Water Foul - Cryptosporidiosis
Cryptosporidiosis is a diarrheal disease caused by several species of the genus Cryptosporidium, which are single-celled parasites. The disease can cause severe diarrhea. It tends to make the news when outbreaks occur associated with contaminated drinking water, but outbreaks only account for the minority of cases reported each year. Infection can be very serious (even fatal) in immunocompromised individuals, such as HIV/AIDS patients, but even immunocompetent (i.e. otherwise healthy) people can get sick. Different animals have their own species of Cryptosporidium. It is still unclear which of these species can normally infect people as well, and make them sick. Frequently cats and dogs with Cryptosporidium don’t look sick. Here are some facts:
- Cryptosporidium hominis primarily infects humans. Clearly it can make people sick, whether their immune systems are weakened or not.
- Cryptosporidium parvum primarily infects calves, and clearly makes people (and calves) sick. However, because it is relatively common in people as well, in many cases it is hard to say if a person with C. parvum was infected by contact with calf stool or human sewage.
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Both the dog-associated C. canis and cat-associated C. felis have been found in people, and C. felis can cause diarrhea even in immunocompetent individuals. Infection with these species in humans is very uncommon compared to C. hominis and C. parvum- The largest outbreak of cryptosporidiosis ever reported in North America occurred in Milwaukee in 1993, when an estimated 1.6 million people were exposed to the parasite and over 400 000 people became sick as a result of the infection.
- In most studies, contact with pets is either not associated with the risk of cryptosporidiosis or may even have a slight protective effect. One study showed no significant association between pet ownership and cryptosporidiosis in HIV patients.
Old pet, new baby...new problems?
Arrival of a baby results in dramatic lifestyle changes. As we try to emphasize at Worms & Germs, pets are a part of the household, and they can also be affected by the new arrival. While most pets handle the transition well, there can be some concerns. Foremost is aggressive behaviour towards the baby, which may occur due to inadvertent rough play, anxiety at household changes, territoriality or other causes. Even previously "perfect" pets can develop (and cause) problems as the social structure of the household changes. The potential problems can also change over time, as the baby starts to crawl, and starts to try to touch the pet or its toys or food bowls. Bites and scratches can occur, sometimes with tragic results. General recommendations for introducing a baby to your pet are available, including "And Baby Makes Four" and "Preparing Your Pet For Baby's Arrival" from the Calgary Humane Society. The Calgary Humane Society offers a program call New Baby, Old Pet, which is designed to help families make the introduction of babies to pets safe and happy. If you are expecting a new arrival in your family, you should consider contacting your veterinarian, local humane society or public health unit to see if a similar program is available in your area.
Controversy over Crohn's and Cows
A temporary departure from the Worms & Germs conventional companion animal theme!
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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.
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.
Why does my cat get vaccinated more than I do?
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People often wonder why it is recommended that they have their pet vaccinated every year, but rarely get vaccinated themselves after childhood. Traditionally, dogs and cats receive a series of vaccines as puppies and kittens, and then yearly booster vaccines for the rest of their lives. However, there are concerns about rare but serious adverse effects associated with vaccines. There are also questions about whether yearly vaccination is truly necessary for most pets and most diseases.There is no doubt that the beneficial effects of vaccination greatly outweigh the risks, but even so adverse effects cannot be ignored. Information about duration of immunity after vaccination, vaccine safety and disease rates need to be considered when determining how often to vaccinate an animal. Unfortunately, minimal information is available about how long most vaccines are protective in dogs and cats. So there is a logical tendency to err on the side of caution and vaccinate more frequently, rather than less.
New guidelines for vaccination of cats are now available from the American Association of Feline Practitioners. The guidelines recommend longer intervals between vaccines in most older cats that have been previously (and adequately) vaccinated.
Rabies vaccination also has important legal aspects to consider. Different jurisdictions have different requirements. While a three-year rabies vaccine is available, many regions still require more frequent vaccination. Even if an animal is properly vaccinated with a three-year vaccine, if local rules require yearly vaccination, an animal vaccinated more than one year earlier could be considered unvaccinated. This can have a tremendous impact if the animal is exposed to rabies - it could mean the difference between monitoring the pet at home, or a long quarantine, or even euthanasia. Therefore, it is important to consider the duration of immunity induced by the rabies vaccine used AND the local regulations. Rabies vaccination is even important for indoor cats.
The bottom line is:
- Vaccination is an important part of your pet's preventive medicine program.
- Different cats need different vaccination programs, depending on their age and what diseases they may be exposed to.
- Potential vaccine reactions should be reported to your veterinarian, who should then report them to the appropriate regulatory authorities, so that a better understanding of adverse reaction rates can be obtained.
- Don't let vague fears of adverse reactions deter you from vaccinating your pet. If you have concerns, get informed, talk to your veterinarian, and get accurate information.
Hot spots
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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.
The pinworm myth
Pinworms are small white worms that live in the rectum (the very last section of the large intestine). The human pinworm is called Enterobius vermicularis. Pinworm infections tend to be fairly mild (the sight of them is often more distressing than what they actually do), causing itching around the anus. Pinworms are common in young children and can be spread between people living in the same household. Pinworms are transmitted by swallowing pinworm eggs, which can survive in the environment for up to 2 weeks. Handwashing after using the bathroom is a key way to reduce the risk of transmission.A recurring myth is that pets are a source of pinworm infections in people. Pets cannot spread human pinworms, nor can they become infected by human pinworms.
If your child has pinworms, there are various measures that should be taken to reduce transmission and prevent recurrence. But testing, treating or banishing the household pet is not one of them!
Can dogs and cats get Clostridium difficile?
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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.
Petting zoos: What's wrong with this picture, Part II
Recently, my family went to an Ontario aviary/animal park. It was possible to touch many of the animals, and contact was encouraged because they sold food for the animals. The kids enjoyed having contact with animals, but this facility was an example of completely inadequate (or negligent) infection control practices. There's actually not much wrong with the picture in this post. The problem is that there was absolutely no means for people to wash or disinfect their hands after touching the animals. This is truly astounding in this day and age, with the increased awareness of the need for hand hygiene in these situations. Even at small, temporary animal exhibits and local fairs, handwashing facilities have become standard. I can't fathom why a large, permanent animal park wouldn't be set up properly. (It was even possible for people to touch aquatic turtles, which are very high risk for Salmonella transmission, but that's another story. More information on turtles can be found on the Resources page). What do you do if you want to have contact with animals but don't know whether you'll be able to wash your hands? Bring your own alcohol-based hand sanitizer. They're cheap, easy to find and effective, and it never hurts to have them on hand (pardon the pun).
Discussion of other petting zoo issues and links to other resources can be found in our Petting Zoo archives.
Deadly Hendra virus resurfaces in Australia
A small outbreak of the potentially deadly Hendra virus was identified in a group of horses near Brisbane, Australia. This virus has caused periodic cases of illness and death in horses, and can be transmitted to people working closely with infected horses. In the latest outbreak, 3 horses have died, making this the worst outbreak since 1994 when 14 horses and 2 people died. Now, a human case has been identified. This person works at a veterinary clinic that treated infected horses. This individual was admitted to hospital overnight but was discharged, so is presumably not very ill.
While Hendra virus (genus Henipavirus) is only found in Australia, it is a good reminder for everyone about the strange nature of some infectious diseases. The natural reservoir of the virus is the fruit bat. It is believed that horses become exposed when infected fruit bats give birth and contaminate horse pastures with uterine fluids. Horses develop respiratory disease ranging from mild to fatal. Human cases have been reported in people working closely with infected horses. A horse trainer and veterinarian's assistant died in the 1994 outbreak. Close contact is required for transmission to people.
Picture: Locations of previous Henipavirus outbreaks (red stars – Hendra virus; blue stars – Nipah virus) and distribution of Henipavirus flying fox reservoirs (red shading – Hendra virus; blue shading – Nipah virus)
It's very difficult to take specific measures to protect horses, people or other animals from sporadic, rare diseases such as Hendravirus infection. However, common sense infection control measures can reduce the risks associated with any animal contact.
- Wash your hands after contact with any animal.
- Avoid contact with sick animals - consider sick animals to be potentially infectious until proven otherwise.
- Remember that new animal diseases are regularly being identified, and that they might be able to infect people.
- People that work in veterinary clinics must be diligent and use good infection control practices because they are at higher risk of exposure to various diseases.
Petting zoos: What's wrong with this picture?
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.
Is it a spider bite or MRSA?
Skin reactions from spider bites are usually very mild, if they are even noticed. However, bites from certain kinds of spiders can cause severe skin lesions that may develop into deep open wounds. These are sometimes called "volcano lesions". Deaths due to such bites have been reported, mainly in children. However, the relatively small brown recluse spider, Loxosceles reclusa (see picture), is the only one of approximately 20 000 different species of spiders in the Americas that can cause these severe lesions. This spider is native to the midwestern and southeastern US, and is rarely found elsewhere. In many cases (particularly in people but also in pets), a variety of focal skin lesions, including volcano lesions, may be diagnosed as a "spider bite" without any further testing. This is even done in areas where brown recluse spiders don't live! Another possible cause of a volcano lesion that may be mistaken for a spider bite is methicillin-resistant Staphylococcus aureus (MRSA). It is clear that many MRSA infections in people are being misdiagnosed as spider bites, but I have also talked to various pet owners whose dogs had MRSA infections that were originally diagnosed as spider bites. Most of these were from areas where brown recluse spiders would never be found. If an MRSA infection is diagnosed initially as a spider bite, the delay in starting proper treatment can lead to more prolonged and potentially more serious disease.
In addition to MRSA, the related bacterium methicillin-resistant S. pseudintermedius (MRSP), which is more common in dogs and cats than in humans, could be involved in similar skin infections. This is just as serious for the pet, but less of a concern for people in contact with the pet. For more information about MRSA versus MRSP, check out our blog on Methicillin-Resistant Staph: What's in a Name?
- MRSA, MRSP and other infectious agents should be considered as potential causes for focal skin lesions, particularly if they form deep open wounds or an abscess containing pus.
- Volcano lesions should not be assumed to be spider bites unless a bite from a brown recluse spider was observed. Such lesions should definitely not be diagnosed as spider bites in regions where the brown recluse spider does not live.
- Wash your hands if you touch any unusual skin lesion on a person or a pet.
"Black Death" in South Dakota - Plagued Prairie Dogs
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
(Centers for Disease Control and Prevention (CDC) / Janice Carr)
Happy Household Hamsters
The right kind of pet can be an invaluable source of learning experiences for a child. But there's always the question of what is the right kind of pet for a child, a family and a household? A dog or a cat is not ideal for everyone. Sometimes a small pet, such as a hamster, is easier to take care of, and is more easily kept in a smaller area or a single room, if necessary.
Hamsters can be wonderful pets, and overall, hamsters are relatively low-risk when it comes to diseases they can potentially transmit to humans. However, they can sometimes carry bacteria like Salmonella in their feces, and the virus that causes lymphocytic choriomeningitis, to name a couple. But there are a few simple things you can do to help greatly reduce the risk of transmission of these and other diseases from hamsters. Doing many of these things will also help keep your hamster as healthy as possible. It is very important to learn about what a hamster needs and how to take care of hamster (or any kind of pet) before you decide to get one.
Here are a few important hamster care tips to keep in mind:
Also check out the new information sheets about hamsters posted on the Worms & Germs Resources page!
Hamsters can be wonderful pets, and overall, hamsters are relatively low-risk when it comes to diseases they can potentially transmit to humans. However, they can sometimes carry bacteria like Salmonella in their feces, and the virus that causes lymphocytic choriomeningitis, to name a couple. But there are a few simple things you can do to help greatly reduce the risk of transmission of these and other diseases from hamsters. Doing many of these things will also help keep your hamster as healthy as possible. It is very important to learn about what a hamster needs and how to take care of hamster (or any kind of pet) before you decide to get one.Here are a few important hamster care tips to keep in mind:
- Keep your hamster in a clean enclosure with good ventilation and enough space for your hamster to have separate areas to eat, sleep, exercise and poop/pee.
- Prevent contact with wild rodents. This means keeping your hamster in its cage and not letting it roam around the house. Also ensure that your hamster cannot escape from its cage and wild rodents cannot get into the cage.
- Most importantly, always wash your hands after handling your hamster.
Also check out the new information sheets about hamsters posted on the Worms & Germs Resources page!
Should all dogs in Ontario be vaccinated for leptospirosis?
From Guest Author Dr. John Prescott, Professor, Department of Pathobiology, University of Guelph. More information about Leptospira and leptospirosis can be found on our Resources page.
The last decade has witnessed a surge in leptospirosis in dogs throughout much of North America. Ontario and Québec have been part of the surge, which is associated with two serovars of Leptospira, grippotyphosa and pomona.
The reasons for the dramatic increase relate to: 1. The apparent spread of infection in raccoons and to a lesser extent skunks; 2. A changing climate that favours prolonged survival of these bacteria outdoors in the milder fall temperatures; 3. Perhaps to a minor extent increased awareness of the disease by veterinarians. Gillian Alton, a Masters student at the University of Guelph, has shown that the increased infection rate observed in recent years appears to have leveled off, which may be the result of widespread vaccination.
Leptospirosis should be suspected whenever there is kidney or liver inflammation of unknown origin, particularly in the fall of the year. In 2007, there were about 80 positive and 170 suspicious cases in Ontario based on blood tests submitted to the Animal Health Laboratory (AHL), University of Guelph. Since not all such blood tests go through the AHL, it is likely that there would have been about 160 positive and 350 suspicious cases based on this testing throughout Ontario, and an unknown number of cases diagnosed by PCR (a DNA-based test). If one includes cases diagnosed based on clinical signs but without laboratory testing, and about half the suspicious cases as positive cases, then there may be about 400 clinical cases (i.e. cases where the animal actually gets sick) of leptospirosis in dogs occurring annually in Ontario. Clinical leptospirosis in dogs is a serious disease and this number, if the assumptions are correct, represents a high burden of infection.
Arguments for recommending the new 4-way leptospiral vaccines as a “core” vaccine (i.e. all dogs should be vaccinated) in Ontario are:
The last decade has witnessed a surge in leptospirosis in dogs throughout much of North America. Ontario and Québec have been part of the surge, which is associated with two serovars of Leptospira, grippotyphosa and pomona.The reasons for the dramatic increase relate to: 1. The apparent spread of infection in raccoons and to a lesser extent skunks; 2. A changing climate that favours prolonged survival of these bacteria outdoors in the milder fall temperatures; 3. Perhaps to a minor extent increased awareness of the disease by veterinarians. Gillian Alton, a Masters student at the University of Guelph, has shown that the increased infection rate observed in recent years appears to have leveled off, which may be the result of widespread vaccination.
Leptospirosis should be suspected whenever there is kidney or liver inflammation of unknown origin, particularly in the fall of the year. In 2007, there were about 80 positive and 170 suspicious cases in Ontario based on blood tests submitted to the Animal Health Laboratory (AHL), University of Guelph. Since not all such blood tests go through the AHL, it is likely that there would have been about 160 positive and 350 suspicious cases based on this testing throughout Ontario, and an unknown number of cases diagnosed by PCR (a DNA-based test). If one includes cases diagnosed based on clinical signs but without laboratory testing, and about half the suspicious cases as positive cases, then there may be about 400 clinical cases (i.e. cases where the animal actually gets sick) of leptospirosis in dogs occurring annually in Ontario. Clinical leptospirosis in dogs is a serious disease and this number, if the assumptions are correct, represents a high burden of infection.
Arguments for recommending the new 4-way leptospiral vaccines as a “core” vaccine (i.e. all dogs should be vaccinated) in Ontario are:
- The suggested size of the problem;
- The often serious nature of the disease;
- The zoonotic potential of the infection (a small number of human infections acquired from dogs have been recognized in Ontario and Québec in recent years);
- The ongoing widespread presence and sometimes large numbers of raccoons in suburban and urban Ontario;
- The diagnosis of canine leptospirosis throughout the province;
- The diagnosis of the disease in dogs of all types, not just the “male hunting dog” which is sometimes conventionally regarded as “high risk”.
- The sporadic nature of the infection, including the lack of exposure of some dogs to raccoons and other wildlife sources;
- The number of vaccine reactions associated with leptospiral vaccines (this is not a significant problem with at least one of the vaccines);
- The considerable confusion caused by the (almost certainly totally unfounded) suspicion that serovar autumnalis causes canine leptospirosis, but is not in the new vaccines;
- The lack of inclusion of serovar bratislava in the vaccine (although this serovar seems to cause only mild disease in dogs);
- The annual cost of revaccination.
Should I have my pet tested for Clostridium difficile?
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.
"Pet" bat bites child
A woman from Kansas was cited for keeping exotic pets within city limits after her son was bitten by one of the family's pet bats. The bats were confiscated and will be tested for rabies. Some animals make good pets, some are mediocre and some are completely inappropriate. Bats are in the last category. Bats are the main vector for rabies virus in North America and they do not have to look sick to be carrying rabies. Bats can bite when being handled and bites are often very small, so they are not always taken care of or even noticed. A person not reporting a seemingly harmless bat bite is a common history in human rabies cases.
Even if rabies didn't exist, keeping pet bats would still be a bad idea. Bats are very difficult to care for properly, and rarely survive for long in captivity, except in well-run zoos with excellent facilities and very knowledgeable caretakers.
More information on rabies is available on our 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).
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.
Rabies infection in adopted Iraqi dog
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.
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.
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.
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.
