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

Israel has experienced a major upswing in canine rabies cases since 2009. There had been a significant decline since 2003, when oral rabies vaccination of foxes was started, but the recent increase has been in dogs and jackals, not foxes. Now, stray jackals and dogs are the main rabies vectors in northeastern Israel, the area affected by the current outbreak.

Stray dogs are a significant concern in terms of rabies because they can have close contact with humans and wildlife. Dogs are the most common source of human rabies internationally and thousands of people die each year from rabies acquired from dogs.

The increase in rabies in stray dogs and jackals has lead to discussions about how to control the stray population and reduce the risk of rabies. Previously, it was common for authorities to shoot strays in parks and nature reserves. This practice was stopped a while ago, however the Israel Nature and Parks Authority has now asked for permission to shoot strays in the interest of rabies control. The proposed regulations would allow strays to be shot in national parks, reserves, and "any other open area where wildlife species are considered at risk", but not unless their presence poses "an immediate discernible risk to wildlife and never within 1 km of human habitation."

This seems to be a wildlife protection program disguised as a rabies control program. The emphasis is on protection of wildlife, since packs of stray dogs have had major impacts on some endangered wildlife (e.g. fallow deer). It's not really a good rabies control program, since culling alone is unlikely to be effective, and only culling when the dogs pose a risk to wildlife and away from human habitation presumably would only have a limited impact on the prevention of human rabies. If they want to control the dog population to protect endangered species, they should just say that. If they want to control rabies, they need a comprehensive rabies control program that involves consideration of various approaches such as vaccination of strays and jackals, sterilization of strays, public education to decrease the risk of exposure, and vaccination of domestic animals. A cull alone won't cut it for rabies control.

Photo: A pair of Golden Jackals (Canis aureus) in Israel (photo credit: Michael Baranovsky)(click for source)

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A field worker from Mexico died in Louisiana this weekend from rabies. This is the first case of human rabies in Louisiana in over 60 years, but based on the time the man had been in the country and the incubation period of rabies, it is believed that he was infected in Mexico. Human-to-human transmission of rabies is rare, but healthcare workers and other people he had recent contact with are being evaluated to determine if post-exposure treatment is required.  In the case of the man's co-workers, they could have also been exposed to the same source of rabies that infected him.

The original source of infection isn't known, or at least has not been reported. Wildlife are the main source of rabies exposure for people in the US, but dogs are the most common source of human infection internationally. Dog-associated rabies cases in people from Mexico have been previously reported in the US, and it's certainly possible here.

(click image for source)

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A few UK news outlets published a story the other day about a toddler with a severe eye infection that was attributed to Toxocara canis, the canine roundworm. Some parts of it didn't make a lot of sense so I held off commenting, but the story's spreading more widely now so I might as well raise a few issues.

The story is about a toddler that fell into a pile of dog feces while playing at the park, then wiped her eye. Her mother took her right home and washed the eye out. Then, according to the BBC:

"She woke up in the early hours screaming and her eye was bright purple and red and swollen shut with the eyelashes inside. She had a temperature and was very lethargic and in a lot of pain." Hospital tests confirmed toxocariasis, which resulted in Amiee contracting optical lobe cellulosis, which can lead to blindness and death if not treated within 72 hours.

Here's where I start to get confused. Eye infections are one problem cause by Toxocara canis. However, the disease (ocular larva migrans) develops when someone ingests infectious T. canis larvae from feces. It takes a few days to a few weeks after being passed in feces before the larvae become infective, so this would have to have been a pile of old feces (something that's certainly possible).

Nonetheless, as I said, ocular larva migrans develops when someone ingests the larvae, which then migrate out of the intestinal tract, journey through the body and end up in the eye. This doesn't happen in a few hours, as is described here. It takes much longer. Even if infective T. canis larvae were injected in the eye, you wouldn't see the type of severe inflammation around the eye that is shown in the picture on the BBC website. Fever is also rarely present with ocular larva migrans. The parasite gradually causes inflammation within the eye, not around it.

The girl is being treated with 3 antibiotics and an eye ointment. Again, this makes no sense for toxocariasis, since it's a parasitic infection within the eye. Antibiotics aren't going to be useful.

The rapidity of onset, the involvement of tissues around the eye, the presence of a fever and the reported treatment suggest to me that this is actually a bacterial infection of the eye and surrounding tissues, something that certainly could be related to the multitude of bacteria present in dog feces.

Regardless of the cause, the notion that dog owners need to be responsible and clean up after their dogs remains. Let's hope the physicians know what's going on and are treating Amiee properly.

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"NDM-1 superbugs" have received a lot of press the last day or two. That's lead to questions about whether there may be any risks for pets.

It's good to see that people are thinking about how this might affect other animal species. That's a thought process that would have been rare a few years ago, and which was probably fostered by the emergence of MRSA in animals.

What it NDM-1?

• NDM-1 stands for New Delhi metallo-beta-lactamase 1. It is a type of beta-lactamase, an enzyme that inactivates certain antibiotics (those of the beta-lactam class). The concern with NDM-1 is that it inactivates carbapenem antibiotics, an important class of drugs that is often used to treat serious and life-threatening infections.

Where is it a problem?

• It's currently mainly a problem in India and Pakistan.

Will is spread to other regions?

• Probably. It's easy for people to travel around the world quickly, and it's easy for new microorganisms to travel with them. A bug that originates in one region can very easily spread across the planet. NDM-1 has been found in a few other countries, including Australia, parts of Europe and Canada. There is concern that the increase in health tourism (traveling to countries like India for cheap and quick procedures like elective surgeries) will result in spread of NDM-1, since people could pick up the bug in hospitals and bring them home. Transmission of NDM-1 in hospitals from patients that had healthcare procedures abroad has been documented in the UK. People traveling to regions where the organism is present for other reasons are also possible sources.

Can it affect pets?

• Probably. Two important types of bacteria, E. coli and Klebsiella spp, can carry NDM-1 (and probably other related bacteria can as well). These can cause infections in many different species. As more people carry bacteria with NDM-1, there's a greater chance that pets will be exposed, as we've clearly seen with MRSA. Dogs that visit human hospitals and pets owned by people who visit India for healthcare are probably at greatest risk, with pets of people who have been hospitalized and pets of healthcare workers likely also at increased risk.

What can we do to reduce the risks?

• Nothing specific. The most important factor here is control of NDM-1 in human hospitals. At the animal level, there's nothing in particular we can do about NDM-1 at the moment. The keys are prudent use of antibiotics (to reduce the likelihood that resistant strains will get established in pets), good general infection control in households and veterinary hospitals (to reduce opportunistic infections by bacteria that can carry NDM-1), and making sure that cultures are taken when infections are present (to find out if/when this becomes a problem).

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The recent run of Salmonella recalls in dry foods, raw foods and supplements has resulted in a lot of questions about when animals should be tested for Salmonella. In general, testing is only indicated in animals that have disease suggestive of salmonellosis. Diarrhea is the main issue, but other problems such as fever, decreased appetite and bloodstream infections can also occur. Clearly, any animal with signs such as these needs to be tested for Salmonella. However, there is no indication to test healthy dogs and cats that have been exposed to recalled products.

Why is that? An important concept in medicine is that you should always have a plan about what to do with the results of diagnostic tests - the result should have an impact on what you do. When you think about what would happen with a negative versus a positive test for Salmonella in a healthy pet, it shows why testing is not useful.

What would I tell you about a negative result?

• I'd say it means the animal is probably negative, but it could be a false negative because of intermittent shedding of Salmonella in stool or a false negative test result.
• I'd also say that even if there was no Salmonella, every animal is shedding multiple potentially harmful pathogens in its stool.
• So, I'd emphasize that if the animal became sick, Salmonella still needs to be considered and that good hygiene measures should be used around the animal (particularly its stool).

What would I say about a positive result?

• I'd say that means the animal was shedding Salmonella at the time the sample was collected, but that doesn't tell us if the animal is still shedding or how long it will do so.
• There's no indication to treat the animal. There is no evidence that treatment of dogs and cats that are shedding Salmonella is needed. There's also no evidence that it's effective. In fact, there are concerns that giving antibiotics could prolong shedding of Salmonella and that it could increase antibiotic resistance.
• Salmonella is certainly a public health concern, but there's not much specific to be done.
• So, I'd emphasize that if the animal became sick, that Salmonella still needs to be considered and that good hygiene measures should be used around the animal (particularly its stool).

Since my recommendations for a positive result and a negative result from a healthy animal would be the same, why test?

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What happens when you combine a festering toe wound, a doctor-averse person, a dog and a lot of alcohol. Well, I guess you get Jerry Douthett and his dog Kiko, a Jack Russel who is being called a "lifesaver" for gnawing off Jerry's infected toe.

Apparently Mr. Douthett had what he believed was a small sliver in his toe a few months earlier. He picked away at it for a while, later using a knife to trim away infected tissue. The toe became so inflamed that he couldn't wear shoes. Eventually, he decided to numb the pain and his fear of doctors with a large volume of alcohol. After having 4-5 beers at a local restaurant, he downed two giant margaritas, then passed out after his wife drove him home. His wife explained "Jerry had had all these Margaritas, so I just let him sleep, but then I heard these screams coming from the bedroom, and he was yelling, 'My toe's gone, my toe's gone!'" 

Indeed it was, or at least most of it. "The toe was gone," he said. "[Kiko] ate it. I mean, he must have eaten it, because we couldn't find it anywhere else in the house. I look down, there's blood all over, and my toe is gone."

After the Jack Russel relieved Jerry of most of his big toe, Jerry ended up finally going to the hospital. Doctors confirmed that the rest of the toe needed amputation and the infection (which had reached the bone) was probably the result Type II diabetes.They removed the rest of the toe and treated the infection.

Jerry's not upset with his dog. Rather, he's grateful that Kiko's snacking made him go the the doctor, which led to him finally being diagnosed with diabetes which can now be properly managed. The dog is under a 10-day quarantine for rabies observation, as would happen with any dog bite.

People with diabetes are at high risk for various types of infections. I've heard of diabetics with serious foot infections that developed because their pets were licking foot wounds or chewing on their toes. Diabetics can have decreased nerve sensation and sometimes don't notice when their pet is doing damage by licking or chewing.

Diabetes is not a reason to avoid pets, but the increased risk of infection means that extra care needs to be taken to reduce the risk of infections caused by pets, particularly from pets licking wounds directly and from people indirectly spreading bacteria from a pet to a wound. Simple, logical preventative measures around pets and good attention to hygiene are important.

Not drinking yourself into a stupor also helps.

(click image for source)

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Peritoneal dialysis is used to treat some people with chronic kidney failure. Infection is a major concern, particularly peritonitis (infection of the lining of the abdomen) because peritoneal dialysis involves having an indwelling catheter that goes through the skin and body wall directly into the abdominal cavity.

Infections can occur from bacteria that inadvertently get flushed into the abdomen during dialysis treatment or potentially migrate along the side of the catheter. Accordingly, most infections associated with peritoneal dialysis are caused by bacteria that are found on peoples' skin, such as Staphylococcus aureus.

While the vast majority of peritoneal dialysis infections are human-associated, infections from pets have been reported. Multiple different pet species have been implicated, even hamsters - one case report described an infection in a child that was thought to be caused by a hamster that slept in the same bed as the child (Campos et al 2000).

A recent study in the journal Seminars in Dialysis (Broughton et al 2010) involved a review of the scientific literature for reports of pet-associated peritoneal dialysis infections, as well as a review of records from the authors' peritoneal dialysis unit.

In their review, they identified 124 reported infections caused by zoonotic microorganisms in the literature, involving 12 different microorganisms. The most common microorganisms were Campylobacter, Pasteurella, Zygomycetes, Neisseria, Rhodococcus, Listeria, Mycobacterium avium complex, Capnocytophaga spp, Salmonella, Brucella and Bordetella bronchiseptica. However, only a subset of these were probably associated with pet contact, and retrospectively determining the sources is quite difficult for some. For example, Campylobacter and Salmonella could as easily (or more easily) come from contact with raw meat as from pets. Infections were fatal in 13.5% of cases, demonstrating why this is an important issue.

The most common bacterium causing convincing pet-associated infections was Pasteurella, which can be found in the mouths (and other places) of healthy pets. It is a common cause of pet bite infections and it makes sense that Pasteurella could contaminate pet owners' hands or the dialysis catheter site. In the study of their own hospital's cases, the authors found similar findings, with a low rate of zoonotic infections and a predominance of Pasteurella among those.

Literature reviews aren't a great way of determining the true scope of a problem, because they require people to:

1. identify the infection
2. identify a pet as a possible source (often the weak link; furthermore, identifying an infection caused by a potentially zoonotic microorganism doesn't necessarily mean a pet was the source)
3. decide to write a case report
4. get that case report accepted by a journal

Studying medical records has limitations as well, since steps 1 and 2 still need to be performed (with the weak link again being thinking about a pet-association). So, care should be taken when interpreting the results of this study. However, while the results indicate that pet-associated peritoneal dialysis infections do occur, they are probably relatively uncommon.

While pet-associated infections are likely uncommon, any peritoneal infection can be a major problem, so common sense measures that would likely reduce the risk should be used:

• Avoid contact of pets with the dialysis catheter and catheter site
• Wash hands after having any contact with pets
• Don't let pets sleep in the bed
• Wash hands before touching the catheter

Additionally,

• Physicians should be aware of the potential for pet-associated infections, and pet contact by their patients
• If a pet (usually a cat) bites the tubing, this should be reported to a physician ASAP and preventative treatment for infection might be indicated
• Initial antibiotic therapy choices should cover common pet-associated pathogens if there is a history of contact of pets with the catheter or tubing.

People with peritoneal dialysis catheters shouldn't fear their pets, and there is no need for these people to get rid of pets (although they should avoid high-risk pets like reptiles). Pet owners are presumably at somewhat higher risk than non-pet-owners, but the risk appears to be fairly low. In most situations, the positive aspects of pet ownership probably outweigh the risks.

Image: Schematic diagram of peritoneal dialysis (click image for source)

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Methicillin-resistant S. aureus (MRSA) and methicillin-resistant S. pseudintermedius (MRSP) get a lot of media attention because of the ever increasing numbers of infections in dogs and cats, and concerns about transmission to people. However, there are many other methicllin-resistant staph of varying relevances. One is an interesting related bug called Staphylococcus schleiferi.

There are actually two types of S. schleiferi:

• S. schleiferi schleiferi: This is a coagulase-negative subspecies that occasionally causes skin and ear infections in dogs (and uncommonly cats). It can also be found in healthy animals. There are a few reports of infections in people, mainly surgical site and wound infections in individuals who are at high risk of infection because of hospitalization, surgery or other factors.
• S. schleiferi coagulans: This is a coagulase-positive subspecies that may be more common in dogs and cats than S. schleiferi schleiferi, causing skin and ear infections and also being found in healthy animals. Human infections are very rare.

Currently, there is little to no evidence the animals are a source of human infection with S. schleferi and human infections appear to be very uncommon. However, this is an area that hasn't been studied much so it's hard to say with any confidence that there is no risk. My assumption is that the risk is very low, but not zero, so while we shouldn't be paranoid, it makes sense to use some very basic infection control practices when dealing with infected animals to reduce any possible risk. These would include:

• avoiding contact with infected sites
• if contact with infected sites is necessary (e.g. cleaning or treating infected ears), gloves should be worn and hands washed after glove removal
• hands should be washed thoroughly after any contact with the infected site, and regularly after contact with the animal

Quarantine of infected animals in households isn't necessary, because of the limited evidence of transmission and because healthy dogs and cats can also carry this bacterium. In veterinary clinics, isolation of infected animals is reasonable because other animals in the clinic may be at higher risk of developing infections should they become exposed.

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ProMed has a new list of recent rabies incidents. The whole report can be seen by clicking here, but these are some examples of common or important issues they touch on:

- Roaming pets + wildlife = bad news: One person's dogs killed a raccoon while out for their "romp around the yard." The raccoon was rabid. There's no mention about the vaccination status of the dogs. If they were vaccinated, they probably got a rabies booster and are under a 45-day "house arrest" for observation. If not, they either need to be placed under a strict 6-month quarantine at a separate facility, or they'll be euthanized. Another report describes a different dog that is now under a 6-month quarantine after attacking a raccoon. In yet another report, a North Carolina woman's dog was euthanized because it killed a rabid fox and was unvaccinated (the owner chose euthanasia over quarantine).  That dog is now dead mainly because the owner didn't take the simple and relatively inexpensive step of ensuring that her dog was vaccinated.

- Pissed-off wildlife bite. Sometimes they're rabid too. Get too close at your own peril: A South Carolina man is undergoing post-exposure treatment because he was bitten by a raccoon while removing it from a trap. I'm glad that he had the animal tested. It's pretty easy to see someone in a situation like this just yelling at the raccoon and letting it go, thinking they were bitten because the raccoon was upset and not realizing that they might have been exposed to rabies.

- Some people just don't get it: In response to rabies exposure of close to 50 church members from a rabid bat while on a mission trip, the mission leader stated "It's just part of being in rural America, so there's really not a lot to talk about." Ugh. Rabies exposure should not be written off as some benign, unavoidable rural American experience. It's exposure to an almost invariably fatal disease that requires a series of expensive treatments. It's also not a rural thing. Rabies exposures can occur commonly in urban areas as well.

- Stray kittens can be cute but deadly: A rabid cat and kitten were identified in Ocean City, Maryland, and authorities are looking for people that may have come into contact with them. Human exposure to rabies from handling cute but infected kittens is not uncommon, and sometimes involves a lot of people. If you see a stray kitten, it's best to leave it alone. If you feel the need to rescue it, make sure that you get it to a vet for an exam, and that it subsequently goes somewhere where it can be properly observed and taken care of. If you're bitten in the process, make sure the kitten is quarantined for 10 days to see if it's rabid, or euthanized and tested. The worse case scenario is when people play with stray kittens, get nipped in the process, dismiss it as a minor or playful bite, then release the kitten back into the wild, never knowing whether they might have been exposed to rabies.

(click image for source)

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The internet can be a strange place at times. You can find great, reputable and unbiased information right next to complete garbage. Often, the garbage is pretty apparent, but sometimes it's dressed up well or mixed in with some good information. That's a problem with veterinary advice and information sites.

Among the creative myths identified in a couple of minutes of searching:

- Metronidazole is a proven treatment for parvovirus: No. Metronidazole is an antibiotic that doesn't have any effect on viruses. Antibiotics are sometimes used in the treatment of parvovirus, but they are drugs that are used to prevent or treat problems caused by bacteria from the gut entering the bloodstream as a result of the intestinal tract disease. Metronidazole won't do that.

- MRSA is a virus: You can't make much more of a basic mistake than confusing a virus and a bacterium. Anyone who says this when purportedly writing medical advice is completely clueless.

- If your dog gets an MRSA infection, your veterinarian will likely prescribe vancomycin: Only in extreme circumstances (if ever) should this ever happen. For more information on vancomycin and its use in treating animal and human infections, see our archives. (This gem is on a page that says it's information from infectious disease specialists).

-MRSA in dogs can easily become resistant to vancomycin so linezolid may be required: Fortunately, vancomycin resistance is extremely rare, having been found only a few times in people, in specific circumstances. It's never been found in a dog. Hopefully it will stay that way. (This site didn't even spell vancomycin correctly.)

- Cats can easily get a urinary tract infection if their litterboxes are not cleaned: No. There is no evidence of this and no reason to think it's an issue. Poor litterbox maintenance can lead to urinating outside of the litterbox or other problems like idiopathic cystitis, but not infection.

- In order to have a very healthy dog, it is often required to supplement your pet's diet to provide a high amount of probiotics: Nope. Certain probiotics might be useful in certain animals in certain situations, but we have no proof of this in dogs and cats, and they are certainly not needed for all animals.

There's no way to guarantee that a website is reputable or that the writers are knowledgeable, but here are some things I consider when scrutinizing information on the internet:

• Who set up the website? Is it clear who's in charge?
• Who wrote the information? Is it someone with actual credentials? For veterinary medical advice, is it a veterinarian? If it's a veterinarian, is it a specialist? If it's not a veterinarian, what expertise does the person have? Some people without veterinary degrees have expertise in some fields, but try to determine whether they truly have the qualifications to give advice on a particular topic. That's harder to do these days given the proliferation of mail-order "PhD" degrees, something that's not uncommonly encountered in unqualified people making poor veterinary recommendations. 
• Why is the website there? Is it an educational site or is it there to make money? Commercial sites aren't necessarily bad but you have to consider any conflicts of interest or ulterior motives. If there is an article about something, and the last sentence tries to sell you a product to fix that problem, be careful.
• Does the information make sense and is it consistent with other websites? You can probably find a site somewhere to support any notion that you have, but does it really make sense?
• Is the site relevant to your geographical area? This is particularly important for infectious diseases since they can vary greatly between regions. A disease may be a big problem in one area, and a website might provide excellent advice... but only for that area. It may be completely irrelevant or inappropriate for other regions.
• Can they spell? The odd typo probably isn't a major issue (I do it myself). However, rampant and blatant abuse of the English language and an inability to spell important words properly should be red flag.

Searching the internet for pet health information is certainly not a bad thing to do. But, you have to critically assess what you read and remember that it's not always right. Use the internet as a resource but make sure that it's to supplement advice from your veterinarian, not to replace it.

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Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is becoming a huge problem in dogs (and to a lesser degree cats). I think it can easily be called an epidemic, and probably even a pandemic, considering the degree of spread, the massive increase in cases and the international distribution of this multidrug-resistant bacterium.

Public health concerns regarding MRSP have received attention because of the huge problem with MRSA (methicillin-resistant Staphylococcus aureus) in people. My line with S. pseudintermedius in general is that while there are only periodic reports of infections in people, exposure to this bacterium is very common, since it is carried by a large percentage of healthy dogs. Given the frequent exposure and very small number of infections, it’s not a particularly pathogenic bacterium for people. The same should apply for MRSP, since methicillin resistance doesn’t’ make it inherently any more able to cause disease, it just makes it harder to treat. However, I always add the statement that, while the risk is pretty low, I’d rather not have an infection with a highly drug resistant bacterium, so we need to pay attention and try to reduce the risk of transmission.

A paper in an upcoming edition of the Journal of Antimicrobial Chemotherapy (Stegmann et al 2010) shows that these concerns are not unfounded. This report, from Switzerland, described an MRSP infection in a person that developed after sinus surgery. The bacterial strain that was involved was sequence type 71 (ST71), the predominant strain found in dogs in Europe. The affected person had a dog with various health problems, but unfortunately the dog was euthanized (presumably not because of the person’s infection) before samples could be taken to see if it carried the same strain. Since we know that S. pseudintermedius can move between pets and their owners (although usually without causing any problems), it's reasonable to assume that the dog was the source of infection here.

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

(click image for source)

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Attacks on guides dogs... not by guide dogs.

The June 19th edition of Veterinary Record (Brooks et al 2010) contains a study that investigated the incidence and impact of 100 dog attacks on guide dogs in the UK. Here are some highlights:

• 61% of attacks occurred while the guide dog was harnessed and working with an owner or trainer.
• Labrador Retrievers and Golden Retriever/Flat-Coated Retriever crossbreeds were more commonly attacked than other guide dog breeds. This was disproportionate to the percentage of guide dogs that were these breeds, so it wasn't just a factor of more Labs being guide dogs so there were more to be attacked. I'm not sure why these breeds would be attacked more often.
• Most (97%) attacks occurred in public places: 26% occurred in town centres and shopping areas, and 23% occurred in public parks or exercise areas.
• 43% of attacks were considered unprovoked.
• Most (61%) of attacking dogs were off-leash and with their owners. The surprising thing to me is that 23% of attacking dogs were leashed and with their owners. 15% were roaming free.
• 38% of attacking dogs were bull breeds, which is much greater than the percentage of the general dog population that is made up of bull breeds (5.9%).
• 41% of attacked guide dogs required veterinary care.
• In 19% of attacks, a person was also injured.
• After 45% of attacks, the working performance and behaviour of the attacked (guide) dog changed. Over half of these were reported to be fearful, nervous and wary, or to display a lack of confidence. Two dogs had to stop working as guide dogs.
• The attacking dog's owner was charged in 31% of incidents.

It is clear that attacks on guide dogs can result in major problems. These include injury to the dog, injury to the handler, impacts on the performance of the dog as a guide and impacts on the emotional status of the owner. Dog bites are too common and bites from incidents like these, which occur in public places, are largely preventable with responsible ownership. Unfortunately, there are too many irresponsible dog owners out there. The threat of more serious financial penalties may be the only way to change some peoples' behaviour.

(click image for source)

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It's not like we needed any evidence that rabies is still an active, deadly disease, but a recent ProMed-mail posting contains 16 different rabies notices. They include:

• An animal control worker who was bitten by a rabid, stray cat that was trapped by a person in Texas.
• Rabies exposure in an unvaccinated dog in Maryland, that resulted in euthanasia of the dog  because the owners didn't want to undertake the required 6 month quarantine for exposed, unvaccinated dogs. The dog was exposed to rabies virus while killing a raccoon.
• Diagnosis of rabies in two trapped raccoons in New Jersey.
• Rabies exposure in an Arizona woman who was attacked by a rabid fox while in her yard.
• More marauding (presumably rabid) foxes attacking people and dogs in Maine and South Carolina.
• Rabid bats and skunks in Colorado.
• A rabid fox in Alabama.
• Rabid raccoons in Virginia.
• A rabid raccoon attacking a vaccinated dog.
• Rabies exposure in people bitten or scratched by rabid stray kittens in New Jersey, Nebraska and Georgia.

Common themes or take home messages:

• Rabies is here (in most areas, at least) and it's unfortunately not going away any time soon. We can reduce the number of affected animals and decrease the risk of exposure of people and domestic animals, however, with good prevention strategies.
• Vaccination of pets is a cheap and effective way of protecting them, and anyone they are in contact with.
• Keep pets away from wildlife.
• If you are bitten by a wild animal, you must consider it a potential rabies exposure unless the animal can be proven not to have rabies.
• If you see an animal that is acting strangely, stay away and call animal control.

(click image to enlarge and for source)

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In 2005, "Paro," an interactive robotic pet, was introduced in Japan. It looks like a baby seal, and has 12 tactile sensors in its fur, touch-sensitive whiskers and a system of motors that silently move its parts. While this "pet" didn't really catch on in Japan, it's made its way to the US and ended up in some nursing homes.

Paro has been described as a low-maintenance alternative to dogs and cats for pet therapy. It's an intriguing idea. There are certainly some appealing aspects, in that a robotic pet won't bite or scratch, doesn't poop, doesn't need to be fed, can't be injured, doesn't have a large population of resident bacteria in and on its body and can't become infected with various microorganisms from patients. Those are appealing from an infection control standpoint. However, despite this, you can't approach Paro as a way to eliminate infectious disease risks, since the robo-pet could easily become contaminated by someone, then spread  infection from person-to-person. For example, if someone has a bacterium on their hands and they touch the robot, they could transfer the bacterium to its "coat." It could then spread the bacterium to the next person that touches it. Infectious disease risks would be lower, but not zero.

Pet therapy is all about cost-benefit. We know there will never be a zero-risk pet-human interaction. However, socializing with an animal can provide significant benefits to many people, and I'm not convinced that the same degree of benefit would be provided from interaction with a robotic critter. There might be some situations where a robotic pet would be useful in a nursing home or similar environment, but I don't think they're going to replace interaction with a live animal.

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I often write about service dogs, and I'm often fairly critical. It's not that I dislike them - on the contrary, they're incredibly important to people who need them. However, when people do stupid things with service dogs, it can ultimately hurt the people who actually depend on these animals.

I was at the grocery store today and the first thing I saw when I walked in was a woman walking around with a dog in her shopping cart (i.e. the place the next person's food is going to sit). The dog was a poodle puppy wearing the standard "guide dog in training" vest, and the woman thought nothing about walking through the store pushing this dog around. When I asked her about it she said that the dog was just a puppy and it wasn't good to have it walking around on the floor (with no explanation why). She did take the dog out of the cart, but then proceeded to walk around the store carrying the dog in her arms. The site of her holding the dog while pawing (pun intended) the fresh fruits and vegetables raised eyebrows among more than just myself. Eventually, she put the dog down, which mainly resulted in her dragging the dog around as it tried to lay down or walk the other way (which may explain why she wanted it in the cart).

Service dogs are allowed into stores. They have wide access and that's needed. Service animals in training, however, are not service animals and they do not have the same absolute right to access. Training needs to be logical and supervised. Getting these dogs out in different environments is very important. However, how does pushing a dog around a store in a shopping cart help train it to be a service dog? I'm pretty sure part of the dog's ultimate job description doesn't include this particular activity. Being carried around a store while shopping is also not likely to be part of this dog's job. If a dog is not adequately trained to walk around a store on a leash, it shouldn't be there. A little common sense would indicate that basic training in another environment should precede activities such as this. 

Fostering a guide dog is a good thing to do, but it comes with a lot of responsibility. I'm certain this person was well-intentioned, although I'd certainly consider her actions misguided. The "guide dog in training" vest should not be interpreted as a free pass to take the dog wherever you want without any thought. Training such a dog is an important job, and people need to think about what they are doing.

I'd be interested in hearing from anyone that is involved in these programs. I was unable to find any information about guidelines for people fostering service dog puppies, and would love to know what type of guidance people get, and what organizers of these programs think of this incident.

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People like to talk about the "one medicine" concept. It's a great concept, but my big issue with it is there's a lot of talk but not a lot of action.

One way of thinking about "one medicine" in terms of people and pets is to focus on the health of the entire household as a whole, because:

• People can transmit infections to pets.
• Pets can transmit infections to people.
• People and pets can be infected from the same source.
• Infection in a pet or person may indicate that others in the household are also at risk.

It's a complex dynamic. When I speak about this topic, I use a couple of different ways to make the point. One is the concept that we are not a population of people living with dogs, cats, horses etc. - we are a population of animals. Similarly, I sometimes say "pets are people too, at least microbiologically." What I'm saying is that we can't focus just on humans or just on pets. The household as a whole needs to be considered, and care of the health of the all of its members - human and animal - needs to considered together.

What does that really mean?

Physicians need to be aware of the presence of pets in the household and other animal contacts. This information might be important when considering certain diseases. For example, if someone comes to their physician with flu-like symptoms and their physician knows they have pet birds (especially psittacines), then the physician would hopefully consider psittacosis. This disease is caused by Chlamydophila psittaci, a bacterium that can be carried by healthy birds. Not realizing there is a bird in the household can lead to a missed diagnosis.

Veterinarians need to be aware of the health status of people in the household. People with close contact with the human healthcare system and people with compromised immune systems are more likely to be carrying certain infectious agents. They are also more likely to pass these pathogens on to their pets. Therefore, knowing the health status of the owner might lead the veterinarian to consider different diseases in the pet, thereby improving diagnosis. Conversely, people with compromised immune systems are at increased risk for various infectious diseases from pets. If the veterinarian knows a pet owner is at increased risk, they can provide better advice about disease prevention measures to protect the owner. Veterinarians rarely ask owners about their immune status, including pregnancy (even the "how far along are you?" question is dangerous, because eventually you're going to get the "I'm not pregnant!" response.) Ideally, people should have a positive, comfortable relationship with their veterinarian, realize that their veterinarian is a member of their (and their family's) overall healthcare team, and therefore tell their veterinarian about any relevant health issues. For this to work, they need to understand the value of this communication, trust their veterinarian and know that their personal details will be kept confidential. At the same time, the veterinarian needs to understand the issues and need for such information, and have a plan on how to use it.

Veterinarians and physicians need to communicate better. They need to know who to contact when necessary and be able to do it efficiently. This is also relevant for non-infectious disease issues. For example, there could be a situation where a veterinarian has had to euthanize a pet: the veterinarian may realize that the owner is quite distraught, but can't do much beyond offering condolences and providing contact information for resources to help them out. The physician may not know anything about the situation, but it could be of significant relevance to the person's health. If nothing else, the physician could be notified that there's a potential concern. There are privacy issues that need to be considered and sorted out, but a little conversation can go a long way. The ability of veterinarians and physicians to contact each other about relevant issues can help prevent problems with miscommunication, provide general information about certain topics and help provide optimal patient care.

One medicine needs to be one medicine in action, not just in theory.

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I was giving a talk on infection control at a conference in Geneva a couple of days ago, and during a discussion with someone after the talk, I told them to "Live every day like you have MRSA." Not surprisingly, I got a bit of a strange look in response. I wasn't trying to say, "live your life to the fullest because you never know what will happen." Rather, I was trying to get the point across that healthcare workers in both the veterinary and human systems need to realize that at any point in time they could be carrying MRSA, along with various other harmful microorganisms.

People in patient care positions need to make the assumption that they are always a potential source of disease, and act accordingly while doing their jobs. If someone knew they were a carrier of a bug like MRSA, they'd likely do a better job with routine infection control practices such as handwashing. But, you rarely know whether you're carrying MRSA or not, and it's better to go on the assumption that you are and be diligent with your infection control measures.

The same basic concept applies to different situations, such as how people in the general population behave, and how they interact with other people and animals. In some ways, everyone should assume that they are carrying an infectious disease like influenza, and that every person or animal they encounter is carrying something infectious. (In reality, this is actually true, since everyone is carrying something potentially infectious in or on their body at any given time, it's just that most of the time it's not particularly serious or transmissible organisms).

There's a line between prudence and paranoia, and we don't want to create a population of germophobes who won't leave the house. However, we want to increase awareness so people do a better job of things like washing their hands and covering their mouths properly when coughing or sneezing. Assuming that you and everyone around you is mildly biohazardous maybe a way to do just that.

(click image for source)

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Recently, I was speaking with a physician who mentioned that a colleague has recommended that people with raccoons in their yard get rid of their dogs because of the risk of Baylisascaris procyonis. This parasite, also known as the raccoon roundworm, can cause severe neurological disease in people that ingest infective parasite eggs from the environment.

The most severe type of disease caused by the migrating larvae of this roundworm (neural larval migrans) is very nasty, and usually causes death or serious, severe neurological deficits.  However,  the recommendation to get rid of dogs when there are raccoons around makes no sense. Here's why:

• The main host for Baylisascaris is the raccoon. A large percentage of healthy raccoons (over 90% in some areas) are infected and pass large numbers of parasite eggs in their stool.  Exposure to eggs from raccoon feces is the main source of human infection.
• Human infections are very rare. They predominantly occur in people that are at increased risk of ingesting feces or dirt, based on their age or behaviour.
• Dogs can be infected with Baylisascaris, but this is rare.
• The small number of dogs that are shedding Baylisascaris in their feces do not pose an immediate risk to people. Eggs that are passed in feces are not immediately infective. Eggs must mature in the environment (which usually  takes 2-4 weeks) before they are able to cause infections.
• There are no clearly documented cases of dogs being a source of human infection.
• The main risk from dogs is probably the potential for dogs to carry old (i.e. infectious) Baylisascaris eggs into houses on their haircoats, after roaming around raccoon infested areas.
  

How do you reduce the already very low risk associated with Baylisascaris and dogs?

• Discourage raccoons from living near your house. Raccoons defecate in certain areas or "latrines," where the soil becomes heavily contaminated with raccoon feces, and where tremendous numbers of infectious eggs can be present.  If you make your yard uninviting to raccoons, then they won't establish a latrine near your house.
• Carefully clean any raccoon latrines that might be on your property.
• Don't let you dog have contact with raccoon latrines.
• If your dog has had contact with a raccoon latrine, give it a bath. Baylisascaris eggs are sticky and can stick to the dog's coat quite well, so a thorough bath is much better than a quick rinse or brush. Wear gloves and some form of protective outwear (e.g. a coat that you take off after and promptly launder) while bathing the dog. Wash your hands thoroughly when done.
• Closely supervise people at increased risk of ingesting feces or dirt (e.g. young children) when they're outside.
• A routine deworming program will eliminate Baylisascaris in the intestinal tract of a pet dog, in the unlikely event it's been infected.
• Prophylactic treatment of dogs that have eaten (or have a tendency to eat) raccoon feces could be considered, but the need and usefulness of this is not clear.

Bottom line: You don't need to get rid of your dog if there are raccoons in your yard.  The risk of Baylisascaris infection from your dog is extremely low, and the steps above can help you decrease the risk even further.  Getting rid of the raccoons (instead of the dog) will be much more effective.

More information about Baylisascaris and neural larval migrans is available in our archives.

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When multiple studies report the same results, it gets more and more convincing that the findings are true. This is becoming the case with antibiotic use as a risk factor for methicillin-resistant Staphylococcus aureus (MRSA) infections in dogs. Late last year, I wrote about a study of ours that identified prior antibiotic use as a risk factor in dogs for infections caused by MRSA versus those caused by methicillin-susceptible S. aureus. Recently, a similar study was published, with some similar results. This study (Magalhaes et al, Vet Res, 2010) compared dogs and cats and with MRSA infections to a group of dogs and cats with susceptible infections. They found that MRSA infections were associated with:

• the number of antimicrobial courses
• the number of days admitted to veterinary clinics
• having had surgical implants

Additionally, animals with MRSA infections more often had had contact with people that had been in hospital, but the difference was not statistically significant.

That's two studies that identified antibiotic use as a risk factor for MRSA infection. It makes sense biologically, and it's likely that antibiotic use is an important driving force for MRSA infection in pets (like it is in people).

How do we reduce the likelihood of MRSA infections? It's pretty clear that reducing antibiotic use is a key factor. Antibiotics are important drugs and are certainly needed in many situations, but they're also prone to overuse and misuse. Here are some things that can (and need to) be done:

• Only use antibiotics when necessary. Antibiotics are often used without evidence of a bacterial infection and in situations where bacterial infections are uncommon (e.g. urinary tract disease in cats, viral upper respiratory tract infections).
• Use logical and prudent peri-operative antibiotic regimens. Only use antibiotics for surgeries when there are actually needed, and only for as short a period of time as possible.
• Ensure that proper doses are given (and actually get into the animal). Unfortunately, underdosing (and overdosing) of antibiotics are not uncommon.
• Promote more research regarding effective antibiotic treatment regimens. We often use much longer courses of antibiotics in pets compared to people, in part because we have no research data telliing us whether we can use shorter treatment courses.

Another thing to consider is the fact that these studies looked at factors for methicillin-resistant versus methicillin-susceptible infections. Therefore, a dog had to have an infection to be included. While certain things are risk factors for MRSA versus susceptible infections, there are other factors that increase the chance of any infection, and reducing these will also help reduce the risk of MRSA (and other) infections (i.e. if your dog doesn't get an infection in the first place, it won't have an MRSA infection).  One very important factor is proper management of underlying skin diseases, such as controlling atopy, flea allergy dermatitis and food allergy. Proper wound care, good veterinary clinic infection control practices and myriad other factors probably also affect the risk of infection in general. Further, good general preventive medicine practices, including overall healthcare and proper nutrition, play a role by decreasing the pet's susceptibility to infections.

Fighting antimicrobial resistance isn't easy or clear cut. There is unlikely a single measures that will turn out to be the "magic bullet." To limit the impact of resistant bacteria, we need to take a multifaceted approach, and we need a lot more information to figure out what specific measures should be emphasized.

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Delta Society has recently announced a policy prohibiting animals fed raw meat or raw animal products from participating in their Pet Partners program. This policy was established because of research indicating dogs fed raw meat are much more likely to be shedding harmful bacteria like Salmonella and drug resistant E. coli in their feces compared to dogs fed commercial or home cooked diets, and the fact that these dogs come into close and frequent contact with people that are more susceptible to infections and at increased risk having severe infections.

Not surprisingly, internet chat sites are abuzz, and there's much condemnation and consternation from some. Some of the more vocal minority are stating that they'll just lie and say that they're not feeding raw.  I guess such dishonest actions would be based on a combination of ignorance and arrogance - feeding raw is your own decision, but blatantly flouting a policy that was put in place to reduce risks to those most susceptible is stupid and irresponsible.

One of the problems with peoples' reactions is the fact that they are confusing two separate issues. One debate is whether raw feeding is more healthy or more harmful to the pet. That's a controversial area, but this policy has nothing to do with that. This policy deals with the increased likelihood that raw-fed pets are shedding harmful bacteria. That's been very well proven in scientific studies. Do raw-fed pets cause disease in people in hospitals? We don't know. However, we have enough evidence to indicate there is the potential for increased risk to patients, and that added risk can be eliminated by not feeding raw meat products.

Hopefully, people will realize that this policy has been put in place for a good reason, and that it's focused on protection of people at high risk of serious illness. It's not a broad condemnation of raw diets, it's just a statement that it is not considered appropriate for dogs that will have contact with high risk populations - a recommendation that's far from new.

Details about this policy can be found here.

Disclosure: I'm a member of Delta Society's Medical Advisory Board. However, the opinions expressed here are mine and do not necessarily reflect the views of Delta Society.

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The recent ringworm outbreak in a Newmarket, Ontario shelter has focused a lot of attention on shelter outbreaks, outbreak prevention and management. A common question that I've been getting in the last couple of days is "Why do these outbreaks occur?"

There are many reasons why an outbreak can develop. I have no first-hand knowledge of the Newmarket outbreak, and don't know what prompted that outbreak, but here are some general causes of outbreaks.

Inadequate protocols:

• Shelters need clear and logical protocols for all things dealing with animal care. This needs to include aspects like where new animals go, what types of evaluation and monitoring are performed, vaccination and deworming plans, when animals need to be tested or treated, when they can be released from quarantine, how to record and report infectious diseases, how to clean and disinfect areas and items, personal hygiene, and protective clothing, among other things. These protocols need to be in writing and accessible to all personnel.

Inadequate training:

• Shelters often have large numbers of staff, many with minimal training in animal husbandry or medicine. Proper training is required to ensure that they know what to do and why. (The latter is important because if people know why they need to do something, they are more likely to do it.) Training programs need to be well-structured and formal, not casual, follow-someone-around-and-see-what-they-do training.

Inadequate supervision:

• Even with good protocols and training, the facility managers need to ensure that protocols are followed. They need to enforce protocols and address problems with compliance. They need to make sure their protocols are up-to-date and consistent with best practices.They need to monitor disease rates and concerning trends of illnesses, so that problems can be identified early. They need to know when to get advice and who to ask (see below).

Infrastructure challenges:

• Some facilities (or actually, most facilities) are not well designed in terms of infection control. That makes it harder to prevent disease transmission and contain problems. Limitations in isolation/quarantine areas may result in mixing of new (and more likely infectious) animals with those ready for adoption. Few sinks may reduce handwashing, a key component of infection control. A facility that is too small for the animal load results in cramming in too many animals.

Poor awareness:

• If staff (from management on down) don't understand the issues, they may not act appropriately. Proper routine preventive measures and outbreak response measures may not be convenient, easy or cheap. There must be motivation to implement them. If there is little awareness of the problem, people are less likely to do what is needed.

Failure to act appropriately when the first cases are identified:

• It is much easier to contain a problem when you act early. If only a few animals have been infected or exposed, it's much easier to take aggressive measures. Once you get a large number of infected or exposed animals, it's much harder to do things like properly separate different groups (e.g. infected vs potentially infected vs non-infected). The more animals affected, the greater the chance of further transmission. Keeping your head in the sand and hoping things will go away can result in a small containable outbreak becoming a facility-wide,  difficult-or-impossible-to-contain outbreak.

Failure to get good advice:

• People working in shelters can't be expected to be experts in all aspects of infectious diseases and infection control. That's why getting good advice (and following it) is critical. Sometimes, people don't ask for advice or don't go to the real experts. This can happen because they don't really understand the problem, don't know who to contact, don't want to admit they don't know everything or don't realize they are in over their heads. A little good advice, especially early, can make a world of difference.

Bad luck:

• Ultimately, you can have an exceptionally run facility and still get an outbreak. By the nature of what shelters do, they bring in a lot of animals with potentially infectious diseases and have many animals that are at higher risk of getting sick if they get exposed. It's much less likely to occur with a good infection control program, but you can never 100% guarantee nothing bad will happen. You can't do much about this. All you can do is make the best program possible, and try to limit any problems that develop.

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I'm not sure what to think about the recent increase in scientific papers about Staphylococcus pseudintermedius infections in people. This dog-associated bacterium has been well known for quite a while, and human infections have been sporadically reported, but it seems like there has been a big increase in reported cases over the past year.

The latest case, published in the Journal of Clinical Microbiology (Chuang et al 2010) describes a bloodstream infection in a 6-year-old boy. The infection was associated with an intravenous catheter site. The bacterium was initially misidentified as Staphylococcus aureus, a related bacterium that is more commonly found in people. It seems that the patient's history of having contact with dogs led to further testing of the bacterium. That's pretty surprising (and encouraging) from a few standpoints:

• The attending physicians asked about pet contact. That's not always done.
• The physicians recognized the potential for dog-human transmission of bacteria and considered the possibility that there was a misidentification by the lab. I'm quite surprised that they did further testing, since S. aureus is so common.

Unfortunately (as is commonly the case), they didn't take the investigation any further. It would have been nice for them to have tested the patient's dogs to see if they carried the same strain of S. pseudintermedius, to provide more evidence that the infection was truly from the dogs.

Concern has been raised before regarding the potential that S. pseudintermedius infections might be misdiagnosed as S. aureus, such that we don't know the true extent of the problems caused by the dog-associated bacterium. The ability of medical diagnostic labs to differentiate these two bacteria is something that needs to be investigated to help determine whether there may be more going on than we realize.

The increase in reports of S. pseudintermedius infections in the literature could also just be because infections that have always been occurring at a low level are being properly diagnosed, and people are bothering to write them up. The fact that people are still finding single cases of this infection noteworthy suggests that it's still a very uncommon condition. When you consider that the majority of dogs are carrying this bacterium, and millions upon millions of people have close contact with dogs on a regular basis, it's clear that people get exposed to this bacterium very often. The fact that infections appear to be so rare indicates that the risks to humans is likely quite low.

It's also possible that there truly has been an increase in these infections. It's hard to think of a reason why that might be the case. There's no evidence that the types of S. pseudintermedius have changed such that current strains are better able to infect people than older strains. Most likely, this is still a rare infection in humans that is often associated with dogs, but is of pretty low risk for the average dog owner. Regardless, continued study in the area is required, to make sure that this is not an emerging problem, especially when you consider that multidrug-resistant forms of this bacterium are also becoming much more common in veterinary medicine. Increased physician awareness about pet contact and zoonotic diseases is required to properly diagnose this and other potentially zoonotic diseases.

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In 2007, there was a massive equine influenza outbreak in Australia. A large number of horses were infected in this country that was previously equine influenza-free, and there was tremendous economic disruption caused by containment measures. It turns out horses weren't the only animals infected. A report in the April edition of Emerging Infectious Diseases describes influenza infections in dogs associated with the equine outbreak.

In some ways, it's not too surprising. Canine influenza in North America is caused by H3N8 influenza that moved from horses to dogs. Similarly, H3N8 influenza of equine origin has been identified in dogs in the UK. So, while it's an uncommon event, we know that in some situations, the "standard" equine H3N8 influenza virus can infect dogs.

The first dog that was diagnosed lived near a large horse stable. The dog developed typical signs of influenza: decreased appetite, lethargy, nasal discharge and cough. After the first dog was identified, other dogs were noted to have similar signs, including dogs whose owners had contact with infected horses and dogs that had contact with other sick dogs. Some dogs had severe infections. Influenza was diagnosed through detection of antibodies in their blood, and the influenza virus was isolated from one dog. The virus that was isolated was the same as the one present in horses (and different from that in US dogs).

For influenza to jump between species a few things have to happen.

• First, the virus has to be able to infect the other (non-natural) species. This can happen because the virus is inherently able to infect different species or because of a random viral mutation that allows for infection of the new species.
• Second, the virus must encounter that host (in this case, dogs). It must then be able to multiply within the new host.

All this can happen with or without development of disease. For the virus to truly establish itself in the new species and spread (like canine flu did in the US):

• The virus must be able to multiply well in the new host, and adequate virus levels must be produced for the new host to be a source of infection to other individuals.
• The new host must come into contact with other susceptible individuals.
• The virus must be able to infect new hosts readily enough to maintain infection in the population, instead of dying out after a couple transmission cycles.

In these Australian cases, while it is apparent that equine flu was able to infect dogs, there was no clear evidence that perpetual dog-to-dog transmission occurred. Influenza virus was rarely detected in nasal secretions from infected dogs, making it unlikely that the virus would spread between dogs.  Therefore, the virus was not able to establish itself in the dog population. This means it ended up being only an interesting situation that affected a limited number of animals, instead of the creation of a new, self-propagating infection that could continue to circulate in dogs in the country.

(Click image for source.)

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A large percentage of advice calls that I get about methicillin-resistant staph infections in dogs are regarding skin infections. Skin infections (pyoderma) are a common problem, a leading cause of antibiotic use in dogs, and an often frustrating problem for vets and pet owners alike. One problem is that, unlike many other types of infections, skin infections are often recurrent. This frequently leads to an ongoing cycle of infection-treatment-resolution-infection-treatment-resolution... The net result is some dogs get treated very regularly and for long periods of time with antibiotics, and it's not particularly surprising that highly drug-resistant bacteria like MRSA or MRSP eventually become involved.

Normal, healthy, intact skin is an excellent barrier to bacterial infection. Various bacteria normally live on the skin but do not usually cause infection. Skin infections typically (if not always) develop in response to some underlying skin disease, such as flea allergy dermatitis, food allergy, atopy, Cushing's disease or hypothyroidism. Identifying and treating a skin infection is one thing. Identifying and treating the reason for the infection is another, and that is arguably the most critical component. Ignoring the underlying cause may not be the end of the world for a single infection, because proper treatment and a susceptible bacterium can result in a successful outcome, but ultimately ignoring the real problem can lead to a difficult-to-treat, resistant infections.

Any diagnosis of pyoderma should be accompanied by consideration of the underlying cause. If a cause is apparent, this should be treated (if possible). If a cause is not readily apparent, it should be investigated. By investigated, I mean a real search for the problem, not a cursory examination, half-hearted feeding trial and little more. There is almost certainly an underlying cause and, at the end of the day, time, effort and money are better spent on trying to identify the root issue rather than just throwing round after round of antibiotics at the dog. In some cases, the cause (while it's probably there) can't be identified, but it's definitely worth trying anyway.

If your dog has been diagnosed with a skin infection, ask why it happened. If there is not a clear answer, talk to your veterinarian about the best plan to identify the cause. If at all possible, follow through with the plan. It may include certain diagnostic tests (which cost money) or dietary restriction (which  takes effort), but it should be thought of as an investment in your pet's health, as well as a potential way to keep multidrug-resistant bacteria (some of which can infect people) out of the house, to save future treatment costs, and to keep your pet much more comfortable.

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A couple of recent news reports highlight potential issues surrounding good Samaritins helping injured animals:

• A person that tried to help a cat that had been hit by a car was bitten. It turned out the cat had rabies, so the person would have required post-exposure treatment.
• A veterinarian was struck by another vehicle and killed while trying to help a neighbour's dog that had been hit by a car.

These two incidents highlight some of the problems that can occur when people try to help injured animals. Wanting to help an injured animal is an instinctive behaviour for many people. I know, I'm the same way - but you have to look after yourself as well.  No matter how much you want to help the animal, you have to make sure you don't put yourself at risk of injury or infection.

The key point is to think before you act.

• Can you actually do anything useful? Are you better off calling animal control or someone else? In most situations, you may be better off getting other help. If you don't actually know how to help the animal, having contact with it just puts you at risk. Injured or frightened animals are more likely to bite. If you are bitten or otherwise exposed to the animal, you need to be concerned about rabies or other infectious diseases.
• Can you do something safely? Despite your best intentions, if the animal is in the middle of a busy highway or in a situation where traffic can't see you (e.g. dark, bad weather, blind corner), don't put yourself at risk. You may think that you can be careful but odds are reasonable once you get to the animal, you are going to focus on it, not traffic.
• Is the animal even alive? This may take a little effort to determine.
• How is the animal acting? Does it look aggressive or fearful? These things might lead to an increased risk of biting. Is it acting normally? The hard part is assessing injured animals. An animal might be acting abnormally because it's injured. It's also possible, however, that it's acting strange because it has rabies.  It may have been hit by a car because it has rabies, or it may not have been hit at all and just looks like it's been injured because it has severe neurological disease.

If you are bitten by an injured animal, you need to make sure rabies is considered. If the animal survives, it needs to be observed for 10 days to make sure it doesn't develop signs of rabies. If it dies, it needs to be tested. Once you've made the commitment to get involved, you need to follow through.

I'm not trying to dissuade anyone from helping out. You just need to understand what you can do to help and what risks might be present. In most situations, you're probably better off trying to get proper help and trying to prevent the animal from being injured again. Calling animal control, sending someone to a nearby house to identify the owner and trying to make sure other drivers don't hit the animal again may be the best you can do, for the animal and for you.

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Warm spells in early spring, like the recent warm spell in our area, inevitably lead to (premature) thoughts of summer, and for many people, this includes thoughts of spending time in the swimming pool. I've previously written about the presumably low risk of disease transmission from dogs swimming in pools, and common sense measures that can be taken to reduce any risks. Since more and more people and dogs are carrying resistant bacteria like MRSA, there are increasing questions about the potential for pools to be a source of transmission. A recent paper in the journal Clinical Pediatrics (Gregg & LaCroix, 2010) sheds some light on the issue.

In this study, the researchers obtained different types of swimming pool water (chlorinated water, saltwater, and biguanide (Baquacil) nonchlorinated water) from local pools. No MRSA was identified in any of the samples. They then inoculated the water samples with MRSA. They used a lot of MRSA - roughly similar to the amount that would be released from an MRSA abscess (and much, much greater than the amount that would be released from someone who was just an MRSA carrier). MRSA numbers were greatly diminished after 30 minutes and no MRSA was detected after 1 hour.

This study suggests that pools are likely not a significant source of MRSA exposure. Even with high-level contamination, MRSA died quickly. Presumably, there would be little MRSA shed by a person that was only a carrier, and when you consider the dilutional effect of a small amount of MRSA in a large volume of water, plus the bactericidal effects of treated water, the risks should be extremely low. Common sense would dictate that someone with an MRSA infection shouldn't go in the water because they could shed large numbers of bacteria, but this study suggests that the risks are probably minimal and short-term even then.

Bottom line: Don't worry about pools in terms of MRSA. Pools are a greater risk for certain causes of gastrointestinal disease like norovirus and Cryptosporidium. If you or your dog has an infectious disease, stay out of pools. If not, and you are otherwise healthy, then don't worry. There's always some risk of exposure to infectious disease, but it's very low. Life is full of risks and swimming in a pool is not a big one (at least from an infectious disease standpoint.  If you can't swim, that's a different story!).

Image from: http://blog.timesunion.com

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A large rabies outbreak continues in Moscow.  There were 257 rabies cases reported in the area in 2009 - ten times the number from previous years, and well above the very low numbers that occurred for a decade of so after an aggressive control program to control the post-World War II rabies epidemic. Control of that outbreak mainly involved shooting of potential rabies vectors: stray dogs, foxes and raccoon dogs. 

Various more humane but still aggressive control measures are being considered to help control the current epidemic, including banning movement of pets to suburban cottages (probably better to just vaccinate the pets first), canceling a dog show (pretty low yield - better to vaccinate), and mass immunization of wild and domestic animals (the key approach).

An aggressive approach makes sense. Rabies is almost invariably fatal and large numbers of people who are exposed require post-exposure treatment every year.  Local wildlife population patterns, wildlife rabies hotbeds and rates, pet numbers, pet movement and vaccination must all be considered when determining the best approach to control. Apparently, about 30 000 pet dogs visit cottages in the Moscow area each weekend, and there's concern that they could bring rabies back to the city with them. Authorities have warned about traffic jams that might develop, presumably from police stopping traffic looking for contraband canines. However, instead of banning dog movement, it would likely be more effective to increase vaccination (or even mandate it for dogs in those high risk regions) and control roaming dogs. If a dog doesn't roam freely in the country, it's less likely to encounter a rabid animal. If it's vaccinated, it's unlikely to get infected if it does get exposed. If it's not allowed to roam when it returns to the city, it's less likely to spread rabies to other animals and people in the very rare event that it was exposed and infected. Furthermore, if wildlife are vaccinated through rabies bait drops, the chances that a roaming dog will be exposed get even lower.

Ensuring the highest possible canine vaccination rates is the key measure. Whether that's through mandating vaccination, providing it at low cost, or making it more convenient for owners to get it done, it's a great place to focus efforts and resources. In principle, it's a simple concept. In practice, it can be more difficult, especially when compliance of the general public is required.

For those of you that want to practice your Russian reading skills, here's the original story.

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PetProductNews.com reports that Nature's Variety, a raw pet food company, has unveiled results of a recent "research study" on their products. Whenever you see "research," especially on the web, you need to consider whether it's really valid scientific information or a marketing ploy. This particular case certainly doesn't seem like anything approaching real research.

Apparently the study, commissioned by Nature's Variety, involved the feeding of six adult dogs variations of different diets over a 4.5 month period. They looked at stool quality, volume and odor, blood chemistry, quality of their skin and coat and body weight.

• In research, we worry about sample size. You need to have enough animals to detect any real differences. With 6 dogs, 4.5 months of feeding and different diets, you don't have much of a chance to detect a problem (or a benefit, usually). You could have a diet that kills 10% of the dogs that eat it every year and not detect it in study of that size!
• The number of dogs and time don't even fulfill AAFCO feeding trial requirements, so this doesn't provide any information that would be accepted using standard requirements.

Nature's Variety director of research stated “It’s kind of a sigh of relief.”

• It's pretty concerning that the head of research would be relieved that there were no obvious health problems in such a small study. If they don't have real confidence in the quality of the food, why are they selling it? If you have confidence in your diet, you say "Of course, as expected, our diet was shown to be nutritious and safe..." not "Wow, we're really happy no dogs died!" Research to indicate safety and nutritional value should be done before you sell, not well after.

Duclos said she expects the study to be published in a peer-reviewed journal in about one year.

• Not likely. For one thing, from what they are releasing, it's very weak and not defensible scientifically. For another, they've already released the results. It's inappropriate for people to release results before they've undergone peer review, and releasing data in a press release will probably prevent any reasonable journal from even considering the study.

It's good that Nature's Variety is trying to do some research. It's also good that they're addressing Salmonella contamination following their recent recall. The fact that they are doing something progressive is an encouraging sign. However, they need to do proper research, and make sure it undergoes appropriate scrutiny, instead of using small and relatively useless studies to generate press releases.

Raw feeding has inherent risks of exposure for people and pets to potentially harmful bacteria like Salmonella. Raw feeding can probably be done safely for both the pet and people in some, but not all, situations. More information about raw meat feeding can be found on the Worms & Germs Resources page. 

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This is a question I get a few times a week. Because methicillin-resistant Staphylococcus pseudintermedius (MRSP) infections are becoming so common and people are aware of potential concerns regarding transmission of methicillin-resistant Staphylococcus aureus (MRSA) from pets to people, it's a logical concern.

Here's my basic thought process when answering this common question:

• Staphylococcus pseudintermedius is very common on the skin and in the nose of healthy dogs. A large percentage of dogs are carrying this bacterium on any given day, and you can never tell who's a carrier by looking at them. Therefore, a large number of people are exposed to this bacterium on any given day.
• Staphylococcus pseudintermedius is a common cause of infection in dogs, particularly skin infections.
• Staphylococcus pseudintermedius can be found in the nasal passages of a small but appreciable percentage of healthy people, most likely acquired from their dogs.
• Despite the frequent exposure, S. pseudintermedius infections in people are extremely rare.

So, the risk of getting a S. pseudintermedius infection from a pet is quite low. What about the methicillin-resistant version of this bug?

• MRSP and the susceptible version differ by the presence of antibiotic resistance, and not necessarily anything else. Methicillin-resistance does not, to our knowledge, increase the virulence of this bacterium or make it more transmissible.
• If transmission of S. pseudintermedius from pets to humans is very rare, and methicillin-resistance doesn't increase the risk of transmission, there should be no greater likelihood of someone getting MRSP from a dog compared to susceptible S. pseudintermedius.

So in the end there's not too much to be concerned about. Yes, there is a reasonable chance that MRSP can be passed between people and pets, but that's different than getting sick. Transmission of MRSP from healthy and sick pets to owners probably occurs on a regular basis, but since MRSP is not a normal bacterial inhabitant of people and it is not well adapted to cause disease in humans, not much happens.

But the disclaimer I always put in is "rarely doesn't mean never." The risks are very low, but they are not zero. While the odds of me picking up MRSP from a dog are very low, I'd rather not have an infection with a highly drug-resistant bacterium. Accordingly, the use of proper hygiene and infection control measures, particularly around an animal with an active infection, is always important. These measures include:

• Frequent handwashing after contact with the pet.
• Avoiding contact with the infected site.
• Keeping the infected site covered with an impermeable dressing, whenever possible.
• Reducing contact with the nose of the infected animal, since it may also be carrying the bacterium there. In general, reducing close contact (e.g. snuggling, nuzzling, hugging, kissing) during the period of infection is a good idea.
• Regular washing (in hot water with hot air drying, whenever possible) of pet beds and other items that come into close and frequent contact with the pet.

Is all that overkill? Probably. But it's also an easy and practical plan, and a reasonable approach to reduce the already-low risks.

More information about MRSP is available on the Worms & Germs Resources page.

(Photo credit: John Haslam)

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

They mentioned that one of the composters they highlighted (NatureMill) can apparently handle pet waste, but composting animal feces is not a good idea. Pet waste (feces +/- cat litter etc.) can contain a wide range of potentially harmful parasites and bacteria. The composting process can generate enough heat to kill these 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, and (maybe more importantly) compost usually ends up in gardens where the bad bugs can contaminate the soil, as well as anything grown in the garden.

One concerning microbe is the protozoal parasite Toxoplasma gondii. Cats are the natural reservoir of Toxoplasma and can pass it in their feces (usually only for a short period), but most people that become infected by Toxoplasma are likely exposed to the oocysts ("eggs") outside in gardens, or from contact with contaminated foods (e.g. unwashed vegetables). (Undercooked meat can also be a source of infection, but that's another story).  Composting may not kill this parasite, so when pet-waste compost is put into flower gardens or vegetable gardens in which people work, the risk of exposure to Toxoplasma may be increased. The risk of transmission from an individual cat is admittedly low, since only a very small percentage of cats are shedding the parasite at any one time (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 afterward, of course).

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 a bit differently: pay careful attention to hand hygiene after handling the compost, and make sure the compost isn't used in gardens or other areas where people might have contact with the soil.

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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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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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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.

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We've seen reasonably good evidence of the potential involvement of pets in the transmission of methicillin-resistant Staphylococcus aureus (MRSA) for a few years, and a study recently published in the Journal of Hospital Infection (Loeffler et al 2010) sheds a little more light on the subject.

In this UK study, they tested 608 veterinary staff and pet owners in contact with pets that were carrying MRSA or methicillin-susceptible S. aureus (MSSA). MRSA carriage was identified in 12.3% of veterinarians that treated MRSA-infected animals and in 7.5% of their owners (although the chicken vs egg conundrum comes up, i.e. are vets that treated MRSA -infected pets more likely to have MRSA because they got it from the pet or because they already had MRSA and infected their patient?). These numbers are relatively consistent with a small number of other studies that have looked at these groups, and are higher than the expected carriage rates in the general population. This is highlighted by the results from people that had contact with animals only carrying methicillin-susceptible S. aureus, since MRSA was only identified in 4.8% of veterinary staff and 0% of owners in this group. Veterinary personnel were significantly more likely to carry MRSA than pet owners. As expected, virtually all MRSA from people and pets in the study were the predominant strains present in human hospitals in the UK.

We shouldn't fear MRSA or our pets, but we should respect the potential for infection and act accordingly. Mainly, this involves basic practices like:

• Good hygiene: washing hands regularly after handling pets
• Avoiding contact with infected body sites in pets, and preventing pets from having contact with infected body sites in people
• Prudent antibiotic use in both veterinary and human medicine
• Proper and timely diagnostic testing to identify MRSA infections, to permit proper treatment and earlier implementation of appropriate infection control practices.

Ultimately, MRSA in pets is a human-borne disease. Most pets that have MRSA presumably acquire it from a close human contact, so efforts at controlling MRSA in pets need to be directed at both the pet and human aspects. Uncontrolled MRSA in people will lead to increased risk for pets, and for pets to be a source of subsequent human infection.

Image: Seven-month-old British Shorthair (photo credit: Tamila Aspen)

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When we have a -30C windchill and snow on the ground, my first thoughts usually aren't about survival of bacteria in the outdoor environment. However, some microorganisms are well adapted for survival in various adverse conditions and we shouldn't assume that cold=dead for every bug of concern. Along that line, we received a question recently about survival of Leptospira and I passed it along to our lepto expert, Dr. John Prescott. Here's his guest post:

A reader in Ohio owns a dog that had leptospirosis, and had some questions about leptospirosis that may be of general interest.

Q1. Since the yard is likely contaminated with leptospires, she asked “How cold does the temperature have to get before the Lepto organisms are killed?”

A1. Once it’s frozen, as it is now in January, they’re dead. Leptospires are fragile bacteria that are killed by dry heat and by freezing. They survive well in moist or wet environments, with moderate temperatures. In some countries leptospirosis is called “mud fever” or “fall fever” since this description captures so well the environmental conditions under which they thrive.

Although leptospirosis in dogs can occur at any time in the year, it mainly causes disease in the fall, late September to December, peaking in November. The increasingly mild and prolonged falls that we have experienced in the last decade are thought to be an important reason that leptospirosis has resurged in dogs. Interestingly, there is often a “blip” of leptospirosis in dogs in March in Ontario (and likely Ohio), since this is when the snow melts and conditions are wet, even though we can still get freezing at that time. I suspect that this is also the time when the raccoons that are thought to be the main source of leptospirosis for dogs are again active after the winter, and are foraging for food for themselves and their babies.

Q2. Do dogs still shed leptospires after they’ve been treated?

A2. No. Leptospires are quickly killed by the antibiotics used in treatment, amoxicillin or doxycycline. There is no danger that dogs treated for a week with these drugs are a risk to people or other animals. You may read in otherwise very reputable textbooks that these antibiotics “do not eliminate the carrier state” but I have no idea where this misunderstanding comes from.

Q3. Where can I find out more about leptospirosis in dogs?

A3. I like the web site http://www.leptoinfo.com, which is maintained by a vaccine company. I was surprised how many web sites devoted to leptospirosis that there are, but like much on the internet some contain highly misleading information. The “Worms & Germs” site has good past blogs about canine leptospirosis and is usually (just kidding, Scott) a reliable source of information.

One very common entrenched misconception, which is very hard to kill, is that vaccination does not stop animals shedding the organism. This is quite wrong. I suspect this misconception came from an experimental study half a century ago when dogs with pre-existing kidney infection with a leptospiral serovar called Canicola were vaccinated. It would not be expected by anyone that these animals would stop shedding since antibodies don’t penetrate into the place in the kidney where the leptospires live and from which they are shed in the urine. What vaccination does incredibly effectively is to prevent leptospires from actually reaching the kidney and setting up home there. The leptospires are removed by antibodies in the blood, so they never reach the kidney.

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A recent study just published in the journal Emerging Infectious Diseases evaluated risk factors for dogs having an infection with methicillin-resistant Staphylococcus aureus (MRSA) versus methicillin-susceptible S. aureus (MSSA). This study, headed by Dr. Meredith Faires, compared dogs with MRSA versus MSSA infections from three different veterinary referral hospitals in Canada and the US. Among the more important findings were the following:

• Staying in a veterinary hospital was not a risk factor for MRSA infection, reinforcing the notion that this is predominantly a community-associated disease in dogs (meaning it typically develops in dogs in the general population).
• Most infections, in both the MRSA and MSSA groups, were skin infections. While serious deeper infections can and do occur, skin and ear infections are very common.
• Prior treatment with antibiotics was associated with development of MRSA versus MSSA infections. Dogs that received any antibiotic within 90 days were approximately 3.8 times as likely to have MRSA versus MSSA infection. Dogs treated with drugs from the fluoroquinolone class of antibiotics were 4.6 times as likely to have MRSA versus MSSA infection.

The association between prior antibiotic use and development of a resistant (i.e. MRSA) infection is not surprising, but it is important to document these events and to be aware of them. Antibiotics are critically important drugs in veterinary and human medicine. They save countless lives, but are also overused and misused frequently, and resistance is a critical problem. Studies such as this demonstrate the need for prudent antibiotic use - use them when needed, but use them properly.  Don't use them when a bacterial infection is not present or unlikely to occur.

The study can be downloaded by clicking here. More information about MRSA in available on the Worms & Germs Resources page.

Image source: http://animalphotos.info/a/

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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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A large number of rabies cases in Santa Cruz County, Arizona has lead to the rare practice of implementing a county-wide rabies quarantine. Fifty-four cases of rabies have been diagnosed so far this year, mainly in skunks. That's about twice as many as normal.

Quarantine is probably not the best description of what they are doing, but they are taking measures to improve vaccination of pets, reduce roaming pets and discourage human-wildlife interaction.

For the next 60 days, the following rules are in place:

• Dogs and cats must be vaccinated against rabies.
• Dogs must be confined to the property or on a leash.
• People are not allowed to feed wild animals.
• Pet food must not be left outdoors after sundown.

Those are all pretty standard measures that should be used anytime. It sounds like these rules already exist in Santa Cruz County but their "quarantine" means that they will be aggressive in enforcing them. Increasing enforcement is a good idea, but ongoing efforts after this quarantine period are also needed because rabies will continue to be a risk in that area.

Image source: www.acmeanimalremoval.com

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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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InsideToronto.com published an article entitled "Unsuspecting resident contracts Lyme disease from pet dog". However, Lyme disease cannot be transmitted from dogs to people.

Lyme disease is a tickborne disease caused by the bacterium Borrellia burgdorferi. This bacterium is transmitted from wildlife reservoirs to people and pets by ticks that have fed on an infected animal, and then latch onto a person or pet.

The article reports that a woman and her son from Scarborough, Ontario, were diagnosed with Lyme disease after there dog was infected. The owner frequently walked her dog in the Rouge Valley and Morningside Park. After finding a tick on her dog, the owner took the dog to the vet, and it was diagnosed with Lyme disease. She and her son were later diagnosed. The fact that people and pets in the same house got the same disease does not mean that the dog was the source of infection. Lyme disease cannot be transmitted directly between people and animals; ticks must be involved. Additionally, ticks must be attached for approximately 24 hours to efficiently transfer the bacterium. So, if multiple people and a pet in the house got Lyme disease, they were all bitten by ticks, presumably while walking in the woods. (It's also possible that a tick could have been brought into the house by a dog, and then it jumped onto a person). Identification of Lyme disease in a dog does not mean that there is a risk to people from the infected dog, but it does indicate that people may have been exposed in the same manner as the dog, and they should pay attention.

The dog owner in this case is upset that her veterinarian did not warn her about Lyme disease. She wants the College of Veterinarians of Ontario (the provincial licensing body for veterinarians) to "require members to tell people when they may have been exposed to Lyme disease through a pet, as well as what the symptoms are." That's reasonable, to a point. Veterinarians should engage their clients with discussions about zoonotic diseases. If they identify a pet with a zoonotic infection, they should talk about the implications. Similarly, if they identify a pet with an infection to which the owner may have also been exposed (such as Lyme disease), they should mention the risk. However, requiring vets to talk about signs of disease in people starts to cross the line between veterinary and human medicine. Vets should introduce the issue and let physicians take over from there.

People in the Toronto area should not panic based on this report. Lyme disease is quite rare in Ontario, especially in the Toronto area, as the ticks that transmit Lyme disease are not commonly found there.Toronto Public Health reports that an average of nine cases of Lyme disease a year have been diagnosed in people between 1998 and 2007, and that most of these cases were acquired in the US.

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.An article about a therapy dog demonstrates some good points of these programs and places to improve. The story is about "Taco", a Chihuahua involved in pet therapy at the Livingston Regional Hospital (Tennessee). The obvious benefit of the program is highlighted by the owner's comment "She creates smiles when there were none." There are definite social and emotional benefits of pet therapy. There are also some potential health benefits, although the research on that isn't the strongest. On the downside, there are disease transmission concerns. These can be greatly reduced through attention to some simple procedures, but this article describes a number of concerning yet common problems:

"(Taco) greets each patient (ones who are comfortable enough to have her in their lap) with kisses on the nose."

• Being allowed to lick patients has been shown to be a risk factor for visitation dogs acquiring MRSA. Being allowed to like the nose is about as good of a model of MRSA transmission as you can develop, because the nose is the number-one site where this important bacterium lives. This type of licking can also transmit various other infectious agents to this compromised hospital population. Licking is an unnecessary behaviour that should not be permitted because it can be associated with infectious agent transmission.  Not permitting licking does little to decrease the value of visitation.

"(Owner Gerry) Cotnoir has had Taco since she was 9 weeks old.  She worked at Bethesda [Health Care Center) in Cookeville then and brought Taco with her to work every day. "She got used to people at an early age,""

• Socialization of dogs is important, but a hospital is not the place to do this. Only dogs older than 1 (and ideally older than 2) years of age should be in hospitals. Young animals are more likely to bite or scratch; not necessarily from aggression but also from playful or excited behaviour. Young animals also have much higher rates of shedding of various infectious agents such as Campyobacter.
• People in hospitals should not be bringing pets to work. Animals that are in hospitals should be there for formal, structured, short-term, properly observed and properly scrutinized visitation activities. That's not the case when someone brings a pet to work. A hospital is not a doggie day-care, although some people use them as such, with the occasional visit of a patient to explain why they are there.

The hospital's infection control personnel have approved the use of Taco in the Livingston facility, but you have to wonder how much they investigated the issues. There are clear guidelines for hospital therapy programs which aren't being followed here. Hopefully other important aspects of the guidelines, especially hand hygiene, are being followed. It's likely this is a situation where people don't understand the issues and don't realize that there are both concerns and resources to help them out.  Any facility that has, or is thinking of having, a visitation program, should be aware of these guidelines, plus other information from reputable groups such as Delta Society.

(Image source: www.studentsoftheworld.info)

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This morning, as my dog Meg and I went out to get the newspaper, she ran towards our pool fence, barking (pretty unusual for a dog that is afraid of chipmunks). I wondered what the issue was until I saw a black and white tail sticking out. The pool has been closed for the season and there was a skunk standing on the cover. The cover's about 1.5 feet below the deck and the skunk couldn't get out.

After going over various options, like putting things in for the skunk to climb out on (unsuccessful), getting a live trap (too lazy to go find one), scooping it up with the pool skimmer net (a matter of how badly I'd be sprayed, not whether I'd be sprayed), getting a wildlife removal person in (too cheap to get someone else to do it) or lacing food with a sedative, I came up with the following plan:

1. Find a large garbage pail with a handle. Tie a long rope to one handle.
2. Place the garbage pail on its side in the pool, with the handle tied to the rope on top.
3. Lure the skunk into the pail (e.g. with food) or, as I did, herd it in using a LONG pole.
4. When the skunk is inside, pull on the rope to tip the garbage pail back up.
5. Cover the garbage pail. A plastic kiddie pool works well.
6. Carefully but quickly lift the covered garbage pail out of the pool.
7. RUN... upwind.

It worked for me... no guarantees however.

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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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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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Streptococcus equi subspecies zooepidemicus (usually just called Strep zooepidemicus) is a common cause of infection in horses. It is an "opportunist" that is often found in healthy horses, but which can cause disease in certain situations. While horses are the natural host of this bacterium, sporadic infections and outbreaks are occasionally reported in dogs at cats, particularly in shelters or other crowded situations. Severe (including fatal) pneumonia can occur, as was reported in a recent outbreak in a humane society in Ottawa. Rarely, S. zooepidemicus can also cause infections in people.

A report in the Journal of Medical Microbiology (Abbott et al) describes a serious S. zooepidemicus infection in a person, that was traced back to a dog. The dog lived on a farm that also had horses. It developed pneumonia and S. zooepidemicus was isolated from its respiratory tract. The dog was treated and recovered. However, the dog owner also became ill with fever, headache, a stiff neck and general malaise. Penicillin was prescribed, but the person's condition did not improve and he/she ended up in the hospital. Streptococcus zooepidemicus was also isolated from this person's nose and throat.  When the dog and human strains were compared using molecular tests, they were related. An investigation of the farm was performed, and while all the horses present at the time were negative for S. zooepidemicus, the bacterium was isolated from a healthy dog.

This is a rare situation and one that shouldn't result in too much concern. It does highlight a couple points that are good to remember:

• Getting cultures is very important for obtaining a diagnosis.
• Animal contact and pet health should be considered whenever someone is sick with a potential infectious disease. Physicians need to know whether their patients have contact with animals. They need to be told if a sick animal is present so they can consider whether the pet and human illness might be related. Knowing to what someone may have been exposed might speed up diagnosis and appropriate treatment.
• Rare things are rare, but they happen. We shouldn't focus on rare events but we have to keep our minds open and recognize that strange things happen with infectious diseases.

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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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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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Recently, a relative was bitten by a dog, and the incident emphasized that you need to take such things seriously and pay attention to making sure things get taken care of properly.

So what should you do if you've been bitten?

1) Identify the dog.

• You need to know who the dog is, and who owns it. If you can't identify the dog, you have to assume it's rabid (even though it's extremely unlikely) and get treated with a series of vaccinations.

2) Get medical care as needed.

• Bites can be associated with significant trauma and risk of infection. Getting to a doctor is particularly important if the bite is severe, occurs at a high risk body site (e.g. over the hands, joints, tendons and nerves, groin, prosthetic devices) or if you are at higher risk of infection (e.g. immunocompromised, don't have a functional spleen, very young or very old, pregnant). If in doubt, go to a doctor to be on the safe side.

Once you've done this, it's important to make sure that the offending dog actually doesn't have rabies. If you go to a doctor, they will (in most regions) report the bite directly to public health. Public health inspectors will investigate the rabies vaccination status of the animal and ensure that it is quarantined for 10 days. If the dog has rabies and is infectious, it will develop signs of infection within this 10 day period. If the dog is healthy after 10 days, it did not have rabies at the time of the bite.

Seems pretty simple, eh?

Unfortunately, there are a few places where this process can break down.

Reporting: All bites need to be reported. Bites that do not result in people going to the hospital may be missed. You don't need a serious bite to contract rabies (or another serious infection).

Public health follow-up: This is hopefully not an issue, but you should make sure that public health has investigated, and done so promptly. Don't be afraid to call to find out the status of the investigation, and make sure information has flowed quickly from the physician to a public health inspector. Hopefully they'll be in touch with you, but don't be afraid to initiate contact. The main issue with follow-up relates to the next point:

Prompt euthanasia of the dog: Sometimes, people will decide to euthanize a dog after a bite, because it's done it before, because they consider any bite unacceptable, and/or they fear for family members or legal liability. Dogs (or cats) that have bitten someone must not be euthanized before the 10 day quarantine period is over. If the dog is euthanized and the body is not available for testing, you have to consider the dog rabid and undergo post-exposure treatment. Veterinarians are required to ask whether a dog has bitten someone in the preceding 10 days prior to performing euthanasia, but it's possible that this could be missed, or people may not tell the truth because they want to have the dog put down ASAP. This is why public health inspectors need to investigate promptly - to provide another level of assurance that the animal is not euthanized inappropriately. You should follow up with public health to make sure things are underway and the dog is quarantined.

Rabies associated with dog bites is extremely rare in Canada (and many other countries) but still kills tens of thousands of people every year, mainly in Asia and the Middle East. Considering it's almost invariably fatal and pretty much 100% preventable, you need to pay attention to the risks, no matter how small.

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As public awareness of zoonotic diseases increases, some new marketing opportunities are created. One is offering screening of pets for "protection" of the family. One company, Healthgene, offers a Family Protection Program that involves screening pets for selected zoonotic pathogens. Unfortunately, it involves the use of non-validated PCR tests for pathogens for which screening of healthy animals is not considered useful. They make various unsupported, illogical and sometimes downright incorrect statements such as "If, by chance, any positive results should occur, not only should the animal be treated immediately, but the client and anyone having contact with the animal should also notify their family physician." Despite the fact that the tests themselves are of questionable quality and the results are essentially useless, I'm sure they are developing a market.

Also, it's pretty concerning that this company misspells the names of various microoganisms for which they test on their website - they even misspell "protection" in one of their Family Protection Plan info sheets! Inability to spell isn't necessarily linked to inability to test properly, but it shows a lack of care and attention to detail that raises further red flags in my mind.

Zoonotic diseases ARE a concern. We need to pay attention to them and try to reduce the risks of transmission to people. Screening healthy animals is almost never a component of this. Save your money when it comes to "routine" screening of healthy animals - talking to your vet about potential problems and washing your hands are much better ways to reduce the risk of infection.

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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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A reader's question to InsideToronto.com highlights numerous issues with antibiotic misuse is pets (and people). Here's the situation, with my comments.

The reader has a cocker spaniel that's had a urinary tract infection for a year. She took it to her vet and a urine culture was recommended but she declined it. Antibiotics were prescribed but she stopped giving them after 48 hours because the dog looked better. She has not mentioned it to the vet since then.

• This dog has had a treatable, painful infection for a year. I have major ethical problems with this. Instead of turning to InsideToronto.com, she needs to see her vet. Fortunately, she got some good advice from the columnist and hopefully was convinced to take her dog to a vet.
• Simple urinary tract infections that go untreated can lead to other, sometimes serious or life-threatening problems. Infection can ascend from the bladder to the kidneys. More commonly, bladder stones can develop. One type of bladder stone is associated with urinary tract infections and it's quite possible that, in addition to a severe (and potentially difficult-to-treat by now) urinary tract infection, the dog also has bladder stones that will need a prescription diet or surgery to eliminate.
• She stopped treating an infection before the recommended treatment course was finished. That's too common and a recipe for treatment failure and antibiotic resistance.

When signs of the infection returned, she gave the dog "a few antibiotics" and stopped again when the dog looked better.

• See above. Perfect recipe for treatment failure and resistance.

When she ran out of the originally prescribed drugs, she used a different antibiotic from an "open prescription" from her MD that she had for her own medical problems.

• Where do I start? Many drugs used in dogs are used in people, but not all. Some human drugs can be harmful in dogs. Dosing may be different. This is completely irresponsible (but unfortunately, probably not uncommon).
• I wonder who paid for the drugs? If her insurance company paid for it, that's insurance fraud.
• This is also a good reason why "open prescriptions" from MDs are a problem. Who knows how often these drugs are used by the patient for the wrong reason or given to other people or pets?

Antibiotic misuse is a huge problem. It goes on in human medicine and veterinary medicine. We need to clean up what we do from both sides to address the critical problem of antibiotic resistance. Cases like this highlight the need for better controls and better education.

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The latest newsletter from the University of Guelph's Animal Health Laboratory contains a brief update on the percentage of positive MAT tests for canine leptospirosis that the lab has seen in the first half of 2009.  Approximately 30% of the tests have been positive, which is up from the previous two years.  However, the prime time for lepto cases (and therefore typically also lepto testing) is just starting: the cool damp fall weather provides a great environment for lepto bacteria to survive outdoors for the next several weeks.

Prevention of lepto in dogs, as with most diseases, is preferred to trying to treat sick animals.  The best way to avoid the bacterium is to keep your dog out of areas where infected wildlife may urinate frequently, particularly out in the bush.  But of course, skunks and raccoons can be found as close as the backyard as well, so even in the city the risk isn't zero.

If your dog does frequently go into the bush and is at increased risk for leptospirosis, hopefully you've already discussed vaccination with your veterinarian.  While the vaccine available doesn't protect against all types of lepto, it does help protect against the most common ones - in Ontario, these are believed to be the lepto serovars grippotyphosa and pomona.  We also received the following question from a reader the other day:

"Should a dog who has shown positive for early stages of kidney disease be vaccinated against leptospirosis?  Can the vaccine accelerate the illness to acute renal failure?"

I can see where the question comes from, but the simple answer to the second part of the question is no.  Although the infection can certainly affect the animal's renal function (and can push even healthy dogs into renal failure if it is severe), the vaccine works on the dog's immune system and does not affect the kidneys directly.  The answer to the first part of the question is, of course, much more complicated, and depends on many other factors including the dog's overall health status, lifestyle and other risk factors, and vaccination history.  The decision about whether or not to vaccinate your dog should be discussed on an individual basis with your veterinarian.

More information about leptospirosis is available on the Worms & Germs Resources page and in our archives.

Image: Scanning electron micrograph of Leptospira sp. bacteria (source: CDC Public Health Image Library ID#138))

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Allowing dogs into restaurants continues to feed debate in the US. Some cities (even those that were previously rather dog-friendly) are banning dogs from restaurants, much to the chagrin of some restaurants that have catered to pets and pet owners. At the same time, some businesses in other areas are trying to attract pet-owning clientele. I don't imagine there's going to be a consistent policy any time soon, and rules will probably vary with the whims of politicians and creativity of restaurateurs. There certainly are public health concerns with pets in restaurants, but they are also quite manageable with a few logical, practical rules and common sense. The question is will people (restaurant staff and pet owners) actually do what needs to be done to reduce the risks? We know that food safety violations are already way too common in restaurants, so  just making up a few rules and expecting people will follow them is not adequate.

Should dogs be allowed in restaurants? I don't know. I can argue either way. I think having dogs on patios would be better than giving them free range of the restaurant. That makes it easier to keep them away from people that don't want to dine with them. People that are allergic, afraid or otherwise averse to dogs could request a seat in the main restaurant and know that no dogs would be present. It also creates a more contained area that can be addressed if a problem occurs. I wouldn't be bothered by having a dog at a table next to mine (although it's understandable that some people would, especially those with allergies or a fear of dogs). I would have an issue with a dog wandering around, tripping people that walk by, barking incessantly, being petted by a server who was going to handling my food, or pooping on the floor. All of those a certainly possible.

Do we need rules if dogs are allowed in restaurants? Absolutely. Rules need to be clear and outline the responsibilities of restaurants and dog owners. Things such as no contact with pets by servers, maintaining constant control of dogs (i.e. always on a short leash), exclusion of sick animals and keeping dogs on the floor need to be in writing and enforced. There also need to be contingency plans for possible events such as a dog having diarrhea in the restaurant.

On a related note, the picture above is from a pizza restaurant in Dresden, Ontario, that I was in the other day. I'm not sure whether this sign means that I have to take my dog inside to get served, or whether I must leave my dog, shirt and shoes outside to get served.

A good commentary on dogs in restaurants by Doug Powell and Amy Hubbell of Barfblog can be found by clicking here.

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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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The Centers for Disease Control and Prevention (CDC) has released updated Guidelines for the Prevention and Treatment of Opportunistic Infections Among HIV-exposed and HIV-infected Children. A small but still important part of this document involves recommendations for contact with animals. It's a nice, balanced document that acknowledges the risk but doesn't make unnecessarily restrictive recommendations.

Among the important recommendations regarding animals:

• When getting a new pet, avoid dogs and cats less than 6 months of age or strays: These animals are at higher risk for shedding various infectious diseases and are more likely to have problems with biting and scratching.
• Avoid contact with animals that have diarrhea.
  
• Wash hands after handling pets.
  
• Avoid contact with pet feces.
  
• Avoid contact with reptiles, chicks and ducklings: These are very high risk for Salmonella.
• Avoid contact with calves or lambs at farms or petting zoos: These animals are high risk for various infectious diseases such as Cryptosporidium and Salmonella.

These recommendations also largely apply to other high-risk groups, including people (of all ages) with compromised immune systems and young children (especially less than 5 years of age). A key point is normal contact with common household pest using basic hygiene practices is considered a low risk. Infection control isn't rocket science. It involves basic and practical measures that can reduce risks associated with animal contact.

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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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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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Yesterday, I received a bulk email ad advertising a book about Chinese herbal medicine in pets.One of the introductory statements said that Chinese medicine is "becoming more popular as people realize the powerful yet gentle ways of TCM healing." On the same day, I received a Morbidity and Mortality Weekly Reports article entitled "Hepatitis temporally associated with an herbal supplement containing artemisinin."

Also known as qinghaosu, artemisinins are a class of compounds (drugs) that are used for the treatment of malaria. They are the active constituents of the herb Artemisia annua (sweet wormwood). Herbal supplements containing these compounds are marketed for "general health maintenance" (whatever that means), treatment of parasites and treatment of cancer.

In the MMWR case report, the CDC was notified about a person who developed hepatitis while taking an herbal supplement containing artemisinin. The person was prescribed the supplement by a naturopathic practitioner who attributed the patient's chronic abdominal pain to a parasitic infection. Six weeks of treatment was prescribed but 1 week into treatment, signs of hepatitis developed. No other causes of hepatitis were identified, and it resolved after the person stopped taking the supplement. That doesn't prove the supplement was the cause, but it is suspicious.

The supplement was tested and it had the amount of artemisinin that the label claimed. Artemisinin is generally considered a safe treatment for malaria, however the prescribed dose was much higher than the dose that is conventionally used for malaria treatment. It's unclear whether the liver damage occurred because of the dose, interactions with other compounds in the supplement, or an unusual reaction in this patient.

It's important to remember that herbal therapies are drugs. The fact that they are still in their natural state does not necessarily mean they are safer. In fact, there can be increased risks because of inconsistency in potency, dose and the presence of other compounds. With conventional drugs, extensive testing is done before they are released, to reduce the risk of them making people sick. With alternative therapies, the opposite occurs. There is no mandated pre-release testing so harmful products are only identified after they make a lot of people or animals sick.

A drug is a drug, whether it comes in a pill, liquid or leaf form.

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A Windsor, Ontario woman is convinced that her dog acquired listeriosis afetr eating recalled hot dogs.  Last week, Maple Leaf Foods recalled various hot dog products because of low-level contamination with the bacterium Listeria monocytogenes, the cause of listeriosis. Her dog Tigger was fed four hot dogs one evening, and the next morning starting vomiting. He recovered after a few days of treatment. No specific testing was done to investigate the possibility of listeriosis.

Dogs can get listeriosis.  Non-specific signs of infection including vomiting, diarrhea and fever are most common. Neurological disease can occur in a small percentage of cases. Listeriosis is extremely rare in dogs, however, despite the fact that dogs are certainly exposed to the bacterium periodically. Just because the dog ate recalled meat and got sick, it does not mean that the dog had listeriosis.

No human illnesses have been reported in association with this recall, and it's very unlikely that this dog actually had listeriosis. It's possible but I really doubt it. Dogs get gastrointestinal disease like this all of the time, from a variety of causes. Eating four hot dogs in one night could itself cause diarrhea in some dogs.

Some tips come to mind from this story:

• Limit feeding of treats to dogs. Four hot dogs is pretty excessive. Low fat, nutritious treats are better.
• Pay attention to recalls. Don't eat recalled food or feed it to your pet. At the same time, don't overreact to recalls. We are exposed to potentially infectious agents on a daily basis, but a combination of our immune system, normal bacterial populations in the intestinal tract, low levels of contamination and other factors mean that we don't usually get sick. If you are concerned about listeriosis, make sure processed meats are cooked before feeding.
• If you are really concerned or suspicious about a disease, make sure testing is done.
• If you think food is the source of a problem, save a sample. It might be useful to test the food.

More information about listeriosis in animals is available in the Worms & Germs archives.

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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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New research provides more information on the debate about testing and treating of healthy dogs for Giardia. Two abstracts on the subject by researchers at Colorado State University were presented at the recent American College of Veterinary Internal Medicine conference.

In the first study (Clark et al), fecal samples were collected from 220 healthy dogs. Giardia was detected in 11.4% of samples, but no dogs carried assemblages (types) known to cause disease in people.

In the second study (Lappin et al), they evaluated whether treatment of healthy dogs that were shedding Giardia would eliminated the parasite. Sixteen infected dogs were treated with either fenbendazole or nitazoxanide. Eight (50%) of the dogs had to be removed from the study because of adverse effects from treatment! Of the dogs that completed the study, Giardia was still detected in 63% of dogs 34 days after treatment, indicating that the infection wasn't eliminated or that dogs were quickly re-infected.

These studies provide more support of the notion that there is no indication to test or treat healthy dogs for Giardia. Testing makes no sense when the parasite is so common but most infected dogs are healthy, and when strains carried by infected dogs are usually of no consequence to people. Giardia is essentially a normal part of the intestinal microflora in many healthy dogs. Treatment of healthy carriers isn't indicated because it can make dogs sick and because it doesn't work very well.  Remember: above all do no harm.

The bottom line is don't bother testing healthy dogs for Giardia or treating healthy dogs in normal households.

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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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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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A canine influenza virus vaccine has recently been released. Canine influenzais a virus that originated from a horse influenza strain and is now circulating in some dog populations. (To my knowledge, we have yet to find it in Ontario. We didn't find any evidence of it in an earlier surveillance study). It typically causes mild disease, as with influenza in people, but can also cause serious (including fatal) infections. These cases are most common in densely-populated, stressful environments like shelters and racing greyhound facilities.

Like most vaccines, this canine influenza vaccine does not claim to provide 100% protection. Veterinary vaccines can get conditional licensing and be marketed with little evidence of effectiveness. The manufacturers have produced data "supporting product purity, product safety under normal conditions of use in field safety trials and demonstration that the product has a reasonable expectation of efficacy." That means they have shown the vaccine is produced with good practices, had no obvious adverse effects in a safety study, and there is a possibility that it could be effective (presumably from showing vaccinated dogs produce antibodies against canine influenza virus). During the conditional licensing period, the manufacturers "will continue to submit data obtained in support of the product’s performance, which will be evaluated by government regulators to determine whether a regular product license may be issued."

There's a good likelihood the vaccine will be effective at reducing the incidence and severity of disease, as with influenza vaccines in other species. Basically, if a vaccinated dog gets exposed to the virus, it should be less likely to get sick, and if it gets sick, it should be less likely to have severe signs. Reducing the incidence and severity of influenza also has the benefit of reducing the chances of developing a secondary bacterial infection, which can cause very serious disease.

Deciding whether to vaccinate your dog largely comes down to the risk of exposure and the implications of your dog becoming ill. In an otherwise healthy dog that is not in a high risk environment (e.g. kennel, shelter, greyhound racetrack), it's questionable whether vaccination is needed. If canine influenza virus is in the area, it's something to consider, but the virus seems to be rare (or at least rarely identified) in pets in most regions. Discussing the risks and benefits with your veterinarian is the key.

Canine influenza is NOT considered a zoonotic disease. There is no evidence that it can infect humans. Therefore, there is no public health argument for vaccination.

Image source: www.petinsurance.com/healthzone/pet-articles/pet-health/Canine-Influenza.aspx

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Because service animals are so important to the people they assit, they have much greater access to various venues than other animals. In the US, the Americans with Disabilities Act (ADA) specifically addresses service animal access issues. It was a landmark act that ensured appropriate access for these animals so that people who require them are able to take them into areas where other animals are not allowed. However, some aspects of this Act can lead to abuse of the regulations and unwanted scrutiny of "real" service animals. I was at an infection control conference recently and numerous people commented on problems they have had with people with questionable "alleged" service animals, the inability to find out whether they really are service animals, and the potential legal implications of trying to do anything to prevent them from entering certain areas.

These problems occur because of a combination of strong and vague statements in the ADA:

One problem is the definition of service animals: "Service animals are animals that are individually trained to perform tasks for people with disabilities such as guiding people who are blind, alerting people who are deaf, pulling wheelchairs, alerting and protecting a person who is having a seizure, or performing other species tasks."

• The definition itself is fairly straightforward, but there is no clear indication of what "trained" entails, and no requirement for formal training or certification, nor restriction of any animal species. Based on this, I could say that my sheep are trained to do something for me and then take them into a restaurant with me.
  

Some other key points in the ADA:

Businesses may ask if an animal is a service animal or ask what tasks the animal has been trained to perform, but cannot require special ID cards for the animal or ask about the person's disability.

• This means that while businesses can ask, all someone has to do is say "yes, this is a service animal" and the conversation is done. Some people that truly need service animals are not visibly disabled and you can't tell whether someone needs an animal by simply looking at them or talking to them. Back to my sheep example, if someone asked why I had a sheep on a leash in a restaurant, all I'd have to say if that he's my service sheep and he's trained to do something. Theoretically, I could walk into a crowded location with a Salmonella-spewing baby chick, adult cow or some other inappropriate animal and no one could do anything. Yes, those are extreme examples, but people like to test extremes.

A person with a disability cannot be asked to remove his service animal from the premises unless: (1) the animal is out of control and the animal's owner does not take effective action to control it (for example, a dog that barks repeatedly during a movie) or (2) the animal poses a direct threat to the health or safety of others.

• The problem here is who defines "direct threat." This is an issue because it is subjective, yet people can be penalized if they ban an animal and a complaint is upheld. Think back to the recent example of the pet chimp that almost killed someone. It wasn't a service animal in this case, but some people claim their monkeys are service animals. Some probably are, since some monkeys are specially trained to help the disabled (especially people with spinal cord injuries). Monkeys can be very dangerous, yet it might be hard to look at any given monkey and say it poses a "direct threat" to another person. A properly trained and temperament-tested monkey is probably low risk and justifiable. But, proper training and temperament-testing aren't required by the ADA

Businesses that sell or prepare food must allow service animals in public areas even if state or local health codes prohibit animals on the premises.

• Public health codes are there for a reason... to protect the health of the public. Therefore, careful consideration must be taken before breaking public health rules. The risks posed by a properly trained service dog are inconsequential, and properly trained and tested animals of appropriate species absolutely should have free access. Other species have different risks and these need to be considered. All animals are not created alike.
  

Violators of the ADA can be required to pay money damages and penalties.

• This is good for true violations such as someone refusing access to someone with a trained seeing-eye dog. However, it also leads to difficulties excluding high risk situations.

I'm know I'm going to get nasty emails from people with various untested, unregulated (and probably untrained) "service animals," but I think this is an important issue. The ADA provides a great framework for ensuring proper access to and by service animals. However, I don't think it's clear enough. Vague acts create the potential for stretching the rules and violating the spirit of the law. I'd never advocate getting rid of this Act, however I think it needs to be rethought. There is a great need for a clearer definition of what constitutes a service animal. Service animals should be specially trained, temperament-tested and certified by an independent body. If someone thinks they need a service monkey or horse, the need for that should be clear and the animal should be properly trained and scrutinized. Otherwise, it's a pet and shouldn't be given the same access. Problems that occur from inappropriate "alleged" service animals risk unnecessary scrutiny of, and barriers to, real service animals.

If you disagree, please comment. However, don't just send me the typical "I have a service horse and you're an idiot" comment that comes through periodically. Tell me why you disagree with better defining species, training and certification.

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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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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.

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There is a nice, concise commentary in the most recent issue of the Canadian Medical Association Journal about preventing infections in the home. It covers three important organisms: MRSA, Clostridium difficile and vancomycin-resistant enterococci (VRE). An excellent aspect of this particular commentary is its relatively low-key approach, with an emphasis on routine, basic practices such as hand hygiene. It also includes some comments about pets that are similarly well-balanced and go along with a lot of what we've been saying on Worms & Germs Blog. For example, in discussing MRSA, they state:

"Because domestic pets may serve as a reservoir of MRSA, hands should always be washed thoroughly with soap and water after contact with animals or their feces. In cases of outbreaks within a family of an infection caused by community-associated MRSA that cannot be arrested, a colonized pet may need to be temporarily removed from the home. However, it may be prudent to re-emphasize the importance of personal hygiene before taking such a drastic measure."

Overall, it's a commentary you might find useful. It can be downloaded by clicking here.

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Another study we presented at the recent European Conference of Clinical Microbiology and Infectious Diseases was about Clostridium difficile in the household environment. In the study, we collected samples from various locations and surfaces in households, as well as five fecal samples (one per day) from pets, and tested them for C. difficile. Some of the most interesting findings included:

• Clostridium difficile was found in one or more locations in 31% of households. The toilet was, not surprisingly, the most common site, but the kitchen sink, refrigerator and dog food bowl were close behind.
• The most common strain found in households was the international outbreak strain ribotype 027. Ribotype 078, a strain that is commonly found in food and food animals, was the second most common type.
• Clostridium difficile was isolated from 10% of dogs and 10% of cats, however in most cases only 1 of the 5 daily samples was positive.
• All of the strains of C. difficile found in pets were strains that have previously been recovered from people. This fits with previous reports that strains found in animals tend to be the same as those found in people, and supports concerns that C. difficile can be transmitted between humans and animals.
• In no households were C. difficile strains found in the pets the same as those found in the environment.  This suggests that pets are not an important source of household C. difficile contamination.
• Dogs that lived with an immunocompromised person were 7.9 times as likely to shed C. difficile than other dogs. Presumably, immunocompromised people are more likely to carry C. difficile and subsequently transmit it to their pets.

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

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The latest issue of Oprah's magazine "O" features the icon talking about her recent puppy dog adoption drama involving canine parvovirus. It just goes to show that even the pets of the biggest celebrities in the world are not beyond the reach of common microscopic infectious pathogens.

A couple of months back, Oprah adopted two cocker spaniel puppies from a shelter in Chicago. Unfortunately, within two weeks they both came down with parvovirus infection and had to be hospitalized. I'm sure both dogs received top-of-the-line care with no expense spared, but even so one of the puppies died. The other puppy came very close to dying as well, but happily she apparently has now recovered completely and is doing just fine (or quite likely better than fine, considering who her new owner is!).

Oprah also mentioned how one of her other dogs, Solomon, also suffered from a parvo infection years ago, but that dog was over a year old when he became ill. It's actually quite unusual for any dog to get parvo beyond one year of age - most adult dogs are not affected by the virus, unless perhaps their immune system is compromised for some reason.

These stories bring up a few interesting points to ponder:

It's great to adopt an animal from a shelter and give a homeless animal a home. It is an act of great kindness that I don't want to take anything away from in the least. However, it's important to realize that you never know what shelter dogs may be carrying, nor how well vaccinated they are.

• Even if the animals are vaccinated once at the shelter, the protective effect may be less than ideal if a properly timed vaccination series is not completed.
• In this case the pups may have been exposed to parvo after leaving the shelter, but they could have just as easily been exposed at the shelter, which begs the question of what else might they have been carrying? Bacterial pathogens such as Salmonella and Campylobacter are also particularly common in young dogs and cats (even healthy ones), and these are potentially zoonotic agents.

Young animals, particularly from shelters, are higher risk in terms of the infectious diseases they can carry and transmit. That doesn't mean they shouldn't be adopted, but it does mean taking some extra precautions for the first several weeks they're in their new home. These include being very diligent about controlling stool contamination of any kind (which can be easier said than done during the house-training phase), preventing contact with high-risk individuals (e.g. young children, the elderly, anyone with a weakened immune system) and lots of handwashing on the part of everyone involved with the puppy (or kitten!).

Parvo is a very serious disease in puppies, yet people sometimes become a little complacent about vaccinating for parvo and other puppyhood diseases.   Remember, though, that the reason parvo has become so much less common than it used to be is largely because of widespread and effective vaccination.  I have to wonder about how well vaccinated Oprah's dog Solomon was to get the disease at the age he did, but there could easily be other factors involved as well.  The virus is still out there, and if we become lax in our infection control practices - including decreasing exposure of puppies to the stool of other dogs, as well as vaccination - it's waiting in the wings for its opportunity to move in. Even with the very best care the infection can still be fatal.

It's also relevant to note that, as demonstrated by Solomon's case, just because parvo is very uncommon in adult dogs doesn't mean it's impossible for them to get it.  It's important to always remain diligent.

Parvoviruses are quite species specific, so thankfully people cannot get parvovirus from dogs, but remember that puppies can get diarrhea from pathogens like Salmonella, which can be transmitted to people. There is also a human parvovirus which is the cause of Fifth disease. Just like the dog virus cannot infect people, the human virus cannot infect dogs.

Image source: http://omg.yahoo.com

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Spring appears to have finally sprung in earnest in Southern Ontario (although we may still get one more frost on the weekend, so I hear) and people are getting back out into the garden.  An increasingly  popular trend in recent years, particularly this year now that the Obama's are doing it too, is vegetable gardening.  Lots of people like the idea of growing their own veggies in their own backyard, or perhaps in a community garden plot for city dwellers who still want to get their hands dirty - it's economical, good for the environment, and the plants can be grown "organically" without the use of chemicals or pesticides.  However, pesticides and garden bugs aren't always the only things to worry about having on your fresh veggies.  We received the following comment from a Worms&Germs reader:

"...What if veggies get infected with raccoon stool[?] Can eggs be killed after [the] veggie is grown and ready to eat?"

Great question.  The concern in the case of raccoon stool is the eggs of the roundworm Baylisascaris procyonis, which can be passed in huge numbers by a relatively high percentage of raccoons in many regions.  If swallowed, the eggs release larvae which can migrate through the tissues of the body, rarely causing visceral, ocular or neural larval migrans.

The good news:

• Raccoons like to defecate in the same areas most of the time, usually on a relatively flat, elevated surface (e.g. woodpile).  These areas become raccoon "latrines", and the soil in the area can become very heavily contaminated with roundworm eggs.  The good part is that most raccoons therefore not defecate in your garden.
• Vegetables cannot become "infected" by the parasite - the eggs cannot be absorbed or otherwise get inside a vegetable, they can only contaminate the parts of the plant that are directly in contact with soil.

The bad news:

• Even though raccoons may not poop in your garden, they can still track roundworm eggs into the soil on their fur or paws when they come by to explore your crop, so you should always consider soil outside as potentially contaminated.
• Baylisascaris eggs are highly resistant to disinfectants and chemicals, so they can't be killed this way.
• Raccoon roundworms aren't the only parasites that may be found in garden soil.  Dogs and cats can carry other roundworms (Toxocara spp.) which are also capable of causing larval migrans if swallowed (although infection with these worms in dogs and cats is not nearly as common as infection with Baylisascaris in raccoons).  Cats in particular, unfortunately, do sometimes like digging in gardens and may sometimes use a garden as a litterbox.
• Soil, particularly if it's contaminated by the stool of any animal, can also contain many different kinds of bacteria such as Salmonella.  Even if you can somehow protect your garden plot from animals, purchased garden soil and fertilizers may contain or may have come in contact with animal stool somewhere along the way.

So how do you make your garden veggies safe to eat?

• Wash wash wash: Because Baylisascaris eggs are so difficult to kill, the best thing to do is physically remove them from all surfaces of your vegetables by washing thoroughly to remove all visible dirt before doing anything else.  If you cut into a vegetable before washing it, the soil on the outside can contaminate the inside.
• Peel peel: Peeling vegetables ensures that all dirt (including any dirt stuck in tiny crevices on the vegetable's surface, or dirt you may not be able to see with the naked eye) is removed prior to consumption, but it's still crucial to wash the veggie first (and your hands) before peeling.
• Cook: From an infection control perspective, it's best to cook vegetables before eating them.  This actually won't do anything to Baylisascaris eggs - these have to be removed by washing and peeling - but it does help kill bacteria that either contaminated the veggies out in the garden or that contaminated the veggies during their preparation in the kitchen.  For those of us who like our nice crunchy vegetables, obviously cooking them won't do, therefore washing and peeling become that much more important.

And, of course, always wash your hands thoroughly with soap and water after you've been working in the garden, even if you wear gloves.

In a lot of urban areas, it's hard to prevent raccoons and other animals from getting into yards and gardens.  There are things you can do to discourage raccoons from hanging around your house, and if raccoons establish a latrine on your property it must be very carefully cleaned up.  For more information on Baylisacsaris, raccoons and cleaning up raccoon latrines, please see our archives.

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A few years ago, I wrote a commentary in the journal Emerging Infectious Diseases about pets and household quarantine. It was written after SARS (severe acute respiratory syndrome) had caused tremendous problems in many areas, including Toronto. The point I was trying get across was that while there was a strict household quarantine implemented for exposed people, there was no consideration of pets. We now know that cats can become infected with the SARS coronavirus, and can transmit it to other cats. However, when people were quarantined, there were no recommendations for pets - pets could interact with quarantined people, then visit non-quarantined family members, or interact with other animals or people outside. From my standpoint, this was a significant concern.  If cats had become infected with SARS, they could have been a source of transmission in households and potentially beyond. If SARS had infected the feral cat population in Toronto, it might have been very difficult to eliminate. I encouraged groups to ensure that pets are included in household quarantine guidelines.

The topic is front and centre again with swine flu. We don't know whether dogs and cats can be infected with this particular swine flu virus, but we DO know that cats can become infected with H5N1 avian flu and shed the virus. In my mind, that means that we should consider pets susceptible until proven otherwise.

So what should we do if people are being quarantined?

• If you are quarantining the family, quarantine the WHOLE family, including pets.
• Quarantined cats must be kept in the house. Quarantined dogs must be kept in the house as much as possible. They should only be taken outside to urinate/defecate, and this should be in a "remote" area where they can't have contact with other people or animals. They should always be under physical control (e.g. on a leash) when outside.
• If a quarantined pet gets sick, a veterinarian should be called first. That way, it can be determined if the pet needs to be examined, and if so, the clinic can know when it's coming and have protocols set up to handle it with infection control precautions.

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