Check out the new information sheets about Clostridium difficile now available on the Resources page!
Exposure to animal blood
Periodically, pet owners may be exposed to blood from a pet. This can range from exposure to small amounts of blood through minor injuries like cut foot pads or broken toenails, to large amounts of blood following severe trauma.
In people, there are detailed protocols for avoiding blood exposure in healthcare situations, and protocols for managing people exposed to human blood in hospitals and in the community. This is mainly driven by concerns about HIV and hepatitis viruses that can be transmitted by contact with blood. But these viruses are not present in animals, and the risks of transmission of disease from pets to people through blood are very low. Even contact with blood from a rabid animal is not considered rabies exposure, because the virus is found in the saliva, not the blood. This has led to a rather cavalier approach towards blood exposure in veterinary medicine, which is understandable but not ideal. New infectious diseases continue to emerge in animals and people, and eventually there is likely to be one that can be transmitted between species by blood. Therefore, it is prudent to try to reduce exposure to animal blood when possible, but without getting overly concerned (or paranoid).
- Direct contact with animal blood should be avoided whenever possible.
- In particular, avoid getting animal blood on any cuts, scrapes or other broken skin, and avoid getting the blood in your mouth, nose or eyes.
- If you do get animal blood on your skin, wash it off as soon as possible.
- While it is extremely unlikely for a person to get sick from touching animal blood, make sure you tell your physician about the incident if you do become ill.
Tapeworms in dogs and cats
Finding a tapeworm in a pet's stool can be a concerning event for some people. Tapeworms are intestinal parasites that can be found in varying percentages of dogs and cats. A common tapeworm (at least in North America) in dogs and cats is called Dipylidium caninum, and it can be found in a high proportion of dogs and cats in some regions, particularly animals that go outside and are infested with fleas. There is minimal concern about transmission of this tapeworm to people. Taenia pisiformis (dogs) and Taenia taeniaeformis (cats) are also common, and neither of these can infect people. 
People typically realize their pet has tapeworms when they see small tapeworm segments in the animal's stool. These whitish, rice-sized pieces (called proglottids, see the picture on the right) are parts of the adult tapeworm, which break off and are passed in the stool.
Tapeworms are not usually harmful to dogs and cats, particularly if only one or a few worms are present. In some situations, weight loss can occur. Affected animals may 'scoot' (drag their rear end across the ground) because of irritation from tapeworm segments that are passed in the stool.
Diagnosis of a tapeworm infestation is easiest through identification of tapeworm segments in stool. Identification of tapeworm eggs in stool samples through routine testing used for other intestinal parasites is less useful, as the bare eggs are infrequently shed in stool. Therefore, a negative fecal egg examination does not rule out tapeworms.
Dipylidium infections are extremely rare in people. Children are at greatest risk. Disease in people, if present, is usually mild and easily treated. However, finding tapeworms in a person's stool can be distressing to the individual (and their family). Dipylidium cannot be transmitted directly from animals to people. People and pets get infected by ingesting a flea that is infected with tapeworm larvae. Therefore, flea control is the most important aspect of tapeworm prevention. People that find tapeworm segments in their stool should contact their physician to determine whether they are actually tapeworms (people often mistake other things for tapeworm segments) and to determine whether any treatment is needed.
There are specific dewormers that can be prescribed by your veterinarian to eliminate tapeworms in pets. It is also important to take measures to control fleas and prevent dogs and cats from catching and eating animals that might be carrying fleas.
Cat bites - Why it's not "just a scratch"
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).
Rabies awareness month
June has been declared Rabies Awareness Month in New York State. The focus of the occasion is on education, particularly with respect to bats. Since 1990, 38 of 41 human rabies cases in the US involved bats. Approximately one-third of bats tested in New York are positive for rabies. In 2007, 559 animals were confirmed as infected with rabies in New York, and more than 3000 people were treated for rabies exposure. Further, more than 1400 New Yorkers undergo treatment each year following exposure to bats that were not caught and tested. State health personnel are emphasizing the need to catch and test bats if people have had contact with them, or when a bat has been present in a house with a sleeping person. They have produced a video on how to safely catch a bat in the house.
Important points to remember about rabies and bats are:
.jpg)
Never touch a bat.- Consider every bat to have rabies until proven otherwise.
- If you have slept in a house overnight with a bat, you are considered exposed. Unless the bat is caught and tested (and shown to be negative) you should undergo post-exposure treatment.
- If you or your pet may have been in contact with a bat, try to catch it (safely) so that it can be tested for rabies.
- Vaccinate your pets against rabies, even if they never leave the house.
Photo: Little brown bat (M.B. Fenton)
EU Antibiotic Awareness Day
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.
FDA Requests Seizure of Animal Food Products at PETCO Distribution Center
The US Food and Drug Agency (FDA) has issued a warning about pet food produced by PETCO in the US and sold at PETCO stores in Alabama, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Missouri, Nebraska, Ohio, Oklahoma, Tennessee, Texas, and Wisconsin. The food production facility was inspected in April and had a serious bird and rodent infestation. The problems had not been corrected by the next visit so the FDA seized the food. They are concerned that the poor hygienic conditions in the facility could put pets at risk from eating the food, or people at risk from handling the products. No illnesses in people or pets have been reported, but au
thorities are urging people to report any possible cases. They are also recommending that people wash their hands thoroughly if they have had contact with these products (including packaging), and that they wash any surfaces that have come into contact with these products (including packaging). Presumably, people should contact the store about a refund (I'm not sure I'd want a replacement from a plant that was shut down for repeated serious hygienic breaches).
Any potential illnesses associated with these products should be reported promptly to the FDA's consumer complaints coordinators.
There is no indication any of these products were sold in Canada.
Toxoplasmosis - Why Your Cat Shouldn't Get the Blame or the Boot
Toxoplasma gondii is one of the most widespread zoonotic pathogens in the world. Toxoplasma is a protozoal parasite that can infect almost any warm-blooded animal, including humans. In most people and animals, infection doesn’t cause any illness at all, and after the initial infection, the body usually produces strong immunity which protects it from subsequent Toxoplasma infection. Problems arise when infection occurs in a person with a weakened immune system. For example, toxoplasmosis (i.e. illness due to Toxoplasma) has been a major problem in HIV/AIDS patients, although better HIV treatments have decrased the incidence of the disease in this group in recent years. Toxoplasma can also cause problems when a woman is infected for the first time, before her body has developed immunity to the parasite, while she is pregnant. In these cases, the parasite can infect the fetus. This may result in birth defects or loss of the pregnancy altogether.
Our friendly feline companions have the unfortunate distinction of being what is called the “definitive host” of Toxoplasma. This means that even though the parasite can infect many species of animals, cats are the only species that shed the parasite “eggs” (which are called oocysts in this case) in their stool after they’re infected. But what most people don’t realize is that the number of cats that are shedding oocysts at any one time is very small – usually less than 1 in 100. And after the first time a cat is infected, it usually doesn’t shed oocysts again, and if it does it sheds them in very low numbers.
Depending on individual lifestyle and eating habits, a person is just as likely or more likely to be exposed to Toxoplasma from working in the garden or eating undercooked meat (particularly free-range pork or wild game). People who are pregnant or who have a weakened immune system do NOT need to get rid of their cats because of Toxoplasma, but they DO need to take steps to avoid exposure to Toxoplasma from all sources. This includes avoiding contact with cat stool and kitty litter by asking someone else to clean their cat’s litter box for them if possible, or wearing rubber gloves and being very careful to wash their hand very well afterwards if they need to clean the box themselves. Here are a few more tips that can help reduce their risk of exposure to Toxoplasma:
- Clean your cat’s litter box every day. The oocysts usually take about 24 hours to become infective once they’ve been passed in your cat’s stool, so daily cleaning helps remove them before they reach this stage.
- Always wash your hands with soap and water after cleaning your cat’s litter box, after working in the garden or in any soil, and after handling raw meat.
- Cook all meat, especially pork, lamb, mutton and wild game, to an internal temperature of 67ºC/153ºF or higher.
- Keep sandboxes covered so outdoor cats don’t contaminate them with stool.
- Keep your cat indoors. Outdoor cats are more likely to be exposed to Toxoplasma and shed oocysts in their stool.
Methicillin-resistant staph: what's in a name?
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.
Rabies kills...vaccinate your pets!
A recent report from South Carolina stated that 3 cats were euthanized because they were exposed to
a rabid raccoon. One of the cats was acting strangely and may have actually been infected with rabies (it is being tested). The other two cats appeared healthy, but none of them had been vaccinated for rabies, so the only options were to euthanize the animals or quarantine them for 6 months. In South Carolina, such a quarantine entails keeping the animals at a veterinary clinic or in a cage in an isolated room or yard, 24 hour a day. The owners did not want to quarantine the cats so they chose to have them euthanized instead. If the cats had been vaccinated, a much shorter and easier quarantine period could have been applied. Rabies vaccination is a cheap, easy and effective way of protecting pets and the public.
If you care about your family and your pets, vaccinate you pets against rabies.
More information about rabies is available in our Resources page.
I've been diagnosed with MRSA....could my pet be the source?
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.
Indoor cats and vitamin D
We've made statements supporting keeping cats indoors in different posts, and on our Cats fact sheets in the Resources section. There were many reasons for this, including keeping your cat safe from predators and other cats, and reducing the risk of infectious disease exposure. Outdoor cats are much more likely to pick up various infectious diseases, some of which can be harmful to the cat and some of which can be spread to people. This is a particular concern in households with people that are at increased risk of infection or where infections might result in more serious disease (i.e infants, elderly, people with compromised immune systems, pregnant women).
Recently, a comment was submitted in response to one of those posts. It questioned whether indoor cats would get enough vitamin D. It's a logical question and a good example of the differences between animal species. In people and some animal species, sunlight (UV light) exposure is important for production of vitamin D. Vitamin D is an essential vitamin and numerous health problems have been associated with vitamin D deficiency. However, cats are very poor at producing vitamin D in response to sunlight exposure. They get their vitamin D from their food. In the wild, cats get it from the prey they hunt. Pet cats get it from good quality pet foods that are supplemented with vitamin D.
Cats do not benefit from sunlight, from a vitamin D standpoint, so concerns over vitamin D should not be a factor in deciding whether your cat goes outside or not.
Stray kittens
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.
West Nile virus in dogs and cats
One thing that has become very clear around my house the past few days is that mosquito season has arrived. Along with the annoyance, buzzing and itching, mosquitoes are of concern because they can transmit various viruses, including West Nile virus. While West Nile season tends to be later in the summer and fall in most regions, West Nile virus awareness and mosquito bite avoidance should be considered whenever mosquitoes are around. 
Most of the attention about West Nile virus has been paid to humans, horses and birds, because of widespread illness and death in those species. Dogs and cats can certainly be exposed to West Nile virus if they are bitten by an infected mosquito; just like people and other animals. However, there are very few reports of West Nile virus infection in dogs, and even fewer in cats. Most dogs and cats that are infected do not develop signs of disease and simply develop antibodies against the virus.
Even if dogs or cats develop West Nile virus infection, there is no risk of transmission to other animals or human. This is because there is never a large enough amount of virus in the blood of these animals for a mosquito to pick it up and transmit it to another animal or person. The virus also can't be transmitted by direct contact with an infected dog or cat. West Nile virus is not found in saliva, so it is also unlikely to be transmitted by an animal (instead of an insect) bite.
There is no reason to be concerned about transmission of West Nile virus from your pets. If you live an area where West Nile virus is present, you should take precautions to avoid mosquito bites, such as avoiding mosquito-dense areas, wearing insect repellent with DEET, wearing long pants, long sleeves and socks when outside, avoiding peak mosquito hours (dusk and dawn) and eliminating any areas of standing water where mosquitoes can breed.
Pets and strep throat
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.
Prescription pets
It’s not “take 2 doses of Fido and call me in the morning”, but contact with pets has been shown to be beneficial to people in hospitals and nursing homes. However, concerns have been raised about whether Fido could be spreading more than good will; from Salmonella and ringworm to superbugs like methicillin-resistant Staphylococcus aureus (MRSA).
Recently, new international guidelines for these programs were published in the American Journal of Infection Control. A joint effort of physicians, infection control personnel, veterinarians and visitation program representatives, these guidelines provide comprehensive recommendations on how to run these programs and reduce the risk of disease transmission. Among the areas covered are appropriate animals, health care for visitation animals, appropriate human-animal interaction and the roles of visitation programs, pet owners and hospitals. “The goal of these guidelines is to keep these highly beneficial animal-assisted interventions safe for all involved. That means protecting not only the patients but the pets, as well as other people and animals the pets may subsequently interact with”, said lead author Dr. Sandi Lefebvre.
The Great Indoors - Keeping Kitty Content
Many a cat owner still believes that a cat’s natural habitat is outside in the great outdoors, where they can hunt mice and birds, chase insects and climb trees. Even after being domesticated and bred in captivity for hundreds and hundreds of years, house cats of all breeds still have those basic feline instincts – they love to prowl, hunt, stalk, pounce, and some delight in tearing their toys limb from limb. But from a health and infectious disease control standpoint, the great indoors is a far better place for your feline friend.
- A cat that goes outside, especially one that hunts, is more likely to pick up bacteria like Salmonella, or parasites like Toxoplasma and intestinal worms, which can potentially be transmitted to people, whether or not the cat gets sick. Outdoor cats are also more likely to come home with parasites like fleas which, in addition to being a major nuisance to you and your pet, can also transmit tapeworms and may contribute to the transmission of cat scratch disease (bartonellosis).
- Cats that live exclusively indoors are also not at risk of contracting two very important viruses, namely feline immunodeficiency virus (FIV, which is the cat equivalent of the human HIV/AIDS virus) and feline leukemia virus (FeLV, which is sometimes also called Fe-Leuk). These viruses are transmitted by direct cat-to-cat contact, particularly during cat fights. They cannot be transmitted to people, but they can make your cat very sick and prone to other infections, some of which may be zoonotic.
- It’s also easier to keep track of your cat’s health if it doesn’t go outside. Changes in your cat’s drinking and litter box habits, which can be important indicators of various health problems, can be detected much faster if your cat isn’t finding alternate sources of water or places to do its “business” outside.
- And there are still other benefits to keeping your cat indoors, including not having to worry about your kitty being hit by a car, not having to treat fight wounds and cat bite abscesses, and not having your feline friend bringing little “presents” into the house, like dead (or not so dead) rodents and birds.
See our Resources page for more information on zoonotic diseases in cats.
Cats and avian influenza
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.
UK Chief Vet says no pets in bed
The UK’s Chief Veterinary Officer Fred Landeg recently declared that pets should not be allowed to sleep in peoples’ beds or even be allowed in the bedroom. The reasoning behind this recommendation was the potential for transmission of bacteria such as Salmonella and Campylobacter. This was in response to a publication in the Veterinary Record describing animal-human interactions in households in the UK. It reported that 20% of participants let their dogs sleep in the bedroom and 14% let their dogs sleep in their bed.
.jpg)
While it is certainly true that any healthy animal (and person) can carry infectious diseases, and that prudence is reasonable, there is simply no evidence supporting this recommendation for the average household. Any contact with pets carries a very slight risk of disease transmission, just like any contact between people. There is currently no evidence, however, that sleeping with a pet in the bed increases the risk of disease. For your average pet and average household, this is probably exceedingly low risk and the recommendation is very difficult to justify. It is a reasonable recommendation when the pet is known to be carrying something that is transmissible to people (such as MRSA or Salmonella) or when a person has a compromised immune system. Banning pets from the bedroom completely doesn’t make any sense.
Personally, my dog is not allowed in my bed. However, that’s not because of disease concerns, it’s because she’s a large dog that snores and certainly can be a bed-hog. I have no problems with my cat on the bed. Life is never completely free of risk. If you enjoy having your pet in the bed, and you’re both healthy, I don’t see a reason to stop.
Not-so-likable licks
Sometimes when you fall and scrape your knee, or cut your hand, your favourite furry friend, in an act of unhindered devotion, will do to you what they would do to their own cuts and scrapes – they will try to lick it clean. The story that is often cited is the one about dogs and cats having enzymes in their saliva that help clean the wound. While it can’t be denied that there are various enzymes in the slobber, when you consider what else is in your little friend’s mouth, you’d be better to pass on their touching offer to help you clean up your cuts.
First of all, think about where that mouth has been, and what’s been in it! Does your cat hunt mice and birds around your house? Does your dog have a habit of eating unidentifiable bits of garbage or poop when out on walks? Or maybe your dog, like so many, enjoys a snack from the cat’s litter box every once in a while. You probably want to keep things like garbage and poop out of your cuts, and if your pet’s mouth has been there, it shouldn’t be near your wounds either.
Even dogs and cats that don’t have any distasteful eating habits have millions of bacteria of many different kinds in their mouths. Most of the time the bacteria don’t cause a problem, and the “good” bacteria help to keep the “bad” bacteria in check. But if the “bad” bacteria are put somewhere the body’s defense systems have already been breached – like an area of broken skin – those same bacteria suddenly have a prime opportunity to move in and start multiplying in their new home. Some bacteria like Pasteurella multocida can cause very serious infections in situations like this. This species of bacteria is one of the primary culprits in bite wound infections, which are especially common with cat bites.
So why do animals lick their wounds in nature? Well, “dirty” is in fact a relative term. An animal can use its tongue to get the worst of the dirt and debris out of a wound, and the wound will be cleaner. But compared to how clean you can make a cut by even just washing it with a lot of water and some soap, and maybe a little disinfectant, a lick from a cat or a dog is counterproductive to say the least. So the next time you have a boo-boo that Fifi or Fido wants to kiss better, say thanks, but no thanks.
Sandbox fun...
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.
Why should I vaccinate Fluffy, he's an indoor cat? (aka Why I'm glad I vaccinated Finnegan, my indoor cat)
Picture this. I’m driving home from the airport and get a call from my wife who’s locked in the bedroom with our kids because a bat is flying around the house. It’s not necessarily a big deal, except for the fact I thought I might have seen a bat in the house a couple days earlier, and a bat in a house with access to sleeping people = rabies exposure! I’ll save you the long but somewhat funny saga, and just say I eventually caught the bat. Our sigh of relief was short-lived, however, because it came back rabies positive. That meant we all needed rabies post-exposure prophylaxis (2 shots for Heather and I who have been vaccinated, but 6 shots for each of the kids). We also have a dog and cat, and they had to be considered exposed as well (the cat almost caught the bat). The cat, Finnegan, is an indoor cat but
was vaccinated. The repercussions on the animals were much less than on us. However, if they had not been vaccinated, we would have had a problem.
Protocols for rabies exposure in non-vaccinated animals vary between jurisdictions, but long quarantines are the norm, and euthanasia often is chosen.
The take home message is, even with indoor-only animals….if you care about yourself, your family and your pets, vaccinate your pets against rabies. In most places it’s the law. It’s also good sense.
Are cats the root of all evil?
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 h
ad 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.
Information Sheets for Pet Owners
INFORMATION SHEETS specifically for VETERINARIANS and for KIDS are also available on the Worms & Germs RESOURCES page!
Click on the highlighted topics below for information sheets. Topics that are not highlighted are in development and coming soon. Sheets for other animal species and diseases are also under development and will be added when they are available. 
| Animals | Diseases | Other |
| Dogs | Rabies | Litter Boxes |
| Cats | Giardia | Sandboxes |
| Turtles | Toxoplasma | Cat Bites |
| Hamsters | Leptospira | |
| Clostridium difficile | ||
| Cryptosporidium | ||
| MRSA | ||
| Campylobacter | ||
| Salmonella | ||
Please Remember:
- Your veterinarian and physician are your ultimate resource for information about the health of your pets or your family.
- Information provided here is accurate to the best of our knowledge, but infectious diseases can be unpredictable and these sheets are for general information purposes only.
- There can be great variation in disease risks in different geographic areas. The information provided was developed for Ontario, Canada, but most of the information is relevant for other regions as well.
