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

The following is a post by guest-blogger, Dr. David Waltner-Toews.

For North American veterinarians, the term “companion animals” covers a wide territory, from dogs, cats, and caged birds, to a variety of rodent and porcine escapees from barnyards and burrows. But when does a companion become something else? In my work with Veterinarians without Borders/ Vétérinaires sans Frontières – Canada, I find that I sometimes have to change my ideas of what companion animals are.

We have all heard about bird flu, and the fear that it might become a global pandemic. We know that wild water birds are the main reservoir for all the different kinds of influenza viruses that emerge every year from Southeast Asia and circle the world. The viruses are unstable, and historically haven’t caused many problems in birds. The disease in people can be serious, especially in older people, but large scale vaccination programs have helped. The big concern is that a new variation of the virus has evolved and has spilled from water birds into domestic poultry. A virus that not only kills birds, but also kills a high percentage of people – and other animals such as cats. Fortunately, it is difficult to contract – you pretty much have to be the one killing and cleaning the bird.

To some people, the way to stop a global pandemic is easy. If you suspect bird flu on a premise, kill all the birds and disinfect the area. Easy, isn’t it? They are, after all, “just chickens”. Or are they?

When my wife and I recently visited a part of the island of Java, Indonesia, where this new virus is thought to be endemic, that is, a lot of birds are carrying it, I already knew it was more complicated than just killing chickens. Often, poor people will “salvage” sick, dying or even already-dead birds by cooking them up and eating them before the authorities discover them. If you are hungry, it seems such a waste not to.  As a result of such situations, about 120 people in Indonesia have died of bird flu since 2003.

But, we discovered, poverty is not the only “complication”. We held a town hall meeting in one village, in the middle of this endemic area, to explore how they were coping with the disease. They told us that they didn’t have any bird flu. Certainly, sometimes, they had some sick birds, which they threw into the river, but no bird flu. They attributed their disease-free status to the fact that they fed their birds a warm porridge made from snails and papaya leaves.

After our town hall meeting, we trundled through the rain to one of the nearby chicken-owners.  When we entered the well-kept concrete-walled yard, a young boy proudly showed us his pet pigeon. His father, however, did him one better. It turns out that this family raised singing roosters, so-called Ayam Pelung, beautiful birds, about a metre high. I knew that wild jungle fowl had first been domesticated in Southeast Asia tens of thousands of years ago as fighting birds, now referred to in Indonesia as Ayam Bangkok.

I had heard about the singing birds, and had seen them in their cages at a competition at the veterinary college in Yogyakarta when I worked there in the mid 1980s, but this was my first close-up view. The men who owned them proudly crouched next to them for pictures. Periodically, one of the roosters would stand still and give a long, drawn out, low, throaty call, an avian version of some sultry lounge singer. These birds, if they win competitions throughout the country and region, apparently bring in up to 500 to 1000 U.S. dollars each. In a country where the average annual income is between $3000 and $4000, a few birds can represent a huge investment. Are these birds companion animals? Are they friends, workers, threats… or just chickens?

When is a dog or a cat or a bird more than a companion? When they sing? Race? Fight? When they are worth lots of money? In Thailand, where fighting cocks are common, and are valuable, the authorities have issued “vaccination passports”, with pictures of the roosters, indicating vaccination with a reputable influenza vaccine. When, in trying to control a disease, do we cross the line from “culling” economically important “units” to killing companions? When do we hand out passports?

If you had an amazing purebred dog worth tens of thousands of dollars, and the public health authorities threatened to kill it if it was found to be harbouring some virus which might or might not make you sick, what would you do? What if that dog was not only your companion, but your retirement investment?

Suddenly controlling a bird flu pandemic is a lot more complicated than killing “just chickens”. Welcome to the real world.

David Waltner-Toews is the founding President of Veterinarians without Borders/ Vétérinaires sans Frontières – Canada (www.vwb-vsf.ca) and a Professor in the Department of Population Medicine at the Ontario Veterinary College.

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An article by Toronto Star columnist Linda Diebel prompted me to write about a topic I've wanted to address for a while -  needlestick injuries. In the column, Ms. Diebel discusses her cat with idiopathic cystitis (a bladder disorder) and the need to treat it at home periodically with subcutaneous fluids (injections of fluid under the skin) and injectable medications. These are relatively easy procedures that most pet owners can manage with a little training, and it can be instrumental to improving the quality and length of life of some animals. However, safe and appropriate needle handling and needlestick injuries are rarely discussed.

Needle handling, needlestick injuries and avoiding contact with blood are (generally) very poorly managed by the veterinary profession. Needlestick injuries are incredibly common in the veterinary field, yet there is often little effort taken to reduce the risk of such injuries occuring. In contrast, there is a great deal of effort expended to prevent needlesticks in human medicine, largely because of concerns about transmission of viruses such as HIV and hepatitis B.  Fortunately, (currently) there are no common pathogens in pets that are transmitted by contact with blood and that are a significant concern in people. However, new diseases are emerging all the time, and there's no way to guarantee that the next big infectious disease in dogs or cats won't  be a bloodborne virus that can be transmitted to people by blood or dirty needles. It's not very likely, but you don't want to be the first person to get it if it does happen!

When it comes to injecting pets at home with fluids or drugs (e.g. insulin for diabetic animals) , some very basic precautions can greatly reduce the risk of injuries. The most important are:

• Know how to handle needles. You should be properly instructed on how to handle needles and treat your pet by your veterinarian.
• Make sure your pet is well restrained. If the animal is squirming around, you're more likely to inject yourself by accident.
• Never recap a needle. This is a very common cause of injury!  When trying to recap, it's easy to miss the cap and stick yourself.  Instead of recapping the needle, after use dispose of it immediately in an approved sharps container. These containers are puncture-proof and are designed to help prevent anyone from getting the needles back out (either by accident or intentionally).  You can get a sharps container from your veterinarian or a medical supply store. Once the container is 3/4 full, put the cap on it (once on the cap cannot be removed) and take it to your veterinarian for disposal. There may be a small fee for disposal, but it shouldn't be too expensive.
• Never leave an uncapped needle lying around anywhere for any period of time.
• Never put a needle in your pocket.  Pretty obvious why.
• Never put needles in your regular garbage.  People collecting and handling your garbage could get stuck by the needles.

Even though needlestick injuries associated with animals are incredibly common, fortunately they don't usually cause problems (although they still hurt, of course!). However, various types of infectious, allergic and other reactions can occur, and serious consequences, while rare, can develop. More information on needlestick injuries in veterinary medicine can be found in a commentary published recently in the Canadian Veterinary Journal.

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The latest edition of the Centers for Disease Control and Prevention (CDC)'s publication Morbidity and Mortality Weekly Reports consists of the revised Guidelines for Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents.

Among the highlights relevant to pets:

• HIV-infected patients should be advised to wash their hands after handling pets or other animals.
• They should avoid direct contact with diarrhea or any stool from pets, particularly stray pets or dogs and cats less then six months of age.
• Gloves should be worn when handling stool or cleaning areas that might have been contaminated with stool from pets.
• Contact with calves or lambs (e.g. on farms or at petting zoos) should be limited or avoided. Attention should be paid to hygiene and avoiding direct contact with animal manure when visiting such premises.
• Contact with reptiles, chicks and ducklings should be avoided because of the risk of Salmonella.

So, nothing earth-shattering or nothing we and others have not been saying all along. That's because basic measures, while not flashy, are the most useful tools. Use common sense, avoid contact with stool and high risk animals, and above all wash your hands.

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The spleen is an important part of the immune system. It is especially important for fighting off certain types of infections. People who have had their spleen removed or whose spleen is not working properly are therefore at greater risk of some infectious diseases. The risk of infection is highest in the first few years after the spleen is removed or stops functioning, but the risk remains increased for life. In general, people who are immunocompromised (i.e. have a weakened immune system (including lack of a working spleen)) can get sick from microorganisms that would not usually cause illness in other people, and bugs that would only make most people mildly ill can cause severe infections in immunocompromised individuals.  This is a particular problem in children.  Kids that have their spleen removed are often treated with antibiotics for a few years to help prevent infections.

Infection with Streptococcus pneumoniae and Haemophilus influenzae, which are both common  pathogens of humans, are two of the major concerns in people without a functioning spleen.  The most commonly discussed zoonotic disease threats in these individuals are the bacterium Capnocytophaga canimorsus and Salmonella.  Capnocytophaga lives in the mouth of a large percentage of healthy dogs.  Infection in immunocompromised people typically occurs as the result of a bite, but is very rare in other people.  There is no indication to test dogs for Capnycytophaga, because it is difficult to identify and we do not know how confident we can be about a negative result (e.g. it may be in the dog's mouth even though it doesn't grow from a sample in the lab).

Here's some general advice for individuals who don't have a working spleen:

• Talk to your physician or an infectious disease specialist about the risks associated with animal contact (including pets).
• In general, you do not need to give up your pets. The risk of infection may be increased, but the risks can be minimized in most situations, and the risks are often outweighed by the beneficial aspects of pet ownership.
• Be wary of any possible exposure to an infectious disease, and be diligent about infection control precautions. If you are bitten by an animal (of any kind), see a doctor as soon as possible.
• Make sure your pets do not touch any open wounds you may have.  In particular, do not let a dog lick skin that is damaged in any way.  Since Capnycytophaga is commonly carried in the mouths of healthy dogs, licking in general should be discouraged.
• Don't feed your pet raw meat or raw treats, because this increases the risk exposure to Salmonella from your pet's stool.
• Be very careful when handling stool to avoid contaminating yourself or other objects/surfaces. If you have a cat, ideally its litterbox(es) should be changed by someone else.
• Always wash your hands well (and frequently) after contact with pets and pet foods, including dry commercial pet food (kibble).

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A reader asked this question the other day:

"I was walking with my dog, when it got hold of a used condom. Is it possible that my dog got HIV or AIDS or something?"

The short answer is NO. Dogs cannot be infected by HIV, nor can dogs transmit the virus (although there is a theoretical concern that a dog could transmit HIV from one person to another if it bit someone with HIV, got blood from the person in its mouth, and then immediately bit someone else). The virus that causes HIV/AIDS does not survive long outside the human body and would quickly die in a dog's mouth. So HIV infection in a dog from chewing on or swallowing a used condom is not a concern.

Dogs are not susceptible to the other important sexually transmitted diseases in people either. The biggest potential problem in this situation (and a slim on at best) is if the dog swallowed the condom, it could cause a blockage in the dog's intestine. Most likely, though, the dog would pass the condom in its stool and nothing untoward would happen.

(The "ick" factor with dogs eating things like this furthers my objections to being licked in the face by any dog, however!)

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Headlines can sometimes be very misleading. The title of this post is from a news article that implies that rabies is a foodborne disease. The first sentence of the article states:

"A new study has detailed how two people in Asia contracted rabies after eating dog or cat meat."

This is a prime example of why it is so important to read more than just the first few sentences of any article, and ideally find the original source of the information. The article refers to a paper in PLoS Medicine. The paper describes two cases of rabies in men from Hanoi, in Vietnam. One had no known history of an animal bite or other rabies exposure, while the other had been bitten a month before becoming sick by a non-rabid dog (the dog was still healthy when the man developed rabies - if the dog had been rabid at the time of the bite it would have died within two weeks). Both patients had butchered and eaten either a dog or cat, including the brain, within 3-8 weeks of becoming sick.

• The first patient had butchered and eaten a dog that had been killed in a traffic accident. He took out the dog's teeth before butchering it, thinking that this would protect him if the dog had rabies (because rabies is so often associated with bites, he likely didn't realize the virus is actually in the saliva and brain tissue).  The skull was opened to remove the brain.  The man wore work gloves, and didn't report any injuries during butchering.  All parts of the dog that were eaten were cooked first.  No one else that ate any part of the dog got sick.
• The second patient had butchered and eaten a sick cat that had been acting abnormal for a few days. Again, all parts of the cat that were eaten were cooked first, and no one else that ate any part of the cat got sick.  However, the man who developed rabies had prepared the cat's brain for cooking using his bare hands.

In both cases, the affected people were exposed to animals that were sick (cat) or may have been sick (dog hit by car). Only the people who butchered the animals got rabies, while no one else who ate the animals got sick. It is most likely that the two men were exposed to rabies virus during butchering, through contact of infected nervous tissue (e.g. brain) with any tiny bit of broken skin, or even possibly the eyes, nose or mouth, before the tissue was cooked.  In Vietnam, butchering  (not eating) dogs is a recognized risk factor for developing rabies.  It is extremely unlikely that eating cooked meat from a rabid animal would result in transmission of rabies to a person.

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A large outbreak of rabies continues to have devastating effects in Angola, Africa. While rabies outbreaks are not uncommon in some parts of the world, the number of people affected in this outbreak is remarkable. A hospital in Luanda, the nation's capital, has diagnosed rabies in at least 93 children in the past 3 months. All have died. The main source of the disease in this case is Angola's large stray dog population. Stray dogs can transmit rabies to other dogs and people through bites. The poor socioeconomic status of the country increases the risk of outbreaks like this because:

• Vaccines are not readily available (for dogs or people)
• It is difficult to organize and fund vaccination programs for stray dogs
• It is difficult to educate the general population about how to avoid and manage rabies exposure
• The healthcare system is relatively limited

These problems, all related to a poor economy, create a "perfect storm" for a rabies outbreak. The shortage of human rabies vaccine and the high cost of post-exposure prophylaxis (PEP) makes it much more likely that people will actually develop signs of rabies after being exposed. The cost of PEP is more than the average Luanda family makes in a month.

Fortunately, the outbreak seems to be waning. However, without improvements in stray dog management (including vaccination) and access to adequate PEP, future outbreaks and problems are inevitable. It was reported that "adequate" supplies of canine rabies vaccine are now available. Hopefully, a concerted effort to vaccinate as many dogs as possible will reduce the rabies load in the canine population, thereby helping to decrease the risk to the people living in the area as well.

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Methicillin-resistant Staphylococcus pseudintermedius (MRSP, sometimes misidentified as methicillin-resistant S. intermedius (MRSI)) is an increasing problem in dogs and cats. This highly drug-resistant bacterium is a particularly problem in skin and ear infections, and the number of infected animals appears to be increasing significantly. A related bug, methicillin-resistant S. aureus (MRSA) has been a major problem in people for decades, and MRSA is now being found with increasing frequency in animals as well. Sometimes people get confused when they are dealing with methicillin-resistant staph, and it's important to realize some of the differences between these two related bugs:

• MRSA is a huge problem in people and can be transmitted between animals and people. The role of animals in human disease is unclear, but there is concern that people can develop infections due to contact with infected or colonized animals.
• MRSP is rarely identified as a cause of infection in people. Transmission of MRSP between animals and people has been reported. However, this is much less concerning than with MRSA because people are much less likely to carry, transmit or develop infection from MRSP than MRSA.
• The recommendations that have been made for management of animals with MRSA largely involve improving general household infection control practices. These guidelines are only based on expert opinion (i.e. there are no studies (yet) to back them up), but they are reasonable and practical.
• Even less information is available regarding MRSP, mostly because it's not considered a major human health issue. That being said, you don't want to get a multidrug-resistant bacterial infection, even if it's uncommon. Therefore measures to reduce the risk of transmission of MRSP from pets to people is should still be considered.
• Strict isolation of infected pets is probably excessive. General infection control practices (e.g. handwashing after contact with the animal, avoiding contact with the infected site, limiting contact overall) are probably adequate, especially in households with no high-risk people (e.g. people with weakened immune systems, infants, elderly individuals).

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

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Wild birds are the natural hosts of all influenza type A viruses, of which there are numerous subtypes distinguished by their hemagglutinin (HA – 16 types) and neuraminidase (NA – 9 types) surface proteins. Subtypes H5, H7 and H9 can infect both birds and humans, but H7 and H9 infections in humans are uncommon. Within subtypes H5 and H7 there are both low pathogenic and highly pathogenic strains. Highly pathogenic strains can cause severe illness in both domestic birds and people, and death rates are high, although many wild birds (particularly water fowl) seem to be resistant to disease even from these more virulent viruses. Both sick and seemingly healthy birds can shed the virus in their respiratory secretions and droppings, and contact with this contaminated material can spread the virus to other birds.  Transmission of the currently circulating avian influenza viruses from birds to people is uncommon. Fortunately, person-to-person transmission of avian influenza is uncommon.

The big worry with influenza viruses is that they have a high propensity to "mutate" - sometimes they change slowly (i.e. antigenic drift), and sometimes they change quickly (i.e. antigenic shift).  When two different influenza viruses infect the same animal or person, the different components of each virus can recombine to make a new virus that will share some characteristics of both the original viruses.  For example, if a highly pathogenic avian influenza virus (like the H5N1 virus from Asia) were to recombine with a human influenza virus, it could create a virus that causes severe disease like the avian virus, but which can be readily transmitted between people. This would  create the potential for a serious outbreak of severe, even fatal illness in people.

Highly pathogenic avian influenza of either the H5 of H7 subtype is reportable in many areas of the world (including Canada), due to the potential for massive mortality in domestic bird flocks, as well as the risk of severe illness in people should such a virus start to circulate in the human population.   Since 2004, avian influenza has been detected in Canada four times - highly pathogenic H7 types were found in British Columbia (2004) and Saskatchewan (2007), and low pathogenic H5N2 viruses were found twice, also in British Columbia (2005, 2009).  The latest outbreak in January 2009 resulted in the destruction of 60 000 birds on the BC premises where the virus was originally detected, as well as all the birds on a second premises where the virus was found just over two weeks later.  This disease is taken very seriously, and the response to these outbreaks by the Canadian Food Inspection Agency (CFIA) must always be swift and definitive.

The risk of highly pathogenic avian influenza to the general public in countries such as Canada that are (usually, though not at the moment) considered free of the disease is very low.  The virus cannot survive in poultry products (i.e. meat, eggs) that are properly cooked.  Contact with wild birds (dead or alive), particularly migratory birds that could potentially be from other continents, is likely the highest risk.  Pet birds are also susceptible to these viruses, so its important to prevent them from coming in conatct with wild birds as well, especially because owners have such close contact with their feathered friends.

More information on influenza in animals and people is available in our archives.

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In contrast to dogs, urinary tract infections (UTIs) are uncommon in cats, although urinary tract disease is very common.  The vast, vast majority of cats with signs of feline lower urinary tract disease (FLUTD) (e.g. straining to urinate, frequent urination, bloody urine) do not have an infection.  However, many cats with urinary tract disease are treated -  unnecessarily -  with antibiotics. That's a problem, for several reasons:

• Antibiotics are not effective if there is no infection, and treating with antibiotics delays addressing the animal's real problem.
• Use of antibiotics in these cases unnecessarily increases the risk of antibiotic resistance emerging. Even if there is no infection in the bladder, resistant bacteria may emerge elsewhere in the body. Antibiotics don't just go where we think the infection might be - they also go to areas where there are always bacteria, like the intestinal tract, and resistance can emerge there.
• Adverse reactions to antibiotics can occur. Vomiting and diarrhea are most common.
• Proper diagnostic testing should be performed in every cat with urinary tract disease. This includes evaluation of a urine sample under a microscope to look for signs of infection (such as white blood cells) and a urine culture.

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