Leptospirosis and Pot-Bellied Pigs

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

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

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

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

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

Flu problems: people vs pets

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

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

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

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

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

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

Cleaning up raccoon latrines

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

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

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


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

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

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

Rabies in the US in 2007

A recent report in the Journal of the American Veterinary Medical Association by Jesse Blanton and colleagues provided a detailed report of rabies infection in the US in 2007. Here are some of the more interesting points:

  • Rabies was diagnosed in 7 258 animals and 1 person. That's a 4.6% increase in animals from 2006, but 2 fewer human cases.
  • 93% of cases were wildlife: 37% raccoons, 27% bats, 20% skunks, 7% foxes.
  • 0.8% of cases were in cattle and 0.6% were in horses.
  • 4% of cases were cats, with the largest numbers of feline cases in Virginia, Florida, Pennsylvania, North Carolina, Maryland, New Jersey, New York, Georgia, Texas and Kansas.  Cat cases peaked in June and July.
  • 1.3% of cases were dogs, with the largest number of canine cases in Texas, Georgia and North Dakota. Dog cases did not appear to have a seasonal pattern.
  • Small numbers of a variety of other species were diagnosed, including pigs, wolves, opossums, bobcats, coyotes, otters, bears, deer, mongooses (in Puerto Rico), groundhogs and beavers.
  • The largest number of rabies cases occurred in Texas (969).
  • The infections that occurred were due to several rabies virus variants in circulation in North America, including raccoon rabies virus, skunk rabies virus, arctic fox rabies virus, bat rabies virus and Texas gray fox rabies virus.  In each region of the continent, one or more of these rabies virus variants may be more common.
  • No infections with canine rabies virus were identified. Dogs and coyotes were infected by other variants of the rabies virus, but not with the dog variant.  It is believed that dog-to-dog transmission of canine rabies virus no longer occurs in the US.
  • The one human rabies case in 2007 occurred in Minnesota, and was probably due to exposure to a rabid bat.

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


Nontraditional Pets and Children: Beware

A report about the health risks in children associated with nontraditional pets was recently published in Pediatrics, the official journal of the American Academy of Pediatrics. The report also discusses diseases associated with animals in public settings such as petting zoos and pet stores.  Although contact with pets and animals can be beneficial to growth and development in children, it is very important to be aware of the risks associated with certain kinds of animals.  Physicians, veterinarians and public health personnel can help parents select appropriate pets in order to maximize the benefits while minimizing the risks to children.

One of the most important pathogens discussed in the report is Salmonella. Although Salmonella can be transmitted by many animal species, including traditional pets like dogs and cats, it is a particularly high risk with certain other kinds of pets, including reptiles, amphibians and baby poultry (chicks and ducklings). It has been estimated that direct or indirect contact with reptiles or amphibians is responsible for 6% of all sporadic Salmonella infections in the US, and 11% of cases among people younger than 21 years. There is also a relatively high risk of Salmonella transmission associated with animal-derived pet treats, such as pig ears, and raw meat.

The report makes several recommendations about how to reduce the risk of infection, injury and allergies from nontraditional pets, many of which you may have seen before on the Worms & Germs website. Just a few of these are:

  • Always wash your hands after contact with animals, animal products or their environment, and after contact with animal-derived pet treats.
  • Supervise hand washing for children less than five years old

Children less than five years of age and individuals with weakened immune systems should avoid contact with reptiles, amphibians, rodents, ferrets and baby poultry. These animals:

  • Should not be kept as pets in households where children less than five years of age or individuals with a weakened immune system live.
  • Should not be brought to childcare centres.
  • Should not be allowed to roam freely in ANY house or living area.
  • Should not be permitted in kitchens or anywhere food is prepared.

More information about Salmonella in pets and the risks associated with feeding raw meat and animal-derived treats to pets can now be found on the Worms & Germs Resources page.

...but pet fish are absolutely safe... aren't they???

Fish are very popular pets. It has been estimated that freshwater fish are owned by over 14 million people in the US, and saltwater fish are owned by approximately 800 000 people. Fish can be interesting, low maintenance pets, and the risks of disease transmission to people are low. However, low does not mean zero, and there are some diseases than can be spread from fish to people.

The most common (but still quite rare) disease that can be transmitted from fish to humans is infection with Mycobacterium marinum. This microorganism can be found in both freshwater and saltwater. It can cause skin infections, usually in areas where the skin is already broken, such as pre-existing scrapes and cuts, or skin that is damaged while cleaning an aquarium. Serious or long-term problems are rare in otherwise healthy people, but infection can be fatal in individuals with a weakened immune system.

Various other bacteria found on fish and in aquariums can cause infection in people as well. These are usually also "opportunistic infections" that tend to occur in people with weakened immune systems or infected wounds.

While fish are low risk pets, you can still minimize the risks that do exist by following a few simple precautions:

  • Wash your hands after contact with aquarium water or items in the aquarium. Gloves should be worn to prevent skin damage if you need to touch rough or sharp surfaces.
  • Do not clean an aquarium in the kitchen.
  • Do not dump aquarium water down the kitchen sink.
  • Prevent contact of aquarium water or contents with open wounds on your skin.
  • Keep aquariums covered. This helps keep other pets (e.g. cats) from drinking or playing in the water. (It also prevents escape attempts by the fish, which never end well!)

More about Echinococcus tapeworms in dogs

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

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

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

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


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

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

Lower photo credit: Ontario Veterinary College

Stupid things done with bats

I'm constantly amazed at what some people do with bats. Bats are a leading cause of human rabies exposure in North America.  Despite extensive efforts to educate people about the importance of avoiding contact with bats, some people still either don't know or don't take these warnings seriously.

The latest bizarre example of stupid things done with bats occurred in Montana, where a parent brought a dead bat to a school and let young children (kindergarten and grade 5 students) touch it. Touching a bat in itself is a bad idea, let alone touching one that has died of unknown causes and encouraging kids to touch it. The teachers apparently had no objections to this activity. The parent who brought the bat had the students use an alcohol hand sanitizer after touching the creature, but it is still very irresponsible for someone to encourage children to touch a high-risk animal, regardless of what is done after. I'm sure the parents of the children didn't know beforehand, and certainly some were no doubt very upset when they found out about the incident (or livid would be a better description, if it was my kids that were involved). School officials did not find out about the dead bat until after its little visit, at which time the local and state public health authorities were contacted. The bat was tested and was positive for rabies.

Overall, the risk of rabies transmission is probably low in this case, but not zero.  It has therefore been recommended that the 80 students that may have touched the bat be given post-exposure rabies shots, which may cost up to $800 per child!. Another ten children may have touched the bat at a soccer practice - for a dead bat, it sure covered a lot of ground!

  • Never touch a bat, dead or alive.  Obviously, if you shouldn't touch a bat, you shouldn't encourage kids to do so either!
  • Unstructured and unapproved contact with animals in classrooms should be prevented. Animals can be good educational tools, but only if student and animal health and welfare are properly addressed.

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

Your mother was right! Wash your hands

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

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

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

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

Updated: Speaking of Baylisascaris...

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

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

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

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

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

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

Updated: Raccoon Roundworms - Baylisascaris procyonis

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

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

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

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

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

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

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

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

Cows to vultures to dogs to rabies: unintended consequences

"Unintended consequences" are outcomes (usually negative) of a particular action that are unexpected. For example, in some areas, hospitals now receive decreased reimbursement for MRSA infections.  This policy was meant to help encourage hospitals to reduce MRSA infection rates. However, there are concerns are that this has actually lead to decreased MRSA testing (and potentially compromised patient care), because if the MRSA infection isn't documented, payment will not be withheld.

Unintended consequences can be found in many diverse areas. An interesting example was recently published in Ecological Economics and reported by the Toronto Star.  It described the unintended consequences that linked use of a cattle drug to rabies deaths in India. Here's here story:

  • Didofenac is a drug that was routinely used in cattle in India
  • The drug is apparently highly toxic to vultures
  • Vultures fed on cattle that died of natural causes, but that had didofenac in their bodies
  • Millions of vultures died, which led to a larger food supply for feral dogs
  • It was estimated that this lead to 5.5 million more feral dogs in India from 1992 to 2006
  • These additional dogs would have accounted for at least 38.5 million dog bites
  • Rabies is a serious problem in feral dogs in India
  • In India, 123 people die of rabies per 100 000 dog bites.

Putting these numbers together, the unintended consequences of didofenac use in cattle may have result in 47 000 human deaths from rabies and $34 billion in health care costs. There are a lot of assumptions in this report, but it is an interesting story and highlights the unpredictable nature of infectious diseases, and the varying effects that seemingly unrelated actions can have.

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

Q Fever - From goats to people (and pets!)

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

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

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

Q fever is one of the most infectious diseases in the world. As little as one C. burnetii organism is enough to infect a susceptible person. There are a few things to keep in mind to help reduce the risk of being exposed to this pathogen:
  • Only eat/drink pasteurized dairy products.
  • The main risk from cats and dogs (especially cats) is when they give birth. If you have a cat or dog that has kittens/puppies, wear gloves if you have to touch the babies or any placentae. Afterwards, cleaning the area very thoroughly to physically remove any tissue or fluid residue is very important, because most disinfectants cannot kill C. burnetii. Always wash your hands thoroughly after handing newborn kittens or puppies.
  • On dry, windy days, avoid farms or areas where sheep or goats are kept.
  • Avoid sheep and goat farms during the lambing/kidding season.
More information on Q fever can be found on the websites of the Ontario Ministry of Health and Long-Term Care and the Centers for Disease Control and Prevention (CDC).

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.
  • 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.
A scientific review of the transmission of Cryptosporidium (and Giardia, another common waterborne parasite) is available from the International Journal of Parasitology. For more information on Cryptosporidium in pets, check out the information sheets on the Worms & Germs Resources page.

Controversy over Crohn's and Cows

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

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

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

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

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

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

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.

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.

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

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.

Keep the 'wild' in 'wildlife'

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

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

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

Hazardous hedgehogs

While most people that want a pet stick to the tried-and-true species, there are a huge number of different animals available. Some make good pets, some are relatively harmless but not suitable for most households and some are potentially dangerous. Hedgehogs probably fit into the latter 2 categories.

No...hedgehogs aren't sneaking out of their cages and attacking people as they sleep. Rather, they can carry a variety of microorganisms that can be transmitted to people. There have been a few reports describing infections associated with hedgehogs, particularly Salmonella and ringworm. An excellent report in the journal Emerging Infectious Diseases  highlighted the diseases hedgehogs have been shown to, or could, transmit to people. Hedgehogs don't have to be sick to be a source of infection.

Hedgehogs have been available for years, but they may be a fad pet at the moment. One breeder is quoted as saying “They are going up these last two months we actually have a waiting list about twenty people,” said Sarah Roberts a breeder in Mansfield. “That's never happened in the year’s of breeding we've done.”

While any pet could transmit infections to people, certain pets are higher risk. Overall, species that are rare or 'fad' pets may be of greater concern because we simply don't know much about them (i.e. what diseases they can transmit, how to reduce risks...).

These small creatures can probably be safe pets in some households, but are they really better than other species? You probably should not have a hedgehog if you or someone else in the household has a compromised immune system or if you have small children. If you do have a hedgehog, don't let it roam freely in the house and wash you hands after handling it.

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.