Animal Health & Diseases : University of Guelph : Ontario Veterinary College : Zoonotic Diseases : Guelph, Hamilton, Ontario

Back in the 1980s, Vietnamese Pot-Bellied Pigs were a popular fad pet.  These stout little oinkers are still out there, though they're not quite as popular as they once were.  Potbellied pigs are cute (at least to some people... to each their own!), supposedly quite smart, and can even be house trained/litter trained.  As with any new pet though, it's very important to do your research before going hog-wild and getting yourself a pot-bellied pig.  Talk to your veterinarian about what your pig will need in terms of medical care - vaccines, deworming, spay/neuter, hoof trimming, tusk trimming... Because they are uncommon pets, some veterinarians may not be comfortable treating a pig.  Make sure you ask ahead of time so you know to which veterinarian(s) in your area you can (and will!) take your pig.

We recently received a question about vaccination of pot-bellied pigs.  Just like dogs, in some areas pigs need to be licensed by the city, and certain vaccines are required in order to obtain a license.  In this particular case, pigs are required to be vaccinated against rabies, swine erysipelas and leptospirosis.  Regular visitors to this site are no doubt familiar with the issues around rabies and why it's important to vaccinate for this deadly disease.  (More information about rabies is available on the Worms & Germs Resources page and in our archives.)  Swine erysipelas is a systemic bacterial infection caused by Erysipelothrix rhusiopathia, which can rarely cause a skin infection known as erysipeloid in humans.  This is not to be confused with human erysipelas, which is a skin infection caused by various species of Streptococcus (particularly Streptococcus pyogenes). 

But the question was about leptospirosis vaccination in pot-bellied pigs.  Pigs are susceptible to infection by Leptospira interrogans, just like dogs and people, and if infected a pet pig would be equally capable of shedding the bacterium in its urine and potentially transmitting the disease.  The issues around requiring vaccination of pigs for leptospirosis are very similar to those around making leptospirosis a "core" vaccine in dogs.  More information about this is available in the Worms & Germs post entitled "Should all dogs in Ontario be vaccinated for leptospirosis?"  A pet pig would likely be exposed to the same serovars of Leptospira as a dog kept in the same area, typically by coming in contact with urine from infected wild animals such as raccoons and skunks when they go outside.  However, the risk of exposure for a pig that rarely or never leaves the house would be extremely low compared to a pig that has outdoor access.  Another important consideration is whether or not the pig vaccine is against the same serovars that a pet pig, instead of a commercial pig, might encounter.  This will also vary depending on in what area the pig lives.  The Leptospira servoars pomona and bratislava are actually host-adapted to pigs.

It is also important to vaccinate an animal with vaccines that are labeled for use in its own species.  Vaccinating a pig with a vaccine meant for dogs could have unpredictable results - it may increase the risk of an adverse reaction, or it may not adequately stimulate an immune response, thereby leaving the pig essentially unvaccinated.  Your veterinarian can discuss the pros and cons of vaccination in your pet with the available vaccine products.

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

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Most of the infectious disease topics that we've covered on Worms & Germs involve bacteria or viruses. Fungal diseases (other than ringworm) are often overlooked because they are less common, and because they tend to be more of a concern in certain areas only. However, when fungal infections occur they can cause serious problems.

Blastomyces dermatitidis is a dimorphic fungus (meaning it can exist in the form of a mold or a yeast) that lives in the soil in some areas. It is more common in wet, sandy, acid soils that have a high organic content.  Animals (and people) can become infected by exposure to the mold form of the fungus in the soil. If the fungal spores are inhaled, it can result in severe pneumonia. Blastomycosis (infection with Blastomyces) can be difficult to diagnose and very difficult (and expensive) to treat.  So while blastomycosis is rare in general, it is still an important disease, especially in areas where it is more common.

Recently, a study was published in the journal Medical Mycology (Chen et al, 2008, 46: 843-852), regarding blastomycosis in dogs in Tennessee. This was a case-control study that compared dogs with blastomycosis to dogs that did not have the disease. Here are some of the results:

• Male dogs were 2.7 times as likely to be affected as females.
• Working and sporting dogs were at higher risk (4.6 and 6.2 times as likely, respectively).
• Dogs 2-4 years of age were at highest risk.
• Close proximity to water was also a significant risk factor for infection.

In Ontario, blastomycosis seems to be most common around Georgian Bay. In the US, it is more common in central and northern states, with most cases reported in Wisconsin, Tennessee, Mississippi, Kentucky and Arkansas.

Blastomycosis can also occur in people, but blastomycosis cannot be transmitted from dogs to humans (or between any animal species). Only the mold form of the fungus that lives in the soil is infectious.

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It's that time of year again - we're coming up on flu season, and the ads on the radio and the television are out, encouraging everyone to get their "flu shot," (aka influenza vaccination).  Influenza isn't just a problem in people - it is a very versatile group of viruses that can infect many different species of animals. 

Equine and swine influenza viruses cause serious problems in horses and pigs, respectively.  Last year there was a massive outbreak of equine influenza in Australia.  Because Australia was previous free of equine influenza, most of the horses there had never been vaccinated against the virus.  Therefore the entire population was very susceptible to the disease and it spread very quickly.  The outbreak has since been brought under control.  A previous Worms & Germs post talked about an outbreak of canine influenza in dogs in Chicago IL this past summer.

Equine and canine influenza (and usually swine influenza) cannot be transmitted to people.  However, there are some strains of influenza that can cross species.  The most well-recognized one is certainly avian influenza (bird flu), which caused outbreaks in a number of Asian countries in 2004.  Although people are much less susceptible to avian influenza than birds, the H5N1strain has caused significant illness and fatalities in people.

A lesser known fact about influenza is that pet ferrets are very susceptible to the virus, including human strains.  This is part of the reason ferrets are often used as animal models of the disease in research studies.  Signs of the flu in ferrets are similar to what you'd expect to see in people - fever, sneezing, runny nose and lethargy.  A pet ferret can both transmit to and catch the flu from a person.  Unfortunately for the ferrets, there is no available vaccine for the flu in these animals.

Lucky for us, people can be vaccinated against influenza.  Most people are still far more likely to get the flu from another person than from any kind of animal.  Getting your flu shot is the best way to help prevent yourself from getting the flu, and spreading it to others.  However, it's important to remember that no vaccine is 100% protective, so it's still important to take a few common-sense precautions, like washing your hands frequently, and sneezing/coughing into the crook of your arm, not into your hands.  (And watch out for sick ferrets!)

There is lots of information about influenza and flu vaccine available on the web, including some of the links in this post, and also on the CDC Influenza (Flu) website.

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Raccoon latrines are a major source of eggs of the raccoon roundworm, Baylisascaris procyonis.  Accidental ingestion of large numbers of eggs from these latrines can lead to a disease known as visceral larval migrans.  The most severe forms of this condition are known as ocular or neural larval migrans, which are damage to the eyes or brain/spinal cord (respectively) due to the roundworm larvae migrating through the body tissues.  The disease is very rare, but the consequences are very severe.  Previous Worms & Germs posts have discussed Baylisascaris and larval migrans in more detail.

Raccoons tend to form latrines - areas where they will return to deposit stool repeatedly.  In some ways this is handy, because it means you generally don't find raccoon stool all over the place.  On the other hand, the latrines themselves contain large amounts of stool, and along with that are large numbers of Baylisascaris eggs, not to mention bacteria and sometimes fungi.  So it is important to recognized latrines, particularly when they occur near your house, garden, or anywhere children may play.  Raccoons like to used flat, raised areas for latrines, such as roofs, decks, woodpiles, fallen logs or even large rocks, just to name a few.

Cleaning up raccoon latrines warrants some special precautions in order to avoid swallowing the roundworm eggs and to avoid spreading them around.  Recommendations include:

 

• Wear rubber gloves, and always wash your hands thoroughly when you are done.
• Wear disposable overboots, or rubber boots that can be scrubbed and disinfected.
• Wear an N-95 rated particle mask if you are cleaning up a latrine in an enclosed space, such as an attic or crawl space.
• Thoroughly wash your clothes with soap and hot water when you are done, and dry them completely.

Follow this link for detailed information on how to clean up a raccoon latrine.  A few of the more important points about dealing with these latrines include the following:

• Avoid stirring up dust.  Misting the area with water first can help with this.
• Double-bag and carefully dispose of any garbage/debris you remove from the area.
• Most chemicals will not kill roundworm eggs.  Removing the eggs is usually the best option, but extreme heat will also kill eggs instantly.  Flaming contaminated areas can be effective, but contact your local fire department about local regulations and safety precautions before attempting to flame a latrine site.

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As we see more and more infections caused by antibiotic-resistant bacteria, we have to re-think our approach towards antibiotic therapy. This often involves using new drugs, but sometimes it also involves considering the use of older drugs that we haven't used very much for a long time.

One such drug is chloramphenicol. Years ago, this antibiotic was widely used, and is still used in people and animals in some situations. In some respects, it is a very good antibiotic - it is often effect against many bacteria including those that are resistant to many other drugs, such as MRSA.  Chlormaphenicol can also be given orally, and it's relatively cheap. Unfortunately this drug can also be very toxic, both to the animals being treated with it and to people that come in contact with with it in the process. In some animals, chloramphenicol can cause suppression of the bone marrow, where red and white blood cells are produced. This is more of a concern with long term use, but if the bone marrow does become suppressed, stopping treatment with the chloramphenicol typically resolves the problem.  Unfortunately, this bone marrow suppression is much more of a concern in people - the supression is very severe, and can occur with exposure to even a very low dose (or probably single dose) of chloramphenicol.  This results in a condition known as aplastic anemia,  which it typically fatal.  Fortunately this reaction is very rare in people, but there is no way to predict who might develop this condition, and since it is usually fatal, we obviously need to be cautious about using this drug. In some countries, chloramphenicol use in banned in all animals. In many others, it cannot be used in food animals, but can be used in pets.

• Chloramphenicol should only be used as a drug of last resort. There are situations where it is useful and may be life-saving, but the human health risks cannot be overlooked.
• If chloramphenicol is being considered, it is critical that  people who would need to handle the drug understand the risk and how to safely handle the drug to avoid exposure.
• Chloramphenicol tablets should not be crushed or otherwise processed at home because of the potential for breathing in the drug when it is in powder form.

Direct contact with pills or liquids should be avoided by use of gloves or other safe handling practices.

• If a liquid form is used and is squirted onto food, the food bowl should be handled as if it is contaminated.
• If pills are being used, the animal should be observed to ensure that the pill is ingested and not spit up and left on the floor.
• Contact with the mouth and face and animals that are being treated with chloramphenicol should be avoided in case drug residues are present.

If people are unable or unwilling to follow safe handling recommendations, they should not use this drug.

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Hartz Mountain Corporation has voluntarily recalled one lot of its chicken-basted rawhide chews for dogs because of potential contamination with Salmonella. 

Rawhide treats, as the name suggests, are raw treats that  are literally made from the hide of typically cattle or pigs. The finding of Salmonella in rawhide treats is not particularly surprising, since Salmonella is commonly found in raw meat products, especially chicken.  In this case it is not known exactly how the product may have become contaminated. High rates of contamination of raw pet treats have been reported, although a recent study reported improvement in products in Canada.  This has likely occured because of action from the industry in response to outbreaks of disease in people that originated with treats. It's important to remember that any raw animal-based product that has not been treated (e.g. irradiated) to get rid of bacteria could contain harmful pathogens like Salmonella. They are best avoided, especially if high risk individuals (e.g. very young children, elderly persons or anyone with a weakened immune system) might come in contact with the treats or the pet to which the treats are fed. If you do decide to feed your pet raw animal-derived treats, care should be taken to reduce the risks of transmitting pathogens like Salmonella, as is recommended with raw meat diets. More information about raw meat feeding and Salmonella in pets can be found on the Worms & Germs Resources page.

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Echinococcus granulosus is a tapeworm of dogs that causes a condition known as hydatid disease or hydatidosis in humans.  The parasite is found in many parts of the world, and is very common in some regions of southern South America, the Mediterranean, the Middle East, southwestern Asia, northern Africa and Australia.  To the best of our knowledge, E. granulosus does not occur in southern Ontario, but it is present in other parts of Canada including the western provinces and northern Ontario.  A related, but much nastier, tapeworm called Echinococcus multilocularis is much less commonly found in North America.

A previous Worms & Germs post described what is known as the sylvatic cycle of Echinococcus granulosus, which is thought to be a common route of infection for dogs in Canada.  In the sylvatic cycle, dogs become infected with Echinococcus by eating the internal organs (usually lungs and liver) of wild game such as moose and caribou.  The dogs then pass tapeworm eggs in their stool, which can cause infection in other wild animals (thus continuing the cycle) or in people who accidentally swallow the eggs.  In humans, Echinococcus forms slow-growing cysts (called hydatid cysts) in different organs of the body which can be very difficult to remove or treat in some cases.

Echinococcus also has a pastoral or domestic cycle.  In this cycle, dogs acquire the parasite by eating the internal organs of infected sheep, and sometimes other livestock such as cattle and swine.  This cycle is potentially very important in areas where there is a lot of sheep farming.  In some areas of Latin America, 20-95% of sheep at slaughter may have evidence of hydatid cysts in their organs.

It is much more difficult to tell when a dog is infected with Echinococcus compared to other tapeworms such as Taenia or Dipylidium.  An adult Echinococcus is tiny - only a few milimetres long (see picture right), very unlike the long, stringy white tapeworms that most people picture.  Dogs can carry hundreds, even thousands of these tiny tapeworms without showing any signs of illness at all.  The eggs can sometimes be difficult to detect on fecal examinations, and when they are seen they cannot be differentiated from Taenia eggs.  Nonetheless, this is still the best way to detect infection, so fecal examinations should be performed regularly.

Remember:

• In areas where Echinococcus is known to exist, it's important to have your veterinarian perform fecal examinations on your dog's stool more frequently than the usual once-a-year, because of the serious zoonotic potential of this parasite.
• Always wash your hands well after handling dog stools.
• Do not let your dog eat uncooked meat, or the organs from farm animals or wild game.

For more information on Echinococcus, see Worms & Germs post entitled Echinococcus and hydatid disease - not your average tapeworm.  There is also information available on the Michigan State Department of Natural Resources site.

Lower photo credit: Ontario Veterinary College

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You may notice a recurring theme in many of our posts and on virtually all of the information sheets on the Worms & Germs Resources page: an emphasis on handwashing. There is increasing emphasis on hand hygiene (i.e. hand washing and use of alcohol hand sanitizers) education in hospitals because the hands of healthcare workers are a major (if not the most important) means of disease transmission between patients. Despite hand hygiene being easy, cheap and effective, people rarely wash their hands as often as they should, and they often don't do it properly.

Most of the research about hand hygiene that has been published has focused on its use and impact in human hospitals, but this area is now also being studied more with regard to animals and veterinary medicine. A study published earlier this year in Veterinary Microbiology provided more evidence that hand hygiene is a critical infection control measure when dealing with animals. The study, coordinated by Dr. Maureen Anderson (of Worms&Germs fame) looked at MRSA carriage rate in veterinarians who work with horses. In addition to finding a high rate of MRSA carriage among these veterinarians (which was consistent with other reports indicating that equine vets are at higher than average risk for exposure to MRSA), the study looked at factors associated with MRSA carriage. Vets that reported routinely washing their hands between farms and those that reported washing their hands after contact with potentially infectious cases had a significantly lower rate of MRSA carriage. That should come as absolutely no surprise, but it's one more piece of evidence that we need to pay more attention to this routine infection control measure, in human hospitals, in veterinary environments and in households.

Remember, the 10 most important sources of infection are the fingers on your hands!

Click here for instructions on how to wash your hands properly.

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This post has been updated with new information as of October 2, 2008.

An article was published on Sunday in a local Guelph newspaper about a 14-month-old child who has been battling infection with Baylisascaris larvae in a Hamilton (Ontario) hospital for the last two weeks.  This comes on the heals of a very recent Worms & Germs post about Baylisascaris procyonis - the raccoon roundworm.

The disease caused by migration of Baylisascaris larvae through the body - visceral larval migrans - is uncommonly diagnosed in North America, although it may be more common than we think because it is difficult to diagnose with certainty, and the signs in mild cases may be very non-specific.  The most severe form of the disease is called neural larval migrans, which occurs when the larvae migrate through the brain or spinal cord, as in this most recent case.

The parents of the toddler in the article, a toddler who is still blind and cannot sit up on his own as a result of his infection, have a message for parents: keep raccoons out of your yard and away from your house.  The disease may be rare, but the effects can be devastating, and the risk can be significantly reduced by a few simple steps:

• Keep garbage in tightly-sealed containers.
• Clear brush and seal openings in buildings where raccoons may nest or form latrines.
• If you find raccoon stool or what appears to be a raccoon latrine on your property, clean it up very carefully.  Follow this link for more information on identifying and cleaning up raccoon latrines.
• Always wash your hands well after you've been working outside in soil, dirt or water which could be contaminated with raccoon feces.

For more information, see the last Worms & Germs post about Baylisascaris.

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If you are looking for an interesting website to play around with, you should try HealthMap. This is a website created by the Harvard-MIT Division of Health Sciences and Technology that maps infectious disease reports from various sources. You can search by region and see what disease problems have been reported recently, or select specific diseases and find out where they've been reported.   Some examples are shown below. The top image shows all disease reports worldwide (in the last 30 days), while the bottom image shows reports of Salmonella in North America during the same time period. The site relies on reports of diseases (many cases of various diseases occur but are never reported), so it focuses mainly on outbreaks or high profile cases , but it is still quite interesting.

Above: All reported disease outbreaks/cases worldwide in the last 30 days.
Below: Reported outbreaks/cases of Salmonella in North America in the last 30 days.
See the HealthMap site for more details.

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Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant S. pseudintermedius (MRSP) are important causes of infection in pets, and are resistant to many different antibiotics. It's therefore very important that these bacteria are cultured and tested in a lab to determine what antibiotics may be effective.  Even then, choosing an effective medication can be difficult due to the limited number of potentially effective drugs.

Treatment selection is further complicated by problems that can occur when methicillin-resistant staphylococci are tested against certain drugs in the lab - problems that are not readily apparent unless extra testing is done.  One "problem" drug is the antibiotic clindamycin. Clindamycin can be an effective treatment for MRSA or MRSP infections, but some MRSA strains may be resistant to it despite appearing to be susceptible based on normal laboratory testing. This is because the bacteria can have "inducible resistance".  Inducible resistance can be detected by a special test called a D-test (see picture), but this test is not widely performed in veterinary laboratories.

In recent study presented by Dr. Meredith Faires (University of Guelph) at a conference last week, 55% of MRSA from dogs and cats that were reported to be resistant to erythromycin and susceptible to clindamycin were actually inducibly resistant to clindamycin.  But no MRSA that were susceptible to erythromycin were inducibly resistant to clindamycin. In contrast, inducible resistance to clindamycin was not identified in any MRSP. Therefore, in the absence of specific testing for inducible resistance (i.e. a D-test), it is wise to consider all erythromycin resistant MRSA to be clindamycin resistant as well, regardless of the results of traditional antibiotic susceptibilty testing.

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This post has been updated with new information as of October 2, 2008.

Raccoons, just like dogs and cats, can have roundworms in their intestine. Dogs are typically infected by the species Toxocara canis, and cats are infected by Toxocara cati. Raccoons are infected by a type of roundworm from a different genus, called Baylisascaris procyonis. There is one thing that all three of the parasites have in common – the larvae of these worms can infect humans, causing a condition called visceral larval migrans.

Dogs and cats are usually dewormed as puppies and kittens, and often as adults as well, which dramatically decreases the number of pets that are infected with roundworms. Raccoons are not so lucky – in the northern and northeastern parts of North America, over 70% of raccoons may be infected with Baylisascaris.  In Ontario, it has been estimated that only about 20-30% of raccoons are infected, but usually with high numbers of worms. In either case, younger raccoons are even more likely to be infected.  Infected animals may shed millions of parasite eggs in their stool, and the eggs can survive in the soil for months or even years.

After a few weeks, the eggs in the raccoon stool become infective. If a person swallows the eggs, they hatch in the small intestine and release larvae. These larvae can then burrow through the wall of the intestine and migrate through tissues all over the body, causing tissue damage and inflammation. The signs of illness are often not very specific, and may include things like fever, fatigue and nausea. If the larvae migrate through the brain or spinal cord, a person may develop neurological signs like loss of coordination and muscle control. This is called neural larval migrans, which is the most serious type of disease caused by these larvae.  If the larvae migrate through the eye, they can cause blindness.  This condition is known as ocular larval migrans.

There have been less than 25 cases of confirmed visceral larval migrans due to Baylisascaris in the USA as of 2003, but the condition is very hard to diagnose with certainty, and it is possible that many cases are mistaken for other illnesses. The disease is also very difficult to treat, and neurological damage from neural larval migrans is usually permanent, so the best thing to do is prevent infection in the first place. Here are some tips on avoiding Baylisascaris:

• Avoid contact with raccoons. Many people think raccoons are cute, but they are wild animals. Raccoons are also a risk for transmission of rabies if a person is scratched or bitten. NEVER keep a raccoon as a pet.
• Discourage raccoons from hanging around your house. Clear brush and seal access to basements and attics where raccoons may try to nest or form latrines. Keep garbage in tightly-closed garbage cans. Eliminate outdoor water sources.
• Always wash your hands well with soap and water after working with soil (e.g. in the garden).
• Clean up raccoon latrines.  This must be done very carefully - avoid getting any raccoon stool on your hands or clothes. The stool should be burned, buried or sent to a landfill. Clean the area where the stool was found with boiling water. Wash your hands very carefully when you’re done.  Follow this link for more detailed information on how to identify and clean up raccoon latrines.

Baylisascaris procyonis less commonly infects animal species other than raccoons, including skunks, and it has even been found in dogs.  It's important to have your dog's stool examined for parasite eggs on a regular basis (typically once or twice a year) and to follow your veterinarian's recommendations for deworming your dog.

More information about Baylisascaris is available on the CDC’s Baylisascaris Infection website.

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In a recent post, I discussed a study about the health effects of feeding raw meat diets to pets. Because of the significantly higher rates of shedding of certain potentially harmful bacteria by dogs that are fed raw meat, I think raw meat diets are a bad choice - especially in households with young children, elderly individuals or people with compromised immune systems. However, if you are going to feed raw meat to your pet, you should take some basic precautions.

• Only use meat that is suitable for human consumption. Don't buy 'adulterated' meat or meat labeled unfit for human consumption.
• Keep raw meat frozen until you need it. Only thaw out the portion that is need for the next feeding, and thaw the meat in a sealed container on the bottom shelf of a refrigerator.
• Handle raw meat with care. Do not allow it to contaminate kitchen surfaces or items that may come in contact with other food. Clean and disinfect any items that come into contact with raw meat.
• Wash your hands thoroughly after handing raw meat or anything that has touched raw meat (e.g. your dog's food bowl).
• If your pet does not finish all the meat fed right away, discard any uneaten raw meat promptly. Do not allow raw meat to sit in a bowl at room temperature. Some dangerous bacteria can multiply rapidly under these conditions.
• Regularly clean and disinfect your pet's food bowl, but bear in mind that  a recent study showed that it is very hard to eliminate Salmonella from raw meat in food bowls.
• Make sure your veterinarian knows that you feed raw meat. This is particularly important if your dog develops vomiting or diarrhea.
• It is very important to make sure that your pet's diet is well balanced, which can sometimes be difficult to do when feeding non-commercial or raw diets.  Read about raw meat feeding, and try to find good sources of information (which is not always easy) to reduce the risk of problems caused by feeding an unbalanced diet.
• Never feed raw meat to sick dogs, puppies or pregnant dogs.

 

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Brucellosis is an infection caused by bacteria of the genus Brucella. The most common species of Brucella in companion animals is Brucella canis, which typically causes infection in dogs. This bacterium is very rare in Ontario - in a survey of 2000 dogs, only 0.3% had evidence of exposure to B. canis. So it was unusual that a case of canine brucellosis was recently diagnosed in the province, until it was discovered that the dog originally came from a rescue shelter in the southern USA - an area where exposure to the bacterium is much more common (approximately 8% of dogs).

Brucellosis in dogs typically causes reproductive problems such as infertility and an enlarged scrotum in males, and late-term miscarriage in bitches (breeding females), with few or no other signs of clinical illness. But in some cases the bacteria have been found to infect tissues other than the reproductive tract, including intervertebral discs (leading to back problems), the eyes, the kidneys, or the tissues around the brain and spinal cord (i.e. the meninges). The bacteria, and antibodies to the bacteria, can be very difficult to detect in the early stages of infection. The infection is usually diagnosed by a blood test, but it may take 8-12 weeks before test will yield a positive result.  There are also problems with high numbers of false-positive test results due to cross-reaction with other species of Brucella.  Any positive test result should therefore be confirmed by a second, different laboratory test.

Human infection with any species of Brucella is now uncommon. When illness does occur, the signs are often non-specific (e.g. fever, headache, myalgia), but more severe infections have been reported.  Transmission of B. canis from an infected dog to a person is possible. The bacterium is transmitted by contact of a mucous membrane (e.g. eyes, nose, mouth) with blood, urine, milk, semen, or vaginal discharge from an infected animal. The highest-risk materials (i.e. most likely to contain a high number of the bacteria) are placental tissues and fluids that are passed during whelping (delivering puppies).  Treatment for infection is available, but the course is often long and recurrence of infection can occur.

Although brucellosis is very rare in dogs in Ontario (and Canada in general), here are a few things you can do to help avoid B. canis:

• Always wash your hands right away if you accidentally come in contact with blood, urine, milk, semen or vaginal discharge from any dog.
• Prevent contact between your dog and urine, milk, semen or vaginal discharge from other dogs, especially if you travel with your dog to an area where the prevalence of B. canis is relatively high (such as the southern USA).
• Dogs used for breeding should be tested for B. canis.  Many breeders will require dogs to be tested before allowing their animal(s) to be used, because the infection can be transmitted through breeding and can have such detrimental effects on fertility.
• Newborn pups should be handled as little as possible, but if you must handling them wear disposable gloves and wash your hands as soon as you take your gloves off. Exercise the same precautions when cleaning up the area where a bitch has whelped.

More information about brucellosis can be found on the CDC's Brucellosis website.

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Everyone is familiar with the human immunodeficiency virus (HIV) - the retrovirus that causes acquired immunodeficiency syndrome (AIDS) in people. Although HIV can only infect humans and some primates, cats can be infected by a very similar virus from the same genus (Lentivirus) with a similar name – feline immunodeficiency virus (FIV). The FIV virus is transmitted from cat to cat by contact with blood, usually through a cat bite.  In Canada and the USA, up to 3% of healthy cats may be infected with FIV.

As with HIV in people, FIV attacks a cat’s immune system, which can leave the animal susceptible to many different infections that a healthy cat could normally fight off. Some of these infections, like toxoplasmosis, are similar to those that occur in AIDS patients. (More information on toxoplasmosis and Toxoplasma is available on the Worms & Germs Resources page). Depending on a number of factors, an FIV-positive cat may remain healthy for years, but once the animal begins to show signs of a weakened immune system, it will often develop chronic or recurrent health problems. The infection is life-long – there is no “cure” for FIV.

Some key points to remember:

• Cats cannot get HIV. People cannot get FIV. They are related but different viruses.
• Keeping your cat indoors will prevent fighting with other cats and decrease the risk of your cat contracting FIV.
• There is a vaccine available for FIV, but it remains uncertain if the vaccine can protect cats from all strains of the virus.  The vaccine also interferes with tests for FIV infection.  Therefore, preventing exposure to the virus is still the best way to prevent FIV infection.
• If your cat already has FIV, it is important to keep it indoors to decrease exposure to pathogens that could make your cat sick, and to prevent your cat from spreading the virus to other cats.

More information about FIV can be found on the Cornell Feline Health Center website.

                                                                    

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Many dog owners love to take their canine companions to the beach with them during the summer. Unfortunately, other people (particularly non-dog owners) sometimes take exception to having Bowser on the beach. These individuals often cite potential infectious disease risks as a reason to ban dogs from the beach.

While there are some potential infectious disease risks associated with having pet dogs at the beach, they are minimal. Also, some simple, common-sense steps can greatly reduce the risks that do exist. The infectious disease risks from feral (wild) dogs and wildlife defecating in the sand are much greater.

• The biggest health risk is actually probably from dog bites. Bites can be avoided through proper handling and training of dogs that are brought to public beaches.
• Many different bacteria (e.g. Salmonella, Campylobacter) can be passed in the stool of even healthy dogs. Some of these can be harmful to people, but only under certain circumstances, such as if they are swallowed or if they contaminate an open wound.
  • Promptly picking up any stool passed by a dog greatly reduces the risk of significant contamination of the sand. Also, sunlight is an excellent “disinfectant” and will help kill any residual bacteria left behind.

• Dogs can also have different kinds of zoonotic parasites in their stool.
  • Some of these parasites (e.g. roundworms, hookworms) are passed in a form that takes days to become infectious to people. So promptly removing dog stool from the beach minimizes the risk of transmission.
  • Other parasites, such as Giardia, are immediately infectious when passed in the stool, but must be swallowed to cause infection. Prompt removal of dog stool, good hand hygiene with soap and water or an alcohol-based hand sanitizer before eating, and avoiding sand contamination of food and drink should largely eliminate this risk as well.

Overall, the risks of having dogs on beaches are very low if people behave responsibly, specifically properly restraining their dogs and promptly picking up stool.

More information about zoonotic diseases associated with contamination of sand and Sandboxes is available on the Worms & Germs Resources page.

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A horse in Ontario was recently diagnosed with Eastern Equine Encephalitis (EEE), a serious neurological disease caused by a virus of the same name, which is transmitted by mosquitoes.  The horse was from the North Durham region.  The last reported cases of EEE in Ontario were in 2004.  A few weeks ago, the Worms & Germs Blog talked about a large number of cases of EEE that have been reported in Florida this year.

Here are some of the key points to remember about EEE:

• Like West Nile, EEE is a seasonal disease.  It is more common in warmer areas, especially some regions of the southeastern US.  It is rare in cooler climates, but occasionally EEE is found in horses in Ontario.
• EEE is usually fatal in horses, and there is no effective treatment.
• EEE can also occur in people, and can be fatal in some cases.
• Infected horses cannot transmit the EEE virus to people, but if a horse gets EEE from the mosquitoes in the area, then people could also potentially be exposed to the virus by mosquitoes.
• A vaccine for EEE is available for horses, but most horses in Ontario are not vaccinated for EEE because it is so rare.  Nonetheless, vaccination can be considered because the disease is so devastating when it occurs.
• As for West Nile virus, avoiding mosquitoes - for both horses and people - is an important preventative measure for EEE.

For more information, see the Worms & Germs Blog post "Eastern Equine Encephalitis – Not Just For Horses", or the CDC's website on arboviral encephalitides.

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Rabies is an important disease that is almost always fatal. An important part of rabies control programs is mandatory vaccination of pets such as dogs, cats and ferrets. In general, rabies vaccination is very safe and effective. Complications from rabies vaccination are rare, but in recent years concerns have been raised about vaccine-associated sarcoma, a type of tumour that can develop at the site of vaccination. Since this complication was recognized, the vaccines themselves and the way they are administered have been changed in order to decreased the likelihood of this problem occuring, but the risk cannot be eliminated completely. For this reason, some people have tried to avoid having their pets vaccinated for rabies. 

A blood test can be performed to determine antibody levels (also called a titre) against rabies virus. However, there is not enough information available to determine what antibody titre is high enough to say that an animal does not need to be re-vaccinated. Skipping rabies vaccination based on blood test results is dangerous and not recommended. While rabies is uncommon in most areas, exposure can occur, even in strictly indoor animals (e.g. if a bat gets into the house). Rabies vaccination is a legal requirement in most areas of Ontario. The implications of rabies exposure in an animal that is not "up-to-date" on its vaccines can be severe, including prolonged quarantine or euthanasia. I do not know of any jurisdictions that allow rabies antibody levels to be used in place of vaccination, and animals that are not recently vaccinated are treated as non-vaccinated, regardless of their antibody titre.  The risk to your family or your pet from rabies is greater than the very tiny risk of vaccine-associated sarcoma. If you care about your pet and your family, make sure your pet is properly vaccinated against rabies.

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

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People often ask me questions about "Clostridium" in dogs and cats, with the impression that "Clostridium" is a specific disease. Actually, Clostridium is a large bacterial genus (a group of related bacteria), which includes species that range from harmless to deadly. Some of the more important species are described below:

Clostridium perfringens: This is a common bacterium that can be found in the stool of a large percentage of healthy animals and people. It is a common cause of "food poisoning" in people, and is probably an important cause of diarrhea in dogs and cats. Our understanding of the role of this bacterium in disease in dogs and cats is limited by the fact that it is found in so many healthy animals, so simply growing it from the stool of a diarrheic dog or cat does not prove that it is causing the animal's illness.

Clostridium difficile: This bacterium is a very important cause of diarrhea (and more severe intestinal disease) in people, and is possibly an important cause of diarrhea in dogs and cats. It is rarely found  in healthy adult pets, but is relatively common in puppies and kittens.

Clostridium botulinum: This bacterium produces the toxin that causes botulism, a potentially devastating disease that is very rare in dogs and cats. Botulism usually occurs following ingestion of food that has been improperly stored, in which C. botulinum has grown and produced its potent toxins.

Clostridium tetani: This bacterium produces the toxin that causes tetanus, which can occur in dogs and cats, however these species are relatively resistant to this disease. Tetanus usually occurs when a wound becomes contaminated with C. tetani from the soil, followed by growth of the bacterium and production of potent toxins.

Other clostridia: A large number of different species exist, and it is likely that many more clostridia are around but have not been identified and named. Many clostridia are part of the normal bacterial population in the intestinal tract. Some of these can probably also cause disease.

As you can see, "Clostridium" is more than a single bacterium or disease. An understanding of this concept, and the different disease-causing clostridia, is important.  More information on Clostridium difficile can be found on the Worms & Germs Resources page.

Image: Photomicrograph of C. botulinum stained with Gentian violet.  From CDC's Public Health Image Library (PHIL), ID number #1979.

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Pet treats derived from raw animal products such as rawhides and pig ears (yes, pig ear treats are actually dried, raw pig ears) are widely available and commonly fed to pets, particularly dogs. Being a raw product, there is an inherent risk of contamination with potentially harmful bacteria such as Salmonella. In 1999, an outbreak of salmonellosis linked to contact with raw pet treats was identified in people in western Canada. A subsequent investigation found Salmonella in over 50% of pig ear treats and 38% of other animal-derived treats. Similar results were reported by a later study in the US, and other outbreaks of disease have been reported. In Canada, the pet treat industry and government groups met and made various recommendations to reduce the risk of contamination.

To evaluate the effect of these changes, a Canadian follow-up study was performed. Only 4% of treats were contaminated with Salmonella, which was a marked contrast to the earlier study. Even so, the fact that Salmonella was present in a detectable percentage of treats means that certain precautions are warranted.

• Always wash your hands thoroughly after handling pet treats such as rawhides and pig ears
• Avoid buying treats from 'bulk bins', as there may be an increased risk of cross-contamination between treats in the bin
• Buy packaged treats so that you don't have to touch them directly when buying them or bringing them home
• Never store treats in areas where other food is kept or prepared
• Ask whether the treats you are buying have been produced under the Guidelines for the Manufacturing of Natural Pet Treats for Pets.  There guidelines were developed by the American Pet Products Manufacturers Association with input from the Food and Drug Administration (FDA)
• Avoid buying raw treats if you have young children or anyone with a weakened immune system living in the household, as these treats may pose a small but unnecessary risk of exposure to Salmonella
• Contaminated treats seem to be a bigger problem for people than pets, however Salmonella can also cause disease in pets. If your pet develops diarrhea after eating an animal-product treat, be sure you tell your veterinarian

Image: Pig ear dog treat from www.foodpoisonblog.com

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The inquest was told that there were three main possible sources of E. coli: food, travel and animals. The coroner determined that the owner most likely acquired E. coli from handling the cat or cleaning its litter box.

There is no indication why this conclusion was reached, and it seems to be a rather strange conclusion based on the reported information. There is no reported evidence that the same strain of E. coli was even present in the cat. I suspect that they are blaming the cat because there is no other obvious source (e.g. an identified foodborne outbreak of E. coli).  I doubt the cat played any role in this person's illness.

The risk of contracting E. coli from contact with a cat is very low. However, common sense should be used when handling cats and particularly cat stool. The most important measures are avoiding contact with stool and appropriate hand washing after handling a cat or its litter. More information about litter box management is available on the Worms & Germs Resources page.

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A major outbreak of Q fever associated with goats has occurred in the Netherlands. Over 500 human cases have been reported since the beginning of 2008. Prior to 2007, the average number of cases per year in the country was only 15.

Q fever is an infection caused by the proteobacterial organism Coxiella burnetii. Although usually not very common, C. burnetii can be carried by sheep, goats, and cattle, as well as birds and even sometimes cats and dogs. Animals often show no signs of illness, although the infection sometimes causes miscarriage, particularly in sheep and goats. Coxiella burnetii is also transmissible to humans. People are much more susceptible than animals to disease from Q fever. Even so, only about 50% of individuals that become infected show signs of illness, which can range from flu-like symptoms to pneumonia and hepatitis (liver infection). About 1-2% of infections in people are fatal.

Infected animals shed C. burnetii in their stool, urine and milk, but the highest number of organisms are shed in birth fluids and placentae. Coxiella is able to survive very well in hot, dry soil, and when dust and dirt from contaminated areas are stirred up into the air, the organism can be inhaled. This is the most common means of transmission, although direct contact with an infected animal or its stool or urine can also transmit the disease. Transmission from drinking milk from an infected animal is very rare, but is more likely if the milk has not been pasteurized. Cats and dogs can be infected by and transmit C. burnetii in all the same ways (especially through birth fluids), but they very rarely get sick. Ticks can also transmit the disease.

Q fever is one of the most infectious diseases in the world. As little as one C. burnetii organism is enough to infect a susceptible person. There are a few things to keep in mind to help reduce the risk of being exposed to this pathogen:

• Only eat/drink pasteurized dairy products.
• The main risk from cats and dogs (especially cats) is when they give birth. If you have a cat or dog that has kittens/puppies, wear gloves if you have to touch the babies or any placentae. Afterwards, cleaning the area very thoroughly to physically remove any tissue or fluid residue is very important, because most disinfectants cannot kill C. burnetii. Always wash your hands thoroughly after handing newborn kittens or puppies.
  
• On dry, windy days, avoid farms or areas where sheep or goats are kept.
• Avoid sheep and goat farms during the lambing/kidding season.

More information on Q fever can be found on the websites of the Ontario Ministry of Health and Long-Term Care and the Centers for Disease Control and Prevention (CDC).

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Over 50 horses have died from Eastern Equine Encephalitis in Florida this year. The disease, caused by a virus of the same name, affects the brain, resulting in a broad range of clinical signs from behaviour changes to blindness to irregular gait. The disease is also sometimes called “sleeping sickness” because some horses may become severely depressed, with low head carriage and droopy eyes, ears and lips. Almost all horses that develop neurological signs from this infection die. Only 35 cases were reported in Florida in 2006 and 2007 combined.

There are actually three related equine encephalitis viruses – Eastern, Western and Venezuelan – which are called EEE, WEE and VEE for short. VEE is found in South and Central America and Mexico, and occasionally in the southern United States, but has never been reported as far north as Canada (VEE is a reportable disease in Canada). It is unique among the three diseases as the only one in which an infected horse will carry enough virus in its bloodstream to infect a mosquito, which could then pass the virus on to another animal. The EEE and WEE viruses, just like the West Nile virus, do not reach high enough levels in the bloodstream of horses to do this. The mosquitoes usually pick up the viruses from passerine birds, which do not become ill from the viruses (unlike West Nile virus in birds from the family Corvidae).

People can also be infected by EEE, WEE and VEE. About 10 fatal cases of EEE in people are reported in the United States every year. But horses cannot transmit EEE or WEE to humans, even if they’re bitten by the same mosquito. A higher number of cases in horses, however, may mean a higher number of mosquitoes that are carrying the virus. There is no vaccine for these viruses for humans, but there are vaccines available for EEE, WEE and VEE for horses.

In the end, EEE is just one more good reason to make sure you wear mosquito repellent when you’re enjoying the great outdoors during the summer. Visit the Health Canada website for safety tips on using personal insect repellents. EEE is very uncommon in Ontario, but horses that live in or travel to the southern United States should be vaccinated. Talk to your veterinarian about whether or not your horse should be vaccinated. Remember that fly control is also important for our equine companions (and also helps protect them against West Nile!).

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A temporary departure from the Worms & Germs conventional companion animal theme!

In 1894, HA Johne and L Frothingham discovered a tiny bacterium that was later found to be the cause of a disease in cattle characterized by chronic and severe weight loss and diarrhea. The condition ultimately became known as Johne’s disease, and it has been a thorn in the side of even very well-run dairy farms ever since. The disease is caused by a bacterium called Mycobacterium avium subsp. paratuberculosis (or MAP for short), which is in the same group as the bacterium that causes tuberculosis (TB). These bacteria typically live inside cells (usually white blood cells), and can therefore hide from the body’s immune system, which makes them hard to kill, even with antibiotics. It can also make them hard to detect. In cattle, the bacteria hang out in the lymph nodes and lymph tissue in and around the end of the small intestine (parts of the cow that do not enter the human food chain). The body’s attempts to kill the bacteria over time lead to chronic inflammation, which interferes with the ability of the animal to absorb nutrients from the intestine. This eventually leads to weight loss and diarrhea, even though the cow still eats.  The disease also occurs in sheep and goats.

Yes, cows with Johne’s can still produce milk, and even before they’re sick MAP can sometimes be found in the stool and milk. On July 7, 2008, the CBC National ran a story about the possible link between Johne’s disease in cattle and Crohn’s disease in people. This is a very controversial topic, and arguments both for and against a relationship between bovine MAP and Crohn’s disease have been reviewed. There are even cases of Crohn’s that were thought to have been cured by the consumption of raw milk, which is more likely to contain live MAP bacteria (and potentially a lot of other bacteria most people shouldn’t be drinking). It’s also clear that there are genetic and environmental factors that affect whether or not a person will develop Crohn’s disease. It’s a very complicated picture, but I don’t find there’s enough evidence at this point that people need to start boycotting milk and dairy products for fear of Crohn's disease. For now, I’d say cook your meat well, wash your hands, avoid cattle manure whenever possible, and stick to pasteurized dairy products, but don’t be afraid to enjoy a cheeseburger and a glass of milk on a beautiful summer afternoon :)

Cattle (both beef and dairy) are usually infected with Mycobacterium avium subsp. paratuberculosis (or MAP for short) as newborns, but it may take 2 to 10 years to develop any signs of Johne’s disease. The condition is essentially impossible to treat in cattle, so efforts have focused on trying to prevent young animals from becoming infected in the first place.

The Canadian cattle industry is actively addressing the problem of Johne’s disease through the Johne’s Disease Prevention Project. At the moment, Johne’s control programs are still voluntary in Canada, but more and more farms are getting on board.  It’s a long, slow process that takes years, but eventually the disease can be eliminated from the herd. Whether or not eliminating Johne’s disease from cattle may have an impact on the occurrence of Crohn’s disease in consumers remains unknown, but it certainly won’t hurt. Regardless, being Johne’s free is better for the farm, and better for the cattle.

For more information on Crohn’s disease, check out the Crohn’s and Colitis Foundation of Canada website.

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This time of year, hot spots (aka superficial pyoderma, moist pyoderma, pyotraumatic dermatitis) are a common problem in dogs. Hot spots are more common in males, and most often occur on the cheek (pictured), neck or outside of the thigh. Normal skin is covered with various bacteria but infections don't develop because healthy, intact skin is a natural protective barrier. Hot spots typically occur when the skin's normal barrier is compromised from scratching (e.g. from allergic skin disease, insect bites) or chronic moisture (e.g. under the ear or collar of dogs that swim a lot). Hot spots are typically red, with oozing serum or pus on the surface and a foul smell. They are often itchy, so affected dogs with repeatedly scratch the area, but they may also be very painful.

Various bacteria can cause hot spots. Most commonly, Staphylococcus pseudintermedius is involved. Hot spots are quite low risk for transmission to other animals or to people, although it is possible for concerning bacteria like methicillin-resistant S. aureus (MRSA) to be involved. Only a culture of the infected site can determine the bacterium that is involved.

• Most hot spots are easily treated. This typically involves clipping the hair around the infected site and scrubbing the area with antibacterial soap. Sometimes, antibiotics and/or anti-inflammatories are also needed. The infected site should be kept as clean and dry as possible.
  
• While most hot spots are not caused by bacteria that are a major concern for transmission to people or their animals, any infected site should be handled with care. Direct contact with the hot spot should be avoided.
  • If the infected site needs to be touched, gloves should be used if possible, and hands should always be thoroughly washed after touching the site.
  • Care should be taken when touching hot spots because they can be very painful, and touching them could make some dogs bite.
• Prompt examination by your veterinarian will help ensure your pet gets the treatment it needs as soon as possible, and ultimately helps speed recovery.
• Always follow your veterinarian's recommendations closely and completely. Stopping treatment too early can lead to recurrence of the infection, which may be more difficult to treat.

Image from http://flickr.com/photos/lorimari/2545821104

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I've had this question a few times recently. There isn't really a straightforward answer, and it depends what people mean when they say 'get'. I've broken the question into a few components.

Can C. difficile be found in dogs and cats?
Yes. A small percentage (1-5%) of healthy dogs and cats carry C. difficile in their intestinal tract, and pass it in their stool. Higher carriage rates are found in certain groups, such as young animals, animals in veterinary hospitals and animals that visit human hospitals as part of therapy programs. Most animals that are carrying C. difficile do not get sick.

Does C. difficile cause disease in dogs and cats? (i.e. do they get sick?)
The answer to this one is 'probably'. I don't think we can say for sure, but C. difficile appears to be a cause of disease in dogs and cats, ranging from mild diarrhea to fatal severe colitis. There is evidence indicating that C. difficile might be one of the more common causes of diarrhea in dogs. In people, C. difficile infection is most common in hospitalized individuals and those being treated with antibiotics. The situation is different in dogs and cats, where disease seems to be most common in households (not veterinary hospitals), and in animals not being treated with antibiotics.

Information sheets on Clostridium difficile can be found on our Resources page.

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Petting zoos can be great activities, providing entertainment and education to kids and adults alike. However, contact with animals at these events does come with some degree of risk, and numerous infectious disease outbreaks associated with such contacts have been reported. Because of these risks, most petting zoos are improving their infection control precautions, particularly with respect to handwashing by participants after touching animals. Yet some high risk behaviours continue to occur. The picture at the right was recently published in the York Daily Record. While cute, this picture raises the ire of someone like me (especially since I have young children). My main concern: the goat is licking this baby's bottle.

Where do you think the goat's mouth just came from? The ground, along with manure from various animals.
What might the bottle have been contaminated with? E. coli O157, Salmonella, Campylobacter, Clostridium difficile...
Where do you think this bottle is going next? The baby's mouth.
What will probably happen to the child?: Nothing.
What might happen to the child?: Disease caused by one of the above-named microorganisms (or others), ranging from mild diarrhea to fatal infection.

While there is good information available about precautions that should be taken for petting zoos, such as from the National Association of State Public Health Veterinarians, not all petting zoos take adequate precautions. A recent study pointed out common deficiencies.

Some important points to consider:

• Petting zoos are safe for the vast majority of the population if common sense measures are used.
• Items that will end up in the mouth of a child should never go into a petting zoo.
• Children should be closely supervised in petting zoos.
• Uncontrolled animal contact should be prevent.
• Hands should be washed after contact with animals or the petting zoo environment.

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While people often consider plague (aka the 'black death') to be something from history books, it is in fact still alive and well is some areas of the world. In North America, it is most common in the southwestern US but can extend into other regions.

Plague is caused by the bacterium Yersinia pestis, which is carried primarily by wild rodents.  Infection with Yersina pestis can cause bubonic plague (swollen lymph glands), septicemia plague (bloodstream infection) or pneumonic plague (pneumonia/lung infection).  An average of 13 human cases are diagnosed in the US every year.  In today's modern times, the infection can be effectively treated with antibiotics, but if left untreated the mortality rate is still 50-90%. The Canadian Notifiable Disease Database has never received a report of plague in a human.

Plague has been reported in a variety of animal species, including cats and dogs. However, dogs seem to be relatively resistant to the infection compared to cats. Yersinia pestis gets from rodents to other animals and people mainly by flea bites. Fleas become infected by biting an infected animal, and can then pass on the infection by biting another animal or person.  It is also possible for plague to be transmitted by direct  contact with infected animals, but this is less common.

A recent report described an outbreak of plague in prairie dogs in western South Dakota.  There is  concern that the disease could also affect the endangered black-footed ferret in that area. Plague almost always kills prairie dogs, and black-footed ferrets almost exclusively eat prairie dogs.

When plague is present in wild animals in a region, there is always a risk of transmission to people and pets through contact with infected animals or bites from infected fleas.  Some basic measures to reduce the risk of plague exposure in areas where the disease exists in wild animals are:

• Keep cats indoors
• Talk to your veterinarian about a flea control program for your pets
• Never touch wild animals, especially sick or dead ones
• Don't keep wild animals as pets
• Try to keep wild animals away from your pets

Photo: Scanning electron micrograph of an Oriental Rat Flea, Xenopsylla cheopis.
(Centers for Disease Control and Prevention (CDC) / Janice Carr)

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I often get asked about testing of healthy pets for Clostridium difficile. This bacterium is an important cause of disease in people. While most common in people in hospitals, cases of C. difficile infection are occurring more in people in the general population. Also, C. difficile can be found  in various animals, including dogs and cats. This has led to concerns about the role of pets in C. difficile infection in people. The role of animals in human infections has not been determined, but it is plausible that C. difficile could be transmitted between people and pets, in both directions.

I have been diagnosed with C. difficile. Should my pet be tested?
No. There is no evidence that it is useful. Even if C. difficile is isolated from your pet, it would not tell you if the pet was the source. Your pet could be carrying a completely different strain of C. difficile. Molecular typing of the recovered bacteria (from both you and your pet) would be needed to determine if they are the same strain, and this type of testing is not readily available. Even if you both had the same strain, your pet could have picked it up from you. So, testing of your pet really wouldn't tell you anything.

I'm worried that I may have acquired C. difficile from my pet. Can I just have my pet treated at the same time I'm being treated?
No. Treatment of healthy pets to eliminate C. difficile is not recommended. There is no evidence that we can eliminate C. difficile from a healthy pet with antibiotics.

More information on Clostridium difficile can be found in our Resources page.

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Another incident of importation of a dog with rabies has been reported. A number of dogs have been brought home by US soldiers, and a few cases of rabies have been found. In the latest case, rabies was diagnosed in 1 of a group of 26 dogs that was flown back to the US to join returning soldiers. All customs and health regulations were followed, but rabies was diagnosed in the dog approximately 3 weeks after arrival.

This incident highlights a few things, including the fact that rabies, even in dogs, can be quite common in some areas of the world, and that movement of animals across borders may increase the risk of introducing infectious diseases. Certainly, cases such as this should not be used to say that these dogs should not be adopted. Rabies (or other serious disease) is a rare event in these situations, and the overall risks to people are minimal if proper procedures are followed. This includes making sure that all animals remain accounted for after arrival, and pursing proper diagnostic testing in the event that they show signs of illness (as was done here). The other dogs that came back with the rabid dog are being monitored. The risk of transmission from this dog to the others is quite low, since it is unlikely that the dog was able to transmit rabies 3 weeks ago, well in advance of developing signs of disease. In some cases it can be weeks to months from the time a dog (or other animal) is exposed to rabies until they become infectious to others.  Presumably, people that had contact with this dog recently are now undergoing post-exposure treatment.

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

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Even the most well-natured, lovable cat has the potential to bite. Particularly if an animal is frightened or in pain, it may lash out with teeth and claws, even at its most trusted human companion. Many of us are used to sustaining small cuts and wounds in everyday life, and at times it hardly seems worthwhile to trouble a physician to look at a little cat bite. But 20-50% of cat bites become infected, compared to 4-20% of dog bites. The bacteria responsible are most often combinations of Pasteurella spp., Staphylococcus spp., Streptococcus spp. and others. In some cases, particularly when Pasteurella multocida is involved, the infection can develop very rapidly (within hours) and may become very serious, or even spread to the bloodstream. Cat scratch disease (Bartonella henselae infection), despite the name, can also be transmitted by cat bites. Cat bites can be very deep, even though they look very small at the level of the skin, which may lead to infection of things like joints and tendons under the skin, which are more serious.

You should see a doctor about any cat bite on a hand, over a joint, over a tendon sheath (such as the wrist or ankle), over a prosthesis or implant, in the genital area, or that causes a deep tear. You should also see a doctor for any bite if you happen to have a weakened immune system for any reason (e.g. HIV/AIDS, cancer or transplant patients).

The best way to prevent infection is to prevent the cat from biting you in the first place!

• Use common sense – know how to handle a cat properly so that it is not frightened or uncomfortable. If a cat growls at you or tries to get away, let it go!
• Don’t let cats play with your hands, feet or hair. Use a nice cat toy instead.
• Don’t approach strange cats, especially strays. If you are bitten by a cat that may not have been vaccinated for rabies, it is very important to report the incident to you local public health department and your doctor, as you may need to receive rabies post-exposure prophylaxis (PEP).

More information on cat bites, what to do if you are bitten and ways to prevent cat bites can be found on the Worms & Germs Resources page.

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The European Union has announced that November 18 will be the EU's Antibiotic Awareness Day. Antibiotics are incredibly important drugs and save countless lives (human and animal) on a daily basis. Resistance to antibiotics is a major threat to human and veterinary medicine. While antibiotic resistance is a complex issue, overuse and improper use (in animals and people) undoubtedly contribute to the emergence and spread of resistant bacteria like MRSA. Awareness of these concerns is important for healthcare professionals (both human physicians and vets) and the general public. Here are some general points to remember with respect to pets and antibiotics:

• Do not encourage your vet to prescribe antibiotics when they are not necessary. Vets (and physicians) often feel pressure to prescribe 'something', even though they have no clear evidence of a bacterial infection. Antibiotics do not work for viral infections.
• Never give antibiotics to your pet without the direction of your vet.
• Always give the full antibiotic course, as prescribed. Do not stop early. Your pet may look better but the infection could still be there.
• Never save antibiotics for 'future use'. If your pet develops another infection, you need to have your pet evaluated by a vet to determine if antibiotics are needed, and what antibiotic would be best.

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As the owner of a dog that loves to roll in (and eat) anything she finds, I certainly understand the questions that I get about risks to dogs from dead birds. Eating a dead bird is certainly not an appealing thought to us, but overall, the risks to a dog are pretty low. The greatest potential problem is likely gastroenteritis, often referred to as ‘garbage-gut’, which typically causes diarrhea (with or without vomiting) after "dietary indiscretion" (i.e. a dog eating things it shouldn't have). Another concern is Salmonella. Some birds carry Salmonella in their intestinal tracts and dogs could become infected from eating them. This is a bigger problem in cats that hunt birds - salmonellosis in outdoor cats is also referred to as songbird fever. West Nile virus can cause death in birds, especially species such as bluejays and crows, which may then be found by your dog. The risk of transmission of West Nile virus to dogs from eating dead birds is presumably very low. Further, this disease is very rare in dogs and they appear to be quite resistant to the virus.

• Try to prevent your pet from eating/touching dead birds.
• If your pet develops diarrhea after eating a dead bird, it is probably not a health concern for anyone else but Salmonella infection is possible, so consider taking your dog to the veterinarian. This is especially important if the dog appears sick (i.e. besides vomiting and diarrhea, the dog also is not acting like itself) or if there are people in the household that are at higher risk for getting sick from bugs like Salmonella (i.e. infants, people with weakened immune systems). All diarrhea should be considered potentially infectious to other animals and people.  Extra care should be taken around affected pets and their stool, including extra attention to hand washing, and disinfecting the site of any "accidents" that occur in the house.
• In some areas where bird testing is performed for West Nile virus or avian influenza surveillance, public health personnel will collect dead birds. Contact your public health department if you are unsure what is done in your region.

If you must move or remove a dead bird, precautions should be taken. These include:

• Do not touch dead birds with bare hands.
• Use heavy-duty, leak-proof gloves to place the bird in a leak-proof plastic bag. Alternatively, fold two bags over your hand and use the bag to cover your hand when picking up the bird (like people do when poop-scooping), or use a shovel to place the bird in a bag.
• Double bag the bird.
• If the bird is not being collected for testing, contact your local waste management agency regarding disposal instructions.
• Always wash your hands with soap and water as soon as you're done.

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As we (finally) get nice weather here, a rash of questions about ticks usually follows.  Ticks are very common in some areas, and a short walk in the woods can result in exposure. Ticks themselves aren't the concern. The problem is infectious diseases that ticks can transmit, including Lyme disease. The risk and types of diseases of concern vary geographically. (In Ontario, exposure to ticks that can transmit Lyme disease is most common in Point Pelee, Rondeau, Long Point, Turkey Point and the Thousand Islands area). There are a number of ticks that may feed on people and pets, but only a few that transmit infections. Your veterinarian, physician and/or public health departments should be able to tell you what diseases are of concern in your area.

Regardless of where you live, if you and your pet might encounter ticks, you should know how to remove them. Prompt removal is the key. Most tickborne diseases aren't transmitted immediately. Rather, the tick must be attached for a period of time for infection to occur. Therefore, close inspection of your pet (and yourself) for ticks after spending time outside, is important.

The following tick removal tips come from the Centers for Disease Control and Prevention (CDC).

• Remove a tick as soon as you see it.
• Use fine-tipped tweezers to firmly grasp the tick very close to your skin. With a steady motion, pull the tick away from your skin. Then clean your skin with soap and warm water.
• Avoid crushing the tick’s body.
• Do not be alarmed if the tick’s mouthparts remain in the skin. Once the mouthparts are removed from the rest of the tick, it can no longer transmit Lyme disease bacteria.
• If you accidentally crush the tick, clean your skin with soap and warm water or alcohol.

Tick removal devices are also available and can be used in place of tweezers. If you use one, make sure the device does not squeeze the tick's body as you remove it.

If a large number ticks are present on your pet, you should contact your veterinarian for assistance. Typically, a product that kills ticks will be applied to your pet.

There are various anecdotal recommendations that should be avoided, including burning the tick off with a match and covering the tick with substances such as gasoline, petroleum jelly or nail polish.

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There is a lot of concern and confusion about methicillin-resistant staphylococcal infections in pets. "Staphylococcus" is genus of bacteria which contains numerous different species. All these species can come in 'methicillin-resistant' forms that are resistant to many antibiotics, but some of these species are of greater concern than others. The main species of concern are discussed below.

Methicillin-resistant S. aureus (MRSA): This species is the big concern. MRSA is an important cause of disease in people and an increasing problem in pets. It can cause serious infections and be transmitted between animals and people (in both directions).

Methicillin-resistant S. intermedius (MRSI): Actually, what most laboratories still call S. intermedius appears to be a related species called S.  pseudintermedius. Regardless, MRSI (or MRSP) can cause a variety of infections in pets - usually skin and ear infections. While it can be spread from animals to people, this is likely rare and there is much less concern about MRSI compared to MRSA in terms of risk to humans from infected pets.

Methicillin-resistant S. schleiferi (MRSS): This species is closely related to (and often misidentified) as S. intermedius. It is most commonly found in skin and ear infections. There is no information about the risk of transmission to people from pets. It is probably possible but very unlikely.

Methicillin-resistant coagulase-negative staphylococci: This is a large group of staphylococcal species that are usually lumped together. They are commonly found in or on healthy dogs and cats as part of the body's normal bacterial population. They are less common causes of disease. There is currently minimal concern about transmission to humans.

MRSA is the main concern with regard to staph infections, and warrants particular attention when it causes infection in a pet. In these cases, important precautions to take include washing your hands frequently, avoiding contact with the infected part of the animal's body (plus the nose, where MRSA often hangs out), keeping the infected site(s) bandaged (if possible), keeping infected pets off the bed, and restricting contact with high risk people (e.g. young children, elderly, immunocompromised). For the other staph species, the risks to people are much lower, but it is still reasonable to implement these measures to further reduce the risks.

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Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug resistant bacterium that is often referred to as a 'superbug'. It is an important cause of disease in people, both in hospitals and in the general population. It can also infect various animal species, including dogs and cats. A small percentage of healthy people and animals (1-3%) carry MRSA without knowing it, and usually without ever having any problems. Unfortunately, increasing awareness of the potential for healthy pets to carry MRSA has led to excessive focus on pets in some situations. While transmission of MRSA between people and pets can happen, it is probably more common for it to go from people to pets, than pets to people. Pets should not be 'blamed' for human MRSA infections without good evidence, and there are only certain situations where evaluating pets is currently indicated.

Here are some important points from the Canadian guidelines for management of community-associated MRSA in people.

• Testing of pets for MRSA carriage should only be considered when there is recurrent MRSA in the household and transmission is ongoing despite the implementation of household infection control measures.
• Testing of pets should only be done as part of an overall investigation of the household. Testing of pets but not human household contacts is not indicated.
• Removal of the pet should only be considered in exceptional circumstances, and removal should be temporary. Such circumstances could include households where controlling contact with the pet is not possible and/or when people in the household are being treated to eliminate MRSA carriage. The beneficial effects of pet contact should be considered in any discussion about removal of the pet from the household.

If you have MRSA, wash your hands frequently, limit contact with your pet's face and do not touch wounds on your pet. These should greatly reduce the risk of MRSA transmission.

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While visiting my parents this weekend, we came across a litter of stray kittens in the backyard. This is not an uncommon event and many people obtain their cats this way. Adopting stray kittens can be a great way to get a cat because it provides  a good home for kittens that would otherwise end up increasing the feral cat population. However, there are some things to consider to reduce the risks to your family and your other pets.

Various bacteria that can cause diarrhea in people can be carried by kittens, including Salmonella and Campylobacter. These are shed in the stool of infected animals, and people can become ill from handling the animal or stool-contaminated areas. Kittens may have higher rates of carriage of these bacteria than adult cats. Another bacterium that can be carried commonly by kittens is Bartonella henselae, the cause of cat scratch disease. This is transmitted by bites, scratches and fleas, and is just one reason for proper flea control.

Stray kittens are also more likely to carry Toxoplasma, a parasite that is a concern in pregnant women and immunocompromised individuals. Other intestinal parasites such a roundworms are also a concern. Kittens are more likely to have these parasites than adult cats.  Stool contamination of the haircoat is presumably more common in kittens as well because they are not as good about cleaning themselves as adult cats.  So just handling a kitten, even if you avoid its stool, may result in exposure to some of these parasites and bacteria.

Rabies is always a concern, and widespread exposure of people to rabies has occurred from infected litters of kittens.  While uncommon, rabies is a major concern because it is almost invariably fatal. Any stray (or recently rescued) animal that starts acting strangely should be considered a rabies-suspect and be taken to a vet immediately. [More information on rabies, and other topics, is available in our Resources page].

Stray kittens can also carry various infectious diseases that can be transmitted to other cats in the household, such as feline leukemia virus, panleukopenia, rhinotracheitis and calicivirus.

Overall, the risks from adopting stray kittens are low, but they are real. If you are going to adopt/rescue a stray kitten, keep these things in mind:

• Take the kitten to your vet as soon as possible to identify any health issues and determine the required vaccination, deworming and flea control program
• Wash your hands after handling the new kitten
• Keep the new kitten in a confined area while litterbox training is underway to reduce accidents throughout the house
• If you have another cat, make sure it is up-to-date on vaccinations before the kitten comes into the house.
• If the kitten gets sick, make sure it is taken to a vet. If it dies suddenly, make sure you take it to your vet to determine whether testing for rabies is required.
• Pregnant women and households with immunocompromised individuals should not adopt stray kittens.
  

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The CDC has released the findings of an investigation of a prolonged multistate outbreak of salmonellosis that was linked to dry dog food in 2006-2007. This outbreak implicated two different dog food brands, both made by the same manufacturer in the same plant in Pennsylvania, as the source of a particular strain of Salmonella Schwarzengrund.  The strain infected numerous people, and was also found in some dry dog food samples and stool samples of dogs that were fed the food, with which the affected people had had contact. No illness was reported in the pets. It is unclear whether people were infected from contact with the food or contact with the pets' stool.

This is the first report of  salmonellosis associated with dry pet food. Previous outbreaks have been associated with contact with raw pet treats such as pig's ears. Overall, the risk from contact with dry pet food is quite low, although this outbreak clearly demonstrates that some risk exists. Handwashing after contact with pet food should greatly reduce the already low risk.

This report is certainly not a reason not to feed your dog or cat a commercial pet food. One concern that I have is that this report will (and already seems to) be used by proponents of raw meat diets as support for this feeding practice. Feeding of raw meat has been clearly shown to increase the rates of shedding of potentially dangerous bacteria such as Salmonella. Illness and death from these bacteria have been identified in dogs fed raw meat. The high rates of Salmonella shedding in raw-fed dogs are a significant public health concern, and these concerns have been previously reviewed. Outbreaks of human salmonellosis have not been reported in association with raw meat feeding. This could indicate minimal risk, but could equally be due to lack of identification of sporadic cases that would be more likely with raw food than large-batch commercial contamination or better hand hygiene practices associated with raw meat handling. 

- The risk of Salmonella exposure is still much lower with good quality commercial pet food compared to raw meat.
- Wash your hands after handling pet food (of any variety), as well as food and water bowls.
- Care should be taken when handling animal stool to avoid any direct contact with it.  Wash your hands after picking/cleaning up any type of stool, even if you use a plastic bag or a designated scoop to do so.

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Another question that I periodically get asked is about pets (mainly dogs) and strep throat. The usual situation is a household where there has been strep throat in multiple family members or where someone, usually a child, has had repeated bouts of strep throat. People ask whether their pet could be the source.

Strep throat is caused by Group A Streptococcus, a bacterium that can be found in the throat and on the skin of some healthy people. Strep throat and impetigo are the most common diseases caused by Group A Streptococcus, although severe (‘invasive’) infections can occur, including ‘flesh-eating disease’. Group A Streptococcus is typically spread between people, both from people that are sick and healthy carriers.

Group A Streptococcus carriage by dogs and cats is extremely rare, and it is unlikely that they are involved in transmission to people. There were some older studies implicating dogs in transmission of Group A Strep, however there were weaknesses in the methods used by those studies which probably lead them to misidentify other types of Streptococcus that are often found in dogs as Group A Streptococcus. There is currently no convincing evidence that pets are a source of strep throat infection, although the possibility cannot be completed dismissed.

I have had questions about treatment of pets when recurrent strep throat infections were present in a household, which is not supported by any evidence and could lead to problems like antibiotic resistance and side-effects from antibiotic use such as diarrhea. It’s hard to say whether there is any indication to test dogs or cats when recurrent strep throat is present in a household. Collection of a throat swab by a veterinarian and culture of the swab is fairly easy to do. It’s not unreasonable to consider that but a few things must be remembered:

- Even if Group A Streptococcus is found in a pet, it does not mean that the pet is spreading it. The pet might just be an ‘innocent bystander’ that was infected by a family member. It makes no sense to test the pet if the rest of the household is not being tested.
- Proper identification must be performed by the laboratory to differentiate Group A Strep from other strep. Just finding ‘Streptococcus’ is not useful.
- There are no guidelines for what to do in the unlikely event that a pet is identified as a carrier.

Overall, pets are not likely a major (or even minor) source of strep throat. If strep throat is circulating within a household, it's most likely being spread between people.

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Sixteen people in South Carolina are undergoing rabies post-exposure treatment after having contact with a rabid baby raccoon. Additionally, 20 of their pets are undergoing quarantine.

Wildlife should be left in the wild. While some wild animals, especially babies, are hard to resist, little good usually comes from intervention of the general public. This is particularly true when well meaning people ‘rescue’ baby wildlife. Often, ‘orphaned’ wildlife are not orphans; the parents are hiding nearby and would have returned. Few animal facilities are properly equipped or licensed to properly deal with wildlife, and these ‘rescued’ orphans often end up being euthanized. Some people try to nurse these animals themselves but few can do it properly. It’s also illegal in many areas. Add that to the obvious risk of rabies, as highlighted here, and it should be clear that wildlife should be left alone. It’s also a good reminder of the need to vaccinate your pets because rabies exposure can occur in many different ways. The pets in this situation are reportedly under 45 day quarantine, which is certainly not something you want to do, but is much better than what would happen in many jurisdictions in the case of rabies exposure of an unvaccinated pet (long strict quarantine or euthanasia).

Baby raccoons are very cute and hard to resist, but like many other forms of temptation, danger, in this case in the form of infectious diseases, can lurk just around the corner. More information on rabies is available in our Resources section. 

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A recent issue of CDC’s Morbidity and Mortality Weekly Report described a case of rabies in a person from Minnesota. This person died of rabies in 2007. Approximately one month before he became ill, he held a bat in his hands and felt a ‘pin-prick’. He didn’t see a wound or blood and assumed that he had not been bitten. Since neither he nor his family knew that this type of contact was actually considered rabies exposure, he did not seek medical attention. He died approximately 3 weeks after he developed rabies. Post-exposure rabies treatment would have almost certainly prevented his death.

- Never handle a bat
- Assume all bats are rabid until proven otherwise
- Any contact with a bat is considered to be rabies exposure unless the bat has been tested and shown to be negative. All bat exposures should be reported to the appropriate public health authorities.
- Despite all the old stories, rabies exposure treatment is not horrible…it’s just a series of shots in the arm.
- Vaccinate your pets. You never know when they’ll encounter a bat…inside or out.

More information on rabies is available in our Resources area.

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In Beijing, 700 000 dogs have recently been vaccinated against rabies in order to combat the growing rabies epidemic there, and reduce the risks to people attending the 2008 Olympic games.

Unfortunately, rabies is common in China, with the number of cases increasing dramatically over the last decade.  In 1996, there were 163 humans deaths due to rabies. This number increased to 3380 in 2007.  Because of the seriousness of disease, the number of deaths and the low vaccination rate in dogs, a mandatory vaccination policy for dogs has been put in place. Free rabies vaccination is provided annually for each licensed dog. This could have a tremendous impact on the number of rabies cases, at least in certain regions. Control of rabies in rural areas is more problematic because of the lack of an organized registration and vaccination system for dogs in those areas. Perhaps not surprisingly, most cases of rabies occur in these rural regions.

So, the 2008 Beijing Olympics may have benefits for the dogs of China as well, or at least those in Beijing. This is certainly a preferred approach to the reports from last year of mass killing of thousands of dogs (including pets).  Let's hope this progressive approach continues and the impact of this horrible disease decreases.

On a related note, the latest human death from rabies in Beijing was a person who was bitten by a stray dog two months before he became ill. He didn't seek medical attention at the time of the bite, he just cleaned the wound himself.  If he had been treated for possible rabies exposure, he'd be alive today.  While rabies is uncommon in many areas, no bite from an animal should be taken lightly.  Rabies should always be considered and appropriate measures taken. More information about rabies is available in our Resources section.

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The picture on the right is a Picasso painting entitled "Cat catching a bird". I often use this picture in presentations and ask "What if that bird was infected with avian flu?"

Avian flu is a tremendous concern at the moment. While it is not (currently) easily transmitted between people, bird-to-human infections have been reported in various countries. Mortality rates are very high, and the concern is that this strain could change to become easily transmitted between people, and lead to a pandemic (worldwide outbreak) not seen since the Spanish flu pandemic in the early 20th century. While birds and people are the focus, some attention has been paid to other species, such as cats.
Fatal avian flu developed in leopards and tigers in a zoo in Thailand during an avian flu outbreak. It was suspected that they ate infected chickens. Similarly, avian influenza in a pet cat was thought to have resulted from eating a dead pigeon (the pigeon presumably having died of avian flu).  The potential role of cats in transmitting disease was highlighted by a study that reported that cats can become infected by eating infected birds, and can transmit avian flu to other cats.

While unproven, cats could theoretically play a role in transmitting this virus from birds to people. It's unlikely cats would be a major factor in a flu pandemic, but if such a situation were to arise, any possible source of transmission would need to be considered.

Should we worry about cats and avian flu right now? Worry....no. Be aware....yes. H5N1 avian influenza is not currently present in North America and it's hard to say if/when it will appear.

Should we think about cats when making plans for management of avian influenza if/when if reaches us? Absolutely. It's issues like this that get overlooked in outbreak planning.

Should I keep my cat inside? Yes. Outdoor cats are exposed to a large number of different infectious agents, including parasites and bacteria that can infect people. Outdoor cats can also get into fights, during which animals can transmit important diseases or cause nasty wounds. Also (obviously), an indoor cat isn't like to get hit by a cat...an important cause of premature death in cats.

Avian flu is just one more indication that our relationship with infectious diseases is much more complex than we've thought, and that broad (ecological) approaches to infectious disease control are required. We need to think about household pets when considering emerging infectious diseases because of the close and prolonged contact that millions of people have with their pets.

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This is a question that I get on a regular basis. Methicillin-resistant Staphylococcus aureus (MRSA) is an antibiotic resistant bacterium that is a major cause of disease in people and is also a cause of disease in various animals species, including dogs and cats. It can cause a wide range of infections, from mild skin infections to rapidly fatal disease. Most MRSA infections in animals are treatable if managed properly and most are treated in the home (as opposed to requiring a stay at a vet clinic). Because of this, there are concerns about transmission of MRSA from infected pets to people in the household. Transmission of MRSA between people and pets (in both directions) definitely happens, although we don't really know how often this occurs.

If your pet has MRSA:

• Talk to your veterinarian about how to handle the infection
• Avoid contact with the infected site. If you have to touch it, use gloves and wash your hands         immediately afterwards.
• Wash your hands regularly after contact with your pet
• Avoid contact with your pet's face...MRSA often lives in the nose, in addition to the site of infection
• Try to limit overall contact with your pet until the infection has resolved. Close, prolonged contact such as letting the pet sit on your lap or sleep on your bed should be avoided
• Follow your veterinarian's instructions closely. Always complete the full course of treatment, even if your pet looks better
• Talk to your physician if you have concerns about your health, particularly if you or someone in the household has a compromised immune system

Should I be tested?
Current recommendations are that there is no indication to test people or pets for MRSA carriage when there is an infected pet (or person) in the household. Testing might be reasonable in some circumstances where uncontrolled transmission of MRSA appears to be occurring in a household, but there does not seem to  be a reason to test with single incidents of MRSA infection.


Studies are currently underway looking at transmission of MRSA in households where pets have an MRSA infection. Better information will likely be available in the future as a result of these studies.

More information on MRSA in pets will be available soon in our Resources section.  Another good source of information is the Bella Moss Foundation, a charitable foundation dedicated to MRSA in animals.

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Recently, a story about a man who brought a horse into a hospital to visit his father was widely reported. The horse apparently made it to the man’s room, which included a trip in an elevator. The son, who appeared intoxicated, was eventually asked to leave (and take the horse with him). Said a hospital spokesperson “We do have a pet visitation policy, but it does not include a horse”. Strangely, the horse that was brought to the hospital apparently wasn’t even the father’s horse (which supports suspicions of the son’s lack of sobriety).

There are guidelines about which animals are appropriate for hospital visits, although it shouldn’t take an expert to figure out that a horse is not an appropriate candidate. Kicks, bites, and trauma from being crushed or run over are among the most obvious concerns. Horses can also carry a variety of bacteria that are potentially dangerous, especially to people in hospitals. These include Salmonella and methicillin-resistant Staphylococcus aureus (MRSA). There also aren’t that many house-trained horses out there.

So, while I can easily see how someone in a hospital would like to see his or her horse, there’s no way this should even be considered.

Some closing thoughts
-    Would you like to ride in an elevator with a horse?
-    Would you like to be stuck in an elevator with a horse?
-    Do you think the horse was house trained?
-    Do you think any of the healthcare personnel washed their hands after touching the horse?

This isn't the first time a horse has been in hospital, and some even get invited. The picture is from a story in Veterinary Practice News that described a program where horses were brought into hospitals!

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A sure sign that spring is approach is the advertising of outdoor summer items in stores. A large pile of sandboxes at one store caught my eye the other day, particularly as it followed a discussion I had with some infectious disease physicians about kids and sandboxes. Sandboxes can be a great thing for kids, however there are some infectious disease concerns. Uncovered sandboxes can become litter boxes for cats, raccoons and other outdoor animals. Some of these animals could be passing potentially dangerous bacteria and parasites in their stool. An example of this was reported a few months ago in Morbidity and Mortality Weekly Report. This report described an outbreak of cutaneous larval migrans in 18 children and 4 staff at a day camp. This is a skin disease caused by hookworms. Cats and other animals can pass hookworm eggs in their stool. A sandbox contaminated with cat stool was implicated as the cause.

We really have no clue about how common sandbox exposure causes disease. While this skin disease is usually relatively minor, there are some other groups of parasites that can migrate through other parts of the body, including the brain, and cause devastating illness. All of these are very rare in northern climates like Canada, but measures should be taken to reduce the risk of exposure because of the potential severity of disease. Risks are much higher in warmer climates. These are a significant concern in warmer areas. It’s probably pretty uncommon but some of the diseases that can occur are very serious, so attention should be paid to these risks. The main things that can be done to reduce the risk are keeping animals out of sandboxes and handwashing after contact with sand. Check out our “Sandbox” information sheet for more details.

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A Letter was just published in the New England Journal of Medicine about a woman with recurrent methicillin-resistant Staphylococcus aureus (MRSA) infections and her cat. MRSA is a hot topic because it’s a big cause of disease in people and there are indications that it can be transmitted between people and pets (in both directions). She kept getting recurrent infections and they eventually cultured MRSA from her cat. The cat was not sick and was a carrier. That’s something that we’re seeing increasingly, although we don’t know whether the pets are actually involved in transmission or whether they are innocent bystanders that are infected by their owners. The concerns that I had with this Letter revolve around the fact that the cat was treated for MRSA (in my experience, carriage of MRSA by dogs and cats is transient and antibiotics aren’t needed), they never tested the cat after treatment but they declare that the woman’s infections only ceased after the cat was treated. The problem is, the cat may have gotten rid of MRSA despite the antibiotic treatment, the owner may have handled the cat differently after finding out it was MRSA positive and therefore decreased the risk of transmission, or it may never have played a role in her infections.

Unfortunately, this Letter may lead to unnecessary treatment of pets that carry MRSA or over-assumption of the role of pets in human infections. It also meant that I was stuck doing rounds and rounds of interviews with reporters wanting comments. The key take-home messages from this are:

- Pets are part of the household and should be considered if a household disease investigation is undertaken.
- While pets may sometimes be involved in transmission of MRSA, simply finding MRSA in a pet does not mean that it has infected anyone.
- There is currently no indication that we should be using antibiotics to get rid of MRSA colonization in pets because they almost invariably get rid of it on their own.

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