Service animal scrutiny
Two recent news reports highlight some challenges that people with service dogs face, and some of the controversies that exist.
In one report, a Winnipeg woman was kicked out of a McDonald's restaurant because staff did not want her seeing-eye dog in the restaurant. McDonald's head office has apologized profusely, probably an indication both of damage control and a disconnect between the awareness of service animals among corporate personnel and front-line employees.
The woman involved isn't looking for apologies or a lawsuit, just increased awareness and fewer hassles for her and others that depend on service animals. This situation is therefore being handled from a standpoint of "let's try to improve the situation." The Manitoba Restaurant and Food Services Association has contacted the CNIB for help raising awareness among restaurant staff of the rights of people with disabilities and their service animals.
A different situation has occurred in Wisconsin, where a man is threatening to sue the Oshkosh Area School District unless it fires a teacher. The man got into an encounter with the teacher while picking up his girlfriend's daughter from school. He has a dog that he takes everywhere because he's at risk of seizures (although it's not clear whether this is truly a service dog, i.e. specially trained for such situations). Anyway, as the man was approaching the school on the sidewalk, he was confronted by the teacher. The teacher eventually called the police, claiming she was threatened by the man after telling him to stay away with the dog. There's reportedly a history of conflicts between the man and the school staff, which has evidently spiraled into this confrontational situation. In addition to wanting the teacher fired, he intends to file a lawsuit seeking compensation for "damages," although he claims he's not interested in receiving money.
This is a very different case from the woman in Winnipeg, and there may be many underlying factors that are not being reported. It seems like a combination of a lack of understanding of where service animals can go and some major personality conflicts.
People with service animals not uncommonly (although inappropriately) get asked about their animals, particularly why they have them. They may also be (inappropriately) asked to take them away. There are also situations where people have questionable (or basically fake) service animals, something that creates problems for people with real service animals (see some examples in our "service animal" archives). A little patience, tact and education can go a long way, with education being the key component. Ignorance shouldn't be an excuse, but it's not realistic for everyone on the planet to be fully aware of service animal issues and regulations.
People in service industries (e.g. restaurants, retail) need to have better knowledge about service animals than average, and there needs to be a clear understanding that these animals should be allowed to go wherever customers go. At the same time, there needs to be scrutiny of existing service animal regulations (such as the Americans with Disabilities Act) because the vague nature of many of these regulations lead to abuses that ultimately hurt the people who truly need these animals.
Image source: www.funnydog.net
Baylisascaris and dogs
Recently, I was speaking with a physician who mentioned that a colleague has recommended that people with raccoons in their yard get rid of their dogs because of the risk of Baylisascaris procyonis. This parasite, also known as the raccoon roundworm, can cause severe neurological disease in people that ingest infective parasite eggs from the environment.
The most severe type of disease caused by the migrating larvae of this roundworm (neural larval migrans) is very nasty, and usually causes death or serious, severe neurological deficits. However, the recommendation to get rid of dogs when there are raccoons around makes no sense. Here's why:
- The main host for Baylisascaris is the raccoon. A large percentage of healthy raccoons (over 90% in some areas) are infected and pass large numbers of parasite eggs in their stool. Exposure to eggs from raccoon feces is the main source of human infection.
- Human infections are very rare. They predominantly occur in people that are at increased risk of ingesting feces or dirt, based on their age or behaviour.
- Dogs can be infected with Baylisascaris, but this is rare.
- The small number of dogs that are shedding Baylisascaris in their feces do not pose an immediate risk to people. Eggs that are passed in feces are not immediately infective. Eggs must mature in the environment (which usually takes 2-4 weeks) before they are able to cause infections.
- There are no clearly documented cases of dogs being a source of human infection.
- The main risk from dogs is probably the potential for dogs to carry old (i.e. infectious) Baylisascaris eggs into houses on their haircoats, after roaming around raccoon infested areas.
How do you reduce the already very low risk associated with Baylisascaris and dogs?
- Discourage raccoons from living near your house. Raccoons defecate in certain areas or "latrines," where the soil becomes heavily contaminated with raccoon feces, and where tremendous numbers of infectious eggs can be present. If you make your yard uninviting to raccoons, then they won't establish a latrine near your house.
- Carefully clean any raccoon latrines that might be on your property.
- Don't let you dog have contact with raccoon latrines.
- If your dog has had contact with a raccoon latrine, give it a bath. Baylisascaris eggs are sticky and can stick to the dog's coat quite well, so a thorough bath is much better than a quick rinse or brush. Wear gloves and some form of protective outwear (e.g. a coat that you take off after and promptly launder) while bathing the dog. Wash your hands thoroughly when done.
- Closely supervise people at increased risk of ingesting feces or dirt (e.g. young children) when they're outside.
- A routine deworming program will eliminate Baylisascaris in the intestinal tract of a pet dog, in the unlikely event it's been infected.
- Prophylactic treatment of dogs that have eaten (or have a tendency to eat) raccoon feces could be considered, but the need and usefulness of this is not clear.
Bottom line: You don't need to get rid of your dog if there are raccoons in your yard. The risk of Baylisascaris infection from your dog is extremely low, and the steps above can help you decrease the risk even further. Getting rid of the raccoons (instead of the dog) will be much more effective.
More information about Baylisascaris and neural larval migrans is available in our archives.
Raw Q and A
While I hate to initiate another round of emails from raw diet supporters, here are a few of the more common questions that I get about these diets and some answers:
I use frozen raw food. Doesn't freezing kill harmful microorganisms?
- No. Freezing is an effective way to eliminate most parasites (with an adequately low temperature and adequate time, which varies between parasites). Campylobacter also does not survive freezing well. However, other bacteria, including Salmonella, tolerate freezing quite well. Studies of previously frozen raw diets have found high rates of bacteria like Salmonella.
My dog doesn't defecate in the hospital, so why are we paying attention to intestinal bacteria?
- Inadvertent exposure to fecal bacteria is common. Most gastrointestinal infections in people are from ingestion of bacteria and viruses from feces (e.g. Salmonella, Clostridium difficile, norovirus). We don't knowingly ingest feces, but we get exposed to these organisms nonetheless. Fecal bacteria can end up on pets' haircoats, people's hands and many surfaces in the general environment, and then wind up in the intestinal tract of a susceptible person.
Is there any way to eliminate Salmonella and other harmful bugs from raw meat?
- Yes. Besides the obvious (cooking), there are a couple options. One is irradition, which is a safe and highly effective way to eliminate bacteria. The main problems are cost and consumer fears of irradiation (which is actually harmless). Another approach is high pressure pasteurization. This process uses high pressure (with a slight increase in temperature) to kill harmful organisms. The effectiveness of this for raw meat hasn't been clearly determined, but it's an option, and one company is now doing this for all of their diets.
Why don't you just go into hospitals, ask nurses whether animals visit and compare infection rates, so you can see if there is a true health risk?
- It would be nice if it was that easy. Firstly, asking nursing staff doesn't give enough information. You need to know if animals visit, but also if they visited particular patients, and whether they visited before those patients developed infection. Just comparing infection rates between hospitals or wards that allow dogs to visit, and knowing the dietary status of the dogs, is useless. A proper study would require clear documentation of which animals visited which patients (something that is rarely recorded) and whether patients subsequently developed any infections that were not present before visitation (which is not easy to document), while concurrently investigating other possible sources of infection (similarly challenging). Ideally, bacteria causing human infections would be compared to those found in animals to provide stronger evidence of a link. Because the incidence of infections is relatively low, a large number of people would need to be enrolled. There are significant logistical issues, research ethics board issues, problems with the quality and availability of medical records and other things that make this very, very difficult. It needs to be done but it's not as simple as many people think. If it was easy, it would have been done by now.
Dogs have a short and acidic intestinal tract and are not susceptible to Salmonella.
- This statement appears thousands of times on the internet and there's absolutely no evidence supporting it. Dogs can and do get salmonellosis. For every email I've had talking about how a raw diet has made a big difference in someone's dog's health, I get at least one email from an owner or vet whose dog got salmonellosis while eating raw meat (and sometimes people in the house also got sick). A dog that eats Salmonella can shed it in its feces. The bacterium can clearly survive passage through the intestinal tract. Most dogs that ingest Salmonella do not get sick. Some do. Sometimes their owners do as well.
Wild dogs eat raw meat. That's what they've evolved to do.
- Wild dogs also have a much, much shorter lifespan than domestic dogs. It's obviously not all related to diet, but I don't want my dog to have the lifespan of a "natural" dog, I want her to have the longer and healthier lifespan of a modern pet dog. Take a look at older cemeteries and see the number of headstones of very young children. Raw milk played a big role in many of those.
- Regardless, the question isn't about the health of dogs fed raw meat. That's a completely separate issue. The issue is the risk that raw-fed dogs might pose to the highly compromised people that are found in healthcare facilities. People need to think about the health of those susceptible individuals when they get involved in this debate.
Strep zoo infections in people
Streptococcus zooepidemicus is an important cause of infections in horses. This bacterium can also be found in healthy horses. When you consider the large number of horses that are infected and the larger number of healthy horses that are carriers, along with the close contact that people have with horses, it's pretty obvious that people are regularly exposed to "Strep zoo". This bacterium is not well-adapted to survive in people and cause infections, so human infections are quite uncommon, but they can occur. There are periodic reports of S. zooepidemicus infections in people, with varying degrees of association with horse-contact.
An upcoming edition of journal Epidemiology and Infection contains a report of S. zooepidemicus meningitis in a 51-year-old woman (Minces et al, 2010). This person had a mild upper respiratory tract infection, then developed signs of meningitis (including fever, unresponsiveness, respiratory distress). A spinal tap was performed and S. zooepidemicus was isolated. The woman fortunately responded to treatment and recovered.
Upon initial questioning of the patient's mother, no animal contact or ingestion of unpasteurized dairy products (another risk factor) was reported. However, it was later revealed that the woman's daughter had started horseback riding at a friend's farm approximately one month earlier. The type of contact that the woman had with horses (if any) at the farm was not reported, nor was there any investigation of S. zooepidemicus shedding by horses on the farm.
Based on the fact that this is typically an equine-associated bacterium and the history of contact (albeit potentially limited or indirect) with horses, horse contact was blamed for the infection. It's a reasonable conclusion but it's far from certain because of the nature of the contact, the lack of any proof of the same strain of S. zooepidemicus in horses on the farm, and previous reports of infections occurring in people with no contact with horses.
Exposure to S. zooepidemicus is an inherent risk of having contact with horses. It's nothing to lose sleep over and is probably relatively low on the list of potential health problems associated with horse contact. The risk is probably greatest in people with compromised immune systems and other general risk factors for disease such as advancing age and pregnancy. Good general hygiene measures, avoiding contact with sick horses and close attention to hand hygiene probably minimize these already low risks.
This Worms & Germs blog entry was originally posted on equIDblog on 25-May-10.
MRSA, antibiotics and dogs
When multiple studies report the same results, it gets more and more convincing that the findings are true. This is becoming the case with antibiotic use as a risk factor for methicillin-resistant Staphylococcus aureus (MRSA) infections in dogs. Late last year, I wrote about a study of ours that identified prior antibiotic use as a risk factor in dogs for infections caused by MRSA versus those caused by methicillin-susceptible S. aureus. Recently, a similar study was published, with some similar results. This study (Magalhaes et al, Vet Res, 2010) compared dogs and cats and with MRSA infections to a group of dogs and cats with susceptible infections. They found that MRSA infections were associated with:
- the number of antimicrobial courses
- the number of days admitted to veterinary clinics
- having had surgical implants
Additionally, animals with MRSA infections more often had had contact with people that had been in hospital, but the difference was not statistically significant.
That's two studies that identified antibiotic use as a risk factor for MRSA infection. It makes sense biologically, and it's likely that antibiotic use is an important driving force for MRSA infection in pets (like it is in people).
How do we reduce the likelihood of MRSA infections? It's pretty clear that reducing antibiotic use is a key factor. Antibiotics are important drugs and are certainly needed in many situations, but they're also prone to overuse and misuse. Here are some things that can (and need to) be done:
- Only use antibiotics when necessary. Antibiotics are often used without evidence of a bacterial infection and in situations where bacterial infections are uncommon (e.g. urinary tract disease in cats, viral upper respiratory tract infections).
- Use logical and prudent peri-operative antibiotic regimens. Only use antibiotics for surgeries when there are actually needed, and only for as short a period of time as possible.
- Ensure that proper doses are given (and actually get into the animal). Unfortunately, underdosing (and overdosing) of antibiotics are not uncommon.
- Promote more research regarding effective antibiotic treatment regimens. We often use much longer courses of antibiotics in pets compared to people, in part because we have no research data telliing us whether we can use shorter treatment courses.
Another thing to consider is the fact that these studies looked at factors for methicillin-resistant versus methicillin-susceptible infections. Therefore, a dog had to have an infection to be included. While certain things are risk factors for MRSA versus susceptible infections, there are other factors that increase the chance of any infection, and reducing these will also help reduce the risk of MRSA (and other) infections (i.e. if your dog doesn't get an infection in the first place, it won't have an MRSA infection). One very important factor is proper management of underlying skin diseases, such as controlling atopy, flea allergy dermatitis and food allergy. Proper wound care, good veterinary clinic infection control practices and myriad other factors probably also affect the risk of infection in general. Further, good general preventive medicine practices, including overall healthcare and proper nutrition, play a role by decreasing the pet's susceptibility to infections.
Fighting antimicrobial resistance isn't easy or clear cut. There is unlikely a single measures that will turn out to be the "magic bullet." To limit the impact of resistant bacteria, we need to take a multifaceted approach, and we need a lot more information to figure out what specific measures should be emphasized.
More raw debate
Since my post about Delta Society and raw diets, I've had multiple questions or comments about the research behind it.
Here's one question:
"Please site the research that "clearly show..." that raw-fed animals shed bacteria at a higher rate."
Here's the answer:
Lefebvre et al, Journal of the American Veterinary Medical Association, 2009
- Study following therapy dogs over the course of a year. Diet history was recorded. Raw-fed dogs were 17 times as likely to be shedding multidrug-resistant E. coli compared to non-raw-fed dogs, and more likely to be shedding Salmonella.
Leonard et al, Zoonoses and Public Health, 2010
- Study of healthy dogs in households. Dogs fed a commercial or homemade raw diet were greater than 5 times as likely to be shedding Salmonella than other dogs.
Lefebvre et al, Zoonoses and Public Health, 2008
- Study investigating therapy dogs in Ontario and Alberta. Raw-fed dogs were 23 times as likely to be shedding Salmonella and 17 times as likely to be shedding multidrug resistant E. coli.
Lenz et al, Canadian Veterinary Journal, 2009
- Campylobacter jejuni was found in the feces on 2.6% of raw-fed dogs and Salmonella was found in 14% of raw-fed dogs. Neither was found in any dogs not fed raw meat.
That's pretty clear to me.
Raw diets banned by Delta Society
Delta Society has recently announced a policy prohibiting animals fed raw meat or raw animal products from participating in their Pet Partners program. This policy was established because of research indicating dogs fed raw meat are much more likely to be shedding harmful bacteria like Salmonella and drug resistant E. coli in their feces compared to dogs fed commercial or home cooked diets, and the fact that these dogs come into close and frequent contact with people that are more susceptible to infections and at increased risk having severe infections.
Not surprisingly, internet chat sites are abuzz, and there's much condemnation and consternation from some. Some of the more vocal minority are stating that they'll just lie and say that they're not feeding raw. I guess such dishonest actions would be based on a combination of ignorance and arrogance - feeding raw is your own decision, but blatantly flouting a policy that was put in place to reduce risks to those most susceptible is stupid and irresponsible.
One of the problems with peoples' reactions is the fact that they are confusing two separate issues. One debate is whether raw feeding is more healthy or more harmful to the pet. That's a controversial area, but this policy has nothing to do with that. This policy deals with the increased likelihood that raw-fed pets are shedding harmful bacteria. That's been very well proven in scientific studies. Do raw-fed pets cause disease in people in hospitals? We don't know. However, we have enough evidence to indicate there is the potential for increased risk to patients, and that added risk can be eliminated by not feeding raw meat products.
Hopefully, people will realize that this policy has been put in place for a good reason, and that it's focused on protection of people at high risk of serious illness. It's not a broad condemnation of raw diets, it's just a statement that it is not considered appropriate for dogs that will have contact with high risk populations - a recommendation that's far from new.
Details about this policy can be found here.
Disclosure: I'm a member of Delta Society's Medical Advisory Board. However, the opinions expressed here are mine and do not necessarily reflect the views of Delta Society.
Different shelter outbreak, different issues
An Indianapolis area shelter recently put out a public call for foster homes to help deal with an outbreak of respiratory tract disease in cats. They were trying to find homes for sick cats, presumably as part of a plan to depopulate the humane society to help control the outbreak. This is what a lot of people have said that the OSPCA should have done in the recent ringworm outbreak in Newmarket, Ontario. But these are two completely different issues.
The main difference is the nature of the infection. Feline upper respiratory tract viruses only infect cats. Therefore, foster homes that don't have cats can take them safely. Ringworm can affect people and other animals. Every household has some individuals that are susceptible to ringworm. Therefore, cats with respiratory tract infections pose no risk to appropriate foster households, while the same can't be said about ringworm. Reportedly, six staff members and two volunteers have contracted ringworm so far in the Newmarket outbreak.
Fostering a cat with viral respiratory tract disease is relatively easy. You just treat it like any cat and watch for signs of worsening disease or secondary infection. Fostering a cat with ringworm is not as easy. You need to keep it isolated to keep it from spreading the infection through contact with people and animals, and to prevent contamination of the household environment. You need to wear proper protective clothing when handling it. You probably need to treat it, such as giving it a bath twice a week and/or oral medication every day. It's not rocket science, but it takes a lot of time and commitment. Importantly, it takes long-term commitment, since you need to do this for weeks or months. You can't get into a situation when foster homes get bored and want to return the animal before it is considered non-infectious.
In all outbreaks, one of the most important steps is to figure out what happened and why. A detailed (and ideally arms-length) investigation needs to be performed to identify problems with animal management, medical care, general protocol, communications and other areas, and to make any required changes to reduce the risk of it happening again.
Ringworm recommendations
The OSPCA has changed their plans for management of the ringworm outbreak that is ongoing in a Newmarket, Ontario shelter. Now, some (hopefully all) remaining animals will be fostered out to local veterinarians while the situation is being brought under control.
One question that has been asked widely in the press and by the public is why these animals haven't simply been sent to foster homes. Particularly now, with all the attention, there would presumably be many people willing to take in these pets. However, putting animals infected or potentially infected with ringworm into foster homes is a controversial and potentially problematic situation, because ringworm can be spread easily to people and other animals in the household. Sending out an animal that is or may be shedding a zoonotic disease is a tricky situation, and one that can't be taken lightly. Additionally, proper management of these animals can take significant time and effort.
A better approach is to send the animals to places where they can be properly, safely and humanely isolated and treated. Veterinary clinics are a logical option, and a request has been sent to clinics in the area to take animals for quarantine and treatment. The reason veterinary clinics are being solicited is that many clinics have the ability to properly house these animals in isolation units and have the expertise and commitment to properly treat them.
Nonetheless, this is no small favour to ask of these veterinary clinics. Just as taking an infected pet into a household carries some risk, taking these animals into a clinic is also associated with some risk of transmission to people and other animals. However, with proper facilities and protocols, and the donation of sufficient personnel hours to implement those protocols, the risks should be minimal. To facilitate this, we have developed an information sheet with infection control and treatment recommendations for veterinary clinics. For anyone else who is interested, the document can be found here and on the Worms & Germs Resources page under Information Sheets For Veterinarians.
Image: Ringworm lesions on the paws of a dog. Although this is how "classic" lesions tend to appear, clinical signs of ringworm in pets can be highly variable. (click image for source)
Why do shelter outbreaks occur?
The recent ringworm outbreak in a Newmarket, Ontario shelter has focused a lot of attention on shelter outbreaks, outbreak prevention and management. A common question that I've been getting in the last couple of days is "Why do these outbreaks occur?"
There are many reasons why an outbreak can develop. I have no first-hand knowledge of the Newmarket outbreak, and don't know what prompted that outbreak, but here are some general causes of outbreaks.
Inadequate protocols:
- Shelters need clear and logical protocols for all things dealing with animal care. This needs to include aspects like where new animals go, what types of evaluation and monitoring are performed, vaccination and deworming plans, when animals need to be tested or treated, when they can be released from quarantine, how to record and report infectious diseases, how to clean and disinfect areas and items, personal hygiene, and protective clothing, among other things. These protocols need to be in writing and accessible to all personnel.
Inadequate training:
- Shelters often have large numbers of staff, many with minimal training in animal husbandry or medicine. Proper training is required to ensure that they know what to do and why. (The latter is important because if people know why they need to do something, they are more likely to do it.) Training programs need to be well-structured and formal, not casual, follow-someone-around-and-see-what-they-do training.
Inadequate supervision:
- Even with good protocols and training, the facility managers need to ensure that protocols are followed. They need to enforce protocols and address problems with compliance. They need to make sure their protocols are up-to-date and consistent with best practices.They need to monitor disease rates and concerning trends of illnesses, so that problems can be identified early. They need to know when to get advice and who to ask (see below).
Infrastructure challenges:
- Some facilities (or actually, most facilities) are not well designed in terms of infection control. That makes it harder to prevent disease transmission and contain problems. Limitations in isolation/quarantine areas may result in mixing of new (and more likely infectious) animals with those ready for adoption. Few sinks may reduce handwashing, a key component of infection control. A facility that is too small for the animal load results in cramming in too many animals.
Poor awareness:
- If staff (from management on down) don't understand the issues, they may not act appropriately. Proper routine preventive measures and outbreak response measures may not be convenient, easy or cheap. There must be motivation to implement them. If there is little awareness of the problem, people are less likely to do what is needed.
Failure to act appropriately when the first cases are identified:
- It is much easier to contain a problem when you act early. If only a few animals have been infected or exposed, it's much easier to take aggressive measures. Once you get a large number of infected or exposed animals, it's much harder to do things like properly separate different groups (e.g. infected vs potentially infected vs non-infected). The more animals affected, the greater the chance of further transmission. Keeping your head in the sand and hoping things will go away can result in a small containable outbreak becoming a facility-wide, difficult-or-impossible-to-contain outbreak.
Failure to get good advice:
- People working in shelters can't be expected to be experts in all aspects of infectious diseases and infection control. That's why getting good advice (and following it) is critical. Sometimes, people don't ask for advice or don't go to the real experts. This can happen because they don't really understand the problem, don't know who to contact, don't want to admit they don't know everything or don't realize they are in over their heads. A little good advice, especially early, can make a world of difference.
Bad luck:
- Ultimately, you can have an exceptionally run facility and still get an outbreak. By the nature of what shelters do, they bring in a lot of animals with potentially infectious diseases and have many animals that are at higher risk of getting sick if they get exposed. It's much less likely to occur with a good infection control program, but you can never 100% guarantee nothing bad will happen. You can't do much about this. All you can do is make the best program possible, and try to limit any problems that develop.
Ringworm at the OSPCA
Never a dull moment...
This morning the Toronto Star published an article about the intended euthanasia of 350 animals at a humane society in Newmarket due to an ongoing ringworm outbreak. This was quickly followed by another article about the same event that gave a few more details, including some comments from the OSPCA chief executive officer Kate MacDonald, who confirmed that the euthanasias had begun. A "very aggressive strain" of ringworm and "human error" (related to a breakdown in protocols) are currently being blamed for this morning's actions. A lot of people are (understandably) very upset. No one ever wants to see an infectious disease outbreak come to something like this.
I’m hesitant to comment too much at this stage, because we still don’t have all the facts - apparently even the duration of the outbreak is unknown. No one has said if all 350 animals are infected (or what percentage of them are), nor how many other animals are present at the shelter. We also don’t know what’s already been tried in terms of controlling the outbreak.
A few facts about ringworm (dermatophytosis) that people need to remember:
- Ringworm is a skin infection that can be caused by several species of fungi. It is not a "worm" at all. It is also very easily transmitted by direct or indirect contact with infected animals - their fur, their cages, their blankets, or anything else that may be contaminated with infected skin cells or hair. Such infectious material can even be spread over short distances (e.g. room to room) in dust that is stirred up into the air.
- Ringworm is transmissible to people, so with a large outbreak there are also issues with staff safety, and concerns with adopting out infected animals. For most people ringworm infection may cause itchy, uncomfortable skin lesions, but for higher-risk people (e.g. very young children, the elderly or immunosuppressed individuals) the infection can be much more serious.
- There are also a lot of animals (particularly cats) that carry ringworm without showing any signs of infection. If the Newmarket shelter has 350 animals with clinical signs of ringworm (a detail about which we have no information right now), that’s pretty bad, but even the animals who don't appear to be infected may be carrying the fungus and could spread it to others.
- Crowding, close contact and warm, humid environments are all factors that increase the risk of ringworm transmission. These are also all factors that are very hard to control in a crowded animal shelter.
- Ringworm is treatable, but it is not cheap or easy. Animals typically require systemic therapy (usually oral medication, which can be very expensive particularly in large dogs) as well as whole-body topical therapy (e.g. dips, shampoos, sprays), and they need to be treated for several weeks. Decontamination of the environment at the same time is critical to prevent reinfection.
Cleaning up a ringworm outbreak at a shelter with at least 350 animals is no small undertaking. The second article in the Star also describes personnel at the shelter this morning wearing "white hazardous material suits, latex gloves and plastic covers over their shoes", which would be considered reasonable precautions for entering a highly contaminated environment.
I'm sure we'll hear more about this in the days to come, and hopefully that will include more details about why the mass euthanasia was deemed necessary by the OSPCA.
For more more information about ringworm, download the information sheet from the Worms & Germs Resources page, or check out our archives.
Photo source: yorkregion.ontariospca.ca via www.thestar.com
Another Staphylococcus pseudintermedius infection
I'm not sure what to think about the recent increase in scientific papers about Staphylococcus pseudintermedius infections in people. This dog-associated bacterium has been well known for quite a while, and human infections have been sporadically reported, but it seems like there has been a big increase in reported cases over the past year.
The latest case, published in the Journal of Clinical Microbiology (Chuang et al 2010) describes a bloodstream infection in a 6-year-old boy. The infection was associated with an intravenous catheter site. The bacterium was initially misidentified as Staphylococcus aureus, a related bacterium that is more commonly found in people. It seems that the patient's history of having contact with dogs led to further testing of the bacterium. That's pretty surprising (and encouraging) from a few standpoints:
- The attending physicians asked about pet contact. That's not always done.
- The physicians recognized the potential for dog-human transmission of bacteria and considered the possibility that there was a misidentification by the lab. I'm quite surprised that they did further testing, since S. aureus is so common.
Unfortunately (as is commonly the case), they didn't take the investigation any further. It would have been nice for them to have tested the patient's dogs to see if they carried the same strain of S. pseudintermedius, to provide more evidence that the infection was truly from the dogs.
Concern has been raised before regarding the potential that S. pseudintermedius infections might be misdiagnosed as S. aureus, such that we don't know the true extent of the problems caused by the dog-associated bacterium. The ability of medical diagnostic labs to differentiate these two bacteria is something that needs to be investigated to help determine whether there may be more going on than we realize.
The increase in reports of S. pseudintermedius infections in the literature could also just be because infections that have always been occurring at a low level are being properly diagnosed, and people are bothering to write them up. The fact that people are still finding single cases of this infection noteworthy suggests that it's still a very uncommon condition. When you consider that the majority of dogs are carrying this bacterium, and millions upon millions of people have close contact with dogs on a regular basis, it's clear that people get exposed to this bacterium very often. The fact that infections appear to be so rare indicates that the risks to humans is likely quite low.
It's also possible that there truly has been an increase in these infections. It's hard to think of a reason why that might be the case. There's no evidence that the types of S. pseudintermedius have changed such that current strains are better able to infect people than older strains. Most likely, this is still a rare infection in humans that is often associated with dogs, but is of pretty low risk for the average dog owner. Regardless, continued study in the area is required, to make sure that this is not an emerging problem, especially when you consider that multidrug-resistant forms of this bacterium are also becoming much more common in veterinary medicine. Increased physician awareness about pet contact and zoonotic diseases is required to properly diagnose this and other potentially zoonotic diseases.
Rabies exposure results in 2 dead dogs
The Galesburg Register Mail headline says "Dogs killed for eating rabid bat." It's true, but the more accurate description would be "dogs euthanized because owners failed to vaccinate them." In yet another unfortunate outcome of failure to properly vaccinate pets, two dogs from Galesburg, Illinois were euthanized after being exposed to a rabid bat. They were found chewing on the dead bat, which was subsequently diagnosed with rabies.
When an unvaccinated animal has been exposed to rabies, there are typically 2 choices:
- Euthanasia
- 6 months strict quarantine
The owners couldn't afford the cost of quarantine and decided to euthanize the two dogs.
The sad part is that this was a completely preventable problem. If the dogs were vaccinated, they would have only had to undergo a short period of owner observation, not a long and strict quarantine. Rabies vaccination is cheap insurance for your pets' (and potentially your) health.
World Hand Hygiene Day
Today is World Hand Hygiene Day, an occasion being promoted by the World Health Organization’s (WHO) “SAVE LIVES: Clean Your Hands” campaign. This WHO initiative is aimed primarily at improving hand hygiene in healthcare facilities around the world, in order to help reduce healthcare-associated infections (HAIs) (e.g. infections that people develop while in hospital). Also to mark World Hand Hygiene Day, the CDC has launched its new hand hygiene website, which has tons of information on hand hygiene basics, guidelines, resources for promotional campaigns, and information for patients.
Hand hygiene is one of the most important aspects of controlling infection in human hospitals, but that’s certainly not the only place where it can be beneficial. It is also very important in veterinary hospitals, to help prevent the spread of infection between animals, whether they’re sick or they’ve just had surgery. Here on the Worms & Germs blog, we also talk a lot about using proper hand hygiene to help prevent the spread of zoonotic pathogens from pets to people. Even at home, just like in hospitals, our hands are one of the most common ways bacteria and viruses move from one surface to another, from one person to another, and from just about anything into our mouths (either directly or via our food). Dirt on your hands is easy to see, and it makes it easy to remember to wash your hands. The bigger concern is the microscopic amounts of dirt and germs on your hands that you can’t see, and the best way to take care of that is really to make hand hygiene part of your routine. Make it something that just naturally goes along with playing with your pet, or cleaning the cat’s litterbox, or poop-scooping after your dog. Although most of the time it may not be a matter of saving lives, it’s certainly a matter of saving people from being sick. Make hand hygiene a habit, and don’t just do it for yourself – do it for all the people (and pets!) you live with and interact with everyday.
Dogs also affected in 2007 Australian equine flu outbreak
In 2007, there was a massive equine influenza outbreak in Australia. A large number of horses were infected in this country that was previously equine influenza-free, and there was tremendous economic disruption caused by containment measures. It turns out horses weren't the only animals infected. A report in the April edition of Emerging Infectious Diseases describes influenza infections in dogs associated with the equine outbreak.
In some ways, it's not too surprising. Canine influenza in North America is caused by H3N8 influenza that moved from horses to dogs. Similarly, H3N8 influenza of equine origin has been identified in dogs in the UK. So, while it's an uncommon event, we know that in some situations, the "standard" equine H3N8 influenza virus can infect dogs.
The first dog that was diagnosed lived near a large horse stable. The dog developed typical signs of influenza: decreased appetite, lethargy, nasal discharge and cough. After the first dog was identified, other dogs were noted to have similar signs, including dogs whose owners had contact with infected horses and dogs that had contact with other sick dogs. Some dogs had severe infections. Influenza was diagnosed through detection of antibodies in their blood, and the influenza virus was isolated from one dog. The virus that was isolated was the same as the one present in horses (and different from that in US dogs).
For influenza to jump between species a few things have to happen.
- First, the virus has to be able to infect the other (non-natural) species. This can happen because the virus is inherently able to infect different species or because of a random viral mutation that allows for infection of the new species.
- Second, the virus must encounter that host (in this case, dogs). It must then be able to multiply within the new host.
All this can happen with or without development of disease. For the virus to truly establish itself in the new species and spread (like canine flu did in the US):
- The virus must be able to multiply well in the new host, and adequate virus levels must be produced for the new host to be a source of infection to other individuals.
- The new host must come into contact with other susceptible individuals.
- The virus must be able to infect new hosts readily enough to maintain infection in the population, instead of dying out after a couple transmission cycles.
In these Australian cases, while it is apparent that equine flu was able to infect dogs, there was no clear evidence that perpetual dog-to-dog transmission occurred. Influenza virus was rarely detected in nasal secretions from infected dogs, making it unlikely that the virus would spread between dogs. Therefore, the virus was not able to establish itself in the dog population. This means it ended up being only an interesting situation that affected a limited number of animals, instead of the creation of a new, self-propagating infection that could continue to circulate in dogs in the country.
