouths of most rats (and in the mouths of dogs more often than we’ve previously assumed). Rat bite fever is uncommon but far from rare, and this report focuses on the fact that it was in an AIDS patient. The case report itself isn’t too noteworthy since we know infection with S. moniliformis can happen even in healthy people, and someone with AIDS is going to be at increased risk of any type of infection.
However, there are a few interesting aspects to this particular case. The report described a 30-year-old AIDS patient who had a rather prolonged course of disease with fever, aches, diarrhea and weight loss, with subsequent development of joint pain and swelling. A large battery of tests didn’t identify the underlying cause. Eventually, "it was noted that he had two pet rats, one of which bit the man on his right index finger 1 month prior to presentation." That should have been a "eureka!' moment for the physician. It doesn’t mean the disease was caused by the bite, but it made it clear that rat bite fever should be considered. The diagnosis was then made and the man received appropriate treatment.
While the clinical aspects of the case aren’t remarkable, there are some noteworthy points to consider:
- It wasn’t until re-evaluation that it was discovered that the patient had rats and had been bitten. It’s quick and easy for a doctor to ask “Do you have pets or have you had contact with animals?” and in a case like this, it could have sped up the diagnosis and appropriate treatment.
- The paper repeats the important statement that pet ownership rates among HIV/AIDS patients are similar to that of the general population. That’s also true for other groups at increased risk of infection.
- They say “Physicians need to be cognisant of this [pet/human] relationship in order to prevent missing the diagnoses of zoonotic infections in their patients.” That’s a critical step. It’s easy to do. It’s not often done right.
I haven’t written much about equine herpesvirus type 1 (EHV-1) outbreaks lately because I have a hard time getting excited about them (from a blog writing standpoint… if one occurs here, that will be a different story). Outbreaks of neurological disease caused by this very common equine virus (one that doesn’t spread to people or non-equids) continue to occur, and it’s hard to say whether we've been seeing more of them over the past couple of years or whether we’re just hearing about them more often. It does seem like outbreaks have truly become more common and more virulent in the past 10 years or so, but I’m not sure it’s continuing to get worse.
The latest EHV-1 outbreak has affected 5 of 7 horses on a central Minnesota farm. At last report, one horse had been euthanized and one was hospitalized at the University of Minnesota. The hospitalized horse is presumably receiving supportive care, such as intravenous fluids and general nursing support. Affected horses may become very weak and sometimes they need to be managed in a sling (see photo), since horses don’t tolerate being unable to stand for long (laying down for prolonged periods of time can damage muscles and nerves, simply because they are crushed by the horse's own weight). Sometimes the bladder becomes paralysed and needs to be drained using a catheter. Numerous other problems can occur since the way this disease affects each horse can be quite variable. Fortunately, the prognosis tends to be reasonable (at least compared to other neurological disorders) if the horse is not severely infected and stays standing or is able to remain upright with the support of a sling. The clinical signs are the result of inflammation of the blood vessels in the brain and spinal cord, and the key is to get that inflammation down and keep the horse alive in the meantime.
In the past, we didn’t worry too much about these horses in equine hospitals. EHV-1 neurological disease tended to occur sporadically, not in the form of outbreaks, and dogma was that once the horse was sick, it wasn’t at much risk of shedding the virus. In fact, for a long time our best stall in the main hospital for neurological cases (which had padded walls, and a ceiling anchor for a sling) was right at the front of our main equine ward. A large outbreak in the US in the early 2000s changed that, and now we take much more aggressive measures to contain this virus, including housing affected horses in isolation and using strict infection control measures. With these precautions, the risk of spreading the virus in an equine hospital is low.
Image: A horse with neurological disease being managed in a sling (source: http://coloradodisasterhelp.colostate.edu)
I write a lot about animal bites, and for good reason since they are common and can be very severe. Usually, it’s dog bites. Sometimes it’s cat bites, or more rarely injuries from birds or other critters. Monkey bites not so much, but they happen. I had an email question about rabies exposure from a monkey bite the other day, and there was a paper in the October edition of Emerging Infectious Diseases about monkey bites amongst US military personnel in Afghanistan.
Some highlights of that paper:
From 2001-2010, 643 animal bites were reported by US military personnel.
- More probably occurred since bites are often underreported.
Dogs accounted for 50% of bites, but many other animals were also involved, including rhesus macaques, a type of primate that is present in the wild and also kept as pets in Afghanistan.
- Macaque bites are even more of a concern than dog bites. In addition to the ever-present risk of rabies exposure, these animals can also transmit Macacine herpesvirus B, which is a very serious pathogen that can kill people. Like any animal, macaques also have a wide array of bacteria in their mouths that can cause infections after a bite.
10 monkey bites were reported in this series.
- Most people who were bitten were young (less than 30 years of age) and male. All were junior enlisted personnel or non-commissioned officers.
- Eight of the monkeys that bit were pets, including one that somehow belonged to US military members (despite orders that US military personnel not adopt or interact with local animals or pets).
- Appropriate wound care was provided following only six of the bites. So, there are deficiencies in understanding basic first aid following bites.
- Only five people received appropriate treatment for herpes B exposure. That’s a concern because of how serious this infection can be.
- Eight received antibiotics. Antibiotics are only indicated in a subset of bites, mainly based on what part of the body is bitten, so it's not clear whether this was really needed (while more concerning issues went unchecked).
- Eight received treatment for rabies exposure.
- No one got sick, fortunately.
Monkey bites aren’t something that most people need to be concerned about in their daily lives, but they are a concern for people living in areas where there are monkeys, as well as those who visit such areas. (I have a vivid memory of swinging a camera case at a monkey in Barbados that for some reason seemed to be less than impressed with my existence).
Bites happen, but some are avoidable. Common sense can reduce the risk. If common sense isn’t enough and you’re bitten, don't panic, but you also can't ignore it. After thoroughly cleaning the wound, it's important to get medical advice about what diseases are of concern and whether anything else can or needs to be done. Physicians working in foreign countries also need to be trained on geographically-relevant risks. Monkey-associated infections are not high on the curriculum of US medical schools, so geographically-relevant training is required for people heading elsewhere to work.
Public health personnel in Chapin, Connecticut (USA) are trying to find a woman bitten by a rabid cat. The woman was driving down South Brear Hill Road when she came across a cat. She picked the cat up from the road and told someone else who was there that the cat bit her. She then drove away, and the cat was subsequently identified as being rabid. Now a search is underway to find the woman so she can be given post-exposure treatment.
This is clearly a high risk situation. As opposed to other public health alerts that try to find people who were in contact with a rabid animal on the off chance that they were bitten or otherwise exposed to the virus, this person was bitten and that creates a very high risk of rabies transmission.
The outcome is simple.
- If she gets rabies, she will almost certainly die.
- If she was exposed but gets post-exposure treatment soon (and completes the recommended course), she will almost certainly live.
It's easy to see how this could happen. The woman probably found the cat looking injured or lost on the road, and wanted to help. However, that action, and failure to recognize the risk associated with the bite, have put her life at risk.
A few general rabies reminders:
- Avoid contact with wildlife or any animals you don't know, especially if they seem sick or otherwise abnormal.
- If you are bitten, make sure the potential for rabies exposure is considered. The animal needs to be observed to see if it is rabid, or it needs to be tested. If the animal can't be monitored or tested, you can't rule out rabies and getting post-exposure treatment is the safest course of action.
More information about rabies can be found on the Worms & Germs Resources - Pets page.
I received an email from a relative the other day with a pet question. I get lots of these, but the surprising part is this relative doesn't have any pets (and I think is generally of the opinion that pets are okay, as long as they're not hers). She was asking about turtles. As a responsible prospective pet owner should, she was looking into the issues pertaining to the pet before getting the pet. I think she was more focused on general aspects of care and management, but zoonotic disease risks play into the equation too. This one was a no-brainer, since they have a young child in the house and reptiles shouldn't be present in households with children less than five years of age. So, problem averted, and the need to make a decision later about removing an inappropriate pet from a household was also avoided (along with the awkward "oh, you got a turtle?" Christmas dinner conversation).
But, what happens when people aren't so proactive? Turtles are often passed from house to house as people get bored with them, as they outgrow small aquariums or as parents of young or otherwise high-risk children tune into the Salmonella risks or owning such a pet. If you don't have a friend willing to take your turtle, what do you do?
Petco, a pet products company in the US, has launched a "turtle relinquishment program," whereby they take in "wayward" or unwanted turtles. As of a few weeks ago, 111 people from 10 US states had surrendered their turtles to Petco. The turtles are sent to a turtle farm in Louisiana.
So, this is an option for individuals (at least in the US) with no local way to rehome their turtle. The fact that the turtles are going somewhere to make more turtles (and more Salmonella) is a bit of a concern, but I can see the greater good. Staff at the farm say that turtles are treated for any signs of Salmonella when they arrive. This is a bit strange, since turtles don't typically develop disease from this bacterium - they simply shed it with no signs. Hopefully that doesn't mean the farm is just treating all the animals. It's basically impossible to eradicate Salmonella from turtles, so if they are routinely treating, they're probably breeding drug-resistant Salmonella along with baby turtles.
I know the typical round of emails is going to follow, from reptile advocates who have pretty much done everything except burn me in effigy (or in real life, fortunately). As I've said before, reptiles can make great pets, just not in all households. I've owned various reptiles myself, but reptiles and small kids don't go together. Too many kids get sick every year from pets like turtles. A small number die. That's just unacceptable.
More information about turtles and Salmonella can be found on the Worms & Germs Resources - Pets page.
Life with Merlin has been busy but going pretty well. There's been no pee on the floor in the past 48 hours so we're making progress. Speaking of pee (which, sadly, I seem to do a lot), we need to decide about leptospirosis vaccination for Merlin.
A good preventive medicine program is important for every pet. There's no "one size fits all" version - the program needs to be tailored for every region and pet/owner combination. We have Merlin's deworming covered. I gave him a booster vaccine the other day, which covers distemper, parvo and a couple of respiratory viruses (adenovirus type 2 and parainfluenza). Rabies vaccination will be coming soon, when he's a bit older (at least 3 months). Now that we have the "core" components covered, we need to think about the elective aspects. One of those is vaccination against leptospirosis.
When thinking about vaccination, it's a cost-benefit decision. The costs and benefits can be hard to accurately assess, but a few basic questions are key: Is there a risk of exposure? Is the disease of concern? Is there a safe and effective vaccine?
Is there a risk of exposure?
Leptospirosis, a potentially life-threatening infection caused by different types of Leptospira bacteria, has been called a "re-emerging" disease in many parts of North America since rates of infection have increased over the last 20 or so years.
Leptospirosis certainly occurs in dogs around here. We don't see a lot of cases but it's far from rare and it can be nasty.
Wildlife are the main reservoir. Infected wildlife shed the bacterium in their urine, and urine-contaminated water and wet areas are the main sources of infection. Raccoons are the biggest concern around here, and there is certainly no shortage of raccoons around my house (including in the garage sometimes). Since Merlin is a Labrador, he's bound to spend a lot of time swimming in ponds and wallowing around in wet areas on our property... prime sites to be contaminated by pee from infected wildlife. So, there's a reasonable chance that he'll be exposed.
Is the disease of concern?
There's no doubt here. While it's uncommon, it can be nasty. Life-threatening infections can occur and kidney failure is a major problem. Treatment of lepto can be difficult and expensive.
Is there a safe and effective vaccine?
Lepto vaccines have had a bad rap. Older vaccines weren't very effective (often not protecting against the strains that are of concern) and were associated with a high rate of adverse reactions. Those former concerns have persisted in some people despite the fact that there's a new generation of vaccines that are much more effective and safer. The new vaccines are better designed, better tested and cover a broader range of strains. There's quality research indicating that they work. Like any vaccine, they're not 100% effective but they are quite good overall.
Information about adverse reactions is harder to get. Adverse event reporting is sporadic at best, but the available information doesn't indicate that these vaccines cause a greater incidence of adverse reactions than any other vaccine. Any given vaccine can cause a problem in any given dog, but the overall risk is low.
So, don't tell Merlin but another set of vaccines is in his future.
With the lingering NHL strike, TV networks are looking for replacement sports. One of my PhD students (who claims he doesn't spend too much time playing around on the internet but keeps coming up with these gems) sent me information about one sport that's not coming to a network near you.
Yes, it's ferret legging. That doesn't really seem like a sport to me...more like a fetish or something someone might do when they're really (really!) drunk. Yet, it apparently exists, evolving from its origins amongst Yorkshire coal miners to a not-much-broader audience.
The rules are pretty simple:
- Tie your pant legs securely around your ankles
- Let someone toss two ferrets down your pants.
- Secure your belt.
- Stand there until you can't take it any more.
"Clean the abrasions thoroughly and hope they don't get infected" is the step no one describes. Wounds are, not surprisingly, common, and some people, like world record holder Reg Mellor, wear white pants to show off the blood strains. Mr. Mellor's world record? 5 hours and 26 minutes.
Interest in ferret legging is dwindling, which is probably a good thing for both ferrets and competitors. There's no mention about whether there are any ferret legging family dynasties, but I suspect that regularly shoving sharp-toothed ferrets down your pants severely limits one's chances of reproducing. That's also good for ferrets and humans alike.
An attempt to be inclusive and create a women's competition involving sticking ferrets up a blouse apparently failed - likely due to relative differences in common sense amongst the genders.
As I mentioned the other day, I took a fecal samples from Merlin, our new puppy, to see what I'd find and show how you have to be careful with interpreting diagnostic test results. In addition to an unconcerning (for me) amount of clostridial bacteria in a fecal smear, Campylobacter was also isolated on bacterial culture. It's important to note that Merlin has not developed any diarrhea this whole time.
Interpreting Campylobacter results can be tough. This bacterium is an important cause of diarrhea in dogs and people, and contact with puppies is a known risk factor for human infection. So, should I be concerned for Merlin or the rest of the family?
The answer in this situation is no.
Why? All Campylobacter are not created alike. There are two main groups of Campylobacter: catalase-positive and catalase-negative. Catalase-positive species, most notably C. jejuni and C. coli, are the main concern in both animals and people. Catalase-negative species tend to be of little to no concern and are very common. We isolated a catalase-negative species from Merlin, one that's not been associated with disease in dogs or people.
Understanding test results and ensuring that testing makes sense is critical. If a lab just reports "Campylobacter positive" as is the case with some (especially labs that just offer PCR (molecular) testing), I wouldn't know what to think of the result. I need to know the species, or at least catalase-positive vs catalase-negative, to put the results into context and come up with a plan. In this case, the plan is to do nothing (or at least nothing we weren't doing already).
More information about Campylobacter in pets is available on the Worms & Germs Resources page.
In a rather impressive effort - considering the issues inherent with working with a virus like Hendra virus, the nature of the disease and the low economic value of a vaccine that would only be used in a very restricted geographic area - a Hendra virus vaccine has been released for horses. Equivac HeV should provide a degree of relief to people in Queensland and neighbouring areas who have been battling this uncommon but devastating bat-borne viral infection.
As a virus that comes from wildlife, Hendra virus is tough to contain. Eradicating the virus in the bat population isn't really feasible, and while measures can be taken to reduce exposure, the risk cannot be eliminated in areas where the virus is present. So, finding a way to reduce the risk of a horse developing the disease after exposure is critical, and the logical approach is vaccination.
Vaccination of horses can also play a huge role in protecting people. All human Hendra virus infections (approximately 50% of which are fatal) have come from direct contact with infected horses, so reducing disease in horses should reduce the risk in humans.
As with most vaccines, it's safe to assume this one isn't 100% effective. It therefore may be a great tool, but people can't then ignore all other Hendra avoidance practices. Individuals still need to take precautions when working around horses that might be infected, regardless of their vaccination status. So, while it's important to avoid complacency, this vaccine should provide a degree of comfort to people who have been living with this virus hanging over their heads (both figuratively and literally, as bats fly around) in recent years.
Life with Merlin is going fairly well and the house training has been surprisingly good (so far). He was straining a bit to poop yesterday so I was wondering if diarrhea was on the way. Diarrhea wouldn't be too surprising since he's had a pretty good shock to his system with a big lifestyle change and a new diet (gradually transitioned, but a change nonetheless). But, so far, so good.
This morning, I collected a fecal sample from him. I'm getting it checked for parasites, as I mentioned the other day. I also did fecal cytology, out of curiosity and because I can do it easily and quickly in my lab. Fecal cytology is a controversial area for diagnosis of bacterial intestinal disease in dogs. Some people use it to diagnose "clostridial" disease and certain other problems. A common statement is that seeing more than 5 clostridial organisms per high power field under the microscope is indicative of a problem. However, a recent American College of Veterinary Internal Medicine consensus statement on the diagnosis of bacterial enteropathogens basically said that this "rule" is pretty useless (disclaimer: I was one of the authors). Yet, some people continue to use it.
Why do I think it's useless?
- There's no evidence indicating that it's accurate. All of the (very few) studies that have looked at this test in dogs have found it to have no usefulness for diagnosis.
- On a fecal smear, you look at a couple of hundred bacteria. That's a miniscule percentage of the trillions of bacterial present in the animal, and there's no assurance that bacteria are equally distributed, so there's no way to tell if what you see is truly representative of the entire bacterial population (it probably isn't).
- There are a few hundred species of Clostridium. Only a few species are known to cause disease. Many of the others are probably important components of the intestinal bacterial population that are important for gut health, so they should be there.
- You can't identify a Clostridium species by looking at it under a microscope. It looks like a purple rod when using a typical Gram stain. The "bad" clostridia look no different than the "good" clostridia. Also, there are many other bacteria that have the same appearance. So, finding lots of "clostridia-like" organisms is incredibly non-specific - it really doesn't tell you much of anything.
Back to Merlin's poop sample: When I looked under the microscope, I could see lots of clostridia-like organisms. Certainly, there were more than 5 per high power field. Yet, he's bright, alert, eating well, and has formed stool. Yes, something could be brewing but I don't see any real sign of that. Some people would treat him with an antibiotic such as metronidazole based on this cytology finding alone. I think that's a bad idea because he's not sick, I doubt he's getting sick, I have no evidence that he has an intestinal bacterial disruption that needs to be treated and the last thing i want to do is mess up his developing intestinal bacterial population with an antibiotic. That's just asking for trouble.
So, no antibiotics for Merlin. Dewormer... that's another story.
The new puppy, now named Merlin, is keeping things busy around here. (Note to self: avoid getting a new puppy during miserable weather. Standing in pouring, driving rain at 4 AM is not fun. Okay, enough whining.)
Yesterday, I wrote about the new puppy's deworming plan. One thing I forgot to mention was the rest of the "herd." By that, I mean Meg, our 11-year-old Lab. Herd health gets a lot of attention in food animals and to a lesser degree in horses, but many concepts remain important for pets. Specifically, when you introduce a new member into the herd, you might change disease risks or required preventive measures for other members of the herd.
Meg lives a pretty cat-like existence. She sleeps, eats, walks far enough to go outside to pee and, well, that's about it. As an older dog who has very rare contact with other dogs, her risk of exposure to many microorganisms, such as parasites, is limited. However, since we brought a new little furry vector into the house, Meg might be exposed to some things that haven't been much of a concern in the past. Her habit of eating whatever she can find (including poop), increases that risk further. So, what's the herd health plan?
It's not too detailed, actually.
- One thing is making sure that we deworm Meg and we don't just focus on the puppy. She might be exposed to anything the puppy is/was shedding. We're usually pretty lax on deworming her in the winter months, but she'll get a couple of doses of dewormer alongside the puppy.
- Poop removal. Since Meg's a notorious poop-eater, we'll want to remove Merlin's waste promptly. That's pretty straightforward. If she can't find it, she can't eat it. It's also important to make sure that old feces aren't left around, because some parasites require time in the environment to become infectious, so regular feces removal prevents accumulation of infective forms of some. The current temperature is at the lower limit of where Toxocara eggs are able to develop into infectious larvae, and the risk will probably be pretty minimal as the temperature drops over the next few days, but it's not hard to make sure the yard gets cleaned up.
- If we find something in the puppy, then we'll have to consider whether Meg might be exposed or at risk too, and decide whether she needs to be tested or treated.
The other aspect of the herd is the non-canine component of the household (i.e. the kids). The key points for that, in terms of zoonotic parasites, are cleaning up feces from the yard, avoiding fecal contact, hand washing, treating the dogs appropriately to reduce parasite shedding and other basic feces-avoidance measures.
Here is another equine update from guest blogger, Dr. John Prescott of the University of Guelph.
Research presented at the Ninth International Equine Infectious Disease conference last week in Lexington, Kentucky, highlighted the dramatic impact that the latest inexpensive genome sequencing techniques are having on understanding microbial disease.
This is well illustrated by an epidemic of S. zooepidemicus upper respiratory tract infection in horses that occurred in Iceland in 2010, described by lead author Sigrídur Björnsdóttir of the Icelandic Food and Veterinary Authority. The infection itself was relatively mild but lasted about 4 weeks, and over the course of the summer affected a large proportion of Iceland’s horses. It caused a headline-stopping movement and export of horses. The disease presented as a laryngitis and persistent dry cough, with a serous [watery] nasal discharge. The infection started at a facility with a water treadmill, and was rapidly disseminated by horses moving from there to 18 other centres across the country, with a high transmission rate to horses within these stables. Since S. zooepidemicus was isolated from the nasal exudate only as the disease progressed, veterinarians investigating the outbreak thought at first that these isolates were opportunistic or secondary invaders, layered on top of an unknown virus infection.
This is where bacteriologists Andrew Waller and Carl Robinson from the United Kingdom’s Animal Health Trust in Newmarket and Matthew Holden from the Sanger Centre in Cambridge became involved. Incredibly, these researchers sequenced the genomes of 290 isolates from the outbreak as well as from an earlier national collection. They used this information to find, to their astonishment, that S. zooepidemicus Sequence Type 209 was responsible for the outbreak. This strain was isolated from the affected farms all over the country, as well as from a case of miscarriage in a person. It could clearly be linked epidemiologically to the outbreak; the date that the infection started was pinpointed to within 5 days. The epidemic occurred so quickly that the genomes of this strain showed almost trivial variation compared to S. zooepidemicus strains that were more established in Icelandic horses.
This is the best description ever of the impact of introduction of a more virulent S. zooepidemicus into a naïve horse population, and will change forever the way that equine veterinarians will think about this underrated pathogen. It illustrates the enormous power of genome sequencing in bar-coding the bad guy.
Andrew Waller also gave a really interesting talk about the diversity of S. zooepidemicus. Sequencing and “sequence typing”, based on multilocus sequence typing (MLST), has identified over 300 sequence types of this species. What is emerging from this is the recognition that difference types cluster with different diseases. For example, strains (sequence types) of S. zooepidemicus that cause abscessation of pharyngeal lymph nodes (“mild strangles”) belong to sequence types that have acquired a bacterial virus carrying a superantigen gene. These are, of course, outclassed by the true strangles organism, S. zooepidemicus subspecies equi, which possesses four bacteriophages with these virulence genes, as well as other nasty characteristics.
Andrew Waller told me that it cost him about $35 to sequence an entire streptococcal genome, which for Canadian veterinarians is now about the cost [Weese comment: or much less than the cost] of sending a swab to a diagnostic lab for culture and sensitivity testing. However, don’t start ringing up the lab to ask for a genome sequence just yet, since the real cost is for the analysis, which is still labour intensive. However, it points the way to the future, which has clearly now arrived, and is changing the way we think about S. zooepidemicus and infection in the horse.
Hide the kids’ toys, tune up the carpet cleaner, get ready for some sleep deprivation… there’s a new dog in the house. Last night, the yet-to-be-named ("he who shall not be named" having been rejected by Heather) little yellow critter arrived. Meg (the existing dog) seems relatively content, or at least resigned. The cat... not so much, but he's already established who's the boss.
So, while I'm momentarily not trying to convince the puppy to pee outside, I’ll take this opportunity to hopefully practice what I preach and describe what we’re doing for things like vaccination, deworming and other infectious disease-related topics.
To start things off: What’s the deworming plan?
- Roundworms (Toxocara canis) are the main concern in puppies. It’s generally a good idea to assume that a young puppy has roundworms, regardless of from where it came and how well cared for it was.
- Canadian parasite treatment guidelines are to treat puppies with a drug that will kill Toxocara worms at 2, 4, 6 and 8 weeks of age, then monthly until 6 months of age. Our little guy is 9 weeks old and has already been treated a couple of times for roundworms, plus he's had one treatment for coccidia (a different parasite that was found on a recent fecal exam). He’ll get another dose of pyrantel pamoate in the next day or two, then monthly until he’s 6 months old. (If someone gets a puppy and it hasn’t been treated like this or its vaccination history isn’t known, it is recommended to give 3 treatments 2 weeks apart, then monthly until 6 months).
- A fecal exam will be done on the puppy in the near future. It’s not an emergency since it won’t impact what I do at the moment in terms of treatment, but it’s good to see if there are any parasites that aren’t killed by the chosen dewormer (e.g. tapeworms) and to detect resistant parasites (i.e. Toxocara eggs still found in feces after appropriate treatment).
- No flea treatment now since he doesn’t have any evidence of a flea infestation and it’s not very likely he’ll be exposed to fleas before the spring based on the current climate where we are.
- No heartworm treatment until the spring either. The Canadian Parasitology Expert Panel (CPEP) recommentaion is for dogs to receive monthly heartworm preventive treatments beginning at a maximum of two months of age. So, I’m not really following that one, but given the time of year, the low prevalence of heartworm in the area he's from and the fact that the puppy wouldn’t have had too much risk of mosquito exposure because of its age and indoor housing, the risk of heartworm exposure this season is very low.
More updates to come, and hopefully not too many descriptions of how to clean puppy feces off of various surfaces.
At the recent 9th International Conference on Equine Infectious Diseases (EIDC) in Lexington, Kentucky several sessions were focused on parasite control of horses. Drug resistant parasites are a world-wide problem in equine establishments, and it has become a challenge to define a simple and useful set of guidelines to be used by horse owners. As many readers of the Worms & Germs Blog will be aware, there is no longer a “one size fits all” program, and parasitologists instead often talk about the complexity related to the different parasites that often infect the horses in concert, their interactions with their hosts, and how to interpret fecal egg counts. While this is all useful and important information, it can be frustrating when it does not readily come with some practical guidance.
Equine parasitology is rarely well-represented at parasitology conferences. Usually, there are less than a handful equine abstracts, and often not even enough for a separate session. The three or so participating equine parasitologists often have to create their own little scientific session over a cup of coffee during the breaks. The EIDC was much different. It had participation from leading equine parasitologists from Sweden, Denmark, Finland, Germany, United Kingdom, Canada, Brazil, and the USA. More than 30 parasitology abstracts were presented at the meeting, and a special session critically addressed the most pressing research needs for equine parasite control. During the conference, an international equine parasitology consortium was formed, and it will serve to coordinate future research efforts and to communicate consensus-based guidelines for parasite control.
So, what are these recommendations then? New research presented at the EIDC illustrated very well that general recommendations are more straight-forward than often anticipated. Work performed by Kurt Pfister and colleagues in Germany illustrated that fecal egg counts are useful for monitoring and controlling parasite transmission by the means of selective therapy. Two Danish studies illustrated that one or two yearly strategic treatments applied to all horses are advisable to effectively break the life cycle of large strongyles, particularly the bloodworm, Strongylus vulgaris. In other words, a basic foundation of treatments can be defined, upon which the some of the more parasitized horses can be identified to receive additional treatments with a selective approach. Several presentations underlined the need for yearly routine evaluations of the efficacy of the anthelmintic drugs used on each farm. The fecal egg count reduction test is the most important use of the fecal egg counts. [Weese comment: that's when you do a fecal egg count before and after deworming, and compare the egg counts to see how much they dropped, as an indication of how well the dewormer worked] Perhaps most encouraging was the promising new diagnostic tools presented by several groups for detection of migrating or encysted parasite larvae. These will turn very useful for identifying horses at risk of disease and in need of deworming. One of these, developed by Jacqui Matthews and her group at Moredun Research Institute in Scotland shows great promise for measuring burdens of small strongyle larvae (cyathostomins), which can pose a threat for severe parasitic disease. With these new tools in hand, we will become able to further refine our recommendations in the future.
More from the International Conference on Equine Infectious Diseases, this time from guest blogger and bacteriologist-extraordinaire, Dr. John Prescott of the University of Guelph:
Stellar work on understanding strangles and Streptococcus equi subspecies equi was presented at the Ninth International Equine Infectious Disease conference in Lexington, Kentucky. Researchers at the Animal Health Trust in Newmarket, United Kingdom (Andrew and Carl Robinson) are working with Matthew Holden at the Sanger Centre in Cambridge to use NextGen sequencing to understand better the strangles bacterium, and the impact of the carrier state on the pathogen as it lurks in the guttural pouch. The abstracts of their work are freely available through the conference web site, http://www.eidc2012.com/.
A novel quantitative PCR (qPCR) based on two unique genes of S. equi was was described that will identify S. equi within 2 hours, with a sensitivity of 93% and specificity of over 96%. Not only is it more sensitive than culture but it also overcomes the effects of non-S. equi contaminants which can interfere with culture. Another development reported was an ELISA based on two antigens unique to S. equi that together have a similar sensitivity and specificity to the qPCR. Current thoughts are that the ELISA could be used as a serological test in screening for carriers, with the qPCR then being used on guttural pouch aspirates to confirm the carrier state, which would then be treated.
The strangles (equi) subspecies of S. equi has been thought to be genetically and immunologically identical, but sequencing the M protein SeM gene has shown that there are over 100 strains. Holden and his colleagues have used high throughput sequencing to characterize the genomes of an astonishing 240 isolates from different countries, including one strain from Canada. They have found that genomic diversity is even higher than SeM sequencing had suggested. As a result of this work, they identified a “fitter” clone (ST151) now spreading through the UK population at the expense of an older clone (ST179).
Most interestingly, they have identified the genetic changes occurring as outbreak strains adapt to their different life in the guttural pouch, which is where the organism hangs out in carrier horses. The adaptation involves discarding some genes, stopping the expression of others, but also duplicating others. According to Holden, a Sanger Centre genome veteran, the S. equi genome is more dynamic than any of the other pathogens with which he has worked. The big question is of course the impact of this adaptation on virulence, and the extent and speed with which these genetic adaptations can be reversed if and when the “carrier“ strains revert to cause acute strangles. There is a horrible suspicion that some may be able to borrow back the deleted genes from other S. equi strains in the guttural pouch.
Because of both its species- and niche-adaptation, strangles has all the characteristics of a bacterial infection that can be eradicated. The superb work being done at the Animal Health Trust, all based on genomics, is drawing the noose ever tighter around this ancient scourge of the horse.
- John Prescott, Department of Pathobiology, University of Guelph
Two presentations at the International Conference on Equine Infectious Diseases yesterday discussed equine coronavirus and whether it might be a new or previously unrecognized cause of disease in adult horses. This follows a presentation the day before that mentioned coronavirus diarrhea in racing draft horses in Japan - a rather unique group, pictured at right.
Dr. Nicola Pusterla from the University of California Davis described five suspect outbreaks in boarding facilities from four US states. Seventy-three (73) horses were affected overall, with decreased appetite being the most common sign in affected horses, followed by lethargy, fever, soft manure and colic. Equine coronavirus was detected in the vast majority of sick horses but rarely from healthy horses at the same facilities. Most horses got better without specific treatment, but five horses died or were euthanized. Overall, the attack rate on farms was high but the death rate was low. Fortunately from an infection control standpoint, infected horses only shed the virus for a short period of time (a few days), making control easier.
Dr. Ron Vin followed this presentation with a description of coronavirus involvement in sporadic disease and outbreaks in adult horses from a variety of US states, most often with mild diarrhea and low white blood cell counts. As with the first report, disease severity was usually less than what we see with some other causes of diarrhea in adult horses, such as Salmonella and Clostridium difficile.
One thing that’s not clear is whether this virus is truly a cause of disease or something that’s just being found in horses that have some other undiagnosed disease. No other potential causes were identified in most of the suspected coronavirus infections, but a large percentage of cases of diarrhea that we see go undiagnosed because we don’t know all the possible causes. It’s certainly possible that there was another cause, but these results suggest that equine coronavirus is something for which we should be looking out when we see gastrointestinal (e.g. colic, diarrhea) or non-specific disease (e.g. off feed, lethargic with no other particular signs), especially during outbreaks. The story may be different in foals, since shedding of the virus by healthy foals isn’t uncommon.
Photo credit: http://newshopper.sulekha.com/
I’m at the International Conference on Equine Infectious Diseases in Lexington, Kentucky at the moment, and will try to write about some of the highlights. One interesting discussion yesterday was about canine and equine influenza. It’s well established that canine flu (A/H3N8) originated in horses and subsequently became established in dogs. Canine flu virus is closely related to, but different from, its equine flu virus parent. That raises questions about whether canine flu virus could be transmitted back to horses. The question has significant implications for what should be done with dogs that might have canine flu that may have contact with horses, and for canine-horse contact in general, especially with performance horses.
A study by Yamanaka et al. (Acta Vet Scand 2012) looked at dog-horse infectivity of canine flu by putting infected dogs in stalls with healthy horses for 15 days. All dogs were sick and shedding canine influenza virus, but none of the horses got sick, shed the virus or mounted an antibody response. This study only involved three horse-dog pairs, so we have to be careful that we don’t go too far with the conclusions, but it suggests that while canine flu started off as horse flu, it has changed enough that infected dogs aren’t much of a risk to horses.
But... (yes, there’s usually a "but" with infectious diseases) dogs are susceptible to "normal" equine influenza. It’s uncommon, but dogs can be directly infected from horses with the classical equine H3H8 flu virus. In such a situation, dogs might pose a risk to horses because they are carrying the equine virus, not the adapted canine version.
- If a dog has influenza that is known to be non-horse associated (i.e. typical canine flu) then there’s probably little concern for horses.
- If a dog has influenza and there’s no clear dog link (or there’s a link with infected horses), it’s re