Worms and Germs Blog : Animal Health & Diseases : University of Guelph : Ontario Veterinary College : Zoonotic Diseases : Guelph, Hamilton, Ontario

Nature's Variety has expanded their recall based on more concerns about Salmonella contamination of their products. In a lot of ways, this makes no sense to me since you have to assume that raw meat is contaminated with Salmonella, E. coli, Campylobacter and various other pathogens. That's been clearly shown in studies of raw meat for humans and animals, and that's why we cook meat intended for human consumption and emphasize good food handling practices. It's also why there are concerns about feeding raw meat to pets, and the explanation for various studies showing pets fed raw meat have much higher rates of shedding potentially harmful bacteria like Salmonella. You have to assume that a reasonable percentage of Nature's Variety's food has been contaminated with Salmonella, not that this is an uncommon and preventable event.

Because of the problem or consumer concerns, Nature's Variety has announced that they will be treating all of their diets using high pressure pasteurization. Basically, this process uses very high pressures (with only a slight increase in temperature) to reduce bacterial levels. I can't find any scientific literature about the effectiveness of this method on Salmonella contamination of raw meat (it's mainly used with milk and cheese) but it should be able to greatly reduce bacterial levels in meat. That's a good thing, as long as it works. What's important to know, however, is whether it is really highly effective in this situation and whether all potentially harmful bacterial will be eliminated every time.

I'm concerned that if people think this food is "sterile" and it's not, they might not take the necessary food handling precautions. If this method usually, but not always, kills all of the bad bacteria, or if it reduces levels greatly but not completely, then there could still be the risk of infection of people and pets. This information is critical. In the absence of clear scientific data, I think we need to assume that some level of contamination could still be present (although probably much less often and at a much lower level), and make sure that proper food handling practices are used.

It's good to see this company taking measures to reduce the risks associated with raw meat feeding. Let's hope that some objective research is made available to indicate what risks might remain.

Image source: www.defendingfoodsafety.com

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Yesterday morning, I found part of a goose carcass in the backyard.

Yesterday afternoon, I found more of it... in a pile of dog vomit on the dining room floor. (Yes, my dog's an idiot, but that's a separate story).

Between the vomiting and my dog's rather solid gut, there hasn't been any diarrhea, at least not yet, but it not an uncommon problem in most dogs after an episode like this.

Diarrhea after dietary indiscretion can be caused by a number of different factors, including ingestion of disease-causing bacteria such as Salmonella. It can also simply be from eating too much, overloading the gut with a new substance, effects of fermenting material on the intestinal tract, and other physiological causes.

The best way to prevent this kind of diarrhea is to make sure dogs don't eat anything unusual, but that may be easier said than done. If a dog does get into something it shouldn't, odds are it's not going to be a major problem in terms of infectious diseases. Most of these become typical cases of "garbage gut," the results of which are the dog vomits and maybe has some diarrhea, but is otherwise fine and gets over it quickly. Sometimes they puke once and never look back. Other times, they need to be kept off feed or be fed a bland diet for a couple days to let their system get back to normal. During this period you should be aware that, while the cause is unlikely to be infectious, there's still certainly a possibility that the dog is shedding more harmful bacteria than normal. Vomit isn't that big of a risk, particularly compared to diarrhea, but you should clean it up promptly and wash your hands thoroughly afterwards. Cleaning up diarrhea takes a little more care, as I've previously discussed.

Garbage gut is usually more of a nuisance than a major health problem. You don't necessarily need to go running to your vet every time your dog throws up after eating something, but you also need to make sure you don't miss a potentially serious problem such as ingestion of a foreign body (e.g. bones, indigestible garbage), severe intestinal infection or pancreatitis. You should go to your vet anytime you have concerns. It's particularly important to get your dog evaluated if it has persistent vomiting or diarrhea, signs of abdominal pain (e.g. hunched up stance, crying, moving around like it hurts), doesn't want to eat or drink or is lethargic. It's also wise to get to a vet quicker if your dog has underlying health problems, has a history of pancreatitis or is very young (i.e. a puppy) or very old.

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An article in Saturday's Toronto Star discussed composting options for people without organic waste pickup or the ability to have a backyard composter. The article discussed indoor composters that can be used by apartment or condo dwellers who want to satisfy their eco-friendly side.

One of the composters they highlighted states that you can add pet waste, but that's not a good idea. Pet waste can contain a wide range of potentially harmful parasites and bacteria. The composting process can generate enough heat to kill relevant bugs, but it's not guaranteed to do so, and I'd be especially concerned about small indoor composters. Having a few nasty things in the composter itself isn't necessarily a big deal, but what happens down the line? People can be exposed to these microorganisms when removing compost. Also (and maybe more importantly) compost usually ends up in gardens and can contaminate the soil, as well as anything grown in the garden.

One of concerns is the protozoal parasite Toxoplasma gondii. Cats are the natural reservoir of the parasite and can transiently pass it in their feces, yet most people that become infected are likely exposed outside in gardens or from contact with contaminated foods. Composing may not kill toxo, and therefore lead to a risk of exposure, particularly when compost is put into flower gardens that people work in or in vegetable gardens. The risk from an individual animal is admittedly low, since cats are rarely shedding this parasite (even though most have at one point), but it's a preventable risk. There are also various other microorganisms that are potential concerns. While composting is a great way to dispose of most organic wastes, it's best to keep putting dog and cat feces in the garbage or down the toilet (and wash your hands).

If you really feel the need to compost pet waste, the safest alternative is probably to have a separate composter for pet waste that you handle differently....pay careful attention to hand hygiene after handling the compost and make sure the compost doesn't get deposited in gardens or other areas that people might frequent.

Click image for source.

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A man from Jharkhand, India, was bitten by a dog and realized that there was the potential for rabies transmission. That's good, particularly given the huge problem with rabies in India. However, he didn't take the recommended approach of proper wound care and getting post-exposure vaccination. Rather, he killed the dog (getting bitten a few more times in the process), cut out its heart with a pair of scissors and ate it raw, exclaiming that now there would be no problem with rabies.

Not a good idea.

Rabies is widespread in India. Every year, 25 000-30 000 people die of this disease. A person in India is bitten every 2 seconds and someone dies of rabies every 30 minutes.

Every dog bite needs to be considered a possible rabies exposure. If a dog that bites someone is not available for quarantine or testing to determine whether it has rabies, post-exposure treatment is necessary. That involves an injection of anti-rabies antibodies and a series of 4 or 5 vaccines, not ingestion of the animal's heart.

Hopefully, the dog didn't have rabies and this will go down as a somewhat curious little story. Unfortunately, if the dog had rabies, there is a good chance that this person has been infected, and if infected, he will almost certainly die.

Eating an animal's heart to prevent rabies transmission may just be a bizarre belief of an unusual individual. This is something that needs to be investigated, however, because if the same belief is held by many other people in the area, they will all put themselves at risk if they are bitten by not seeking appropriate and effective treatment. Not only does killing the dog and eating its heart have no chance of preventing infection, it probably increases the risk of rabies by leading to more bites. More rabies education is often needed in problem areas, and this may be the case here.

Image: Canine heart (source: www.historyforkids.org)

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Ear mites are a common problem in dogs and cats, particularly in young animals, as well as in strays and animals in shelters. The species of mite typically involved is called Otodectes cynotis. It is transmitted between individuals by direct contact (basically hopping animal to animal, as it does not survive for long in the environment), and causes an extremely itchy ear infection (which can get even worse if there is secondary infection with bacteria or fungi).

There are a few reports of suspected infections with Otodectes in people. Considering how common ear mites are in cats and the small number of reported human infections, transmission between pets and people is probably rare, but it certainly can occur. Most of the reports are somewhat circumstantial, involving people with itchy skin lesions that developed after a pet was diagnosed with ear mites. However, one curious veterinarian took it a step further. 

Dr. Robert Lopez, of Westport, New York, intentionally infested himself with ear mites from infected animals, and described the outcome in a 1993 edition of the Journal of the American Veterinary Medical Association. First, he took a sample from the ear of a cat with ear mites and placed it in his own ear. He described the scratching sounds and movement that he could feel as the mites explored his ear canal. Severe itching developed, to the point where "sleep was impossible." The intensity of the itching and mite movement decreased over time and the infection resolved by itself within a month.

Personally, I think I would have stopped there. (Actually, I wouldn't have made it to that point, but if I did, I certainly wouldn't have tried it again.) Yet, Dr. Lopez wanted to confirm his findings so, a few weeks later, he infected himself again with mites from another cat. The same type of disease developed, although it was less severe and only lasted two weeks.

Guess what he did next - he tried again, wanting to see if the reduction in severity might indicate development of immunity. So, he infected himself a third time, with the outcome being milder disease. This suggested to him (logically so) that immunity to the mites might develop, something that fits with the fact that ear mite infestations are more common in young animals.

Self-experimentation is generally frowned upon, but has been the source of remarkably scientific discoveries, even Nobel Prize winning discoveries (e.g. the role of Helicobacter pylori in gastric ulcers in people). I don't think Dr. Lopez is in line for any prizes, but it shows how a little academic curiosity along with minimal squeamishness can provide some interesting information.

What's the relevance of all this? If your pet has signs of ear mite infestation (e.g. scratching at the ears, dirty material inside the ears), get it examined and treated. If nothing else, this needs to be done because it's a very uncomfortable problem for the pet. There's also some risk of human infection, but it's probably minimal. The mites have to make it from the pet's ear to your body to cause problems. The quicker they are treated, the lower the likelihood of this occurring. Human ear mite infestations, be they in the ear or on the skin, seem to resolve by themselves, with treatment of the animal being the most important part of control. However, it can be a pretty uncomfortable condition and one most people (with the possible exception of Dr. Lopez) would certainly rather avoid.

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A Fort McMurray (Alberta) SPCA shelter has been closed because of a Giardia outbreak. Giardia is an intestinal parasite that can cause diarrhea in dogs (and other species, including people) but can also be found in about 7% of healthy dogs. Giardia infection was confirmed in four dogs in the shelter, which led to the rather aggressive measure of closing the shelter. Shelter personnel suspect that the infection started with one dog, who spread the parasite to some other dogs that were in close contact with it. Giardia is passed in stool and animals get infected by ingesting Giardia oocysts from stool contamination in their environment or water sources.

 

Shelter personnel speculated that "If [the first dog to be infected] went for a walk with the snow melting, of course there's lots of little presents underneath the snow, so when she goes for a walk and she steps in, say another dog's feces, and then licks her paws, she can get it."

 

It's pretty unlikely that old feces revealed by thawing snow were the cause, since freezing is a pretty effective way to kill Giardia. More likely, the parasite was brought into the shelter by a healthy dog, considering that a reasonable percentage of dogs are shedding Giardia at any time. Why it spread to other dogs is a different question, as is whether the other animals were sick (with diarrhea) and whether Giardia was really the cause if they were. As with any organism that can be found in healthy animals, it's hard to say for sure whether Giardia actually caused any disease or whether there was some other cause that wasn't detected and the affected dogs just happened to be shedding Giardia at the same time.

Giardia usually causes pretty mild disease that gets better on its own or with treatment. Shelter personnel stated "We are in desperate need for help from the public as far as raising funds for medical, because obviously it costs a lot of money to treat the dogs. It's a lot of money to treat an animal with giardia." It's actually pretty cheap to treat individual cases, but this makes me wonder whether they are treating all dogs in the shelter. That's not something I'd recommend because there's little evidence that treatment of non-diarrheic animals is needed or useful. 

Presumably this outbreak (whether it was caused by Giardia or something else) will end soon, either because of or despite of what was done. You never know if you did something to control the outbreak or whether it just ran its natural course. If it truly was Giardia, I'd be surprised if there are more problems, but resolution of the outbreak won't change the fact that many dogs that they bring in will be shedding the organism.

Giardia is a cause of diarrhea in people, but we now know that dogs probably play only a minor role in human disease. The type of Giardia that is most often found in dogs is a dog-specific type (Assemblage D) that cannot infect people. Unless these dogs were infected with a strain that can infect people (uncommon but not impossible), there's no risk to people. Regardless, avoiding contact with stool, especially diarrhea, is still a good idea - for prevention of Giardia and other diseases.

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The Toronto Star had a front page article today about an ongoing distemper outbreak in raccoons, and the potential effects on dogs. Toronto's not alone, as there are distemper outbreaks underway in many different municipal regions.

Distemper is an infection caused by a virus that is related to human measles virus. It mainly affects dogs, raccoons and ferrets. It can cause intestinal, respiratory and neurological disease, with neurological problems being the most severe. Vaccination of dogs against distemper is highly effective, and has greatly reduced the impact of this virus on the pet dog population.

Distemper cannot be transmitted to people, so the disease itself is only an animal health risk. However, there's an indirect effect of which people need to be aware. Rabies always needs to be considered in dogs and raccoons that have signs of neurological disease. If there is so much distemper in an area that people assume every sick (wild) animal they find has distemper, there is a risk that the odd (but important) case of rabies may be missed, leading to human exposure. It's easy to dismiss a neurological raccoon or unvaccinated dog as having distemper, and it usually is distemper (particular in light of the current outbreak), but the implications of missing a case of rabies can be severe since it can be transmitted to people and is almost invariably fatal.

If distemper is present in your area (or, really, even if it's not currently a problem):

• Make sure your dog is vaccinated.
• Keep your dog away from wild animals, especially ones that are acting strangely.
• Keep yourself away from wild animals, especially ones that are acting strangely.
• Don't do things that will encourage raccoons to move into your yard, like leaving out food.
• If you see a wild animal that is acting strangely, call your local animal control agency.

Photo credit: The Star - Toronto edition 18-Feb-10

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Nature's Variety has recalled chicken-based raw meat products because of Salmonella contamination. After a customer complaint about "digestive problems," they tested the food and found Salmonella, prompting the recall. (For more details about the recall, click here.)  In some ways, this doesn't make a lot of sense to me. If you think Salmonella contamination should be an uncommon event and a problem, you should test routinely, not wait until animals get sick. If you think that Salmonella contamination of raw meat is expected (which it is), then why test or recall? Just assume that every raw meat sample is positive for Salmonella (and Campylobacter, and E. coli). Recalling raw meat for Salmonella isn't logical. Presumably, a large percentage of the raw meat that they have sold and which they will sell in the future is contaminated, based on various studies of commercial raw meat. Handling and feeding raw meat carries an inherent risk of human and animal infections with Salmonella, Campylobacter, E. coli and other bacteria. People that feed raw meat need to understand that risk, and consider whether it's a reasonable risk for their pets and the people in the household. I don't think feeding raw meat is a good idea, but in some situations it's a particularly bad idea (e.g. when there are infants, elderly persons or immunocompromised people in the household, when the pet is very old or very young, when the pet visits high risk people).

More information about raw meat feeding can be found on the Worms & Germs Resources page.

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A Phoenix, Arizona man is suing a pet store after he contracted rat bite fever from a rat he had purchased. It's not surprising to see a lawsuit following a serious illness, considering people in the US often try to sue for just about anything, but I'm not sure it won't get very far. I don't doubt that the man had rat bite fever, or that he got it from the rat he purchased - the question is, is the pet store really liable? Specifically, did they do anything inappropriate?

"Rats being sold to people should not have rat-bite fever," Heitzman's lawyer, M.E. "Buddy" Rake Jr., tells New Times.

Actually, the rats don't have rat bite fever... rats are healthy carriers of the bacteria that cause rat bite fever. There are two different bacteria that can cause the disease, Streptobacillus moniliformis and Spirillum minus. Streptobacillus moniliformis is presumably the cause here since it's the main cause of rat bite fever in the US. This bacterium is very commonly found in healthy rats, with upwards of 100% of healthy rats being carriers. You have to assume that every rat is carrying this bacterium.

"It wouldn't be any different if they sold someone a dog with rabies," he says. "I'm not in the nuisance-lawsuit business - he was in rough shape."

It would certainly be a different story if the store sold someone a dog that had signs of rabies. It's possible that someone could buy a dog that had been exposed to rabies but which was healthy at the time of sale, but that's pretty unlikely. However, a big difference is that there is a highly effective vaccine against rabies. There is no such thing for rat bite fever. If a pet store sells an unvaccinated dog of unknown origin that could have been exposed, despite knowing the need for rabies vaccination, there certainly could be liability issues. Selling a rat that is carrying a bacterium that we assume most or all rats carry anyway is different.

PetCo did not immediately return telephone calls this afternoon, but in its defense, there is an information pamphlet explaining exactly how to avoid contracting rat-bite fever available on the company's Web site. ...though it seems the pamphlet's best suggestion is to not get bitten in the first place.

It would be better if everyone who bought a rat was given the information sheet, but it's a start. The fact is, the best way to avoid rat bite fever IS to avoid getting bitten by a rat! Proper rat handling is a very important aspect of disease prevention, since you can never rule out the possibility that a rat is a carrier.

Our suggestion: Don't have a disgusting rat for a pet.

Whoa.  Rats can make excellent pets. They can also carry infectious diseases. However, EVERY animal can carry infectious diseases, and rats are probably no more risky than most other domestic pets. The key is to take common sense precautions to reduce the risk of injury and infection (though the risk can never be completely eliminated). For rats, this includes selection of a rat that is not aggressive or fearful, knowing how to properly take care of a rat, knowing how to take care of a bite should it happen and being aware of some diseases for which you might be at increased risk because you own a rat.

Image source: http://commons.wikimedia.org

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Urine from healthy animals is typically considered to be of little to no risk to people. This is generally true, at least for the otherwise healthy human population, but like with most things in infectious diseases, there are exceptions. An interesting one in rabbits is a bug called Encephalitozoon cuniculi. This microorganism (now classified as a fungus, but previously considered a protozoal parasite) is very common in healthy pet rabbits. In fact, the majority of rabbits have antibodies against E. cuniculi and may have it living in their bodies, particularly in the kidneys. It can cause infection of the brain, and is an important cause of neurological disease in rabbits, but more often than not it lives within the rabbit without causing any problems. Rabbits can shed spores of this organism is their urine, although they mainly do this only in the first few weeks after they've become infected, and shedding after that may be intermittent.

E. cuniculi is one of a group of microorganisms that became much more important when the HIV/AIDS epidemic hit. While rarely a cause of disease in people in the pre-HIV era, E. cuniculi is recognized as a potential cause of infection in people with compromised immune systems, particularly people with AIDS. Infections of people with normal immune systems are extremely rare.

It's always a challenge deciding what to do with a microorganism that can be shed by a large number of healthy animals. One reference "strongly advises" routine testing of rabbits, but that makes no sense to me. Here's why:

• Screening always comes down to a question of what you would do with the results. If you get a positive antibody test, it means that the rabbit has been exposed sometime in its life, but that does not mean that it is necessarily still infected or shedding spores - so it's not really convincing.
• Tests can be done to detect spore shedding but they are not particularly reliable. Since infected animals shed spores intermittently, a negative result here isn't convincing either.
• If the animal is positive, what would you do? If the household has no immunocompromised people, I'd say do what you've always done, and pay attention to good hygiene.
• If the animal was "negative," I'd say do what you've always done, and pay attention to good hygiene... same as for a positive rabbit.
• If there is an immunocompromised person in the house, I wouldn't say to get rid of the pet, since there's no evidence that's necessary. There is also no evidence that treatment is useful to eliminate E. cuniculi shedding rabbits. If the animal is positive, immunocompromised persons should avoid contact with urine and feces, and use good personal hygiene... just as they should do if the rabbit is negative!

More information about E. cuniculi in rabbits can be found in our archives.

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A recent report in the Journal of Pediatrics (Tabarani et al 2010) describes a case of infection around the brain, at the site of a previous subdural hematoma, in a five-month-old child. Four reptiles (all bearded dragons) were present in the child's foster household, but the foster parent reported that the baby did not have any contact with them. Salmonella Houtenae was identified as the cause of the infection.  The reptiles were an obvious potential source given what we know about Salmonella and reptiles, the unusual Salmonella strain that was isolated from the baby, and the lack of any other obvious risk factor. All previous human infections caused by this type of Salmonella have been associated with reptiles, and all occurred in young children. Unfortunately, the reptiles in this case were euthanized before they could be tested.

This report highlights a few important points.

• Direct contact with reptiles is not needed to cause an infection. There are many reports of people (especially infants) being infected by Salmonella from a pet reptile despite them having no direct contact with the animal. The common statement that 'there's no risk to my child because my child is never allowed to touch the animal' is completely false.
• Reptiles should not be in households with children less than five years of age. In this report, the child was in a foster home.  In some jurisdictions, reptiles are banned from foster homes for this very reason.
• The majority of reptiles carry Salmonella. This is expected and impossible to prevent. That's why people at high risk of serious infection (e.g. young children) should not be around them. It's also why euthanasia of the reptiles in this case was highly questionable. Why kill the lizards for carrying a bug that we assume they (and most other reptiles) normally carry? Finding them a new home that doesn't have high risk people would be more appropriate.

Image: Central Bearded Dragon (Pogona vitticeps) (photo credit: Eigene Arbeit, 2007)

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The latest edition of the journal Emerging Infectious Diseases contains a paper describing the 2008  Australian Hendra virus outbreak in horses and people.

In this outbreak, there were five horses infected and two humans infected. The horses predominantly had signs of neurological disease, not respiratory disease like some other reports describing this disease. Four horses died. One recovered but was euthanized for public health reasons.

Two people became infected after working with the sick horses, which represents 10% of the total veterinary staff that were exposed to the infected horses.  Both people started off with influenza-like illness, which seemed to improve initially, but then signs of severe neurological disease developed. They were treated with ribavirin, an antiviral drug, as part of an experimental treatment. One of them died after 40 days of illness, the other person survived.

The authors stressed that the effectiveness of ribavirin could not be determined, but they recommend it nonetheless because of the severity of Hendra virus infection and lack of other options. Ribavirin was also used in the 2009 outbreak, but it is clearly not 100% effective since one person died there also.

A number of concerning activities occurred that put people at risk of infection, including a "percutaneous blood exposure while euthanizing an infected horses" (they didn't explain exactly what this was, but it could have been a needlestick), low use of personal protective equipment, and contact with potentially infectious body fluids. This is unfortunately not surprising since the approach to infection control (particularly in terms of zoonotic infections) is often lax in equine medicine. That certainly has to change, particularly in areas where Hendra virus may be present.

Much more information about how to control this potentially devastating virus is needed. Fortunately, infections are uncommon and it is restricted to a fairly small geographic range in Queensland, Australia.

Image source: http://animalphotos.info/

This Worms & Germs blog entry was originally posted on equIDblog on 27-Jan-10.

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I recently attended a meeting to develop antibiotic use guidelines for dogs and cats. One recurring theme during the discussions was our paucity of scientific evidence about how to use antibiotics in certain situations. It's really interesting when you compare antibiotic treatment regimens that are used in humans and standard practices for dogs and cats. Almost invariably, we treat dogs and cats for much longer periods of time than people, even when very similar diseases are compared. Why is this?

One reason is a lack of people doing research and the difficulty performing (and funding) the large clinical trials that are needed to evaluate different treatment protocols. For example, we tend to treat urinary tract infections in dogs for 7-10 days, while in people, just 3 days of treatment is much more common. However, longer treatment courses were used in humans until various research studies showed that shorter treatment was as effective and had fewer side effects. It's likely that we could treat urinary tract infections in dogs for shorter periods of time but we don't have the data to support it at this point.

It's possible that longer treatments for certain conditions are indeed needed in dogs and cats compared to humans. An argument to this effect is that disease in pets can often be more advanced (and therefore potentially harder to treat) when first detected than similar disease in people. For example, if someone has a urinary tract infection, they are probably going to get to their physician quickly. Many owners may not notice the signs of an infection in their pets as early. More established infections may take longer to treat. Does that really happen? We don't know, but it's something we need to know to determine proper treatment durations.

"If it ain't broke, don't fix it". This isn't a very good philosophy when it comes to medicine but it's understandable. If a certain treatment plan usually works, people are hesitant to look at alternatives. The problems with longer term therapy, such as adverse effects of drugs and development of antibiotic resistance, are not necessarily considered (but they need to be).

Bottom line: We need good research to determine optimal treatment protocols for pets. It's very likely that we can greatly decrease the amount of antibiotics that we use while improving patient care, but without good evidence, it's hard to know what to do and where to start. Being too aggressive and dropping treatment times in the absence of evidence may not be a wise decision - too short a treatment period could result in treatment failures and ultimately more sick animals and overall more antibiotic use.

Click image for source.

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I assume that people wouldn't voluntarily and regularly walk around barefoot on dog feces (or feces of any type), yet it's perplexing that some people regularly clean out horse stalls in bare feet (I've seen it done!). While horse manure may not be as inherently gross as dog poop, it's still feces, and like all feces contains a huge population of various bacteria, some of which can be harmful. The risks of barefoot mucking may also extend to bare feet inside boots, although I don't think sock-averse people need to panic.

An article in the International Journal of Infectious Diseases (Friederichs et al) describes infectious arthritis of the shoulder of a horse owner that was caused by Streptococcus zooepidemicus, a bacterium commonly found in horses but rarely associated with disease in people. The person didn't have a wound in the shoulder area or any other obvious route for the bacterium to get to the shoulder joint. They searched for a source of the infection and all they found was a chronic lesion on the person's foot. This, combined with the patient's history of taking care of his horses in "bare feet in boots", led them to implicate the foot as the source of infection.

The idea, I guess, is that socks would be a barrier to help prevent contamination of the foot wound. That makes sense to a degree - the person could contaminate his foot with S. zooepidemicus from his hands (probably acquired from touching the horse's nose) while removing the boots, or manure could work its way into boots and directly contaminate the wound. Both are possible, but we have to be a little cautious in interpreting these conclusions. However, this is a bacterium that is associated with horses and the foot lesion is certainly a possible route of entry.

Overall, this should be considered an interesting report of a very rare problem, not something that indicates a major concern. However, there are a few good points to take away from this story:

• If you have a wound or chronic lesion of any sort, make sure you take measures to reduce the risk of bacterial contamination when working around horses. This might be as simple as making sure it's covered by clothing, or something more involved like using an impermeable bandage.
• Hands are probably the major source of infection transmission, and good hand hygiene is important after horse or stall contact, particularly if you have an underlying disease.

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Rabies has been diagnosed in a 6-week-old Jersey calf at a Maryland educational centre, raising concerns about exposure of farm visitors, particularly groups of school children. At least 70 kids and an unstated number other visitors had recently visited the farm.

Fortunately, the farm in question is not open to the public, so they should have an easier time identifying people who have been there (e.g. school groups). Contact tracing is underway to try to identify people that had contact with the calf. Simply petting the calf or being in the general area does not pose a risk. The main risk would be from contact of open wounds with the calf's saliva, or a bite. We don't typically associate bites and calves, but it can happen when calves are allowed to suck on someone's fingers - if the person sticks their hand in too far he/she may get chomped by the calf's sharp molars. Public health personnel are trying to identify people who had contact with the calf, then they'll determine whether there was a chance of exposure to the virus. People that were potentially exposed to rabies will undergo post-exposure prophylaxis, consisting of a shot of anti-rabies antibodies and four doses of vaccine over the course of a month. Not fun, but much better than getting this almost invariably fatal disease. At least nine students have started treatment so far.

Petting zoos and similar events are a concern in terms of disease transmission because of the large number of people that can be exposed to animals and the high percentage of children that are involved. Rabies is uncommon in petting zoo animals, but it is periodically identified at such a facility/event, often resulting in the need for post-exposure treatment of large numbers of people. Vaccination of petting zoo animals against rabies should be a standard practice. This calf, being only six weeks old, was too young to vaccinate, but if the calf's mother was vaccinated the risk of rabies would be lower (because the calf would get antibodies from the mother). There's no information about the cow's vaccination status or much else about the calf, apart from it being a recent acquisition.

The fact that a recently acquired young calf was allowed to have contact with the public is questionable management, because young calves are a high risk group for certain infectious agents like Cryptosporidium and Salmonella. The CDC recommends that children less than five years of age not have contact with young calves.  Since young kids are frequent visitors of places like this, having calves (or at least letting people have direct contact with them) is quite questionable as well. Hopefully there will be a good review of vaccination, animal acquisition and animal contact protocols for this facility to reduce the risk of future exposures to rabies or other infectious diseases.

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Just as I'm getting ready to go on vacation (that will hopefully involve some time on the beach), I read an article in the latest edition of Emerging Infectious Diseases about seagulls and beaches as reservoirs of multidrug-resistant E. coli (Simoes et al 2010). In this study, the researchers collected seagull poop from beaches in Porto, Portugal and tested them for the presence of extended spectrum beta-lactamase (ESBL) E. coli, a highly drug resistant form of this common bacterium. Thirty-two percent (32%) of the E. coli they isolated were ESBL, a pretty impressive rate in wild birds that would not be directly exposed to antibiotics. Various E. coli strains were present, including some that can cause severe disease.

In some respects this is pretty concerning, and in other respects not too surprising. We know that birds in various (including remote) regions can carry multidrug-resistant bacteria. The ability of wild birds to carry these bacteria, combined with the wide geographic range that some bird species have, raises concern about the role of birds in the spread of antibiotic-resistant bacteria, as well as the potential for contracting a nasty drug-resistant infection while on the beach. Birds certainly have the ability to help spread certain types of bacteria over wide ranges. However, their overall role is probably very limited compared to the role played by people and (domestic) animals. For birds to become carriers of these bacteria, they have to pick them up from somewhere, which presumably doesn't occur until the bacteria have built up to a good level in people and/or animals. I doubt that birds account for many human infections. Antibiotic exposure through antibiotic residues in water or food sources could also play a role in the presence of these bacteria in birds, but that's an area that's not well understood. 

So, how does this influence my time on the beach? Not much. I wasn't really planning on having contact with seagull poop, and this paper just reinforces that basic precaution. Other basic measures such as keeping open sores covered, avoiding cuts by wearing shoes in rough areas or sand that might be contaminated with sharp objects, avoiding contamination of food with sand, avoiding areas with obvious bird poop contamination, and hand washing before eating and after leaving the beach are easy to do.

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Pets as a source of pinworms in people (especially children) has been a widespread misconception. A recent article at www.medicalnewstoday.com gives a good overview of pinworms in people and has a nice section about pets.

"Pinworms that affect humans cannot infect animals or pets. However, some microscopic eggs may land on a pet's fur and then be transferred to human hands when stroking (petting). It is important to remember that the problem is not the pet, it is human hand washing and hygiene."

This nicely explains two key concepts:

• People are the source of human pinworms.
• Hand hygiene is an important routine practice around pets.

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I've never really understood the appeal of tarantulas as pets. I'm sure there are some people that think they're great pets and I can't really counter with anything beyond "I don't have any desire to have a massive spider in my house." Nevertheless, many people have them. Recently, a rather unusual health concern was reported at medpagetoday.com following publication of a peculiar case report (Norris et al) in the most recent issue of The Lancet.

Hairs on the hind end of the Chilean Rose tarantula, as well as others, have barbed tips. These spiders can release hairs as a defense mechanism. A British tarantula owner was leaning into the spider's terrarium one day when it "doused" his face with a mist of hairs.

When he presented at the ophthalmology clinic three weeks later, his right eye was red, watery, and uncomfortable in bright light. His Snellen visual acuity had degraded to 6/9, versus 6/4 in his unaffected left eye.

Carrim and colleagues reported that initial low-power examination showed diffuse conjunctival injection and multiple corneal subepithelial infiltrates, "visible as scattered white spots."

They initially suspected a viral infection, but higher magnification revealed "fine, hairlike projections" at the center of each spot, with varying depths into the cornea.

At that point, he mentioned the tarantula hair exposure. After 6 months of intensive treatment, his eye problems have greatly improved, and he now wears eye protection around the tarantula.

It's unclear how common this is. There have been other reports of this problem and certainly there must have been other unreported cases. Overall, it's probably rare for tarantula owners to be affected but it seems like a pretty nasty problem and one you'd want to avoid. Pets like tarantulas often come and go in popularity, and any upswing in tarantula numbers could result in more eye injuries. People need to be aware of this problem if they own, or are thinking about acquiring, a tarantula. Animal exhibits that have tarantulas and any other places where tarantulas may be present (e.g. schools) need to think about this as well. Wearing eye protection when handling these spiders in close quarters, keeping your face of the terrarium, avoiding stressful situations that might make the tarantula release hairs, good handling skills and restricting close contact seem like logical and practical measures to reduce the risk.

Image: Chilean Rose tarantula (source: www.wikipedia.org)

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.A Texas couple is undergoing rabies post-exposure prophylaxis after an abandoned puppy they adopted was diagnosed with rabies. They found the puppy outside and brought it into their house. One of them was subsequently bitten and they found out about the rabies diagnosis on Christmas eve.

One of the couple is quoted as saying "The doctor said 'It was a good thing they didn't wait until Monday, because it would have been too late. We couldn't have given you the shot because it wouldn't have done any good. You would have been dead within 48 hours." I really hope they completely misinterpreted what the doctor said, otherwise the doc has no clue about rabies. Prompt treatment is the goal, and you certainly don't want to wait any longer than you have to, however rabies doesn't kill in 48 hours, and you can start post-exposure treatment any time (just the sooner the better).

The couple also have seven other pets, who may also have been bitten. There wasn't any comment about what's happening to those pets. Hopefully they are properly vaccinated so they can be given a rabies vaccine booster and only undergo a short-term "quarantine" at home with the owners. (The alternative is immediate euthanasia or strict, long-term quarantine for months).

This isn't a new scenario - adopting a stray animal then finding out it has rabies. The less you know about an animal at the time of adoption, the greater the risks. I'm certainly not saying don't adopt a stray animal. But, if you are going to do it, recognize the risk, make sure you are in a low-risk household (everyone's susceptible to rabies, but some people are at greater risk for other zoonotic diseases and stray adoptions should be avoided by them), get the animal examined by a veterinarian as soon as possible, and make sure that it gets examined by a veterinarian if it develops any signs of disease.

All this leads into another another story I read a few days ago. Basically, it was a feel-good story about someone who found some puppies, stopped by a nursing home (or similar facility) and the facility adopted one or more of the puppies. This demonstrates some good points (e.g. resident's presumably had a great time watching the pups) and bad points (e.g. disease exposure, unknown temperament, injury risks from rambunctious puppies...) of animals in long-term care facilities. What if the puppies that were adopted by the home had rabies? It's happened before, and you end up having to administer post-exposure prophylaxis to a large number of people that already have enough health issues and risks. Nursing homes and other facilities should never adopt stray animals. Hopefully we don't see a news release in the next few weeks about widespread rabies exposure in that facility. 

 Video from wfaa.com

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.A public health expert has recommended that an exotic animal dealer's facility be demolished or "completely gutted and sterilized" because it is so contaminated with animal feces and vomit, as well as roach infested and swarming with uncaged animals. No evidence of infection control was present in the facility that "reeked of death and decay on a mammoth and overwhelming scale."

26 000 (yes, twenty-six thousand) reptiles, rodents and mammals were removed from US Global Exotic's Texas facility last week, in a raid prompted by an undercover investigation by PETA. An employee working undercover in the facility for PETA documented various abuses.   The company now stands accused by the city of inhumanely housing the animals as well as denying them proper food, water and medical care. Hundreds of dead animals were found, and some animals had started eating one another to survive. An SPCA spokesperson said she stopped counting at 200 dead iguanas.

Buying certain things on the internet is fine. Buying live animals over the internet is something that you shouldn't even consider. This is a multi-million dollar industry that feeds off the naivety of people, the willingness of people to ignore serious welfare issues in their desire to get a unique pet, and the suffering of animals. Exotic pets can be good pets in certain situations, but tremendous numbers of them suffer and die from inadequate care at distributors, pet stores and homes, with many (many) more dying during smuggling.

If you want an exotic pet:

• Read a lot about it first. Make sure you can properly manage the animal and that it's legal in your area.
• Learn about any infectious disease risks and whether it's appropriate for your household. In general, exotic pets should not be present in households with children under five years of age, pregnant women, elderly individuals and people with compromised immune systems.
• Find a small, local breeder. Buy the animal from a place where you can see how they are raised so you can have more confidence they are healthy and have been properly cared for.
• If you want to buy an exotic pet from a pet shop, ask clear questions about the origin of the animal and request supporting documentation. Only buy a pet that was bred locally. US Global Exotics apparently sold most of their animals through pet stores.

Don't support illegal and unethical activities by buying exotic pets - if you really want to have such a pet, remember that it requires a lot of forethought and investigation of the source.

Click image for source.

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A five-year-old Oklahoma boy is recovering after being attacked by a beaver.  Beaver and attack aren't two words that you usually put together, but in this case the boy went to pet a 60 lb beaver that he saw outside and it proceeded to attack him, taking a "chunk out of his calf" in the process. The beaver was killed with a crowbar.

This is a pretty unusual situation. Beavers aren't known for attacking people, which should raise some red flags right there. Rabies should be considered in any mammal that acts abnormally. An aggressive act by a species not known for unprovoked attacks would certainly count.

The boy's mother went to "great lengths" to get the beaver tested for rabies. I'm not sure why great lengths were required since this was a bite from an abnormally-behaving wild animal in a rabies endemic area, but it's great that she was aware of the problem and acted accordingly. While the outcome was unfortunate for the beaver, the family is lucky that the beaver was killed and available for testing. If it had gotten away, they would have had to assume that it was rabid, meaning the child would need rabies post-exposure treatment. That's expensive and somewhat unpleasant (two initial shots and 3-4 boosters) but virtually 100% effective at preventing rabies (and since rabies is almost always fatal, it's a necessary procedure).

This report highlights a two key points:

• Leave wildlife alone.
• If you are bitten by a wild animal, make sure rabies is considered. It's very rare but fatal when it occurs, so you don't want to take any chances.

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As we approach the holidays, a lot of people are going to eat and/or drink too much, and suffer the consequences. The same can happen with dogs, and sometimes both the dog and their owner pay the price. Dogs get into things they shouldn't all the time... too much food, garbage, dead critters and various other "dietary indiscretions" can easily lead to diarrhea (and sometimes more serious problems). During the holidays, there's often a greater opportunity for dogs to steal food or to be fed too many treats or leftovers. Sometimes it's dramatic - like a 60 pound Lab eating a 15 pound turkey - but often the first sign of a problem is the pile of diarrhea on the floor (usually at 3 AM, in the case of my dog).

So, after yelling at the dog, blaming someone else for leaving food out, and perhaps cleaning off your foot (depending on where you stepped), how do you clean up this mess without getting sick yourself?

The good news is diarrhea from dietary indiscretions is not usually associated with zoonotic microorganisms like Salmonella or Campylobacter. However, those and other potentially harmful bacteria can be found in any dog feces, and you have to assume that diarrhea is infectious. The risk of infection of people is probably low, but you don't want to take unnecessary chances (especially over the holidays).

First things first: Clean up as much of the diarrhea as possible. Ideally wear gloves, and clean up the diarrhea using paper towels or something else disposable. Don't wander around the house with the diarrhea-soaked items - bring a garbage bag with you to the scene of the "accident".

After the bulk of the mess has been removed, your next step depends on a few things, including the surface, what you have available, and whether any high risk people are in the house (i.e. infants, elderly, people with compromised immune systems).

• Smooth, sealed surfaces (e.g. tile, laminate, sealed wood) are easy to clean and disinfect. A general cleaner can be used to remove traces of diarrhea. If you want to disinfect the area, use a general household disinfectant or dilute bleach solution (1 part bleach to 50 parts water). While general household disinfectants may not kill everything, I'm not sure aggressive disinfection is needed in most households. Thorough cleaning does a very good job, and we aren't trying to make the house sterile. I'd be more concerned about disinfection in a household with high-risk people (particularly infants who may crawl over that part of the floor). If you are concerned about bleach damaging the surface, use something else or test it on an out-of-the-way area.
• Carpet is problematic because it's pretty much impossible to disinfect. After removing as much diarrhea as possible, use of a carpet cleaning spray might be helpful (but it's more effective for removing stains, not pathogens). A few disinfectants can be used on carpets safely. Bleach isn't a good idea unless the carpet is already (or was originally) white. Even with a good disinfectant, you're very unlikely to kill all of the bacteria present, because of the ability of microbes to hide in fabric. Steam cleaning is another option.

Once that's done, don't forget the most important step: wash your hands thoroughly. (The second-most important step might be to cordon the dog off in a more easily cleanable area for the rest of the night in case further accidents occur).

Overall, the risk of getting sick from overindulgence-associated dog diarrhea is pretty low. I focus on cleaning up the mess and don't worry about thorough disinfection.  That's probably reasonable in a low risk household, but I'd be more wary around high-risk individuals.

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If an unvaccinated person is exposed to rabies (usually by a bite), they undergo post-exposure prophylaxis (PEP), consisting of an injection of anti-rabies antibodies and a series of 4 or 5 vaccines. (It used to be 5, but it was recently recommended to drop this to 4). This is a highly effective protocol which basically guarantees that the person won't get rabies IF the person is treated promptly.

If an unvaccinated pet is exposed to rabies, the situation is much different. The two options are euthanasia or a strict six month quarantine and a single dose of rabies vaccine either immediately or after 5 (of 6) months of quarantine.

So, if there is a  post-exposure treatment for people that is basically 100% effective, why don't we do the same thing in dogs and cats?

There are a few possible explanations for this:

1) Rabies is almost invariably fatal. The significant public health risks take precedence over animal health and pet owner inconvenience, stress and pet loss.

2) There is limited information about PEP in dogs, and results have been mixed.

• In one study (Hanlon et al 2002), experimentally-infected dogs were treated with various protocols. Treatment with rabies antibodies on day 0, followed by vaccination on days 0, 3, 7, 14 and 35 was effective at preventing rabies in 5/5 dogs - a good result, but the small number of dogs tested (5) prevents us from drawing any broader definitive conclusions. Rabies antibodies alone protected 4/5 dogs. All dogs that did not receive the antibodies but were vaccinated on days 0, 3, 7, 14 and 35 died of rabies.
• In another study (Manickam et al 2008), all exposed dogs were protected by rabies vaccination on days 0, 3, 7, 14 and 28. A 3-dose regimen (days 0, 5 and 28) was protective with one vaccine but not another.

Clearly, based on the limited number and small size of these studies, and the differing results, we cannot recommend a canine PEP protocol with confidence. However, these studies strongly suggest that PEP can be effective in dogs, and I think we need to consider when and how to use it. I wouldn't necessarily use PEP to replace quarantine without more evidence (i.e. field studies). I think the use of PEP to help protect the dogs while maintaining quarantine to protect the public is a good start. If canine PEP can be shown to be as effective as PEP in people, then some day quarantine might not be needed.

Regardless, this situation highlights the need for current vaccination of all dogs and cats in rabies-endemic areas. If a vaccinated animal is exposed to rabies, there is no requirement for euthanasia or long, strict quarantine. Rather, standard guidelines recommend giving the pet a rabies vaccine (booster) and having the animal observed by their owner for a period of 45 days. Developing better PEP protocols for unvaccinated animals is useful, but I'd prefer to see it become a moot point as a result of high vaccination rates.

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I had an advice call recently about the risk of hepatitis C transmission by cat scratches. Hepatitis C is a human virus that can cause serious liver disease. It is most commonly transmitted via the blood of infected individuals. The concern with cats in this case was whether there is a risk of transmission if a cat were to scratch someone with hepatitis C and then scratch someone else.

There are no reported cases of hepatitis C transmission via a cat scratch. For transmission to occur, the following must happen:

• The cat must scratch an infected person who has hepatitis C virus circulating in their bloodstream.
• The scratch must draw blood, which then contaminates the cat's claws.
• The virus must survive on the cat's claws.
• The cat must scratch someone else deep enough to draw blood.
• Hepatitis C virus must go from the cat's claws into the person's bloodstream and survive.

The odds of this sequence happening are very low. It's similar to the concerns about HIV transmission from dog bites - theoretically possible, never proven, and probably of very little concern.

This could be seen as similar to the situation with needlestick injuries in people: someone draws blood from an infected person, and then promptly sticks his or her finger with the needle by accident. Hepatitis C is not efficiently transmitted by needlesticks; only about 1.8% of people that get stuck in this manner (with a needle contaminated with blood from a hepatitis C-positive individual) develop antibodies against the virus. The risk is highest with hollow-bore needles (such as those used for injections and blood sampling) compared to needles used for sutures, because of the greater volume of blood that could be transferred via a hollow-bore needle. Cat scratches are presumably more like surgical needle punctures - there can only be contaminated blood on the outside of the claw, not inside it.

The only time I might have any concern would be if I suffered a significant scratch injury from a cat that had immediately before that caused a major injury in a hepatitis C-positive individual, such as in a situation that might be encountered when two people were breaking up a cat fight, or when someone was trying to pry an attacking cat off another person. It's a very unlikely scenario, and the associated risk would still be extremely low.

Bottom line: Don't worry about hepatitis C when around cats and infected people. Use common sense measures to avoid being scratched at all times.

Image source: www.gooddog.co.uk

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A very poorly-written and confusing report suggests that another Streptococcus zooepidemicus outbreak is underway in dogs in a shelter in Ohio. Five of 175 dogs on the premises died suddenly of hemorrhagic pneumonia. The report variably mentioned a "virus that mutated from horses," that it's thought to be "not contagious" despite multiple dogs being affected, and that it's a "rare form of streptococcus" (a bacterium). Presumably, they are dealing with a group of dogs with Streptococcus zooepidemicus pneumonia (technically, Streptococcus equi var. zooepidemicus). This bacterium predominantly lives in horses but periodically causes infections in other species. Outbreaks in dogs are uncommon but have been reported in other shelters. I assume that cultures from the dead dogs identified the bacterium, otherwise other possible causes such as canine influenza would also have to be considered.

The statement about it not being contagious is bizzare. Obviously, it is contagious between dogs. It may have been referring to dog-to-human transmission, but while that's rare it has been reported.

The shelter is apparently treating all dogs with penicillin prophylactically (i.e. to prevent any more dogs from getting sick). There's no clear guidelines regarding management of S. zooepidemicus outbreaks in kennels. It's now known whether mass antibiotic treatment does anything helpful, but it has been used in other outbreaks. I think it's likely that these outbreaks stop on their own, rather than penicillin having a major impact, and that there's probably another underlying cause such as a viral infection to account for outbreaks of this rare disease. However, that's just speculation for now. Hopefully this outbreak will cease with whatever treatment and infection control measures they put in place (or on it's own). Hopefully a good review of routine infection control practices will be performed at the same time, as routine practices (or lack thereof) are often a major problem in shelters.

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An article in an upcoming edition of Transplant Infectious Disease (Gisel et al) describes a case of Bordetella bronchiseptica pneumonia in a person who had received a kidney and pancreas transplant. This person had to board her dogs at a veterinary clinic while she was hospitalized for a bowel obstruction that occurred after surgery. The clinic required her dogs to be vaccinated against Bordetella bronchiseptica, a cause of canine "kennel cough." They were vaccinated intranasally (i.e. up the nose) with a modified live vaccine comprised of live B. bronchiseptica that is modified so it is unlikely to cause disease but can still induce a good immune response. The owner developed pneumonia after returning home and B. bronchiseptica was isolated. Specific testing was not performed to confirm that the vaccine strain caused disease, so it's possible that she was infected by the normal (i.e. "wild type") B. bronchiseptica (which still would have presumably come from the dogs).

Immunosuppressed individuals are at high risk for infection by microorganisms that usually don't cause disease in otherwise healthy people. Bordetella bronchiseptica is a good example of this. Care should be taken around pets by anyone whose immune system is compromised. Here are some recommendations pertaining to kennel cough vaccination:

• Immunosuppressed individuals should not receive modified live vaccines themselves, and it is probably prudent to extend this recommendation to avoid modified live vaccination of their pets with vaccines like the Bordetella (kennel cough) vaccine.
• If vaccination for kennel cough is required for entering a kennel or vet clinic, an exemption should be sought because of the potential risk to the immunocompromised person.
• If vaccination must be performed, injectable vaccination is preferred. It doesn't produce as good immunity in the dog compared with intranasal vaccination but the risks to the immunocompromised owner would be much less.
• If intranasal vaccination with modified live kennel cough vaccine is used, immunocompromised owners should not be in the same room during vaccination. They should avoid contact with the dog's mouth, nose and face for at least a few days after vaccination and should wash their hands (or use a hand sanitizer) regularly after contact with the dog.
• If respiratory disease develops in someone exposed to a dog recently vaccinated against kennel cough, the potential for vaccine-associated disease should be mentioned to the physician.

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H1N1 influenza was diagnosed in two dogs in China, bringing increased calls to pay attention to other animal species when it comes to this disease.

I'm more surprised by this than finding H1N1 in a cat or ferret. Dogs are susceptible to influenza and have their own circulating influenza strain (H3N8, originally from horses) but they rarely get other types of influenza. It's just an example of "rare things happen rarely, but they do happen." As with cats, it is now apparent that dogs are susceptible to this virus, although presumably minimally susceptible given the very low incidence of reported canine infections. This doesn't change our basic recommendations for dealing with H1N1: infected people should reduce contact with all individuals in the household, human or otherwise. People should be aware but not worried about the potential for pets to acquire H1N1. The risk of animals transmitting H1N1 back to people is unclear. It's theoretically possible but in practicality, a pet that gets H1N1 most likely got it from its owner, who's already exposed the rest of the household members as well.

Vaccination against canine influenza will not provide any protection against H1N1.

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I heard this on the radio yesterday morning, I kid you not: Butterball has a "Turkey Talk" toll-free helpline, which naturally gets busy around turkey holidays like Thanksgiving and Christmas.  Like many helplines, they get stories of every kind, and this year apparently one person called in and asked if it was alright that she thawed her frozen turkey in the bathtub - while her kids were in it taking a bath!

Anyone who has read anything about food safety hopefully knows that raw meat can potentially be (and usually is) contaminated with many different pathogens - that's the biggest reason why observing proper cooking times and temperatures is so important.  Raw poultry in particular should basically be treated like it's contaminated with Salmonella and/or Campylobacter until proven otherwise.  You can just imagine the field day that these bacteria could have in a nice warm, wet bathtub - it's just the way they like it, and it's exactly what we try to avoid in the kitchen, where food is ideally kept either nice and cold or nice and hot in order to prevent (or at least minimize) bacterial growth.  Then of all things to put young children in this veritable cesspool of bacteria - turkey and all - it's just a gastrointestinal disaster waiting to happen.  You also needs to consider what the turkey could become contaminated with sitting in bathwater.  Even children who don't have diarrhea can be shedding intestinal pathogens - human pathogens which are obviously transmissible to other people.  If you really cooked that bird well (maybe deep-fried it) I suppose that should ultimatley eliminate any surface contamination anyway, but I don't think I'd be able to get past the "ick" factor.  Don't throw the baby out with the bathwater, but of there's a turkey in there (as far as I'm concerned) that can go.

I realize this is primarily a food safety issue, but it made me think about what else this person (or others) may put in a bathtub.  In previous posts in which we've talked about reptiles kept as pets (all of which should be treated as Salmonella carriers), we've mentioned that ideally (if they need a bath) they should be bathed in their own designated container (like a big rubbermaid) and not in the bathtub.  If there is no other option and the bathtub must be used, it should be thoroughly cleaned and properly disinfected (keeping contact-time with the disinfectant in mind) before it is used again by a person (especially children). 

Ideally the same precautions should be taken if you bathe a dog in the bathtub, but the risks are not as high as with reptiles (unless the dog is very dirty, has skin lesions, or has (or recently had) diarrhea).  We've talked about the limited risks of allowing dogs in backyard swimming pools (but of course there is even less chlorine in bath water).  I hope no one ever bathes their dog with their kids - we could debate the risks, which likely aren't high anyway, but in the end the risk is simply unnecessary.  The pool is one thing, but there's no reason for a dog to be in the tub at the same time as the kids (and really, how clean are the kids going to get with a dirty dog in the tub?).  If you're trying to save water you can always throw the dog in after the kids are out.

If you're attempting to bathe a cat in the tub... well, based on most feline behaviour I'd say your primary risks are bites and scratches more than enteric bacteria and parasites.  Proceed at your own risk!

A happy (and hopefully healthy) American Thanksgiving to all of our US readers!

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A recent editorial in Nature Microbiology Reviews by Dr. Didier Raoult raised questions about the potential role of probiotics in obesity.  It is based both on studies indicating weight gain in humans and farm animals in probiotic trials as well as some laboratory animal data. The conclusions based on clinical trials for treatment of disease are pretty weak, since while animals or people may have gained weight, that does not mean they gained fat (if you get better because of a probiotic, you gain weight, but that is probably a healthy response and not obesity). There is some interesting lab animal work that shows changes in fat deposition in response to some probiotics, but it's rather preliminary.

It's way too early to declare that consuming probiotics is a risk factor for obesity. Several letters to the Editor were submited by leading probiotic researchers in response to Dr. Raoult's editorial, contradicting some of the statements that were made. Personally, I don't see convincing evidence of a risk but Dr. Raoult's comments should serve as a reminder that probiotics can have broad and poorly understood effects on the intestinal bacterial population, and correspondingly broad and poorly understood effects on the body. That's why probiotics should be scrutinized like drugs, in terms of safety, effectiveness and quality control. If someone is using a probiotic for themselves or their pet for a defined reason and it seems to be working, I wouldn't recommend stopping because of these largely theoretical concerns about obesity. However, we should perhaps think about why we are using probiotics and the potential costs versus benefits. I doubt this is really going to be a major issue but it's a good one to think about.

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Campylobacter bacteria are important causes of disease in people. Many Campylobacter species exist, and these different species vary quite a bit in their ability to cause disease in people and animals. Campylobacter jejuni is one of the most common causes of diarrhea in people worldwide, and is most commonly associated with contaminated food.  However, a few studies have reported that having pets (especially pets with diarrhea) is also a risk factor for Campylobacter jejuni infection.

Another Campylobacter species that may be of concern is Campylobacter upsaliensis. This species is primarily associated with dogs and cats, and a large percentage of healthy dogs and cats may be shedding this bacterium in their stool at any time. It doesn't seem to be a cause of disease in dogs and cats, but it may be an important and overlooked cause of disease in people. One study from the US reported that C. upsaliensis was the 2nd most common Campylobacter strain found in people with diarrhea (after C. jejuni). However, the true role of this species is unclear, partly because of common laboratory testing methods. Culture is the main method used to diagnose infection with Campylobacter, but this bacterium can be difficult to grow in the lab. Usually, culture media for Campylobacter contain antibiotics to inhibit other better/faster growing bacteria. Unfortunately, C. upsaliensis is often inhibited by these antibiotics, so it's likely to be missed in these cases even if it is there. Therefore, we might be underestimating the role of this Campylobacter species in diarrhea. This is an critical issue to investigate because C. upsaliensis is so common in dogs and cats, and it's important to determine what role pets play in human disease.

Avoiding Campylobacter infection involves some basic steps: avoid contact with feces, take care when handling diarrhea from pets, wash your hands regularly after handling pets and always wash your hands thoroughly after any contact with feces. Make sure your physician knows you have pets. In particular, if you have a pet with diarrhea or have recently acquired a new pet (especially a puppy or kitten), make sure Campylobacter infection is considered if you get diarrhea. Most infections are mild and go away on their own but some require specific treatment.

More information about Campylobacter can be found on the Worms & Germs Resources page.

Image credit: CDC/ Dr. Patricia Fields, Dr. Collette Fitzgerald

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The topic of the potential for feral (stray) animals, particularly cats, to be sources of human influenza infection came up today. For feral animals to be a public health problem, the following sequence has to happen:

Feral animals need to be exposed to H1N1

• This is pretty unlikely. Influenza is spread through close contact, mainly through aerosols generated by an infectious person coughing, sneezing or breathing. Influenza only travels short distances in this manner. The likelihood of a feral animal being exposed to the H1N1 influenza virus is very low because it is rare for a feral animal to get that close to people. If there is close contact, it's probably very short term, and not high risk for exposure.

They need to become infected AND shed appreciable levels of virus

• Considering the number of infected people, how common pet cats are, and the fact that only one cat has been diagnosed with H1N1, the risk of actually transmitting the virus to a cat is very low even with close contact with an infected person. If tens of thousands of household pet cats have had close and prolonged exposure and only one infection has been diagnosed, this virus is pretty poorly transmissible to cats.

They need to be exposed to susceptible people

• As discussed above, there's not too much contact between stray cats and people. Close and prolonged contact is extremely rare. Influenza is only shed by infected individuals for a short period of time, unlike some other infections. So, the chance of an infected cat having close contact with a person during the relatively short infectious period is very low.

Each one of these events independently is very unlikely. When you combine them, it should be clear that the risks posed by feral cats are extremely low (probably about as close to zero as we get with infectious diseases).

A bigger concern might be someone infecting their indoor/outdoor cat, who would then infect a stray cat, which would then infect another indoor/outdoor cat, which could infect a family member. That's still a VERY unlikely situation - really it's nothing to worry about.

There are certainly public health issues with feral cats. H1N1 is not one of them.

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Three Louisville, Kentucky children and their father recently contracted Salmonella from two lizards (green anoles) that the kids brought home from school. Two weeks after the lizards were brought home, the youngest child got sick. Then the other kids and the father got sick.

This outbreak highlights numerous problems:

Schools are not pet stores: Why is an exotic (and difficult to care for) pet that is a known Salmonella vector being sent home with students? Apparently, the school sent home a standard letter they use when students take home pets. (I assume sending animals home must be a very common event if the school has a standard form for it.) The letter provides "caretaking tips" but apparently mentions nothing about Salmonella and reptiles. The school has now modified the letter to include a "reminder to parents that good hygiene is imperative when dealing with any kind of living organism as a pet, so they need to make sure their kids wash their hands well after handling them or cleaning them out." That's better, but if they are sending home reptiles, they need a clear statement about the risk of Salmonella exposure. They need to be direct and highlight the greater risk associated with reptiles.

Lack of education before getting a pet: Too many pets die and too many people get sick because people don't take the responsible step of finding out about the animal before they adopt it as a pet. This is particularly true with exotic pets, and death of the pet is a common outcome. It doesn't take a lot of effort to find out basic information about reptile care, and information about the risk of salmonellosis should be easy to find.

Poor knowledge (or a poor attempt at damage control) by the school: The teacher "noted that other common pets, such as dogs, can also carry salmonella. Like lizards, they're perfectly safe as long as you practice proper handwashing when you handle them." Except for the fact that 0-1% of healthy dogs carry Salmonella while very high percentages of reptiles do, that tens of thousands of cases of reptile-associated salmonellosis occur every year, that contact with reptiles is a major risk factor for salmonellosis, and that the CDC (among other groups) recommends that children less than five years of age and other high-risk groups not have contact with reptiles.  This type of statement is misleading. It's unfortunately either an indication of ignorance of the issues or an attempt to cover their butts and not take their share of the responsibility for what happened.  Certain reptiles can be good pets in certain situations, but are clearly inappropriate in others.

The "it's never happened before so it must be safe" fallacy: The school's disappointing response was that they've been using lizards in classrooms for years and no one has gotten sick. Well, their luck just ran out. Just because I could drive around without a seatbelt and not get hurt doesn't mean not using a seatbelt is a perfectly safe plan. Risky behaviours tend to catch up with you eventually.

The "it didn't happen here so it's not our fault" excuse: School officials said teachers are well-trained on the proper way to prevent students from getting Salmonella, but that's pretty debatable since three kids got sick because of their actions (i.e. sending the reptiles to the children's home). The infections may not have originated in the school but the school was still the source of the problem.

Poor hygiene associated with reptile contact: The father admitted that they didn't wash their hands regularly after handling the lizards.

There's little excuse for sending reptiles home with kids. Reptiles require specialized care and commitment, and many (many!) die each year from inappropriate care. The last thing we need is to make it easier for people to obtain them without much forethought. Reptile-associated salmonellosis is a serious problem, especially in kids. Serious, including fatal, infections can occur. Schools need to realize the liability they might assume by sending these animals into households, especially with inadequate scrutiny and education. Reptiles should not be kept in  households with kids less than five years of age, pregnant women, elderly individuals or immunocompromised individuals. I doubt they asked whether any such people lived in the household before sending the reptiles home.

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One of the common questions accompanying the onslaught of calls I've taken today is "How do you diagnose influenza in pets?"

Clinical signs, such as sneezing, coughing, fever and lethargy, are not useful for diagnosis. Influenza can produce highly variable disease, ranging from almost none to very severe - so you can't look at an animal and say it has influenza just based on the clinical signs. We don't know much about H1N1 influenza in different animal species (including pets), but this type of influenza can probably cause a wide range of disease in animals as well (at least in those it can infect).

The presence of someone in the household with influenza should get you thinking about flu in a sick pet, but it is far from diagnostic. Many, many people have influenza, but very few pets do. There are many other diseases that can produce signs similar to influenza in pets. The health of people in the household is an important thing to know, but we can't jump to conclusions based on the household history alone.

Laboratory testing is required for the diagnosis of influenza, and there are a few options:

• PCR testing of nasopharyngeal (throat) or nasal swabs, or fluid collected from the trachea: This molecular test detects influenza virus RNA. This is the fastest test and it is most sensitive when samples are taken early in disease. This is the main option for diagnosis at this time.
• Serology: This involves testing blood for antibodies against influenza. Two samples are taken 10-14 days apart. If the antibody level rises 4-fold or greater, that is indicative of influenza infection. This is considered the most reliable method of diagnosis of influenza in many species but takes time. It is not currently a viable option for pets because tests for pets are not available.
• Virus isolation from nasopharyngeal or nasal swabs, or tracheal fluid: Samples are inoculated into eggs to try to grow the virus. This can take quite a while and isolation of the virus can be difficult. This is a method used by specialized labs with laboratory containment conditions appropriate for this virus and may not be readily available.

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I've written a few times in the past about the need for better definitions and guidelines for service dogs. Service animals are incredibly beneficial for some people, but there is great potential for abuse of the "service animal" designation by people who don't really need a service animal and/or are using completely untrained and sometimes inappropriate animals.

An example of such unscrupulous behaviour is RegisteredServiceDogs.com. At this site, you can enter your pet's name and your information, and get a form for your physician to sign requesting the dog be authorized as a service animal - but there is no such process, and this company has absolutely no authorizing power! Additionally, there's a place for a vet to sign affirming  that the dog being "registered" has had all shots required by the state and that, to the best of the vet's knowledge, it will not be a threat to the general public. There is no mention about whether the dog is healthy, is well-trained, is specially trained as a service animal, has undergone any real scrutiny to determine whether it could be a "threat to the general public", or anything else that should be a requirement for a true service animal. In other words, this company does absolutely nothing to ensure that the animal is an appropriate service animal. For their overwhelming effort of providing you with a form to fill out, they charge $49.95 to send you a worthless card saying your dog is a "registered service animal".

Anyone who has a real service animal has no use for a card such as this. If they run into someone who inappropriately tries to restrict their access, they're better off with information from the agency that trained the animal or, in the US, a copy of highlights of the ADA, since restriction of service animals is illegal.

If this company was really in it to help the cause of service dogs, it would have some standard criteria to ensure that the animals it certifies as service dogs are really service dogs. Otherwise, it's a money-grab to provide a useless card to people with true service animals, and a way to help people who just want to take their pets with them to places where they are banned. None of this helps the cause of true service dogs.  It is a disgrace.

Anyone with a service dog that has questions or concerns about access should contact the agency that trained their dog or another reputable (non-profit) source of information such as Delta Society.

Image source: www.guidedogsofamerica.org

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I was asked this the other day, in regards to a post about pets and recurrent strep infections in people: "You listed a few things to remember and one of them was how the pet might be an "innocent bystander infected by a family member."  Is there any indication that a dog  might get sick from licking a person infected with Group A Strep?"

Streptococcal infections in dogs are very rare. When they occur, they are typically caused by Streptococcus canis, a Group G strep. Group B strep infections have also been reported. I'm not aware of any reports of Group A (Streptococcus pyogenes) infections in dogs, despite the fact that exposure is probably very common.

Group A strep is a predominantly, if not exclusively, human pathogen. It can be found in healthy individuals (e.g. in the throats of 10-15% of healthy kids) and is the main cause of strep throat. Group A strep also causes invasive infections such as cellulitis, various soft tissue infections, and in rare circumstances, necrotizing fasciitis (flesh-eating disease). Considering how commonly healthy people carry this bacterium and how common strep throat is, you have to assume that dogs are frequently exposed to this bacterium from household contacts.

Licking a healthy human carrier would certainly create an opportunity for a dog to be exposed. Licking wounds of patients with strep infections would probably be worse. Since exposure is probably common and we don't really identify problems in dogs with this bacterium, the risk of infection in dogs is presumably very low. However, basic measures should always be used to reduce the risk of exposure to infectious agents. Even though we don't recognize Group A strep as a problem in dogs, you don't want your dog to be the first case. Dogs shouldn't be allowed to lick infected wounds for both the health of the dog and the person. Strict avoidance of people with strep throat doesn't make sense, but licking should perhaps be avoided since the sick person could also be at higher risk for a secondary infection from the multitude of bacteria present in the dog's mouth.

Bottom line... the risk of Group A strep infection in dogs is minimal, but basic hygiene practices can make the risks even lower.

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A report from Seattlepi.com is a textbook example of what can happen to certain people after dog bites. Mike Moore tried to break up a fight involving his two dogs and received a minor bite. It barely broke the skin. No big deal, eh? Well, perhaps for most people, but unfortunately not for Mr. Moore.

He cleaned the wound and didn't think much about it. Two days later, he thought he had the flu. The next day, he was worse and went to the hospital. By the time he arrived, "his face and body had a bluish tint" ...never a good sign. When he was being examined, he was asked about the scar on his abdomen and he told the hospital staff it was from his spleen having been removed. They then asked about the bandage on his hand and he mentioned the dog bite. (Insert big ringing bells here!) The article says that the medical staff couldn't pinpoint the problem right away, but hopefully Capnocytophaga was a leading thought. Mr. Moore was critically ill by this point with multiple failing organs. He was admitted to ICU, became septic (overwhelming infection in his bloodstream) and was put on a ventilator. His hand had to be amputated, as did both legs below the knee and three fingers on the remaining hand.  But he survived. (Despite the obvious long-term problems, he's very lucky to be alive after such a severe infection).

People that have had their spleens removed or who have non-functional spleens are at much greater risk for various infections, such as Capnocytophaga infections. No one should be allowed to leave a hospital after having their spleen removed without a letter saying, among other things, if you are bitten by a dog, get thee to a physician (pronto)! If you don't have a functioning spleen, make sure you know the risks and how to protect your health. 

More information about Capnocytophaga and bites can be found on the Worms & Germs Resources page and in our archives.

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Just when all those turkeys that managed to survive Thanksgiving weekend thought their troubles were over, there's new issue: H1N1 influenza (formerly known as swine flu) has been found in an Ontario turkey flock.  The H1N1 virus was first reported in birds in Chile in late August.

This is not a reason to panic.  No one can get the flu from eating a properly-cooked Thanksgiving turkey (nor from any other type of properly-cooked turkey).  The producer has voluntarily (and very responsibly) quarantined the affected flock, and no birds or eggs have left the facility.  There is no risk to the food chain.

Pigs can be infected by human, pig and bird flu viruses, and multiple infections can result in viruses trading genes and producing new viruses that can infect more species.  So it's not too surprising that H1N1can infect people, pigs and now birds as well.  This incident serves as an important reminder that we need to remain diligent about infection control and hygiene, even around animals.  It's highly unlikely that these turkeys had contact with infected pigs - most likely the virus was spread to this flock by a person.  Poultry producers may therefore need to consider getting vaccinated for H1N1 flu not only to protect themselves, but also their flocks, and anyone who may have the flu should definitely stay off these farms.  Hopefully the virus does not become established in wild bird populations (like H5N1 has in some areas), as this would make it much harder to control.

Recommendations for avoiding the flu (H1N1 or other) remain the same:

• Wash your hands and/or use alcohol-based hand sanitizer
• Sneeze into your elbow
• Disinfect commonly touched surfaces
• Stay home if you are sick
• Get vaccinated!

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You'd think, after countless outbreak of salmonellosis associated with pet turtles, that people would learn and things would start to improve. I guess not. A paper published this week in Pediatrics (Harris et al) described a large outbreak of Salmonella Java associated with pet turtles. Between May 2007 and January 2008, 107 infections were identified. The median age (the age in the middle of the range of affected people) was seven years old. Sixty percent of infected people reported exposure to turtles during the week before they got sick; 87% were small (<4 inch) turtles, and 34% were purchased at a retail store (despite the fact that the sale of turtles less than 4 inches long is banned in the US). Five infected people, all less than 10 years of age, reported kissing the turtle or putting it in their mouths.

When they compared people with Salmonella Java infection to people without the infection, 72% of people with Salmonella reported contact with turtles versus only 4% of controls.

Salmonella is far from rare but it's nothing to ignore. Thirty-three percent of infected people were hospitalized. Fortunately, no one died.

The link between turtles and Salmonella has been known for a long time. Healthy turtles can carry the Salmonella bacterium and be a source of infection, particularly for children. The sale of small turtles is banned in the US to reduce the likelihood of close contact between turtles and kids, but this law is widely flouted. An understanding of the link between turtles and Salmonella is surprisingly uncommon - only 32% of Salmonella patients in this study (and 28% of controls) reporting knowledge of this link. Clearly, there are a lot of areas which could be improved.

• If banning the sale of small turtles is truly an effective measure, then it should be enforced. "Black market' turtles are far too easy to find.
• More public education is needed, among the general population and particularly people buying turtles. You shouldn't be able to take a turtle home from a store without an information sheet about the risk of Salmonella and how to avoid it.
• People with turtles (or any reptile) need to recognize the risk and act appropriately. Good general infection control and hygiene measures are needed to reduce the risk of Salmonella exposure.
• Households with children under five years of age, or with immunocompromised individuals should not have pet turtles.
• Antibiotics are not the solution. Attempts to create Salmonella-free turtles with drugs have just led to the production of turtles carrying antibiotic-resistant Salmonella.
• Common sense needs to be a little more common. The picture above (from http://www.familylovezone.com/js_DeepAndWide.htm) was proudly posted by a parent.

More information about infectious disease risks associated with turtles can be found on the Worms & Germs Resources page.

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When I talk about methicillin-resistant Staphylococcus pseudintermedius (MRSP), I usually say that the human health risks are low because human infections are very rare. However, rare doesn't mean it can't happen, as demonstrated by a case report entitled "Beware of the Pet Dog: A Case of Staphylococcus intermedius Infection" published in the American Journal of Medical Sciences (Kempker et al 2009).

This paper reports about a post-operative sinus infection in a 28-year-old woman. Cultures were taken and the bacterium was initially misidentified as a coagulase-negative Staphylococcus. It was then misidentified as S. aureus, and finally determined to be S. intermedius. In reality, that's probably another misidentification because the bug almost certainly was truly S. pseudintermedius. (It's become clear over the past couple years that S. intermedius is basically non-existent in dogs and that what has been called S. intermedius in the past is truly S. pseudintermedius).

It's important to remember that human infection with S. pseudintermedius is a rare event. Whenever you see a single case reported, you know it's a pretty uncommon or novel event. Further, this was a post-operative infection, not a spontaneous infection occurring in a low-risk person. At the same time, we need to make sure we don't completely ignore the potential risks. While the risk of transmission of S. pseudintermedius (including MRSP) seems to be very low, we shouldn't ignore it completely. Isolation and other strict measures aren't indicated when dealing with a pet with S. pseudintermedius infection, but general attention to basic hygiene practices and avoiding contact with the infected site is still a good idea.

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Here's a recent question: "Can a rabies virus get into the body if you pick up a dead animal the roadway and have a cut on your hand? I understand the animal has to carry the rabies virus but sometimes we don't know what killed the animal. It may be infected and didn't use due diligence or perhaps it just wasn't fast enough. After reading stories here I'm less likely to remove a dead animal. Sometimes they are so juicy, the fluids are flung about and you may get some on your clothes or skin and not know it. How likely is contracting rabies from fluids in a cut? The reason I ask is when I was younger I picked up a dead squirrel with my bare hands and then noticed I had cuts on my hands. I went to a doctor who looked at me like I was crazy but I had that uneasy feeling because I knew rabies is almost always fatal. Of course, I didn't get it but when I watch other people remove dead animals from roadways I cringe. I can't even think about eating roadkill or skinning it for the fur but that's just me."

Good question. You've covered most of the important aspects of risk, which are pretty minimal:

• Animal has to be infected
• Live rabies virus needs to be present
• Rabies virus needs to get into a person's body (not just on it)

Let's look at these individually.

Animal needs to be infected

• You never know whether this is a concern when you find a dead animal. Once it's dead, you can't tell if it's acting strange. In general, it's safest to assume that all such animals are infectious until proven otherwise.

Live rabies virus needs to be present

• I haven't come across good information about how long rabies virus can survive in a dead body outdoors.  It probably varies greatly between different situations, particularly depending on the temperature of the body. For very fresh roadkill, there's certainly a possibility that live virus is still present (if the animal had rabies).

Rabies virus needs to get into a person's body (not just on it)

• Rabies cannot be transmitted through intact skin. Rabies infection is transmitted mainly through bites, cuts and scrapes. Saliva or nervous system (e.g. brain) tissue are infectious. Blood, urine and feces are not.
• If you have contact with a dead animal, avoid any direct contact with your skin, and avoid any activities that could result in splashing of fluids. Transmission of rabies from infected fluids is possible if it comes in contact with broken skin or mucous membranes like the eyes or mouth.
• If intact skin has been contaminated with fluid, wash it thoroughly with soap and water, but don't panic - it's really of minimal concern.
• If your clothes have been contaminated with fluid, take them off right away if possible.  If that's not practical (or legal), take them off as soon as you get home. Put them in the laundry immediately and wash your hands.
• If open sores or other broken skin has been contaminated, wash the area thoroughly with copious amounts of soap and water under moderate pressure. Disinfectants can be used to help clean the wound, but there's no consensus about whether that's necessary - these chemicals can be painful to use and hard on tissue, and the flushing action of the water probably does the most to remove the virus from the area. You should go to a physician, who will get in touch with public health personnel to determine if there is any reason for post-exposure treatment.  If the animal's body is available to test, that's useful. If the brain has decayed too much to be tested properly, it's questionable whether live rabies virus would still be present even if the animal had rabies.  Public health personnel will decide whether they think there is any risk.

Bottom line: the risk of contracting rabies from roadkill is very low. Roadkill contact has never, to my knowledge, been identified as a source of infection. Rabies transmission from dead animals has been documented, however, such as a couple cases of rabies from people preparing dead animals for food.

So, if you see a dead animal by the road, leave it alone. If you are going (for some reason) to touch it, first make sure it's really dead. An injured animal might be much more likely to bite. If it's really dead and you are just trying to move it off the road, use a stick, shovel or something else that doesn't involve you having direct contact with the animal. Other than that, I'm not sure why anyone would want to touch roadkill.

Image (top) from www.michiganimaging.com
Image (bottom) from http://users.frii.com/donlight/archive/97arc.htm

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Clostridium difficile is a high-profile bacterium, being an important cause of illness and death in people. It can also be found in various animal species, including dogs and cats. In a study we published earlier this year (Lefebvre et al, Journal of the American Veterinary Medical Association, 2009), factors associated with acquisition of Clostridium difficile by dogs involved in hospital and non-hospital therapy programs were assessed. Things that were significantly associated with a dog acquiring C. difficile were:

- Contact with human hospitals: Not too surprising since it's clear that hospitals can be highly contaminated with C. difficile and the hands of some patients petting the dogs are probably also contaminated.

- Contact with children: Most parents know that kids are biohazardous (we've getting over a round of illness in our house brought home by the kids - not an unusual event). Whether the increased risk for dogs is because kids have higher rates of C. difficile carriage, or because they have closer contact with dogs (with little hygiene) or some other factor isn't clear.

- Recent use of antibiotics: No surprise here. Antibiotic use is a well-recognized risk factor for C. difficile, since antibiotics can disrupt the normal protective bacterial population of the intestinal tract and allow C. difficile to grow.

- Recent use of antibiotics by a person in the house: I think this is a fascinating result and a great example of the close inter-relatedness of people and pets microbiologically. What presumably happens is that when someone is treated with antibiotics, they are more likely to acquire C. difficile and pass it in their feces. By doing so, there is a greater chance that their dog will be exposed to C. difficile, perhaps from the person's hands or the household environment. (The toilet would be a great source if the dog's a toilet-drinker). The implications of this, for both dogs and people, are unclear. It could be primarily an academic risk (i.e. of little practical significance), or it could be that interspecies transmission of C. difficile plays a role in disease in both species. We simply don't know at this point.

This is also a good example of why educational efforts regarding prudent antibiotic use need to be directed at both animal and human healthcare.

More information about Clostridium difficile can be found on the Worms & Germs Resources page.

Image source: www.sciencedaily.com/releases/2009/05/090507101820.htm

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In yet another tragic example of why large wild species should not be kept as pets, a 37-year-old Pennsylvania woman was killed by her pet black bear. She entered the 350 pound bear's cage, a 15 by 15 foot steel and concrete enclosure (hardly a good environment for a bear) and was mauled. A neighbour then shot and killed the bear. A Bengal tiger and African lion were also present on the property. No indication was given about what might have triggered the attack.

Large carnivorous mammals don't make good pets. It's also questionable whether people can adequately and humanely care for such animals. I have a hard time believing the bear had a good quality of life living in a small steel and concrete pen. The picture above is not from this case but from another bear enclosure elsewhere  in Pennsylvania (see link here).

Every year, there are reports of these types of "pets" severely injuring or killing their owners, yet there is little effort in many regions to control the ownership of these animals. Local officials knew about these animals and the woman had permits for them. Why (and how) someone could actually get a permit to keep these species is beyond me.

Pets are great, but pet ownership has to be logical and safe, and there have to be benefits for both the human and animal. Keeping dangerous animals locked up for curiosity's sake is no longer (or at least should no longer be) socially acceptable. These animals should be in the wild or in a properly managed zoo or wildlife rehabilitation sanctuary.

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There is a recent paper in Preventive Veterinary Medicine about a study of Giardia in canine stool samples collected from urban green areas around Pisa, Italy (Papini et al). The authors went to parks and similar areas and collected stool samples off the ground. They then tested the samples for the presence of Giardia and (very importantly) tested the Giardia to determine whether they were types that typically only infect dogs or whether they were types also found in people.

They found that 31% of stool samples contained Giardia. That's higher than in some recent North American reports. The number of Giardia cysts ranged from 2 to 1428 per gram of feces. Less than 1% of the Giardia were types that are of concern for transmission to people. Therefore, they concluded that parks pose a risk to dogs, since there is a good likelihood that dogs could be exposed to Giardia. However, the risk to people from Giardia found in these parks is minimal given the types that were found.

The risks to dogs and people can be decreased by the simple act of picking up poop.

More information about Giardia can be found on the Worms & Germs Resources page, and in our archives.

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A rabies epidemic continues in Bali, with little apparent control and inadequate access to vaccination. Another person died of rabies last week. He was bitten by a dog in July and taken to a local health centre, but rabies vaccine was not administered. It's not clear whether healthcare providers recommended post-exposure vaccination and the person declined or whether they did not offer vaccination. 

Access to post-exposure treatment in such regions is a serous concern. Apparently, up to 50 people a day are denied potentially life-saving post-exposure treatment because of a lack of adequate vaccine supplies. Because of the limited availability, doctors are focusing on treatment of people bitten by dogs in areas that are heavily infected with rabies. That makes complete sense, but it's still not a good situation.  It's not only those heavily infected areas that are a concern. More rabies vaccine needs to be secured so that everyone who has been potentially exposed can be properly treated. Local officials are blaming the current shortage on a holiday weekend, but it's unclear whether the situation is truly going to improve in the near future.

People traveling to any part of Bali need to be aware of the risks. You don't need to cancel your vacation, just use common sense. Don't approach any dogs or other mammalian pets or wildlife. If you are bitten, immediately go a physician. If rabies vaccination is not offered, ask for it. If it's not given, get on the next plane out of the country and get treated. You don't need to be vaccinated immediately after exposure, so don't panic, but you don't want to unnecessarily increase the risks if you have been bitten.

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More from the ASM-ESCMID MRSA in animals meeting…

Dr. Joe Rubin presented some data on antibiotic resistance in Staphylococcus aureus bacteria from dogs and people in Saskatoon, Saskatchewan (Canada). The bacterial isolates came from dogs carrying S. aureus and from dogs infected with MRSA. When you look at the resistance patterns of the S. aureus isolates from the carrier dogs (these are an indicator of what’s around in the general population, and they can cause infections given the right circumstance), resistance was uncommon. Multidrug resistance was present in the methicillin-resistant S. aureus (MRSA) isolates, as expected.

Saskatoon’s an interesting area in terms of resistant bacteria. Various studies from the University of Saskatchewan have reported very low antibiotic resistance rates in bacteria from animals. Certainly, they have some problems like everywhere else, but I find some of their data quite remarkable. They can have a lot more confidence in the use of various first-line antibiotics compared to other regions where resistance is more common and drug options are more limited. I’m not really sure why this is the case.

• Maybe it has to do with the fact that there is less animal movement between Saskatchewan and other regions where there are more resistance problems.
• Maybe the low population density in Saskatchewan plays a role.
• Maybe multidrug resistant bacteria don’t like the frigid Saskatchewan winter (or the fact that there’s no NHL team in the province).
• Maybe they use antibiotics in animals in a much more controlled manner.

Trying to figure out why resistance rates in Saskatchewan tend to be lower would be useful because it might provide some information about how to reduce the risks in other regions.

So, if you’re in Saskatoon and your pet gets an infection, take some consolation in the fact that there’s probably a lower risk that you’re dealing with a resistant bacterium and that your first-line antibiotics will probably work.

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I'm in London (UK) for the ASM-ESCMID conference on methicillin-resistant staphylococci in animals: veterinary and public health consequences. I’ll provide various updates on interesting presentations over the next few days.

Dr. Armando Hoet from the Ohio State University (OSU) presented data on MRSA screening of dogs admitted to the OSU Veterinary Teaching Hospital. They sampled a subset of dogs admitted to the hospital every month over the course of a year.

• 5.7% of the dogs were identified as MRSA carriers. That’s a pretty impressive (and concerning) number. We know that a small percentage of dogs and cats in the general population are positive, but I’ve generally assumed the rate of carriage to be around 1-4%. However, you have to consider the study population whenever you look at numbers like this. Sixty-eight percent of the positive dogs were referral cases, meaning they had had previous contact with the veterinary healthcare system, may have been treated previously with antibiotics and may have had other diseases that increased the risk of MRSA.
• Ownership by people in the human or veterinary healthcare fields were risk factors for infection.  This is not very surprising since such owners would be more likely to pick up MRSA at work and bring it home to infect their pets.

Hopefully the true percentage of dogs in Ohio carrying MRSA is lower than this. Presumably, the rate of MRSA carriage by healthy dogs that are not owned by high-risk people is quite a bit lower. Regardless, it shows that MRSA can be found in a reasonable percentage of animals in the study area (as well as presumably other areas) and that good infection control practices are needed in veterinary hospitals to reduce the risk of transmission.

More information about MRSA can be found in on the Worms & Germs Resources page.

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Here's a reader's question: "Our local water authority here on the East Bay of RI has issued a "boil water" alert because of the presence of e-coli as found in a routine test. My question is:  Do we need to boil dogs' and cats' drinking water as well? Seems that they eat the worst stuff and may have stronger systems?  I gave my dog boiled water at home but then at day care they did not boil the water. "

There’s not a clear answer to this question. Ingestion of bacteria is not necessarily a bad thing. In fact, we ingest huge numbers of bacteria every day. Some dogs (like my dog that eats anything she finds outside) ingest more, and usually no problems develop. Boil water advisories are usually enacted based on detection of E. coli as an indication of fecal contamination. While many (or most) E. coli are harmless, the fact that fecal bacteria are present means that other potentially harmful microorganisms that can be found in feces may also be present. This includes E. coli O157 and Cryptosporidium.

What is the risk for dogs? It’s hard to say. E. coli O157 can cause infection in dogs but this is rare. Dogs that ingest E. coli O157 might shed the bacterium in their stool and potentially infect people. That’s a concern but it’s rare as well. Cryptosporidium is not an important cause of disease in dogs. So, when we look at the highest profile microorganisms in people, the risk to dogs is pretty low. However, we don’t know much about waterborne disease in dogs and it’s certainly possible that other microorganisms could cause disease and that dogs could act as an indirect source of infection of people (i.e. water to dog to person).

So, what should we do during a boil water advisory? I’d probably give my pets boiled water, since I’d be doing it for myself already. It’s not hard to boil a little more water for my pets. Is it really necessary? Who knows? Probably not, but it’s a pretty easy thing to do to reduce any risks that might be present.

It’s never a bad idea to err on the side of caution.

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The investigation into a large E. coli O157 outbreak linked to a UK petting zoo continues, and the number of potentially exposed people is astounding. There are a couple of reasons that I write a fair bit about petting zoos, and they are highlighted here: the potential for exposure of a large number of people and the predominance of children. In this outbreak, it is feared that tens of thousands of people may have been exposed since problems started in August. The exact number of infected people is currently unclear but is in the "dozens," including some with hemolytic uremia, a severe kidney disorder. One report says there are 36 sick people, including 12 children under the age of 10. It's pretty likely that these numbers will increase, and that even more cases will go undiagnosed because they were mild and people didn't get tested. 

This week, testing has been performed on animals and environmental areas on the farm to look at sources of E. coli O157. I'm not sure why this wasn't done a while ago. However, at this point, it's mainly going to be useful to confirm that the E. coli strain infecting people is also present in animals on the farm. Finding or not finding the bacterium at various environmental sites at one point in time really doesn't say much about where it was when people were getting infected. If E. coli was in the animals, it's likely to contaminate various environmental areas. If petting zoo design and hygiene were not optimal, this could result in contamination of visitors' areas.

Some parents have complained that the farm was allowed to remain open for more than two weeks after the first cases of E. coli were reported. That's a very valid concern and one that should be clearly addressed. Once there was reasonable suspicion of the farm being involved, measures should have been taken to reduce further exposure. A good synopsis of these events is available here.  It certainly depicts a less-than-stellar response to a potential outbreak. Although you don't want to over-react and close a facility that was not actually the source, given the potential severity of disease and massive number of people that could be exposed, public health concerns need to supercede economic concerns in situations like this.

Petting zoos will never be "no risk." There is an inherent risk of infectious disease transmission any time you interact with an animal. That being said, there are standard recommendations that are in place to greatly reduce the risk of disease transmission. I don't know much about the quality of infection control practices on this farm, but it's likely they could be better. One writer to timesonline describes how kids are allowed to climb in with the animals and chase after herds of pigs, which certainly suggests a lack of proper control.

People running petting zoos need to take their role in protecting the public seriously. That includes protection from infectious disease and injuries such as bites. Public health authorities need to take a more proactive role. Instead of the standard approach of just providing documents or signs, these events need to be inspected and any problems need to be identified and addressed. The key is to use basic, practical measures that reduce the risk while maintaining the positive aspects of the petting zoo. It's getting better in many areas, but there's clearly still room for improvement.

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The last time I visited the Aberfoyle (Ontario) Fall Fair, the petting zoo was so bad that I ended up writing to the fair organizers and the Wellington-Dufferin-Guelph Public Health Unit. (Neither group replied). It was pretty bad. Young poultry are inappropriate petting zoo animals because of the risk of transmission of bacteria like Salmonella, yet baby chicks were being passed around to young children. One chick was injured by rough handling and the petting zoo supervisor just threw it (still alive) in the garbage. There was a diarrheic calf, poor hand hygiene facilities, and other problems.

We went back to the fair yesterday and I was quite pleasantly surprised: no chicks, no calves, all appropriate and healthy-looking animals, a clean facility and good hand hygiene stations. There were still a couple of suboptimal things, like not having hand sanitizers by one exit, and having a "supervisor" who was staring off into the wilderness and smoking inside the tent filled with kids and straw, but it was night-vs-day compared to the last time. I doubt my letter had much to do with it, but you never know.  I think it's important that people not accept inadequacies that put the public (particularly children) at risk. People need to raise a stink when they see a problem. I wrote earlier today about a child who had her finger bitten off by a petting zoo zebra that had bitten other people. The previous bites may not have been reported because they were minor, but we need to report apparently minor problems so they don't escalate into major injuries, disease outbreaks or other bad scenarios.

Anyway, it was great to see an improvement, and people in the petting zoo appeared to be having a good time. Now if they'd just work on "Big Ned's" food concession, where the only sink seems to be a storage area with no soap or paper towels, and which appeared to be in need of a serious cleaning, or on the little midway, where they were hand cranking the questionable kiddie ferris wheel to get kids off when all the rides stopped working. Baby steps, I guess.

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A friend recently asked me about having service dogs in classrooms. Her sister, who is a learning resources teacher, told her about an autistic child who will be attending her school with a dog. The dog prevents the child from bolting and helps reduce anxiety. She thought this was an interesting topic because of the various pros and cons that need to be considered, and I certainly agree. It may seem simple at first glance, but when you think about it, it's a rather complex situation.

Contact with animals always comes with some risk. We can never eliminate the risk entirely. What we need to do is determine how to maximize the benefits and minimize the concerns, and ultimately decide whether the benefits are worth the risks.

In this situation:

Potential concerns/risks (to the child and/or those around him/her):

• Zoonotic disease transmission
• Bites/scratches
• Allergies
• Anxiety in children/adults who are fearful of dogs
• Management issues (e.g. who's responsible for making sure the dog gets walked)
• Classroom disruption (e.g. barking, whining, wandering)

Benefits:

• Letting the child attend and get the most out of school
  

That's a pretty big benefit, and it's clear this is a good situation as long as the risks are controllable.

What should be done in a situation like this?

• The true need for the dog has to be assessed. Is it really beneficial? Presumably yes, but the question has to be part of the assessment. There should be a formal evaluation/way to determine that "yes, this animal is needed so we should do everything we can to facilitate it." It doesn't  need to be a restrictive process at all, but it should be in place. (The situation in the US with the ADA complicates this - pretty much anyone can say they have a service animal and the amount of scrutiny that can be applied is minimal. More discussion about this can be found in a previous post, just click here).
• The dog should, ideally, come from a recognized service dog organization. This ensures that the dog/person pair is properly evaluated and the dog is trained. If this is not possible, then the next best thing is for the pair to be involved with a service organization so they get similar (but after-the-fact) training. Getting a formally trained dog may be difficult under some conditions because, while some service dog types (e.g. guide dogs for the blind) are well established, formal programs to provide trained dogs for many other conditions are uncommon or or non-existent.
• The school board should be notified as early as possible. This gives them the chance to make any necessary arrangements.
• Parents of other children in the classroom should be notified. They don't need to be told why the dog is needed (privacy of the student bringing the dog is an important issue), but they should be told a service dog will be in the class and what the school will do to reduce any potential problems. If there are any concerns (e.g. serious allergies, fear of dogs) they should be allowed to move their children to another class without any hassles. Ideally this should be done before the school year starts to reduce any possible stigma of someone being moved because of the dog.
• The teacher should be educated about risks and benefits of therapy dogs. The teacher is a critical link as he/she will oversee routine management of the animal. The teacher needs to understand the benefits of service animals in order to accept the animal in the class. The teacher also needs to understand the potential problems so he/she takes his/her role in management of the situation seriously.
• General hygiene practices (e.g. hand washing after touching the dog) should be emphasized and enforced.
• Any "incidents" must be recorded and reported. Furthermore, follow up to figure out  what happened, why and how it can be prevented is crucial. Any aggressive or other disruptive behaviour by the dog cannot be tolerated and requires an immediate review. A proper service dog should not pose any significant behavioural risks (e.g. biting, barking during class, wandering around). The less the scrutiny of the dog at the start, and the less the specific training, the greater the likelihood of such problems occuring.
• The dog's veterinarian should know it's a service animal. The dog must be examined by a vet at least yearly, and at a minimum it must be properly vaccinated against rabies. If the dog becomes sick, it must be taken to a vet promptly. If the vet identifies a disease that might be transmissible to people, the dog must not go to school until the risk period for transmission has passed.
• A plan must be established for walking the dog and handling feces. The dog should not be taken to defecate on the playground. It should have a separate grassed area in which to defecate that is away from where children play. Feces must be promptly removed and disposed of, and hands washed.

Service animals can be a contentious and emotional topic. They certainly do provide tremendous benefits to some people, so we need to do what we can to facilitate them. At the same time, we need to properly manage the situation to reduce risks to others. Usually, a thorough proactive review of risks and benefits, and a detailed discussion of what will be done, can greatly reduce any concerns and maximize the benefits. They key is actually thinking about these issues and doing something about them before there is a problem.

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In April, I wrote about an ongoing rabies outbreak in the popular tourist destination of Bali. Because of widespread rabies in stray dogs and fatal human infections, there were calls for the government to take aggressive action and for tourists to be aware of the risk. Apparently, things haven't improved much since then.

At least 9 people have died of rabies in Bali in slightly over a year. That's completely unacceptable for a preventable disease.

The latest victim (whose father-in-law died of rabies in August) was from an area that has not been officially declared as being part of the epidemic, so it has not received much government support. She was bitten by a stray dog in August. In any rabies-endemic area (even in the absence of an outbreak), that's clearly an indication for post-exposure treatment. However, she did not receive post-exposure treatment until 15 days after the bite, by which point it was obviously ineffective.

• Rabies post-exposure treatment must be started as soon as possible. If you wait until signs of rabies are present, death is almost certain.
• Be informed and be your own advocate. The family in this case may very well have pushed for post-exposure treatment, but it's critical to look out for yourself. If you have potentially been exposed to rabies, make sure you get treated.
• If you are going to Bali, don't be paranoid about rabies. Be smart. Avoid any contact with dogs (especially strays) and other wildlife. If you are bitten, get medical care immediately. If the animal isn't identified and quarantined for 10 days to make sure it doesn't have signs of rabies, you need post-exposure treatment. If you can't get it in Bali, get out and get to somewhere where you can be properly treated.
• If you are traveling to Bali (or any other rabies-endemic area) with the intention of working with wild or stray animals (especially dogs), get vaccinated before you go.
• More aggressive rabies control and education (including physician education) efforts are needed in Bali. Clearly, this outbreak is not under control and the fact that the latest death occurred in a new region suggests that this problem could be spreading.

More information about rabies can be found on the Worms & Germs Resources page.

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A Montreal man is undergoing rabies post-exposure treatment after being bitten by a bat in Lachine's Summerlea Park. He found the bat lying on the ground and when he picked it up to take a closer look (surprise, surprise) the bat bit him.

This incident shows yet again the need for better rabies education. While we don't want to create fear and loathing of bats, we should consider them rabies-positive until proven otherwise. That doesn't mean we want to eradicate them. It means we want to educate people to enjoy them from a distance and never have direct contact with them.

Never try to touch a bat. A bat lying on the ground in a park is not a healthy bat. It may be sick for various reasons, but rabies is certainly a possibility. If you come across a sick bat, call animal control. They can safely remove it so that no one has the chance of being bitten. If someone has had contact with the animal, the bat must be tested for rabies, as was done here. Rabies is preventable using proper post-exposure treatment, but it's very expensive, a hassle and a series of vaccine's isnt' exactly fun.

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As a vet, I've been bitten by a wide range of animal species. When people talk about animal bites, they usually think about dogs and cats. Horses can (and do) bite as well. Most horse bites are probably playful nips that hurt a little yet don't cause major problems, but some bites can cause serious injuries and infections can result.

A recent paper in the Journal of Agromedicine (Langley and Morris 2009), with the rather unwieldy title of "That Horse Bit Me: Zoonotic Infections of Equines to Consider after Exposure Through the Bite or the Oral/Nasal Secretions". Bites apparently account for 3-4.5% of the approximately 100 000 annual emergency room visits in the US that are associated with horses. The authors of the paper review infections associated with bites and contact with organisms in the mouth and nose of horses.

A large number of bacteria have been associated with horse bite infections in people, including Actinobacillus, Streptococcus, Psuedomonas and Staphylococcus species. Some viruses can theoretically be transmitted by bites, but there's little evidence that this actually happens.

Although viruses are not of as much of a concern overall, rabies needs to be considered in every bite from a mammal. We pay a lot of attention to rabies with dogs, cats and wildlife, but it often gets ignored with horses. While I'm not aware of any reports of rabies transmission from horses to humans by a bite, it could happen.  Fortunately, rabies is rare in horses so the likelihood of exposure from this species is very low. However signs of rabies aren't always obvious initially, and rabies in horses may mimic other diseases. Sometimes, rabies looks like colic, and human exposure through bites or other contact is possible when handling, evaluating and treating affected horses.

Unlike with dogs and cats, there are no clearly defined protocols for dealing with bites from horses. Any dog or cat that bites a person is supposed to be quarantined for 10 days. The reason for this is if the animal is rabid and the disease is advanced enough for the animal to be capable of spreading rabies virus, it would invariably develop signs of rabies and die within this time period. We don't have similar guidelines for horses. I suspect the 10 day observation period would be adequate but we don't have good data. The paper states that in Kentucky, a 14 day observation period has been used by the state Department of Public Health.

At the conclusion of the paper, the authors make a few important general recommendations for reducing the risk of disease transmission from bites and oral or nasal secretions of horses:

• Use good general hygiene, especially hand hygiene, after any contact with horses.
• Use gloves and gown or lab coat when examining horses in a veterinary clinic or hospital. (This might be overkill for all horses. We don't require gloves for every horse contact, just contact with mucous membranes (e.g. mouth, nose), wounds, incision sites and other high-risk areas. I think bare hands are fine for general contact as long as there is good attention to handwashing after.)
• Consider mask and goggles if the horse is coughing or sneezing.
• Develop standard operating procedures for handling sick horses.
• Use isolation when needed.

I'd add a few more points:

• Avoid bites. Pay attention to what you are doing around horses to reduce the risk of being bitten. Do not encourage playful behaviours (e.g. nipping) that could lead to bites.
• If you are bitten and it breaks the skin, clean the site thoroughly with soap and water. If there is significant trauma, or if the bite is over a joint, hand, foot, or a prosthetic device, you should see a doctor immediately because antibiotics are most likely indicated. If you have a weakened immune system, you should be evaluated by a doctor after any bite.
• Avoid contact with the horse's mouth or nose if you have skin lesions. Cuts and scrapes can allow bacteria to enter your body and cause infections. If you have a cut on your hand, make sure it is covered with a glove or waterproof dressing if you are going to have contact with the horse's mouth or something that came from its mouth (e.g. a bit).

This Worms & Germs blog entry was originally posted on equIDblog on 02-Sep-09.

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When it comes to methicillin-resistant staphylococci in pets, MRSA (methicillin-resistant S. aureus) gets most of the attention. That's fair since it's emerging as an important health problem, and can be transmitted between pets and people. Now another staph, MRSP (methicillin-resistant S. pseudintermedius) is getting more attention, and it's actually a more common cause of infections in dogs and cats compared to MRSA. There are also some other methicillin-resistant staph that get much less attention. One is methicillin-resistant S. scheliferi (MRSS).

There are actually two different subspecies of this bacterium, S. schleiferi subsp. coagulans and S. schleiferi subsp. schleiferi. Staphylococcus schlieferi subsp. coagulans is the coagulase-positive subspecies. (Coagulase testing is one of the main ways staph species are classified.) Sta[hylocccus schleiferi subsp. schleiferi is coagulase-negative. In general, coagulase-negative staph are considered to be minor concerns and rare causes of disease other than in sick, compromised individuals in hospitals. However, it looks like S. schleiferi subsp. schleiferi is an exception to that rule, as it is able to cause disease in otherwise healthy dogs and cats.

Both S. schleiferi subtypes predominantly cause skin and ear infections. As with other staph, methicillin-resistance is a concern and is increasing. Methicillin-resistant S. schleiferi (MRSS) rates appear to be increasing, which is a concern because methicillin-resistant staph infections are harder to treat due to their resistance to many antibiotics.

One factor that limits our knowledge of the role of MRSS (and really, S. schleiferi in general) in disease is the fact that many, if not most, diagnostic laboratories don't try to differentiate it from S. pseudintermedius because the two species are very similar. (Sometimes, labs don't even try to differentiate any of the coagulase positive staph, including S. aureus).

While MRSA in pets is a public health concern, there is probably much less to fear from MRSS. Staphylococcus schleiferi infections in people are quite rare and there is currently no indication that pets are an important source of human infection. However, given our limited knowledge of this bacterium, it's wise to take some degree of precaution around animals with MRSS infections, particularly basic measures such as avoiding direct and indirect contact with infected sites, and good handwashing habits. These are the same general recommendations for pets with MRSP, and more details about this are available on the Worms & Germs Resources page. 

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Methicillin-resistant Staphylococcus aureus (MRSA) infections are an emerging problem in dogs and cats. They're a huge problem in human medicine, and the emergence of MRSA in pets can be directly traced to the spread of MRSA in people.

A big problem with MRSA infections is that they can be difficult to treat because they can be resistant to many antibiotics (not just methicillin). This complicates treatment, but it's important to remember that most MRSA infections are treatable.

An important concern with MRSA is that it may lead to unnecessary veterinary use of drugs that are critically important for treatment of life-threatening infection in humans. Vancomycin is an antibiotic that is occasionally used to treat MRSA infections in dogs, although I've never had to use it. I stumbled across a supposed "veterinary information website" today that stated vancomycin is the main treatment for MRSA in dogs. It quickly became clear the authors had no clue about the topic, because they kept calling MRSA a virus (always scrutinize the source of information, especially on the internet). Information like this doesn't help with prudent use of drugs like vancomycin.  It's important for pet owners and veterinarians alike to realize that these "big-gun" antibiotics (such as vancomycin) are rarely needed for MRSA infections in dogs and cats. There are almost always other, and usually better, options.

Vancomycin is also sometimes inappropriately used in animals, which can lead to worsening of infection.  For example, if vancomycin is mistakenly given orally, the drug is not absorbed from the intestinal tract and therefore has no chance of fighting infection elsewhere on the body.

In general, MRSA infections are quite treatable. Survival rates tend to be high and, with proper treatment, should be no lower for MRSA infections versus infections caused by susceptible strains of S. aureus. A comparison of MRSA versus susceptible S. aureus infections presented last year reported no difference in survival rates, with an overall survival rate of >80%. The key is diagnosing the infection early and getting started on the right treatment. That means getting cultures done earlier, rather than later.

While increasing antibiotic resistance may lead to more need for "big-gun" antibiotics in some cases, we need to act prudently and restrict their use to situations in which they are absolutely required. Use in animals needs to be very prudent to avoid contributing to antibiotic resistance in people. Inappropriate use in animals could lead to more calls to restrict veterinary access to various drugs, which could threaten treatment of other animals with other types of infections.

Don't confuse "big-gun" antibiotics with the best treatment.

More information about MRSA can be found on the Worms & Germs Resources page.

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I received the following question the other day: "I have a friend who had chemo embolization on tumor on liver in late June. She is in hospital now, and an abscess was discovered on liver.  Pathology results said "equine strep".  Her brother visited immediately after procedure, and he works with horse full time."

Streptococcus is a group of bacteria that includes many different species. There are two main species in horses Streptococcus equi subsp. equi (aka S. equi, the cause of strangles) and Streptococcus equi subsp. zooepidemicus (aka S. zooepidemicus, a cause of various types of infections). As you can guess by the 'equi' name, their natural host is the horse. Strep infections are very common in people, but rarely involve these two species. Nonetheless, infections with either Streptococcus equi or S. zooepidemicus can be found in people, but S. zooepidemicus is most common. Usually, these infections develop in people who are already sick for another reason, have compromised immune systems, or in young children. Interestingly, not everyone that is infected reports direct or even indirect contact with horses.

Back to the question: it's hard to say what's going on here based on the the general term "equine strep", but presumably the person has an infection with S. equi or S. zooepidemicus. Whether horses are actually involved will be tough (or impossible) to determine. It's a tempting hypothesis that the patient's brother carried the bacterium from the farm to the hospital, but I'd be wary about making a definitive statement about the bacterium's origin solely based on that. There are ways to investigate this further, such as trying to isolate Streptococcus species from horses on the farm, typing them and comparing them to the strain that caused disease in the person, but this type of testing is very costly and almost never performed, as human infection with these species is so uncommon.

This should be a good reminder that people who are sick and in hospital are at higher risk for developing infections, and they can get infections from bacteria that rarely cause disease in healthy individuals. While there is no proof of a link to horses (at least in this case), good infection control practices should be used whenever anyone visits someone in the hospital. That would include not wearing barn clothes to the hospital and paying close attention to handwashing.

This Worms & Germs blog entry was originally posted on equIDblog on 26-Aug-09.

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A recent post that discussed, among other things, expired antibiotics generated a lot of comments. Some accused me of various things and stated their belief that expired drugs are fine and that requiring antibiotics to be prescribed is a global conspiracy. I'll leave the conspiracy theory alone and just address the issue of expired drugs.

Expiry dates must be provided by manufacturers. They are essentially a guarantee that the stated level of active ingredient will be present at least until the expiry date. Drugs don't instantly vanish the day after, but once you have passed the expiry date, you no longer can be certain about what is present. It's possible the full amount is present, but it's also possible that less is present, and it's impossible to predict. If you don't know how much is present, you can't be certain that you are giving the proper dose. Giving inadequate doses is associated with treatment failure and increased likelihood of antibiotic resistance developing. Therefore, unless you have a pharmacology lab in your house (or readily accessible) to test expired drugs, you shouldn't use them.

It's not just my opinion.  Here's what some other groups say on the subject:

Centers for Disease Control and Prevention (CDC): "...make sure you properly dispose of leftover and expired antibiotics."

University of Michigan University Health Service: "Do not take expired antibiotics."

The Alliance for Prudent Use of Antibiotics quotes Dr. Alfred DeMaria, an Assistant Commissioner at the Massachusetts Department of Public Health (MDPH) suggests that "stockpiling of antibiotics is strongly discouraged because it could lead to inappropriate patient decisions to self medicate, incomplete courses of antibiotics that might select for resistant organisms, the eventual use of expired medications, and the depletion of national supplies for medically-indicated uses. Antibiotics should be selected according to the specific infection of concern."

The advice from these respected groups, who have no financial stake in the sale of drugs, sounds pretty clear to me. Trying to save a little money by re-using expired antibiotics is a bad idea. The infection might get better, but it might not. If it doesn't then the animal (or person) will be sick longer and may require more intensive (and expensive) treatment. If antibiotic resistance increases because of the use of inadequate doses, then more expensive drugs may be required and infections may be harder to treat. None of these are worth the potential cost savings.  This is a different situation than using expired drugs like painkillers for your headache. If those drugs are no longer effective, the worst thing that will probably happen is you won't get better, which you would know in short order and be able to address. With antibiotics it's harder to tell whether they are working early on during treatment (the critical time), and treatment failure could have much more serious consequences, both for the pet and for drug resistance.

When antibiotics expire, get rid of them.  Always complete prescriptions as directed and you won't have leftovers to worry about.

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People are justifiably concerned about overuse of antibiotics, in both veterinary and human medicine. There's ample talk about restrictions on use of antibiotics in animals (especially livestock), which is an area that needs good, objective research and discussion. Some politicians have made grand statements about restricting antibiotic use and have proposed strict legislation. (In North America, there's a lot more talk than action). However, I continue to be amazed that amongst all the hand-wringing about antibiotic use in animals, governments haven't taken the very simple initial step of making all antibiotics only available by a veterinarian's prescription. This seems to be a very logical first step, but it's one that almost never gets discussed.

A good example of why this type of regulation is needed comes from a website about Terriers, which says:

"Almost all human antibiotics can be used on dogs and almost everyone either has old antibiotics in their medicine cabinet or knows people that do. Look around, and you will probably find what you need."

• What??!! Just what we need... recommendations that people sift through old drug supplies for a dose or two of who-knows-what, which may or may not be expired and may or may not be potentially useful for whatever problem is present, and may even be harmful. Determining whether or not an antibiotic should be used, and determining the drug and dose is not something that should be up to a pet owner. It should be up to a veterinarian.

"Drugs past the expiration date are going to be fine as long as they are no older than a year or so past the expiration date (even then they may be fine)."

• Dumb. Drugs don't instantly go bad at their expiration date, but you don't know what you have left at that point. If you actually need an antibiotic, you need one that works like it's supposed to.

"If you prefer to order your medications outright, you can order cephelaxin (Fish-Flex) from most dog catalogues and it will cure 99% of your flesh wounds as well as most urinary tract and ear infections. Cephalexin or cefalexin is sold as a fish antibiotic in dog catalogues with full-knowledge it is being used for off-label treatment in dogs. It should cost about $30 for 100 250 mg. capsules, which is a perfect dose for a terrier."

• Ugh!!  A good example of why loopholes like easy access to antibiotics for fish use need to be closed. Many dog internet sites sell fish drugs. I wonder what percentage of "fish" drugs actually make it into fish?

"You probably have some old amoxicillin around the house from the last time you got sick. This is fine to use even if "expired" more than a year ago. Expiration dates on non-liquid antibiotics are a marketing tool (i.e. they encourage people to throw good drugs down the drain) and have no scientific basis -- a fact demonstrated by the U.S. military."

• Can't say I've seen that study. Expiry dates aren't a marketing ploy. You should use all the antibiotics prescribed, and if for some reason you have any left, you should throw the rest out. It has to do with health and proper use of antibiotics, not marketing.

Take home messages:

• It's time for politicians to actually do something about antibiotic use and ban all over-the-counter access.
• Beware of internet advice. Scrutinize sources of information carefully.

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Skin and soft tissue infections increasingly caused by highly drug-resistant bacteria, along with various concerns about antibiotic use, have led to a desire to find non-antibiotic approaches to treatment of these infections. Tea tree oil has some potent antibacterial properties when tested in the lab, and there are some studies indicating it might be effective for the treatment of certain infections. Some work that we've done in my lab shows promising activity of a few different essential oils against MRSP.  Some of these oil may be similarly useful treatments for certain infections. 

However, as I've stated before, we need to make sure that we adequately investigate safety of any new drug or therapy. All natural does not mean safer. If something kills bacteria, we need to make sure that it doesn't also harm an animal's cells and tissues.

Tea tree oil can cause damage to skin and soft tissue cells, but it's unclear whether this is really a problem during short courses of treatment. Nonetheless, in humans it has been recommended that tea tree oil not be used for treatment of burns because of concerns about tissue damage.(Faoagali et al, Burns 1997)

Another concern is toxicity from ingestion. This isn't usually a concern in adults, but there are a couple reports of children that became seriously ill (neurological abnormalities, progressive unresponsiveness... fortunately temporary) after ingestion of small volumes of tea tree oil. This leads me to have concerns about ingestion of the oil by dogs and cats if they lick areas where it has been applied, or eat bandages soaked in oil. They probably wouldn't ingest that much, but it's possible.

At this point, the jury is still out on the usefulness of tea tree oil. There are some potentially beneficial aspects and some safety issues that need to be clarified. In the interim, if you want to use tea tree oil:

• Recognize it's not a proven therapy. Don't use it in place of conventional treatment recommended by your vet.
• Keep it out of the reach of children and pets.
• Be judicious about the amount you use, and make sure pets don't lick it off.
• If the infected site seems to get worse after tea tree oil is used, stop applying it and see your veterinarian.

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Clallam County (Washington) is considering dropping the requirement that pets be vaccinated against rabies in order to get a license. It's pretty clear that this is only based on a desire to get more people to pay for licenses. Sheriff Bill Benedict is quoted as saying "My view on this is, we're leaving money on the table by not finding a way to get more people buying licenses."

This money-driven mindset makes no sense, and raises the question "what is the purpose of licensing pet?" Is it only to provide a source of government income (in other words, a tax on pet ownership), or is it for greater purposes such as helping protect the pet and human population?

Another quote from Benedict: "You would still be required to have your pet vaccinated, but that would be more of an issue between the pet owner and the veterinarian." This isn't an issue solely between the pet owner and the veterinarian. Rabies vaccination is still required by law. Veterinarians do not have a mandate or power to require vaccination and enforce the law. With this "You still need have your pet vaccinated (wink, wink, nod, nod)" approach, the municipal government is essentially saying, "We really just want you to pay us for a license. We don't really care whether your pet is vaccinated against rabies or not as long as you give us money."

A local veterinarian wrote to the commission that "Licensing pets is sometimes the only reason an owner will get rabies vaccines... Rabies vaccinance is the law of the state, the law of the county. Licensing, in my view, is less important than vaccinating for rabies and may facilitate even more rabies cases."

Well said. The county may get more money because more people will get licenses, but it's certainly possible that fewer pets will get vaccinated. Just one rabies exposure could negate the increased revenue from more licenses based on the high costs of rabies post-exposure treatment (let alone the risk of disease, stress of exposure, costs required for investigating cases...). Since all those costs would come from other peoples' budgets, however, I doubt they're too concerned.

Benedict also stated "Most pet owners -- in fact the vast majority -- if they're responsible enough to get a license, they're responsible enough to get a pet vaccinated."

Good thing he's not a lawyer. It seems to me that he just shot his argument down. If the majority of pet owners that are responsible enough to get a license are also responsible enough to get a pet vaccinated, then why is this change required?  An attempt to increase cashflow is not a good reason to change rules that are designed to protect the public and pets from a fatal disease.

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A horse in Harford county Maryland has been euthanized because of rabies. The horse first starting showing signs of disease in mid-July, which manifested as "striking changes in behaviour." The report doesn't say when the horse died, but animals typically die within a few days of the onset of neurological disease. The horse was transferred to the New Bolton Center where rabies was diagnosed. Subsequent testing showed it was a raccoon rabies strain, although that does not mean that a raccoon was the actual source of infection.

Public health officials implemented a 45 day quarantine of the farm. Stray cats (about 25) were caught and euthanized. Fortunately, the family pets were properly vaccinated and have received booster shots (plus presumably a period of observation at home... a much better situation than if they were not vaccinated).

People that had contact with the horse have received rabies post-exposure treatment. This includes one person who had to be tracked down overseas.

Harford County Health Department spokesperson Bill Wiseman said "There was never a risk to public safety. This incident was a great example of public health work in action and cooperation between local, state and in this case, international authorities." I don't buy the statement that there was no risk to public health. While the risk of rabies transmission from infected horses is very low, it's not zero. Rabid horses have killed people because of their abnormal and sometimes aggressive behaviour. Further, the fact that this horse had rabies means that it got it from something. Rabies can have a long incubation period so it's not guaranteed that it acquired it on the farm, but you have to be prudent and assume that there is infected wildlife in the area that could pose a risk for other animals or people. Public health authorities managed the situation well and reduced the public health risks, but there were certainly still risks.

Rabies vaccination is highly effective. There is no statement about whether this horse was adequately vaccinated but it's unlikely. Proper vaccination would likely have prevented this horse's death, as well as the death of the stray animals, cost of vaccination of people, cost of veterinary care for this horse, quarantine of the farm and the associated financial and emotional costs. A dose of vaccine that costs a few dollars could have saved thousands of dollars and emotional stress.

Rabies is a rare disease in horses but its severity means it should not be ingored. Vaccinate your horses.

This Worms & Germs blog entry was originally posted on equIDblog on 14-Aug-09.

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Animal bites are very common. Millions of people are bitten every year, and the resulting burden in terms of pain, infection and financial costs is astounding. Dog bites get the most press because they often cause significant trauma. Dogs have larger and stronger mouths, and can bite repeatedly and more aggressively in some attacks. Deaths attributed directly to pet bites pretty much exclusively involve dogs.

Cat bites are smaller and have less chance of causing significant injury to tissues, but they may be more severe in the long run. There's a scientific paper called "Cat bite infections: biological warfare amongst cats," which is a testament to the nasty populations of bacteria that live in cats' mouths. It's not just the presence of bacteria that's a problem (afterall, dogs' mouths are full of potentially nasty bacteria as well) - the nature of cat teeth and the resulting bite wounds is a major factor. Cat bites often result in small but deep puncture wounds. This pushes bacteria deep into the tissues, where they're harder to get rid of and which results in a much greater chance of causing an infection. Furthermore, cats tend to bite areas that are high risk for development of bad infections, especially hands, which have a complex and susceptible network of tendons, tendon sheaths, joints and nerves. Bites that appear to be minor can end up causing serious problems, often much worse that an initially more dramatic dog bite.

Really, you don't want to be bitten by either a dog or a cat (or an iguana, hamster, person or anything else). A large percentage of bites are avoidable, and knowing how to interact with animals and read signals of aggression or fear are critical. If you are bitten, prompt and proper care of bites is required to prevent serious, long-term complications.

More information on bites, including management of bites, is available on the Worms & Germs Resources page. The CDC has a podcast that includes information about bite-avoidance that can be accessed by clicking here.

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A 74-year-old Colorado woman that had been warned repeatedly not to feed bears was killed by one. The circumstances surrounding the attack are not known, but there was clear evidence of mauling. Wildlife officers had received numerous complaints for at least a decade that the woman was habitually feeding bears.  She was warned several times but never ticketed because of difficulty gathering solid evidence of the illegal activity. Wildlife officers and sheriff's deputies killed two bears after the attack. It was reported that a necropsy of the larger 394 lbs animal showed that it appeared to have been feeding on a human, but this has not been officially confirmed yet.

As we've discussed before, people often feed wildlife thinking they are helping the animals, but the opposite is true. Numerous problems are caused by feeding wildlife, including making animals dependent on people for survival, decreasing animals' fear of humans, encouraging animal encroachment into urban areas and generally increasing the chance for both human and animal injury and infection.

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State public health officials are trying to get the word out about a potential rabies exposure in Annapolis, Maryland.  A rabid kitten was discovered outside a Sears store at the Westfield Annapolis shopper center. The concern is that people may have handled the kitten and been exposed. It's a major concern with kittens because they can be hard to resist - a pathetic-looking/cute little kitten sitting around in a public place could easily be picked up by many people. Also, when rabies is found in a young kitten, there are often other rabid kittens from the same litter in the area. Rabid stray kittens have caused widespread exposure in the past, and this case may be no different.

Anyone who recently had contact with a stray kitten in the area in question should contact public health officials as soon as possible. Simply touching the kitten is not a rabies exposure risk, but anyone that has had any contact with a potentially rabid animal should talk to public health officials to determine whether there is any risk of infection and whether post-exposure treatment is required.

While kittens are hard to resist, avoid handling stray kittens. This is especially true if it's transient handling where you will never know what happened to the kitten afterwards (as opposed to someone adopting a kitten off the street - this is still risky from some standpoints, but at least you know if the kitten gets sick and you can make sure that it is tested for rabies or other other zoontic diseses, if need be).

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It seems like whenever a hit TV show or movie features an animal, there's concern about the "101 Dalmatians effect," whereby there's a mad rush to get the animal for a pet. When 101 Dalmatians was a hit movie, there was a huge spike in sales of this rather unusual breed - a breed which is certainly not for everyone. This results in unqualified breeders and puppy mills churning out marginal or poor quality pets and people getting a pet that really doesn't suit them. The end result can be a lot of disappointment, heartache and abandoned pets. This pattern has been repeated with various other breeds and animal species, and there is concern that the same will happen with guinea pigs as a result of the new Disney movie G-Force.

In terms of human health, guinea pigs are relatively benign. Bites and scratches are probably the biggest concern, and are often the result of improper handling. Bites can become infected from bacteria in the guinea pig's mouth or from bacteria on the person's skin. Allergies are also a potential problem. The number of diseases that are known to be transmitted by them is relatively small, and the risk of disease transmission is rather low.

Lymphocytic choriomeningitis virus (LCMV) is a concern with all rodents. It typically only causes disease in people with compromised immune systems, but can result in fatal infection. The risk of a guinea pig carrying this virus is likely greatest in animals from large rodent breeding facilties and when there is contact with wild rodents.

Ringworm is perhaps the most common infection that people get from guinea pigs (apart from infections following bites). Even healthy guinea pigs can carry the fungus that causes this disease.

Guinea pigs can carry Salmonella, but they are quite susceptible to infection and usually get quite sick. The risk of a healthy guinea pig shedding Salmonella, especially for a prolonged period, is pretty low. The risk is presumably greatest shortly after purchase.

Rabies is always a potential problem in mammals but the risk is very low with small rodents such as guinea pigs. (Very low isn't zero though, since hamsters have been sources of potential rabies exposure).

There are other potential problems too, but they are all quite rare.

The keys to reducing the risk of infection are:

• Purchase a guinea pig that looks healthy, is eating well, has no skin lesions or diarrhea, and is active and alert. Ideally, purchase an animal from a local breeder as opposed to a store that might have obtained the animal from a large breeder, via an animal warehouse, hundreds or thousands of miles away.
• Learn how to properly handle a guinea pig to reduce the risk of bites and scratches, as well as injury to the animal.
• Keep pet guinea pigs away from wild rodents.
• Use good general hygiene. Wash your hands after handling the guinea pig and after contact with bedding.
• Thoroughly wash any bites or scratches.
• Take particular care in the period shortly after purchase.
• Even though the cost of the guinea pig is less than the cost of a vet visit, a veterinary examination is important when the animal is sick. Apart from our ethical responsibility to take care of our pets, it's important to make sure that illness isn't caused by a disease that can be transmitted to people.

More information about the diseases mentioned above is available on the Worms & Germs Resources page. While we don't have a specific guinea pig info sheet yet, much of the information on the hamster information sheet also applies to guinea pigs.

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I'm back from a week away with no internet access, so I have some catching up to do. One of the first things I stumbled across on my return was an article in the Guelph Tribune about a summer kids camp at the Guelph Humane Society. At the camp the kids get exposed to various aspects of animal care and welfare, and have field trips to sites like a Donkey Sanctuary and Butterfly Conservatory. Some parts of it sound quite good, but it's clear that the kids get to have a lot of contact with shelter animals, since playing with the animals is the "highlight of the camp," and as the camp director states "Who wouldn't want to hang out with cats and dogs all day?"

I have nothing against young kids having contact with pets (being the father of three young kids and the owner of multiple pets). Contact with animals is very rewarding for children, and a program to increase awareness about pets, animal care and the problems with overpopulation could be a great thing. However, I'm not sure that this is the best way. I only have a superficial idea of what happens at this camp based on the article, but I have a few different concerns.

Child safety

• Any contact between people and pets carries some (albeit very low) risk of infection. Certain things increase the risk. One is young age. Kids are at increased risk of infection. The day camp had children between 5 and 13 years of age - the young end of this range certainly could be considered a high risk group.
• Another issue is the increased likelihood that animals are shedding infectious agents. Shelter animals are definitely a high risk group, because of factors such as young age, stress, mixing of animals from various sources, illness, and under- (or lack of) vaccination and deworming.
• The lack of good knowledge of temperament of these animals is another concern, as it's harder to predict whether an unfamiliar animal might be more likely to bite or scratch. I assume (hope) that the kids are only allowed to have contact with animals that have been assessed in some way, but it's difficult to know how an animal is going to react in certain situations.
• Another consideration is the sometimes unpredictable nature of contact that kids have with animals. Young kids don't inherently know how to interact with strange animals. Even if they act very well around their own pets, they may act differently in a strange situation with animals that act differently, and not know how to detect or respond to signals that the animal is aggressive or afraid.  Education and supervision are important and should be a part of a program, but you can't instantly eliminate these risks.
• The humane society environment can also be assumed to be pathogen-rich - there is a high likelihood that various surfaces (e.g. floors, counters) throughout the facility are contaminated with various bacteria, fungi and parasites.
• Kids could also transfer infectious agents to the household, something that is of greatest concern if there are very young, elderly or immunocompromised individuals present.

Humane society safety

• Humane societies are at constant risk of infectious diseases, including outbreaks. Outbreaks can cause major problems, including temporary closure, illness in staff or owners of newly adopted animals (e.g. ringworm), or mass euthanasia. Infection control measures can be highly variable in humane societies, and adding a group of kids to the mix certainly doesn't help. The more contact and movement in a facility, the greater the risk of disease transmission. Strict adherence to careful infection control protocols (which is not often the case, even at the best of times) is required. Good practices at the camp such as careful attention to hygiene, restricting contact with certain groups of animals, and very careful supervision could reduce the risk of disease transmission, but you can never eliminate the added risk that this type of program would bring.

Pet safety

• Various infectious diseases could be transported home on the bodies of kids or their clothing. Some of these could pose a risk to any pets in the household. Risks are much greater if there are young, old, sick or inadequately vaccinated pets in the house.

I wonder whether the parents of these children were informed (in writing or otherwise) that their kids would be exposed to a increase risk of infectious diseases, bites and scratches, that they should take measures to reduce the risk of disease transmission when the child returns home, and what precautions are being taken at the camp.

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I received a flyer from Zoologix, a company that offers various (typically unvalidated and unproven) PCR tests for animals. The flyer headline was "Pets can carry MRSA - but testing can help."

Testing in certain situations is useful, but this is almost always limited to diagnosis of animals with active infections (i.e. they're sick). PCR is not a good way to make such a diagnosis, because the test doesn't tell you anything about the bacterium's susceptibility to other antibiotics. Screening of pets just to determine whether or not they carry MRSA is rarely needed, and currently there is no evidence that PCR is a reasonable test for this.

There are no validated PCR tests for MRSA in animals. We looked at using a human test in horses and it failed miserably. There are validated tests for use in people, and they are quite good: they accurately identify MRSA and differentiate it from other methicillin-resistant staphylococci and from methicillin-susceptible S. aureus. That's critical, because you have to know what a positive test really means.

I called the company and asked what the test actually detects. They said it detects the mecA gene, the gene that confers methicillin-resistance to staphylococci such as S. aureus. However, this gene can be present in other staphylococci that can be found in many  healthy dogs and cats (10-30% in some studies). It does not actually detect MRSA and a large percentage of samples that give positive results will be false positives. The tests that are used in humans are specifically designed to look at two things in combination: whether S. aureus is present and whether it has the mecA gene (methicillin-resistance). This is the right approach because it excludes all those other false positives. Detecting mecA alone is completely useless. It's interesting that the flyer states "PCR testing is fast, effective and accurately differentiates MRSA from other bacteria - even other Staph strains." Based on what the company told me over the phone, with regard to the test they're advertising, that's a blatant lie.

This is an example of a combination of bad science and bad ethics. This company has no business marketing this test. It's false advertising, because the test isn't an MRSA test. Their justification for using it is similarly weak. Anyone thinking about using this test should run away quickly! The issues with this test (and others) should also be considered when deciding whether to use this company for any tests.

More (and accurate) information about MRSA can be found on the Worms & Germs Resources page.

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A recent case report in the Journal of Clinical Microbiology (Cooke et al. 2009) described isolation of Salmonella Apapa from the feces of a 67-year-old woman with abdominal pain. The patient had a history of various medical disorders but no clear evidence of a compromised immune system. She was hospitalized, and Salmonella Apapa was identified from a stool sample collected the day after admission. Fortunately, her abdominal disease resolved (whether it was caused by Salmonella or whether Salmonella was an incidental finding can't be stated definitively), and she was ultimately discharged from the hospital.

Salmonella diagnoses usually lead quickly to questions about food and reptiles.  In this case, the woman's son had recently moved in with her, along with his two bearded dragons. The lizards were kept in a tank, and the woman reported having no direct contact with them. Samples from the lizards' feces and the tank environment were collected, and the same Salmonella strain was isolated. While getting Salmonella from a reptile is certainly nothing new, this case report highlights some important points.

• The person that was infected did not report any contact with the reptiles or their tank. Therefore, some type of indirect exposure must have occurred. This is why reptiles should not be kept in high-risk households even if the high-risk people don't have direct contact with them. High-risk households include households with young children (less than 5 years of age), elderly individuals, pregnant women and immunocompromised individuals.
• It's not just high-risk people that get sick. This person was perhaps on the crux of being considered high-risk based on her age and previous medical problems, but she was certainly not a clear example of the people we assume are at higher risk. A huge number of reptile-asociated cases of salmonellosis are reported every year. While high-risk people are more likely to get sick (and more likely to develop severe illness), healthy individuals can be infected as well.

Reptiles can make good pets. I used to have a pair of Red-Footed tortoises, so I'm certainly not anti-reptile (despite what the emails I typically get after posts like this say). People who have or who are comtemplating getting a reptile for a pet need to be aware of the associated risks, as they are certainly real and should be taken seriously.

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A stray cat taken by someone to a family gathering in Delaware, USA, resulted in 17 people from 4 states undergoing rabies post-exposure treatment. The kitten was found by the side of the road, taken to the gathering (it's unclear whether it was found on the way there or earlier), and when it became ill after the gathering, it was diagnosed with rabies. This is just one example of the potential for widespread exposure of people handling stray (or recently stray) animals at events like reunions, flea markets and sports tournaments. Because these animals (especially cute little ones like kittens) often get handled by a lot of people, a lot of people can be exposed to rabies if the animals are carrying the virus. These situations create major problems for public health personnel, because it's difficult to identify all the individuals who were potentially exposed when they are dispersed across the country.

While generally uncommon, this type of scenario happens a few times a year.

• Don't bring stray, or recently adopted, animals to public events.
• Ensure that your animals are properly vaccinated against rabies. Animals that have not been properly vaccinated should not be taken to public events.
• Don't handle stray animals.
• If an animal that you have recently adopted gets sick, make sure rabies is considered and, if necessary, make sure the animal gets tested.

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A paper in the July 1 edition of the Journal of the American Veterinary Medical Association (Muller et al) describes a case of encephalitis (brain inflammation) in a rabbit caused by human herpesvirus type 1.  The owner had a severe herpes infection with genital and oral lesions five days before the rabbit got sick, and reported "intensive" nose-to-nose and mouth-to-nose contact with the rabbit. The rabbit started off with a decreased appetite and excessive tear production (epiphora) in one eye. Then other signs of eye and neurological disease developed. Despite aggressive treatment, the rabbit deteriorated and was euthanized after a week of hospitalization. Subsequent testing identified human herpesvirus type 1 in the rabbit's brain.

Human herpesvirus type 1, also called herpes simplex viruses type 1 (HSV-1), is a common sexually transmitted disease (STD) in people. It can cause oral, genital and ocular (eye) lesions. Humans are the primary host of this virus, but it has been found in species such as rabbits, rats, mice and chinchillas. In rabbits, it usually causes encephalitis, and is almost always fatal for these animals.

This case shows how viruses typically associated with one species can sometimes affect others. While we usually focus on microorganisms moving from animals to humans, they can also move in the opposite direction, as was presumably the case here. Close face-to-face contact with the infected owner was probably the source of the virus. This is an example of an uncommon event, but one that should not be ignored.

If you have an active herpesvirus infection:

• Limit close contact with rabbits (and, to be on the safe side, probably restrict contact with other pets as well). In particular, avoid contact with the mouth, nose or eyes.
• Wash your hands or use an alcohol hand sanitizer regularly, particularly after using the washroom or having any contact with infected sites/sores.
• Make sure herpesvirus infection is considered if your rabbit develops eye or neurological disease.

The risk of rabbits transmitting human herpesvirus is completely unclear. Common sense dictates that anyone hanlding a potentially infected rabbit should restrict contact with the eyes/mouth/nose, wear gloves, wash hands after contact (even if gloves were worn) and avoid contamination of clothing.

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In an interview with the San Francisco Chronicle, veterinary dermatologist Dr. George Doering makes a pretty obvious but very important comment that is worth repeating:

"The biggest problem we have in almost all the fields of veterinary medicine is compliance. You say to a client, "This dog needs to take this antibiotic twice a day." Well, the reality is we might be lucky if they get it once a day. ...They don't want to accept the seriousness of the problem."

This very true and very important. Compliance with recommended antibiotic therapy is probably a major factor in treatment failure, recurrent infection and antibiotic resistance. Antibiotic dosing regimens are specifically designed to ensure that the right concentration of drug is present in the body for the appropriate time. Missing doses, skipping days, not making sure the animal actually ingests the drug, and other problems that result in the pet not getting what is was supposed to get are very important.

It's easy to understand why this happens, because administering antibiotics (particularly to some difficult-to-pill dogs and cats who can smell the medication when it comes in the house!) can be a hassle. Because of this (and the very natural human tendency to take the easy way out), it's really important for people to understand the concerns about inadequate antibiotic administration and what they need to do.

• Follow the entire treatment course. You should have no antibiotic left at the end of the recommended treatment time.
• Make sure your pet actually swallows the antibiotic. If you add pills to food, make sure you check to see that the pill isn't left behind. It's amazing how animals can eat a big bowl of food and leave behind a little pill. The picture shows how my dog Meg can, in the process of inhaling her food at an incredible rate, leave behind a tiny ephedrine pill.
• If your pet will not eat the drug voluntarily, talk to your vet about other ways to administer it, such as compounded in chewable treats. Depending on you and your pet, opening your pet's mouth and placing the pill at the back of the tongue may be an option. Talk to your vet about this first and make sure you wash your hands after. If you think there is a risk you might be bitten, if you are at high-risk for infection because you are immunocompromised, elderly or pregnant, don't try to "pill" an animal in this manner.
• If you still can't get the drug into your pet, talk to your vet right away.  If you wait a couple of days or a week or more to tell your vet, your pet may be even sicker by then. There may be other options to oral drugs such as injectable antibiotics. This might end up being more expensive or difficult (e.g. you may have to take your pet to the vet every day for its medication), but it will be better for your pet and may even save you money in the long run by ensuring the infection is properly and completely treated the first time.
• Never stop treatment because your pet looks better. Often, signs of infection get better before the bacterium is completely eliminated. Stopping too soon allows the bacterium to regrow, potentially as a more resistant form.
• If you are supposed to take your pet to the vet for a recheck at the end of treatment, then do so. Sometimes longer courses of antibiotics may be needed, and it's much better to continue the current treatment course than to have to start again a couple weeks down the road when the infection has returned (sometimes with a vengeance).
• If in doubt about anything, call your veterinarian.  He or she is there to help, and wants your pet to get the best treatment possible.

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Tularemia has been diagnosed in five dogs and cats in Sioux Falls, South Dakota. At least one of the pets has died. Tularemia, sometimes referred to as "rabbit fever" is caused by the bacterium Francisella tularensis. Infections occur throughout much of the Northern Hemisphere but are much more common in certain regions, such as the central US. This bacterium has received a lot more attention over the past decade because of its potential use as a bioterrorism agent, but infections have been occurring in people and pets for a long time. In North America, the cottontail rabbit, wild hares and some rodents are the main reservoirs. People and other animals get infected through close contact with infected animals (e.g. rabbit hunting) or through bites from blood-feeding insects. 

There was no mention of human cases in the recent report from South Dakota. One of the implications of identifying this disease in pets is that whatever infected the pet could also be a risk for people. If the pets were infected by contact with wild animals, people with similar contact with wild animals could also be exposed. If there is no chance the animals had contact with infected wildlife, then insect-transmission is most likely, and the same could happen to human members of the household (or elsewhere in the area). Therefore, diagnosis of tularemia in a person or pet should put both veterinarians and physicians on the lookout for further cases in all species.

Transmission of tularemia from infected pets to humans is also a concern. This has been reported in numerous instances, most often with cats. There are published reports of transmission from dogs to humans, but these are less convincing than the numerous cat-to-human reports. There's also a report of tularemia transmission from a hamster to a child. The overall risk of transmission is probably low, but tularemia can be spread from pets to people by scratches, bites, and perhaps regular close contact.

You can reduce the risk of your pet being exposed to tularemia by:

• Keeping pets indoors as much as possible. Cats should stay indoors. Dogs should not have uncontrolled outdoor access.
• Dogs should not be allowed to hunt rabbits in areas where tularemia is endemic.
• Animals that venture outside should be checked regularly for ticks and a preventive medicine program for ticks should be in place.
• Routine measures to reduce bites and scratches from dogs and cats should be taken.

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Here's a question I received the other day:

"Do people who work with animals and who work in barns need a tetanus shot as a result of this type of work?  We have Therapeutic Riding Programs in the region and there is a sense that perhaps the volunteers and those who frequently tend the horses need to receive this.  Is this the case?"

Tetanus is a disease that we are quite concerned about in horses because horses are very susceptible to it. That's why we vaccinate them yearly. Tetanus can also affect people, but very rarely because of vaccination and because people have lower susceptibility to the disease. While we pay a lot of attention to tetanus in horses, this does not mean that being around horses increases a person's likelihood of exposure to tetanus. The bacterium that causes tetanus, Clostridium tetani, lives in soil and commonly present in the environment. The more environmental exposure that you have (especially to soil), the greater your risk of exposure to C. tetani. Being around horses doesn't increase your risk any more than doing other things outside.

Whether you have contact with horses or not should not change your approach towards tetanus prevention. You should be vaccinated against tetanus every 10 years. Many (probably most, actually) adults are not up-to-date on tetanus vaccination. Adults tend not to get booster shots on schedule, and often only receive them when they have had a wound that requires medical care. For example, If you get stitches, the medical staff will almost certainly inquire about your last tetanus shot, and give you another one if you haven't been vaccinated in the past 10 years (or if you can't remember).

More information about tetanus in horses is available on the equIDblog Resources page.

This Worms & Germs blog entry was originally posted on our sister site, equIDblog, on 10-Jul-09.

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My dog, like most labs, loves to swim (actually, she's incredibly lazy and prefers to wallow in the water, not actually exert herself). Many dogs like her often go into swimming pools in the summer, which leads to the question "Is this an infectious disease risk?"

The honest answer is we don't really know. The reasonable answer is the risks are pretty low, especially when a little common sense is exercised. You are probably more likely to get a pool-associated infection from another person than a dog, although the risks are not zero.  A dog is probably less likely to defecate in the pool than an infant or toddler!

Various infectious diseases such as cryptosporidiosis, norovirus infection and E. coli O157 have been linked to swimming pools - all associated with transmission from people. As with most infections, the very young, elderly, immunocompromised and pregnant women are at higher risk.

Like many things in life, there is some degree of risk associated with letting the pooch go for a dip in the pool, but you have to consider the risks and benefits together. The overall risk of infection from swimming with a pet in a well-maintained pool is quite low. The risks is probably even lower in a household pool (where dogs would have access) compared to a heavily-used public pool. Good general practices can reduce the risks further. Chlorine can kill most (but not all) possible causes of infectious diarrhea, but it doesn't work instantly. If someone or something contaminates the pool, there is a window of opportunity, that may last minutes to hours, for transmission of infection. However, some pathogens can survive for days in a pool, if not more. Therefore, chlorination is useful but not fool-proof.

• Keep dogs that have vomiting, diarrhea or skin infections out of the pool. Dogs that have had diarrhea should probably be kept out of the pool for a couple weeks.
• Don't allow dogs known to be shedding infectious agents like Salmonella and Giardia in the pool. Some healthy dogs shed these organisms and it's certain that infected dogs go into pools with no problems, but if you know that a dog is shedding an infectious agent it shouldn't be in a pool.
• Don't allow dogs that have fecal staining of their haircoat in the pool.
• The same rules should apply to people. People with diarrhea should stay out of the pool since they are probably a greater risk for transmitting disease. It has been recommended that people not use a pool if they've had diarrhea in the past week.

The CDC has a good site about recreational water illnesses, which can be accessed by clicking here.

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There are two situations when animals may be quarantined because of rabies concerns:

1. After biting a person.
2. After potentially being exposed to a rabid animal.

The time frame for quarantine in these two situations is quite different because of what the quarantine is meant to accomplish.

Animals that have bitten someone are quarantined for 10 days under observation to see if they develop signs of rabies. Most animals that bite do not have rabies, and this is the easiest way of determining whether the animal could have potentially transmitted rabies by way of the bite. If an animal was rabid and infectious at the time of biting, it would die from the disease within 10 days. Animals can only transmit rabies virus after it has reached the brain and started to spread outwards via nerves - it gets into saliva by working its way down nerves from the brain to the salivary glands. Once an animal gets to that stage of disease, they die quickly. So, if the animal is still alive after 10 days, it was not rabid at the time of the bite. Quarantine is important so that it can be clearly proven one way or the other whether the animal was rabid. If the biting animal was not quarantined and ran away, the recommendation would be to err on the side of caution and treat anyone bitten as if they'd been exposed... but we want to avoid that if at all possible.

The second type of quarantine (for a potentially exposed animal) is based on less solid evidence. The idea in these cases is to keep the potentially exposed animal isolated while waiting to see if it develops signs of rabies, because there is no other reliable test for rabies in a live animal. For example, if an unvaccinated dog gets into a fight with a rabid raccoon, it would be considered potentially exposed. It would be quarantined (or immediately euthanized... the other option) and monitored to see if it develops signs of rabies. The length of quarantine for non-vaccinated dogs is usually 6 months, but this may vary by region. This helps reduce further rabies transmission by ensuring that a dog that develops rabies during the quarantine period is not roaming at large and able to infect people or other animals. One weakness of this approach is the incubation period of rabies, which can be very long. There is not a lot of objective research on which to base the 6 month time frame (unlike the 10 day quarantine described above). After 6 months, it's very unlikely the dog will develop rabies, but we can never say it's 100% because of the rare cases of rabies in humans with extremely long incubation periods. In reality, it's likely that the vast majority of animals that are exposed will develop rabies before 6 months, so it's a reasonable time frame. Would it be better to use 4 or 8 months, or something else? Possibly, we just don't know.

The easiest ways to avoid hassles associated with rabies quarantine are:

• Prevent bites. If your pet is trained and observed properly, it's unlikely to bite anyone, so the 10-day post-bite quarantine shouldn't be an issue.
• Vaccinate your pet. Properly vaccinated pets are not subject to the same long, strict quarantine (although a shorter period of isolation (often at home) is usually still required).

More information about rabies can be found on the Worms & Germs Resources page.

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Recently, I wrote a commentary about the need to better define what service animals are because of potential abuse of regulations regarding service animals and the possibility that illegitimate use of the term could impact true service animals. Here are some good comments from a reader.

As a service dog user and trainer who sometimes lectures at the University of Guelph, I am sorry to see the American-centric slant to this article.  In Canada the guideliines are even more vague and there has to be a charter challenge to support the use of a service dog that has been owner trained.

• The article was intended to discuss the American situation since I was talking about American legislation and responding to problems that people have asked me about in the US. Issues are different in various countries and the legal protections in the US certainly don't apply to Canada.
• The last point raises some concerns. What constitutes "owner trained?" Service animals are highly trained to do their specific task and to work safely in public situations. I'm not convinced owner training makes a service animal. There needs to be at least some degree of supervision/review of the training and certification process.

I use a service dog to mitigate the effects of my invisible disability and the vagueness of the laws related to service dogs in Canada has made travelling and working with my dog difficult.  I get comments that range from "you don't look disabled" (which I usually reply to with -thank you!
neither do you!) to "that dog doesn't look like he is doing anything and how can he help you if he is asleep (believe it or not, he does get to sleep when I stop to work somewhere, but will wake up and work if needed).

• Those are all legitimate concerns and I empathize with the problems you've had. That's why I think the "spirit" of the US's ADA is excellent. Protection needs to be in place for true service animals. Just as important is the need for education about what service animals are, what they do, and where they should be allowed to go. I also think this reader's concerns support my comments: We need to make sure that service animals are properly scrutinized. If people know that service animals are properly trained and regulated, they are less likely to have a problem with them. On the other hand, if people never know whether a service animal is really a service animal, then they may be less likely to give them the degree of respect and access they deserve.

I strongly feel that if you don't need a dog you won't take a dog with you; why would you? It is too much work!  For anyone who would like to take their pet with them to the grocery store, I would be delighted to take them with me to show them what travelling through the meat aisle is like; people stop and stare.  You have to plan your route so that the grocery clerk doesn't park their cart under my dog's nose (no...he won't touch it...but why make his day harder than it needs to be).  You need to be aware of the two year old who is covered in jam who wants to hug the doggy.    And you have to avoid hazards like the display of glass jars that tumbled and broke in front of my dog, surrounding him in glass shards with no way to safely walk out (stand stay! what a useful behaviour).

• Sorry, but I disagree. I think that if a grocery store advertised that it was pet friendly, there would be dogs in there all the time. Some people bring their pets everywhere, no matter how much extra work it is.
• Also, the grocery store example is a great one to highlight concerns. There are public health reasons why we don't want widespread animal access in grocery stores. Check out a previous post about a "service horse" walking through grocery store.
  

Life with a service dog is enriching for certain, but it is not something you want to do unless you need to.  I would advise anyone who is concerned about the illegitimate users to slow down, and think.  We are already protected.  If your dog is causing a problem, you can be asked to leave.

• In Canada you can. In the US you can't. That was the point of the article. In the US, you can't ask someone to make an animal leave except under very specific circumstances that a true service animal should never create. What we need is more protection in Canada and more clarity in the US.

Image source: http://www.assistancedogsofthewest.org

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There's been a lot of talk (hype) in the press about pet bites and MRSA (methicillin-resistant Staphylococcus aureus). This relates to a paper in Lancet Infectious Diseases regarding infections associated with pet bites. Some press articles are more sensational than others, but most are taking the bite infection paper and building in unrelated comments about MRSA in animals to make it seem like there's a major MRSA dog bite epidemic underway.

I realize that MRSA is a hot topic that is easy for reporters to latch onto, but the problem is that the actual research related to MRSA is being taken out of context (and blown out of proportion). MRSA was certainly mentioned in the paper, but it was not the focus of the research nor do the authors play up concerns about pets as a source of MRSA infections. Nevertheless, the impression people are getting from many news articles is that there is rampant MRSA transmission by infected pets.

Is MRSA infection a potential concern after a dog bite?

• Yes, but more because of the bite itself than the particular dog.  MRSA infections that occur after a dog bite are probably the result of contamination of the wound with MRSA from the person's own nose or from another person, for example during a visit to their physician/clinic/hospital. It's possible for MRSA to be in the mouth of the dog and for it to be transferred to the wound during the bite, but that's pretty unlikely. The person bitten or someone treating the wound is a more likely source of the bacterium. So, the bite was the ultimate "cause" of the MRSA infection, because the infection probably wouldn't have developed without that break to the body's normal defensive barriers (i.e. the skin), however the "source" of the infection was (in most cases) NOT the animal.  The same kind of infection could have happened with any similar type of trauma.

What should I do if I'm worried about MRSA and dog bites?

• Worry more about dog bites than MRSA. Bites themselves are major problems, even if MRSA is not involved. The degree of trauma can be significant, and a variety of bacteria can cause serious bite infections, not just MRSA.
• Take measures to reduce the risk of being bitten, both in terms of how you handle and train your dog and how you interact with other dogs.
• If you are bitten, immediately clean the wound as thoroughly as possible. If the bite is over a joint, tendon (e.g. wrist/ankle), prosthesis or genitals, if there is significant trauma or if you have a weakened immune system, you need to see a physician. If you have any other concerns, get examined by a physician promptly.

More information on MRSA in animals can be found on the Worms & Germs Resources page.

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Tuberculosis (TB) is an incredibly important disease caused by Mycobacterium tuberculosis. It's a huge problem internationally, and the problem is getting worse in many areas. Another cause of "tubercular" (or tuberculosis-like) disease is Mycobacterium bovis, a related microorganism whose main natural reservoir is cattle.

Mycobacterium bovis is cause of bovine TB. It can also infect people (usually through drinking or eating unpasteurized dairy products) and pets. Pets can be exposed by a few different routes, including eating contaminated dairy products, eating infected animals (e.g. snacking on carcasses of wildlife like deer that have died of the disease), and perhaps from direct exposure to wildlife carrying the organism. Mycobacterium bovis is an important problem in some areas, typically because of its presence in a wildlife reservoir like deer or the European badger (a major problem in the UK).

Mycobacterium bovis can cause serious disease in pets. It often causes non-specific signs that makes it hard to diagnose until disease is very advanced (and unfortunately likely beyond the point of successful treatment). Some groups recommend prompt euthanasia of infected pets without considering treatment because of the potential for infection of people. The risk of pet-human transmission is completely unclear, but it's such an important disease that some people think any risk is unnecessary and unjustifiable. So, the key is avoiding infection in the first place (for both people and pets). This is of particular concern in regions where M. bovis is present in wildlife and cattle. In areas where it is not known to be present, there should be little to worry about.

Here are some simple steps that can help you reduce the risk of your pet becoming exposed to M. bovis:

• Keep cats indoors.
• Don't allow dogs to roam free outdoors.
• Don't allow animals to have access to unpasteurized dairy products or dead animals.

Pretty basic, isn't it?

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At the same time that the country is drafting an animal welfare law that would ban widespread killing of dogs, a Chinese city has killed 36 000 stray and pet dogs in an effort to eliminate rabies. Since late May 2009, more than 6 000 people in Hanzhong have been bitten or scratched (presumably by dogs), and 12 have died of rabies. Certainly, this indicates multiple problems. One is the massive number of bites and scratches. Contributing factors probably include a large stray animal population, limited routine animal control efforts, and inadequate education of the public regarding bite avoidance. The number of injuries and deaths certainly indicates that an aggressive response is needed. However, there is little evidence that culls (i.e. mass killings of this type) have any effect on controling rabies and animal-associated injuries. Efforts are probably better directed at other forms of population control, vaccination of stray and pet dogs, and education of the public to keep stray dogs away and reduce the risk of bites. These types programs cost money, but the costs of treating 6 000 bites and 12 fatal rabies infections can be enormous. I don't know how many people received post-exposure treatment for rabies, or what such treatment costs in China, but it's estimated to cost  about $1500 per person in North America. That would pay for a lot of rabies vaccine for dogs.

Photo: Hanzhong, China (source: www.panoramio.com)

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There is apparently a thriving black market for baby red-eared slider turtles in Baltimore. The sale  (and possession) of small turtles is illegal in Maryland, like many other regions, largely because of public health concerns regarding Salmonella.

Over 100 hatchling turtles have been seized in the past 2 weeks. Baby turtles offer a good profit margin for black market vendors. They can be purchased from farms in the southern US for about $1 each and then resold for many times that amount. One person was caught selling turtles out of the back of a van. (Why anyone would buy anything from someone selling out of the back of a van is beyond me!)

People buy turtles thinking they make cute pets, not realizing what they need to do to keep them healthy as they grow. Turtles that are fortunate enough to be raised properly create another problem, since most people are not willing or able to take care of adult turtles that reach 10-12 inches in length. This can result in turtles being killed or abandoned.

Another major problem in the risk of Salmonella. Turtles very commonly carry this potentially harmful bacterium, and they are an important source of infection in people. The concerns are greatest with young children who may handle small turtles and put them in their mouths. People need to think before they buy. Before getting any pet, learn about the animal, including requirements for care and human health risks (and also if it's legal). A little common sense goes a long way.

More information about Salmonella and turtles can be found on the Worms & Germs Resources page.

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I recently wrote about a Dutch study of zoonotic parasites in pet feces and pets' haircoats. As part of that study, they asked pet owners about certain behaviours in their pets, and got some interesting answers.

60% of pets visit the bedroom (I'm surprised that's not higher), with 45% of dogs and 62% of cats allowed on the bed, and 18% of dogs and 30% of cats allowed to sleep in the bed with the owner.  While the UK's Chief Vet has warned against allowing pets into bedrooms and allowing them to sleep in people's beds, I don't have the same concerns - as long as common sense prevails.

45% of cats are "allowed" to jump on the kitchen sink. I don't know if they truly mean allowed, or whether the cats simply do this. I certainly don't "allow" my cat to be on the kitchen counter, but it's certain possible he is when I'm not looking. There are some potential concerns about pets hanging around food handling areas, so it's best to actively discourage this behaviour.

55% of owners clean their litterbox more often than twice a week. While daily cleaning is important for high risk people and high risk households, and is ideal for everyone, less frequent cleaning like this is acceptable for most people as long as it's done properly (See our Resources page for details about litterboxes).

15% of dog owners and 8% of cat owners reported always washing their hands after contact with their animals. This is surprisingly high - I wonder if it's really true, or whether some of those do it regularly but not always, or some think they should do it but don't really. Certainly, regular handwashing is important and it's ideal to do it after every animal contact, but that's admittedly hard to do in a household. I try to have good hand hygiene practices but I certainly don't always wash my hands everytime I should. Handwashing after every animal contact is more important for high risk people such as people with weakened immune systems.

39% of dog owners never clean up their dogs' feces. WHAT??!!  That's surprisingly high. When you consider how densely populated the Netherlands is, and that there are around 1.8 million dogs in the country, that's a lot of dog poop. That could be one reason why they found that dogs that were allowed off the leash outside were much more likely to have Toxocara eggs on their coat.

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Giardia is a protozoal parasite that can cause diarrhea in multiple animal species. This microscopic parasite is a zoonotic pathogen that can be transmitted between animals and humans, and there are conerns about the role of pets in human disease.  Various studies have evaluated the presence of Giardia in healthy dogs and, to a lesser degree, cats. Typically these studies report that  about 7% of healthy dogs are shedding Giardia in their stool, but all Giardia are not the same in terms of the risk of transmission from dogs to humans. There are various types of Giardia, and some only infect specific animal species and not people. In dogs, assemblages (types) C and D are most commonly reported. These are considered canine-specific types and are therefore not a concern for transmission to humans. Assemblage A is an important zoonotic type which can infect dogs and humans, and this type can certainly be found in healthy dogs, but it seems to be relatively uncommon.

Emerging information about Giardia typing and zoonotic disease risks shows that this is a more complex issue than previously thought. Studies that determine the prevalence of Giardia shedding in dogs and cats are useful, but they only tell part of the story. Comments about the human health implications of Giardia shedding in pets can only be made when information about the Giardia assemblages found in these animals is also reported.

More information about Giardia can be found on the Worms & Germs Resources page.