Worms & Germs Blog

Canine and Feline Respiratory Infection Treatment Guidelines

Posted in Cats, Dogs, Other diseases

Dog cough SSThe latest set of clinical treatment guidelines from the International Society for Companion Animal Infectious Diseases have been published in the Journal of Veterinary Internal Medicine (Lappin et al 2017): Antimicrobial Use Guidelines for Treatment of Respiratory Tract Disease in Dogs and Cats: Antimicrobial Guidelines Working Group of the International Society for Companion Animal Infectious Diseases.

It’s available via the link above or through the JVIM website.

Rabies and Bite Responses

Posted in Dogs, Rabies, Vaccination

There tends to be confusion about what happens when an animal bites or is bitten, and rabies is being considered. Most of the confusion revolves around how long an animal is quarantined or observed. Yet, it’s actually pretty straightforward if you think about why quarantine/observation is being performed and some basics about the virus and the disease itself.

Scenario 1: A dog bites a person

This one’s easy.

  • The response: 10 day quarantine or observation. Basically, we need to ensure that the dog is normal 10 days after the bite.

Why?

  • To see if it develops signs of rabies. Based on the nature of rabies virus infection, by the time a dog is infectious (shedding rabies virus in saliva) the infection is well advanced. If the dog is neurologically normal 10 days after the bite, it could not have had rabies virus in its saliva at the time of the bite

What if the dog was vaccinated against rabies?

  • That doesn’t have any impact. Vaccination is highly effective but not 100% protective. Since you can’t guarantee a vaccinated dog doesn’t have rabies, even vaccinated dogs may be placed under a 10-day observation period.

Raccoon doubleScenario 2: A dog is bitten by a raccoon (or other potentially rabid animal)

One variable here is whether the offending animal is available for testing. If it is killed/euthanized and tested, and shown not to have rabies virus in its brain, the bitten dog is in the clear (same applies if a person is bitten by a wild animal).  In a large proportion of cases the offending animal is not available for testing, and the rabies status of the animal is never known at the time of the bite.

Why is there a response?

  • Unlike scenario 1, the goal here isn’t to see if the dog was incubating rabies virus when it was bitten. The goal is to determine if there is a reasonable risk that the dog will develop rabies, and to keep it contained during the period when rabies is most likely to develop so it can’t infect someone else. The incubation period for rabies in dogs can be long (months) so the quarantine/observation period has to be longer.

What is the response?

  • The first step is to perform a risk assessment to determine the likelihood that the offending animal transmitted rabies to the dog.  Although the risk from a bite from another mammal is never zero, if the risk is deemed to be very low then no specific action is taken other than to ensure the dog’s vaccination status is up-to-date.  Pet owners must always be vigilant for neurologic signs in their animals that may be consistent with rabies.  Even indoor animals can have contact with potential rabies vectors such as bats.
  • If the risk assessment is that there is a significant risk of rabies transmission, unlike scenario 1, the dog’s vaccination status then plays a role in determining the subsequent response. (Note: These rules are for Ontario. There’s some variation between jurisdictions).

If the dog was full vaccinated, according to the intervals specified by the vaccine manufacturer, and is not overdue for a booster:

  • The dog still requires a rabies booster is given within 7 days of the bite.  If this is done, there is no confinement period, although an informal observation period (45 days) is recommended out of an abundance of caution.
  • If a booster isn’t given within 7 days, then the dog gets a 3 month precautionary confinement period (PCP). During this time, they have to stay on the owner’s property (except for medical care), have contact only with one caregiver, have no contact with other animals, can only go outside on a leash and in a fenced area and must be cordoned off when inside with a double barrier (e.g. kept in a room with a closed door in a house with a closed door).

If the dog received an initial rabies vaccine but is not yet due for its first booster (i.e. within 12 months but no less than 14 days after initial vaccination):

  • Same as for fully vaccinated dogs. The key is getting to booster done within 7 days.

If the dog has been vaccinated in the past but is overdue for a booster:

  • This is handled on a case-by-case basis, thinking about the time since vaccination, the number of vaccines the dog has had in the past and other things that might influence protection. Usually, the response is a booster within 7 days and a 3 month PCP. Without a booster, a 6 month PCP is used.

If the dog has never been vaccinated against rabies or rabies vaccination history is unknown:

  • If the dog gets a rabies shot within 7 days of the bite, it gets a 3 month PCP. If not, it’s 6 months. Euthanasia is the other option and is sometimes chosen because of the issues with long quarantines. That’s particularly true with puppies (who are more likely to be unvaccinated), where long confinement periods can be very difficult and impact socialization.

Incidentally, the same rules apply to cats in Ontario. Don’t forget, all dogs, cats and ferrets over 3 months of age in Southern Ontario are legally required to be fully vaccinated for rabies at all times.  Failure to do so can result in a fine (which usually costs more than the vaccination!)

2016 Rabies Compendium

Posted in Cats, Dogs, Horses, Other animals, Rabies, Vaccination

Vampire smileyThe 2016 Compendium of Animal Rabies Prevention and Control has been released by the US’s National Association of State Public Health Veterinarians (NASPHV). This version has updates in a few different areas, such as some changes to recommendations for dogs, cats and ferrets that have potentially been exposed to rabies. It can be downloaded directly here or be found with other documents at the NASPHV Compendium site.

Is MRSP zoonotic?

Posted in Dogs, MRSA/MRSP

three-dogsI’ve written about this many times (probably because I get asked about it almost every day), but there’s not really a simple answer to the question “Does methicillin-resistant Staph. pseudintermedius pose a human health risk?

My typical answer is along the lines of “Yes, but…” with discussion about how rare Staph pseudintermedius (SP) infections are in people, despite widespread exposure to infected or colonized dogs. However, “low” doesn’t mean “no.”

A recent article in Vector-Borne and Zoonotic Diseases (Lozano et al 2017) describes methicillin-susceptible SP infections in four people. The first question you might have is, why would I talk about susceptible SP in the discussion of MRSP?  It’s relevant because they’re still the same bug – being methicillin-resistant doesn’t make SP more likely to infect a person, but it does make it harder to kill if it causes an infection (which is why it’s a concern). Therefore, understanding aspects of susceptible SP infections is useful in understanding MRSP.

Here are some highlights from the study:

  • Infections were diagnosed in four people in a hospital in Spain over a 10 month period. All four patients had what sounds like relatively straightforward skin and soft tissue infections. Two of the four people were higher risk (one with cancer and one described generically as being immunocompromised).
  • One patient had a surgical site infection and no contact with animals. Not much more is said about this one but is raises questions about where it might have originated.
  • Patient 2 had contact with dogs, but did not own any herself. Patients 3 and 4 both owned dogs.
  • SP was isolated from the 3 dogs owned by patients 3 and 4. That’s not surprising since we can find SP in most dogs at any given time.
  • The same SP strains were found in dogs and infected people within the same households. That’s also not surprising since the dogs were the logical source and we’ve previously shown that when we find S. pseudintermedius in people in households, it’s usually the same strain as in their pet. Most likely, we interchange SP and various other bacteria on a regular basis.

In some ways, this is just a straightforward but nicely documented small series of SP infections in people. It doesn’t change the answer to the “Is MRSP zoonotic?” question that I’ll probably get (again) at some point over the next couple of days. However, it re-inforces the low but ever-present potential risk posed by this bacterium, like many other bacteria that dogs carry.

One final comment to hopefully put things into perspective: When talking about MRSP risk, a statement I often make is “If I had to rank the top 5 zoonotic risks posed by a dog carrying MRSP (or plain old SP), MRSP/SP would probably not make that list.” It’s worth paying attention to MRSP, but at the same time, it’s important to keep it in perspective, realize how rare it is, realize how basic measures probably reduce that risk even further, and remember that all dogs pose some (very low) degree of risk, and we’re better off thinking about routine practices rather than focusing on low risk bugs like this.

For me, this report is just one more reason to emphasize the overall message: the risk is low but you never want a multidrug-resistant infection so you should use some basic infection control and hygiene measures to reduce exposure to MRSP. Most of that is easy, revolving around avoiding contact with infected site (eg. skin infections), avoiding contact with the nose, mouth and feces of dogs with MRSP infections (since they are often carrying the bug at those sites as well) and good old handwashing.

Seoul Virus in Pet Rats

Posted in Pocket pets

White ratAnother day, another new zoonotic disease concern.

Well, it’s not really that bad, but the list of new (or at least newly identified) zoonotic disease issues continues to expand at an impressive rate.

One of the latest concerns is a cluster of Seoul virus infections linked to rats. At last report, 8 infections with Seoul virus have been identified in people in two US states.

Seoul virus is a member of the Hantavirus family, a group of viruses that lives primarily in rodents.  Seoul virus infections in people tend to be relatively mild. Most people who are infected do not develop any signs of disease, but flu-like illness and potentially some more serious complications such as kidney disease can occur. Relatively speaking, it’s much less serious than the life-threatening hantavirus pulmonary syndrome that can develop with other hantavirus infections, but it still warrants attention.

The first reported human case in this series was a at-home rodent breeder in Wisconsin. He ended up in hospital after developing fever, headache and some other vague flu-like symptoms. A family member subsequently tested positive as well. Fortunately, both recovered.

Since this is a rodent-borne virus, tracebacks to facilities from which this person obtained rats were pursued. Six additional human cases were identified associated with two rat-breeding facilities in Illinois. Efforts are ongoing to see if there are any infections in other people who purchased rats from any of these facilities.

One thing that was overlooked in this outbreak report is how the index case was identified. There’s not much information available, but Seoul virus testing isn’t routine, and testing of people with flu-like disease for things beyond influenza (if that) isn’t that common. A CNN news report about the Seoul virus outbreak said “Because of the patient’s exposure to rodents, the doctor had a “hunch” to test for hantavirus, explained [Director of the Wisconsin Dept of Health Services Bureau of Communicable Diseases Stephanie] Smiley.”

  • That’s an important point to me, as it shows that animal contact was queried (which unfortunately isn’t often done) and the information led to consideration of uncommon problems. We need more of this kind of behaviour to improve diagnosis of zoonotic diseases.

CDC’s recommendations for rat owners are pretty straightforward (and are what we tell rat owners to do at all times, since they also help reduce the risk of things like rat bite fever (Streptobacillus moniliformis infection)):

  • Wash your hands with soap and running water after touching, feeding, or caring for rodents, or cleaning their habitats. Be sure to assist children with handwashing.
  • Be aware that pet rodents can shed germs that can contaminate surfaces in areas where they live and roam. Make sure rodent enclosures are properly secured and safe, so your pet doesn’t get hurt or contaminate surfaces.
  • Clean and disinfect rodent habitats and supplies outside your home when possible. Never clean rodent habitats or their supplies in the kitchen sink, other food preparation areas, or the bathroom sink.
  • Avoid bites and scratches from rodents. Be cautious with unfamiliar animals, even if they seem friendly. Take precautions when cleaning out rodent cages or areas with rodent urine or droppings.
  • Visit your veterinarian for routine evaluation and care to keep your rodents healthy and to prevent infectious diseases.

If bitten by a rodent:

  • Wash the wound with warm soapy water immediately. Even healthy pets can carry germs.

Seek medical attention if:

  • Your pet appears sick.
  • Your wound is serious.
  • Your wound becomes red, painful, warm, or swollen.
  • Your last tetanus shot was more than 5 years ago.
  • You develop sudden fever or flu-like illness within 1-2 weeks after being bitten

Tell your healthcare provider that you have been around pet rodents, whether at home or away from home, especially if you are sick or have been bitten or scratched.

Rabies from a mongoose bite

Posted in Other animals, Rabies, Vaccination

Yellow mongooseEvery few days, it seems, I get an email or call that goes something like “I was just bitten by [insert various mammals here]. Do I need to worry about rabies or do anything?”

The answer’s pretty similar every time. While the relative risk posed by different animal species in different geographic regions varies, you have to think about rabies anytime you’ve been bitten by a mammal. Knowing what to do can save a lot of hassles, and maybe your life. While the likelihood of rabies exposure from a bite in most countries is very low, ignoring or not being aware of this low risk leads to deaths.

CDC’s Morbidity and Mortality Weekly Report Recently published an article about a rabies death in Puerto Rico from 2015 (Styczynski et al 2016). The affected person was a 54-year-old man who initially presented to the ER with fever, difficulty swallowing, tingling in a hand, cough and chest tightness. He died the next day. Upon further investigation, his wife reported that he had been bitten by a mongoose approximately 2 months earlier. However, he did not seek care for the bite. Rabies was confirmed on autopsy. After an investigation of his contacts, seven family members and two healthcare personnel received rabies post-exposure prophylaxis (PEP).

Mongooses are a rabies reservoir species in certain areas, and rabies is very common in mongooses in Puerto Rico. An astounding 97% of mongooses that were tested after biting a person between 2005-2008 were positive for rabies. Not surprisingly, rabies PEP is recommended after mongoose bites, as it is for bites from other rabies reservoir species (e.g. raccoons, skunks, foxes, bats) in other regions.

If this bite had been reported, it’s virtually guaranteed that the man would have received PEP, and with that, it’s virtually guaranteed that he would not have developed rabies. There are a number of reasons why people don’t get appropriate care following a bite from a potentially rabid animal. In some regions, it’s because of poor access to medical care, or little to no supply of the rabies vaccine and rabies antibodies required. That’s not the case in Puerto Rico, where failure to obtain treatment is much more likely due to lack of the victim knowing it’s needed.

As the authors conclude, “Public health measures to reduce the risk for human rabies should include increased resources for primary prevention, including routine pet vaccination (canine rabies in Puerto Rico results from transmission from mongooses) and pre-exposure prophylaxis for persons at highest risk. Community education should highlight measures to avoid bites from pets and wildlife. Effective oral rabies vaccine baits targeting mongooses might also be considered as they become commercially available. Interventions should focus on areas with known human-mongoose contacts, as determined by overlaying bite surveillance data and population density. Secondary prevention measures should be aimed at increasing awareness of the need for medical evaluation and PEP after any mongoose bite.”

More avian flu in cats…H5N6 in South Korea

Posted in Birds, Cats

Cat washingFollowing on the heels of an H7N2 influenza outbreak in cats (and one person) in New York, H5N6 avian influenza has been found in two dead cats in Pocheon, Gyeonggi province, South Korea. This highly pathogenic avian influenza strain has been active in South Korea since November 2016, resulting in the death or euthanasia of more than 28 million chickens and ducks from 606 farms. The affected cats weren’t on a farm, but were found only about 2 km away, so may have visited the farm or potentially be exposed to the virus through wild birds in the area.

These infected cats are less surprising than the New York flu outbreak that has affected a large number of shelter cats. Rare spillover infections of avian flu in other species occur, particularly when large outbreaks are present and there are many opportunities for exposure. Cats are susceptible to a variety of flu viruses and can be exposed by eating infected birds (and sick or dead birds are easier to catch of course). The potential for avian flu to spread to other species, and in the worst case scenario to mutate or recombine with another flu virus to become more transmissible in people (while still causing severe disease), is why there’s such an aggressive response to avian flu outbreaks.

The risk infected cats pose to people is hard to determine. Usually, avian flu is not readily transmissible from aberrant hosts (including people), and close, prolonged contact is required for subsequent cases to develop. That’s like the New York outbreak where only one person has (so far) been identified as infected, and that person had very close contact with large numbers of infected cats.

To some degree, these infected cats should just be considered unsurprising but unfortunate collateral damage of the avian flu outbreak, and nothing to get too concerned about. However, roaming cats in areas where avian flu is present cause concern because they are a potential bridge between the bird population and humans. People who are working or living closely with birds are at highest risk of avian flu. If local cats become infected and roam to other areas, they could expose other people outside of these high-risk groups, and outside of standard outbreak containment and surveillance efforts. The two dead cats in this case may have been feral cats, but the potential for cats to act as a bridge is another reason that pet cats should be kept inside in areas where avian flu is actively circulating.

Biohazardous hedgehogs…multistate salmonellosis outbreak

Posted in Pocket pets, Salmonella

HedgehogWhen I talk about hospital visitation animals, I often use hedgehogs as an example of a novelty critter that we want to keep out of high risk situations. They’re interesting, but is there any advantage f seeing a hedgehog vs interacting with a properly trained visitation dog? Probably not. When you add in the greater potential for hedgehogs to be carrying things like Salmonella, it’s pretty clear they shouldn’t be in high risk situations.

Along those lines, a recent paper in Zoonoses and Public Health (Anderson et al 2016) describes a multistate outbreak of salmonellosis associated with pet hedgehogs.

Twenty-six (26) people infected with the outbreak strain of Salmonella Typhimurium were identified in 12 states. Most of those people reported contact with hedgehogs. As ever, the real number of cases was probably much higher, since a large percentage of people who get infected with Salmonella don’t get diagnosed.

  • Not surprisingly, kids were over-represented. The ages ranged from <1 to 91 years of age, with a median of 15 years of age.
  • 35% of cases were hospitalized. That’s probably a bit higher than the average outbreak report. More concerning, there was one death attributed to the infection.
  • When information about hedgehog purchase was available, 8/11 people had purchased the pet in the past 1-5 weeks. That’s pretty consistent with other outbreaks, where recently obtained pets are highest risk. Whether that’s because hedgehogs are more likely to shed Salmonella during that initial period, people have closer contact with them when they are new pets, or other factors isn’t known.
  • Limited hedgehog health information was available, but 3/6 had diarrhea before the person’s illness.
  • Various high-risk behaviours were identified, such as bathing hedgehogs in the family bathtub.
  • Traceback of where the hedgehogs came from didn’t identify any consistent source.  If a point source can be identified, the problem can potentially be controlled (e.g. closing down or eradicating Salmonella from a central facility or source breeder).  In an outbreak like this with no identifiable source, control is much more difficult, so that’s a concern.

This report doesn’t mean that people shouldn’t own hedgehogs. However, hedgehogs should be considered high risk pets, like reptiles, and kept away from high risk people (e.g. kids under 5 years of age). Like reptiles, good basic hygiene practices should be used to reduce the risk of Salmonella exposure. That’s probably particularly true with new pets. While it hasn’t been well-studied, it is likely that most pet species carry more infectious agents when they are purchased/adopted, because they typically come from higher risk facilities (e.g. more animals, more stress, lots of mixing) and can naturally eliminate many pathogens over time when they get into a lower risk household. The initial new pet period is also the time when people tend to have the most contact with pets, especially pocket pets, before the novelty factor starts to wear off.

Another thing to consider with this report is the fact that diarrhea occurred in the hedgehog before the person in some situations. For any pet owner, diarrhea or other illness should be a flag that the pet poses a greater risk, and more precautions should be taken with any diarrheic animal.

A lot of common sense goes a long way… and handwashing can prevent a lot of problems!

Backyard poultry…knowledge, attitudes and practices

Posted in Salmonella

Backyard chickensThe backyard poultry debate continues in many areas. It raised is head again in Guelph recently, with more city government debate about how far you have to keep your backyard chickens from your neighbours. There are a number of issues to consider, like potential for spread of zoonotic bacteria (e.g. Salmonella), avian flu, noise, smell and attracting other critters (e.g. coyotes).

A recent study in Zoonoses and Public Health (Kauber et al 2016) engaged owners of backyard chickens in Seattle to look at their level of knowledge of Salmonella, and practices that might influence Salmonella exposure risk.

Here are some highlights from the study:

  • Owners of the 50 studied backyard flocks were predominantly white (94%), female (74%) and well educated. 36% had a 4-year college degree and 54% had a graduate degree.
  • 90% of flocks were comprised of 8 or fewer birds.
  • Only one person had chicks on the premises at the time of the study. Those were kept inside.
  • 80% of people knew Salmonella was a bacterium, all but one knew people can get salmonellosis.

They also asked people about their infection control practices. You always have to take results like this with a grain of salt because if people know what they should be doing, there’s a chance they’ll give you that answer rather than what they actually do. They also collected video footage of people caring for their birds. This would likely provide more accurate information but still with some potential for people changing their behaviour because they knew they were being watched (the Hawthorne effect).

  • Two thirds of people said they don’t wash poultry-related items in the house or in areas where food is prepared. (The flip side is that 1/3 of people do this, and that is considered a high risk practice).
  • Three quarters rarely (10%) or never (66%) let their birds inside the house (a more obvious way to track bacteria and other bugs into the house).
  • One quarter had close contact with the birds, such as kissing them (to each their own, I guess).
  • Over one half allowed children less than 5 years of age to have contact with chickens, especially chicks. (This is getting into higher risk territory too, since contact with chicks is recurrently associated with salmonellosis outbreaks, particularly in kids).
  • In the videos, young kids were seen petting chickens, playing barefoot in the chicken area and entering the house with shoes worn in the chicken area. (I’m not a germaphobe and think environmental exposures are good for kids. This is to the extreme of that, given the known Salmonella risk. Outside and dirty… good. Outside and dirty with chickens… not so much).
  • People often touched their mouth or face while caring for the birds.
  • When comparing the video and survey results, over 50% of people who said they don’t have close contact with birds were observed snuggling with birds or touching their face.

What does this mean?

It’s hard to say. We really don’t know what the Salmonella risk is to owners of these small backyard flocks. The risk is probably greatest when people buy chicks, since lots of outbreaks have occurred from newborn chicks (both because they often carry Salmonella and because there is often closer contact with them). The risk to neighbours is also unclear, and presumably varies a lot with things like climate, rainfall and the contour of the land (e.g. a sloping lawn that sends chicken-poop-tea into the neighbouring lawn every time it rains).

There are some good aspects of having backyard chickens and some concerns, including disease and other issues. This study helps with one piece of the puzzle, and points out some potential areas to address.

The paper’s conclusions aren’t surprising but are logical: The data from this survey reveal that backyard poultry owners are aware of the association between Salmonella and poultry, but that they do not consistently perform risk-reducing husbandry and hygiene practices as recommended by CDC and the State department of health to help prevent infection with Salmonella. There is a need for better education to effectively communicate the risk of potential for zoonotic disease transmission and provide recommendations for husbandry and hygiene practices.

Bats, rabies and a hospital NICU

Posted in Rabies

SinkWhen a bat is found in a household, the response can be quite variable.  Many public health units may consider it a potential rabies exposure if the bat was in the house overnight, on the assumption that a bite could have occurred without being noticed (I have personal experience with that).  Based on the large number of people that are given rabies post-exposure prophylaxis (PEP) for this type of exposure (and the large cost associated with PEP), along with an estimate that changing this policy would only result in an extra rabies case every few hundred years, many jurisdictions don’t automatically consider sleeping in a room with a bat to be exposure.

But, what about a situation where you have people who can’t reliably report whether they were bitten, who are immunocompromised, and for whom there is no information about whether rabies PEP is safe or effective?

That situation occurred in a neonatal intensive care unit (NICU) in Austin, Texas, as reported in Infection Control and Hospital Epidemiology (Bailey et al 2016).

Two bats were found in a sink in the NICU… a strange place for them to be, and any time bats are in a strange place or acting abnormally, it’s a big red flag that they could be rabid. The bats were released outside, so they could not be tested. That means you have to err on the side of caution and assume they were rabid, then determine whether there might have been any human exposure.

While there was no evidence of them having contact with any patient, there’s no way to rule that out since bat bites can be very small and hard to detect, and the patients in a NICU obviously can’t report a bite.

After considering various factors, such as the nearly 100% fatal nature of rabies infection, the lack of evidence of vaccine effectiveness or safety in premature infants, and the known potential for poor response to rabies vaccination in people with compromised immune systems, it was decided that at least some of the infants should receive PEP (the paper doesn’t describe how those were selected). Rabies vaccination was recommended for 6 and offered for the 13 other infants in the NICU. Families of 5/6 of the high risk and 2/13 of the lower risk group consented to the PEP.  None of the patients developed rabies.

The paper provides some information about response to rabies vaccination. None of the infants developed any identifiable complications. Three infants were tested 6 moths after treatment, and all had developed an adequate immune response (circulating rabies antibodies). It’s a small number of patients, but provides at least some indication that premature infants can mount an effective response to rabies vaccination.

There’s no mention of what they did to figure out how the bats got into the NICU or hanging around in the hospital, nor if they provided any subsequent training to make sure people don’t just release bats that are found inside.