The University of Guelph’s Animal Health Laboratory recently published a summary of selected zoonotic disease diagnoses in its monthly newsletter. It’s an interesting summary of what’s gone through the lab in the last year. It also helps to remind us of the zoonotic potential of all of these pathogens, some of which are relatively common and can be found in a variety of species.
As we were heading into our 5th day without power as a result of a nasty ice storm, the power came back on. It’s been a pain, but with the generator, fireplace and family to visit in unaffected areas, it’s more disruptive than anything.
Not everyone’s that lucky.
If you don’t have a generator or someone with power with whom to stay, what do you do (especially when the temperature dipped to -18C last night)?
Also, what do you do if you have pets?
You might be able to find someone with power to take them or you might find a kennel (if there is one with power and space, and if you can afford it). If not, what then? Warming centres have been opened up, but what would happen if we showed up at one with two dogs, two rabbits and a cat? (The sheep would have to get by on hay and snow, and the fish... well... they’d be screwed.) I doubt our menagerie would be welcomed.
So, you’re left with deciding whether to leave the animals at home with a big pile of food and hoping for the best, or staying behind with them.
It is a serious issue, and I can virtually guarantee there are people toughing it out in freezing houses because they didn’t have any place to put their pets.
When large-scale natural disasters occur, animal care can be an even bigger issue. I heard a figure once about the number of people who died in Hurricane Katrina, having refused to evacuate as it approached because their pets couldn’t be evacuated with them. I’m hesitant to repeat the number since I haven’t been able to find it in a well-documented source, but even if it’s a gross over-estimate, it’s still huge.
It’s also relevant on a smaller scale, on many fronts, such as homeless people staying out of shelters because they can’t take their pets (commonly dogs) with them.
Making plans for management of pets is important for situations such as these. Some people dismiss it as “why would you want me to waste time, energy and money saving a few dogs and cats when people are at risk”? Those individuals are missing the point. The goal isn’t to save the dogs and cats (though that’s a nice side-effect) - it’s to remove barriers to assistance that may be in place when people are unwilling to leave their animals behind. It’s not simple, since you have to consider a lot of things like feeding and housing animals, keeping them controlled, making sure there are no problems with bites or people who are fearful or allergic to animals, and taking precautions to prevent zoonotic diseases.
It’s not easy and it needs to be planned in advance - not during a crisis - but it’s something that needs to be done.
A little knowledge can be a bad thing. We see that with zoonotic diseases. Awareness is great. However, a little bit of awareness can be a problem if it’s enough make people paranoid but not enough to help them understand the real risks. This can lead to excessive and illogical responses (often ending with "...get rid of the cat").
Sound guidelines for preventing infections written by authoritative groups help a lot. An example of that is the recently updated Guidelines for the prevention and treatment of opportunistic infections in HIV-infected adults and adolescents. As a collaborative set of guidelines from the US Centers for Disease Control and Prevention (CDC), the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America, it carries a lot of weight - as it should.
It’s a monster of a document of 416 pages. Pet contact gets a little bit of room and probably just the right amount. Enough to say "it’s something to think about," "we’ve considered the issues" and "here are some basic things to consider.”
Here are their specific recommendations:
Hand-washing also should be recommended in association with the following activities: after handling pets or other animals, gardening or having other contact with soil; before preparing food or eating; and before and after sex (BIII).
HIV-infected individuals—particularly those with CD4 counts <200 cells/μL [i.e. people who have advanced disease]—should avoid direct contact with diarrhea or stool from pets (BIII).
Gloves should be worn when handling feces or cleaning areas that might have been contaminated by feces from pets (BIII).
HIV-infected individuals also should avoid other sources of Cryptosporidium oocysts as much as possible (BIII). These include working directly with people with diarrhea; with farm animals such as cattle and sheep; and with domestic pets that are very young or have diarrhea. If exposure is unavoidable, gloves should be used and practices for good hand hygiene observed.
The letters and numbers indicate the strength of evidence. B means there’s moderate evidence supporting the recommendation and III means it’s based mainly or exclusively on expert opinion, not research trials.
Note that nowhere does it say "get rid of the pet" or "avoid contact with animals altogether." Rather, it endorses the use of basic hygiene practices and common sense. In reality, all these recommendations could apply to any individual, not just people with HIV infection.
The preamble to the pet section includes a great statement:
Health-care providers should advise HIV-infected persons of the potential risk posed by pet ownership. However, they should be sensitive to the psychological benefits of pet ownership and should not routinely advise HIV-infected persons to part with their pets. Specifically, providers should advise HIV-infected patients of the following precautions.
…and those precautions are:
HIV-infected persons should avoid direct contact with stool from pets or stray animals. Veterinary care should be sought when a pet develops diarrheal illness. If possible, HIV-infected persons should avoid contact with animals that have diarrhea.
When obtaining a new pet, HIV-infected patients should avoid animals aged <6 months (or <1 year for cats) and specifically animals with diarrhea. Because the hygienic and sanitary conditions in pet-breeding facilities, pet stores, and animal shelters vary, patients should be cautious when obtaining pets from these sources. Stray animals should also be avoided, and specifically those with diarrhea.
Gloves should always be worn when handling feces or cleaning areas that might have been contaminated by feces from pets. Patients should wash their hands after handling pets and also before eating. Patients, especially those with CD4 cell counts < 200 cells/μL should avoid direct contact with all animal feces to reduce the risk for toxoplasmosis, cryptosporidiosis, salmonellosis, campylobacteriosis, E. coli infection, and other infectious illnesses. HIV-infected persons should limit or avoid direct exposure to calves and lambs (e.g., farms, petting zoos). Paying attention to hand hygiene (i.e., washing hands with soap and water, or alcohol-based hand sanitizers if soap and water are unavailable) and avoiding direct contact with stool are important when visiting premises where these animals are housed or exhibited.
Patients should not allow pets, particularly cats, to lick patients’ open cuts or wounds and should take care to avoid any animal bites. Patients should wash all animal bites, animal scratches, or wounds licked by animals promptly with soap and water and seek medical attention. A course of antimicrobial therapy might be recommended if the wounds are moderate or severe, demonstrate crush injury and edema, involve the bones of a joint, involve a puncture of the skin near a joint, or involve a puncture of a joint directly.
Patients should be aware that cat ownership may under some circumstances increase their risk for toxoplasmosis and Bartonella infection, and enteric infections [although I’d argue data supporting a broad statement of cat ownership increasing those risks that are largely lacking]. Patients who elect to obtain a cat should adopt or purchase an animal aged >1 year and in good health to reduce the risk for cryptosporidiosis, Bartonella infection, salmonellosis, campylobacteriosis, and E. coli infection.
Litter boxes should be cleaned daily, preferably by an HIV-negative, non-pregnant person; if HIV-infected patients perform this task, they should wear gloves and wash their hands thoroughly afterward to reduce the risk for toxoplasmosis. To further reduce the risk for toxoplasmosis, HIV-infected patients should keep cats indoors, not allow them to hunt, and not feed them raw or undercooked meat. Although declawing is not usually advised, patients should avoid activities that might result in cat scratches or bites to reduce the risk for Bartonella infection. Patients should also wash sites of cat scratches or bites promptly and should not allow cats to lick patients’ open cuts or wounds. Care of cats should include flea control to reduce the risk for Bartonella infection. Testing cats for toxoplasmosis or Bartonella infection is not recommended, as such tests cannot accurately identify animals that pose a current risk for human infection.
Screening healthy birds for Cryptococcus neoformans, Mycobacterium avium, or Histoplasma capsulatum is not recommended.
HIV-infected persons should avoid or limit contact with reptiles (e.g., snakes, lizards, iguanas, and turtles) and chicks and ducklings because of the high risk for exposure to Salmonella spp. Gloves should be used during aquarium cleaning to reduce the risk for infection with Mycobacterium marinum. Contact with exotic pets (e.g., nonhuman primates) should be avoided.
As fall fair season starts, concerns about petting zoo outbreaks rise. While deficiencies are still common, petting zoos seem to be getting better with their infection control measures. People too are starting to get better at doing what their asked to do - namely washing their hands after visiting these exhibits. However, as we’ve shown through a few different studies, compliance with handwashing after being in a petting zoo is far from perfect. People also often fail to recognize the need to wash hands after being in a petting zoo even if they don’t touch an animal. It’s not uncommon to see a family come out of a petting zoo and the parents direct the kids to wash their hands, while the parents themselves just stand back and watch. Yes, if you touch the animals you’re more likely to have contaminated your hands. However, it’s been shown in a few studies and outbreaks that just being in the petting zoo area is a potential risk, and that disease-causing bacteria can be spread to a variety of hand contact surfaces. In short, the bugs aren't just on the animals.
A recent study in Zoonoses and Public Health (Pabilonia et al 2013) provides more evidence. Researchers visited poultry exhibits at agricultural fairs in Colorado and collected samples from areas like cages, feed, floors and tables, i.e. areas where there was direct contact with birds and areas that visitors might touch. They were able to grow Salmonella from 10 of 11 fairs that they visited. Overall, greater than 50% of surfaces that they tested were contaminated with Salmonella. It wasn’t surprising that finding Salmonella was fairly easy, but that number is pretty high.
Does this mean that poultry exhibits should be banned? No. But it indicates that there is some risk, presumably with any poultry exhibit anywhere.
How can you reduce the risk?
- Don’t eat or drink in poultry exhibit areas.
- Wash your hands after leaving (even if you don’t touch anything).
- Don’t take in items that might go into a child's (or anyone's) mouth (e.g. sippy cups, pacifiers).
Particular care must be taken with kids less than five years of age, elderly individuals and people with compromised immune systems. That could mean staying out of the exhibit altogether, or just being extra diligent about the basic measures listed above - it really depends on the scenario, the ability to follow these practices, and the level of risk aversion.
What should fairs do?
- Take measures to reduce environmental contamination, such as housing birds in such a way that bedding doesn’t get spread everywhere.
- Regularly clean environmental hand contact surfaces (e.g. railings, arms on seating/benches).
- Provide signs to make sure that people know what to do (e.g. wash their hands, don't eat and drink).
- Supervise exhibits.
- Provide good hand hygiene facilities.
These measures aren’t too hard to implement and they’re much better than dealing with an outbreak.
I have three kids that are all now (thankfully) past the diaper stage. I have no idea how many diapers I changed, but I don't have a huge desire to start doing it again, especially for chickens.
I understand the whole urban chicken concept. I don't actually have many issues with it if it's done right - but that's a big IF, unfortunately. Keep your chickens on your property, don't do it if you have young kids or other high risk individuals in the household, use good basic hygiene practices, feed them right, don't get roosters, and don't run screaming to the newspapers or local politicians if some get eaten by carnivorous urban wildlife. The nuisance and risk of backyard poultry can be limited.
Live chickens inside the house... that's another story.
Chickens aren't house pets in my world. I'm not sure if the chickens benefit at all from living in a house with people, and it's probably actually detrimental in many ways. I'm not sure what the benefit is to people either. Although I haven't seen any studies on this specific topic, it stands to reason that keeping a chicken indoors would be associated with a fairly high risk of widespread contamination of the household with bacteria like Salmonella and Campylobacter, two bugs that cause millions of infections in humans every year.
I'm all for risk mitigation, including using creative (and sometimes off-the-wall) measures - but diapers for chickens? Not so much.
Yet, Pampered Poultry makes diapers for your indoor chickens, and not just run-of-the-mill diapers: they're (allegedly) both functional and fashionable. This isn't the only company that sells chicken diapers either, much to my surprise.
One website states "Our chicken diapers are not just for the fashion obsessed hen. They offer your and your home protection against the inevitable! Our diapers fit comfortably and allow you to enjoy your birds in the house or car [car?] without worry."
Does using chicken diapers make sense?
I have a hard time believing these diapers are very useful. They probably do reduce the burden of pathogens that are deposited in the environment, but they are presumably far from 100% effective at containing all of a bird's droppings. It's also likely that chickens are contaminated with these bacteria on other parts of their bodies. Thinking you've eliminated the risk of household contamination from your pet poultry by using diapers isn't logical. The diapers also need to be changed (risk of more contamination) and disposed (don't we have enough waste already?) or washed (risk of cross-contaminating other items).
If you want fashionable chickens, go ahead and dress them up in diapers. Nothing says haute couture like a chicken walking around the living room in pink floral undies. Just don't convince yourself that you're reducing the infectious disease risk for other animals and people in the house. Better yet, let the chickens be chickens and keep them in a proper coop outside. I've seen too many indoor goats, pigs, miniature horses and other species with profound health problems from owners thinking they're just like people.
Apart from diapers, the store also sells "saddles" for the chickens. I'm not even going to start on that one.
Zoo Atlanta has closed its parakeet exhibit after one of the birds died of Chlamydophila psittaci infection. The concern is that this bacterium can cause infection in people (sometimes called parrot fever). Infection of humans is uncommon and usually just causes flu-like disease, but it can be very serious, especially if not diagnosed properly in a timely manner.
The zoo is going to test the flock and decontaminate the facility. The question is, "what will happen if other birds are positive?" Actually, the question probably should be "what will happen when other birds are identified as being positive?"
Chlamydophila psittaci gets the "psittaci" component of its name because it is commonly found in psittacine birds (e.g. parrots, parakeets and other related birds). The dead bird got the bacterium from somewhere, and living communally with other psittacines means that the odds are very good that multiple birds are now carrying it, since birds can carry this bacterium without any signs of disease. Varying carriage rates in psittacines have been reported in different studies, but in some groups (e.g. breeding colonies) rates can be very high.
Concern about the aviary is reasonable, since this bacterium can be spread through the air, mainly through inhalation of contaminated material that's been aerosolized (e.g. dried feces that end up in dust in the air). If there's no direct contact with birds, through, the risk to the public is probably very low. Some management practices can be used to reduce the risk of aerosolization of the bacterium and reduce the risk of exposure of the public. These could include using cage litter that isn't dusty, regular and thorough cleaning of the area and cleaning in a manner that reduces the risk of aerosolizing the bacterium (e.g. wetting things down before cleaning, not using a vacuum unless it has a HEPA filter).
So, what about testing? One of my standard lines is "never do a diagnostic test without a plan to use the results." Hopefully, the zoo has thought about what they'll do with positive results, since it's likely they'll have many.
Testing is a somewhat controversial area. It's been recommended that birds in areas where they will be exposed to a lot of people be tested. That could apply here, depending on how the birds are managed. One issue with testing is it's far from 100% accurate, so it's only one part of the control program and testing limitations need to be understood. Testing makes the most sense in a population of birds that is closed, meaning there are no new birds coming in. That way, a couple of rounds of negative tests can give you pretty good assurance that the group is negative. Positive birds can be quarantined and treated to try to eliminate the bacterium. If most of the group is positive, it makes it pretty difficult to eliminate. A single round of testing or testing and then bringing in new birds doesn't help too much.
Overall, the risk is greatest for zoo personnel who work with the birds and their environment. Good infection control protocols should already have been in place to reduce the risk of disease transmission, but presumably those are being revisited. It's often a controversial subject since use of barriers such as eye protection and an N95 mask are often recommended when cleaning cages, but this is rarely done and there's (reasonable) reluctance to do so because of the rarity of disease, the commonness of the procedures and the fact that people have been doing this for years without these extra precautions. It's a tough area to address and it requires careful consideration of the costs and benefits. Other important points for psittacosis control include avoiding bringing in new birds, avoiding mixing of different groups of birds, checking new birds for signs consistent with C. psittaci infection before bringing them to the facility, quarantining new arrivals and educating people who work with the birds.
One key factor, regardless of what's done, is that people who work with psittacines need to know that they are at increased risk of psittacosis. Their physicians also need to know that they work with psittacines (and that psittacosis is a potential concern). In this situation, people who have worked with the affected bird (and any other bird that might be a carrier) should know to see a doctor if they develop respiratory or flu-like illness.
Although the weather in Southwestern Ontario seems quite confused lately regarding whether it wants to be winter or spring, at least we're still a few months off from having to worry about mosquitoes and the viruses they carry once again. Warmer parts of the world, however, are in the midst of their mosquito season, and some chickens are lending a hand to give people in the area a "heads up" about what's around.
The Health Department of Western Australia has detected Murray Valley encephalitis virus (MVEV) in chicken flocks in East Kimberley. The department has also tested and found the virus in its sentinel chickens in Wyndham and Kununurra. These sentinel birds play an important role as an early warning system when viruses like MVEV are circulating in the area. Just like West Nile virus, MVEV typically circulates between birds and the mosquitoes that like to feed on them, but problems occur when the same mosquitoes start to bite people (or other susceptible animals such as horses), particularly when there are a lot of mosquitoes, like when the weather is very wet or when there's been flooding. Although most people who are infected with MVEV or WNV fight off the virus with no difficulty, or may simply develop short-term, non-specific signs of illness like mild fever and malaise, in some people these viruses can cause severe infection of the brain (encephalitis) and may even be fatal.
Knowing that MVEV has been found in these "guardian" chickens lets people know (via warnings issued by the health department) to take extra precautions against mosquito bites, such as:
- Staying indoors during peak mosquito activity - dusk and dawn
- Wearing protective clothing including long-sleeves and long pants
- Applying insect repellent
In North America, you can pretty much substitute West Nile for Murray Valley in a case like this. Sentinel chickens have been used to provide early warnings of circulating WNV here, before cases are detected in people or horses. Another means of early detection that is also used is testing pools of mosquitoes directly.
It just goes to show you can still be an important part of the country's defenses, even if you're a little chicken :p
There have been a few large outbreaks of dead birds around Ontario lately, with botulism being the main suspect. In one area alone, up to 6000 dead birds have washed up on Georgian Bay beaches. While dramatic, it's not a rare situation at this time of year, and typically relates to birds ingesting fish that died of botulism. When birds eat enough fish with enough botulinum toxin inside them, they can develop botulism themselves and die. This pattern can continue if dead birds are eaten by other animals.
In response to these events, I often get calls about risks to dogs and people. When thinking about it, it's important to consider how botulism occurs. There are two main forms of botulism:
- Toxicoinfectious botulism involves growth of the Clostridium botulinum bacterium in the intestinal tract, and as the bacterium multiplies it produces toxin which can be absorbed into the body through the intestinal wall. This type of botulism is rare in adults (both people and animals), since the mature intestinal bacterial population usually prevents C. botulinum from overgrowing. It's mainly a risk in young individuals. )This is why you're not supposed to give honey to babies, since C. botulinum spores that can be present in honey can pose a risk to them.)
- The other form of botulism in from ingestion of botulinum toxin that's already been produced. This is the most common form. When birds eat fish that have died of botulism, they ingest both the bacterium and its toxins, but it's the toxins that make them ill and ultimately lead to death. Dead birds will probably have some C. botulinum in their intestinal tracts, but the main concern is the botulinum toxin in the rest of their tissues.
Dogs (and cats) are quite resistant to botulinum toxin, and reports of botulism in these species are rare. It would take a pretty large amount of toxin to cause disease (at least compared to many other species) but it's not impossible. Casual contact with areas where birds have died is of basically no risk. Eating dead birds could pose some risk to the dog, depending on the amount eaten and how much toxin was present in the bodies. Ingestion of some C. botulinum bacteria in the birds is of limited concern.
So, walking in an area where birds have died is very low risk. People should ensure that their dogs don't have uncontrolled access to areas where birds have died, so that they can't eat lots of dead birds.
I also get questions about whether dogs that get exposed to beaches where birds have died pose any risk:
- Even if a dog ate a lot of dead birds and got botulism, a person could only be exposed to that toxin by eating the dog - an unlikely event. The dog could ingest some C. botulinum bacterium, but this also poses minimal risk since the bacterium is pretty widespread and people can be exposed to it from many different sources. Even if a dog had some C. botulinum in its intestinal tract, avoiding contact with feces will reduce the risk of exposure. Even if there was some ingestion of C. botulinum from the feces, there's little risk, especially to adults. Perhaps the main public health concern (which is still very low) would be exposure of infants to C. botulinum from dog feces or perhaps from a dog's contaminated haircoat.
Bottom line: Keeping dogs and cats away from dead birds is a good idea, for several reasons, including botulism exposure, but there's limited public health concern.
Image: Dead birds washed up on the shore of Georgian Bay, on the eastern side of Lake Huron (click for source)
An Irish woman has won a record, multi-million Euro settlement after developing severe disease while working at a pet store. Patricia Ingle was a healthy 19-year-old when she was working in a Limerick, Ireland pet store. Then she developed psittacosis, an infection caused by the bacterium Chlamydophila psittaci, which she most likely contracted from a cockatiel at the store. It doesn't sound like the source of infection was confirmed, but the bird-associated nature of the bacterium (and presumably no other high-risk source of infection for the person) and the timing of disease with respect to contact with the cockatiel, are strongly suggestive.
Exposure to C. psittaci is an ever-present risk when working with psittacines, especially when they come from various sources and are mixed and stressed, as often occurs in pet stores. Human infections are rare, and they are usually treatable if diagnosed and managed properly. Usually, flu-like disease develops in people, however Ms. Ingle developed severe and permanent neurological disease (malpractice in management of her infection was also alleged).
This is yet another example of the need for proper education and training. Not all infections are preventable, and not all infections indicate liability. If this store had a proper training program in place, adequately informed staff of potential risks and had sound protocols in place to reduce the risk of exposure, it would have been possible to argue that this was an unavoidable infection in someone that knew the risks. In the absence of proper training, education and protocols, however, there's no way to successfully argue that any infection was not preventable, and the liability should shift to the employer. Hopefully this is a wake-up call for pet stores (as well as other facilities like veterinary clinics) that while you can never eliminate infectious disease exposure, you have a moral and legal requirement to take practical measures to protect staff, visitors and other people.
An article in the May/June edition of Canadian Vet Newsmagazine (a magazine, not to be confused with Canadian Veterinary Journal, a scientific journal), described an interesting case of an indoor pet bird acquiring an infection from a wild raccoon, despite no direct contact.
The bird was an African Grey Parrot that was admitted to the Ontario Veterinary College because it had developed neurological abnormalities over the preceding few weeks: a head tilt, unsteadiness and problems climbing. Infection of the brain caused by the raccoon roundworm Baylisascaris procyonis was suspected and treatment was started, however unfortunately (but not surprisingly) the bird continued to deteriorate and was eventually euthanized. Baylisascaris infection was confirmed at necropsy.
Baylisascaris procyonis, the raccoon roundworm, is extremely common in raccoons, with the majority of raccoons in some areas shedding the eggs of this parasite in their feces. The eggs are extremely hardy and can survive for long periods of time in the environment. The tendency of raccoons to defecate in the same areas (raccoon latrines) means that very high concentrations of eggs can be found in some spots. While this is a raccoon-origin parasite, it can occasionally cause infection in other species (including people and dogs, albeit very rarely). After ingestion of the parasite eggs, the eggs hatch and parasite larvae migrate through the body, causing damage to various tissues as they go. If they migrate through the brain, severe neurological disease can occur.
An interesting aspect of this case is the fact that it was an indoor parrot. If this was a dog that had been exposed to a raccoon latrine, while it would have been a rare occurrence of disease, the origin of infection would have made sense. Here, the parasite eggs had to somehow make it into the house and then into the parrot. The suspected source was branches that were collected from the backyard and placed in the bird's cage. The branches were presumably contaminated with Baylisascaris eggs, and the bird ingested some while chewing on the branches.
This is a very rare situation, but the article includes some basic recommendations:
- Never adopt a raccoon (for many reasons beyond the Baylisascaris risk to pet birds).
- Don't keep parrots in outdoor enclosures where raccoons have access.
- Don't put parrots in outdoor enclosures that may have previously housed raccoons.
- Avoid putting objects from raccoon-inhabited areas into parrot cages or treat them to kill eggs. Heating objects to 62C for 1 minute should kill any eggs that are present.
- Ensure that cage bedding and bird feed are not potentially contaminated with raccoon feces.
A bird specialty store owner wrote me recently, concerned about potential tuberculosis (TB) exposure. A client's bird had been diagnosed with "human TB" and that person had spent a lot of time with the bird. The source of the TB hadn't been identified, and the store owner was worried about the risk that he/she had been exposed as well.
Is it really TB?
The first thing to consider in a case like this is whether TB was really present. "Human TB" is caused by Mycobacterium tuberculosis. Birds can be infected by M. tuberculosis, but are more often infected by Mycobacterium avium complex (MAC), a related group of bacteria. Based on what the store owner wrote here, it seems that M. tuberculosis was the cause of disease.
Can TB be spread from birds to people?
Probably, but the evidence is sparse. Tuberculosis can be spread from people to birds, and it's likely it can go the opposite direction. However, close and prolonged contact is typically required for TB transmission. Human-to-bird cases tend to be birds owned by people with active TB who have close mouth-to-mouth contact with their birds (e.g. mouth-beak feeding).
What is the likelihood of transmission?
Being in the same room as a bird with TB is probably pretty low risk (just like casual contact with a person carrying TB is low risk). The risk also depends to a degree on the type of disease the bird has. If it has respiratory tract disease it is probably more likely to be shedding the bacterium in its respiratory secretions, which poses a greater risk of transmission than other forms of the disease.
Is there cause for concern?
I guess there's always some degree of concern when it comes to TB, but I assume the likelihood of transmission of TB from the bird to the store owner is quite low. The source of TB wasn't known, but most likely the bird was infected by its owner, and if so, being around the bird's owner is probably as (or more) risky.
A month or two ago, there was a lot of press about the risks of pets sleeping in beds. It was in response to an article in the journal Emerging Infectious Diseases that didn't put forth any new information, but summarized a few diseases that could potentially be transmitted by pets. Unfortunately, the relative risk of those diseases wasn't really explored, and some media reports latched onto diseases like the plague, transmission of which can occur between pets and humans but the likelihood of this in most areas is essentially nil.
Anyway, an article at Scienceline.org has taken a more balanced approach towards the subject. One sentence perhaps say it best: "Many of those scare headlines, however, missed the main point of Chomel’s work: For most people, the risks are minimal, and there are easy ways to go about preventing pet-to-owner disease sharing."
I won't go into details here, since you can read the article yourself, but a key component is that pet ownership is never no-risk, but is usually low-risk. Basic hygiene practices and common sense can reduce the risks further. The cost-benefit needs to be considered, and while we can never completely eliminate the "cost" aspect, the benefits of pet ownership certainly outweigh the costs in the vast majority of households.
Like any animal, disease outbreaks can occur in wild birds. Unless they are large outbreaks they often go unnoticed, but smaller outbreaks can sometimes be encountered by homeowners with bird feeders. Because bird feeders are mixing sites for birds, they are also sites of disease transmission and a place where deaths can be identified. In an outbreak, feeders can contribute to the spread of infection between birds, and potentially be a source of infection for people or pets.
A classic example of this is Salmonella infection in songbirds. Outbreaks occur periodically and are often identified by people with bird feeders who start to find the odd dead bird in their yard. Some birds can be healthy carriers of the Salmonella bacterium (and therefore be a source of infection for others), while other birds may get sick and potentially die from the infection. If you have noted dead birds around a bird feeder, consider the potential for a disease outbreak, particularly salmonellosis.
The risk to people and pets from Salmonella outbreaks in birds is reasonably low, and probably greatest in cats. Most reports of songbird-associated salmonellosis (songbird fever) are in cats, because cats are more likely to catch and eat songbirds. Sick birds are easier to catch, further increasing the likelihood of exposure during an outbreak. Exposure is also possible through scavenging already-dead birds and perhaps from exposure to heavily contaminated surfaces or spilled feed around feeders.
General recommendations during an outbreak of salmonellosis in songbirds include:
- Keep cats indoors. This is a good idea at any time, but if you have an indoor-outdoor cat, keep it indoors if there might be an outbreak underway.
- If your pet has been exposed to a sick bird or an area where sick or dead birds have been found, and your pet gets sick, make sure you tell your veterinarian about the birds.
- Clean the bird feeder and then disinfect it by soaking it in 10% bleach for 30 minutes. Rinse it after the bleach treatment. If the feeder is difficult to properly disinfect (or you don't want to try), get rid of it by double bagging it and putting it in the garbage.
- When cleaning the feeder, do it outside so that you don't contaminate any household surfaces. When handling the feeder, wear disposable gloves and wash your hands after you remove the gloves.
- Keep the feeder down for 1-4 weeks. This reduces the concentration of birds in the area and may help reduce mingling of sick and healthy birds.
- Remove any dead birds by burying them at least two feet deep in a flowerbed (not in a vegetable garden!). This is not very easy or practical however - alternatively, double bag the bodies and put them in the garbage, avoiding direct contact with the birds and washing your hands afterward.
The investigation started off with the identification of the bird-associated disease in three people at a local hospital. All three were hospitalized with respiratory disease, and all had attended the bird fair.
- A critical step in diagnosis of psittacosis and recognition of outbreaks is knowing about bird contact. If bird contact isn't questioned, psittacosis is unlikely to be considered. Too often, physicians don't inquire about animal contact, which limits their ability to detect zoonotic diseases. In this case, a survey on psittacosis was underway, which may have helped.
This finding led to an investigation of the fair to determine what happened and make sure there were no other unidentified cases.
The fair lasted one day, and had 83 exhibitors, 1500 birds and around 600 visitors. The investigators ultimately identified two confirmed cases of psittacosis in people who attended the fair, along with two probable and 44 possible cases. (Possible cases were people who developed respiratory disease and were exposed at the event, but did not necessarily have any diagnostic testing done to confirm the cause).
The reported disease characteristics were pretty typical:
- Fever in 96%
- Pneumonia and cough in 63%
- 98% visited a doctor
- 23% were hospitalized
- No one died (psittacosis can be fatal, but is quite treatable if identified in a reasonable time)
Thirty-eight percent (38%) of exhibitors and organizers got sick. That's a very high attack rate for people casually interacting with a group of (presumably) healthy birds. Poor ventilation may have played a role. The fair was held inside, windows were closed and there was no mechanical ventilation. This might have helped the bacterium build up in the air in the building and result in wider, heavier exposure.
The source of infection wasn't determined. They were only able to obtain samples from birds from six of the 83 exhibitors, and all 64 tested birds were negative. Chlamydophila psittaci can be shed by healthy birds, and identification of the source isn't always easy.
It's not guaranteed that everyone who got sick after the fair had psittacosis. You can't rule out the possibility that there were only a couple people with psittacosis and a large number with the flu or another disease, but the incidence of disease, type of disease and timing of disease are all quite suggestive.
How do we prevent outbreaks like this in the future? It's tough to prevent them completely, because you can't tell that a bird is shedding the bug just by looking at it, and testing every bird before a show is impractical. Risks can probably be reduced by ensuring proper ventilation, limiting crowding of areas, limiting unnecessary direct contact between birds and people, and improving general hygiene practices.
Thanks to Dr. Doug Powell of BarfBlog for sending the article.
More information about psittacosis is available in our archives.
A 44-year-old Taipei man is recovering from psittacosis, a potentially severe infection caused by the bacterium Chlamydophila psittaci, which he may have contracted from his pet bird. This bacterium is commonly found in certain bird species, particularly psittacines (parrot family), and human infections are typically associated with bird contact. Healthy birds can shed the bacterium in their respiratory secretions or feces, and shedding rates can be particularly high in some groups of birds, particularly large breeding colonies.
The affected man had typically vague initial signs of disease... fever, chills, aches and cough. It appears that he was tested for psittacosis about 10 days later, but the diagnosis was only recently made (It's not necessarily an easy diagnosis in some cases). There's no information about the severity of disease or whether it progressed past those initial relatively mild signs, or when treatment was started, but he's apparently responding well to treatment and is recovering at home. His pet bird is the probable source of infection, but it's unclear whether it's being tested.
Psittacosis is an example of a disease for which an understanding of pet contact by the attending physician is critical. Typically, psittacosis starts off with flu-like signs. Most otherwise healthy people with fever, chills and aches that go to their doctor would probably be told to "go home, rest and take an anti-inflammatory" or, less diplomatically "get your infectious body out of my office, stay at home, and get over it." That would be reasonable advice for most people, because most people with these symptoms have a common viral infection, and a disease like psittacosis is rare. However, if the person had contact with psittacines and the physician knew it, psittacosis would hopefully come to mind and testing might be performed. Psittacosis is usually easily treated, but you have to know to test for it to diagnose it, so that proper treatment can be started. Untreated, psittacosis can cause severe, even fatal, disease.
Physicians' knowledge about their patients' animal contacts and zoonotic disease exposure is often very poor, which compromises their ability to promptly diagnose and manage zoonotic diseases. Better understanding of pet-associated zoonoses and communication between both people and their physicians, and between physicians and veterinarians, is needed to help reduce the risks.
A great psittacosis resource is the National Association of State Public Health Veterinarians' Psittacosis Compendium.
A UK woman is both grieving the loss of her husband and battling illness she thinks came from a new pet parrot. The 67-year-old woman, who has chronic lymphocytic leukemia, obtained the bird to keep her company as her husband was dying of cancer. She says that she's never felt right since she obtained the bird. She is also upset that the bird is not very tame, saying "Jasper is clearly a wild bird, and they do carry all sorts of germs, so it is a worry for me."
Since her husband's death, the woman has had three rounds of antibiotics to treat a respiratory tract infection that refuses to go away. No more details are provided, and presumably (hopefully) her doctors have tested or treated her for psittacosis, a disease caused by Chlamydophila psitacii - a microorganism that can be acquired from birds, especially psittacine birds like parrots.
This story raises a few relevant questions:
Was it a good time to get a pet?
- That's a tough question. Getting a petting during a difficult time can help many people cope, and having the pet while a family member is sick can be very beneficial. On the other hand, bringing a new pet (with the associated new pet issues) into an already stressful situation can be a problem. Also, with both the woman and her husband being sick and having weakened immune systems, there are some infectious disease risks that need to be considered. The cost-benefit of getting a pet in a situation like this is hard to determine, and it varies greatly between households. At a minimum, anyone in such a situation who is considering getting a pet should learn about potential pet-associated disease risks first so that they can make an informed decision.
Was a bird a good pet to get for this household?
- Another question without a clear answer. Birds can be good companions, but they also carry a few diseases that are of concern, particularly for people with weakened immune systems. It's hard to say whether a pet bird is higher risk than a pet dog or cat. It probably is lower risk from some standpoints (e.g. bites, scratches) but higher risk for certain diseases. The key is, as mentioned above, being informed about potential disease risks and what can be done to reduce these risks. With that information, you can make a more educated decision about whether a specific pet is appropriate.
- Also, in high risk households like this, getting a new pet examined before it makes it to the household is a good idea. Such an exam provides an opportunity for a veterinarian to identify any concerns, ranging from obvious signs of disease to inappropriate behaviours. Identifying these problems before the pet makes it home allows them to be addressed quickly. This might involve treatment, prompt training, keeping the pet somewhere else for a short time while a problem is addressed, or a recommendation to return it to where it came from because of a major concern. It's much easier to do these things (especially returning the pet) before it has made it home and people have become attached.
Should you assume that a captive-bred bird is a disease-free bird?
- Absolutely not. Captive-bred does not equal disease-free. In fact, for some diseases, rates are higher in captive-bred birds. (I'm definitely not advocating getting wild-caught birds... just trying to make it clear that birds from breeders can carry various infectious diseases too). The point is, getting a bird from a reputable breeder is a good start, but it doesn't negate the risks. Healthy, well cared-for birds can carry a variety of microorganisms that can infect people. Risks are higher for people with compromised immune systems, such as the individuals in the household in this case.
Pet ownership always carries some risk of infectious disease transmission. Almost always, that risk is manageable and acceptable considering the positive aspects of pet ownership. However, thought needs to go into the process to ensure that the risks are minimized and acceptable in any given situation.
Image: Green Indian Ring-Necked Parakeet
Recently, Kings of Leon canceled an outdoor concert after a pigeon (with very good aim, apparently) in the rafters above the stage managed to poop on band members, including one shot that hit the face of the band's bassist.
Besides, the "ick-factor," what are the concerns?
Various studies have found potentially nasty microorganisms in pigeon poop, including:
- E. coli
- Various microsporidia
- Various Cryptococcus species
- Multidrug resistant Staphylococcus spp
- Chlamydophila psittaci
- Mycobacterium avium complex
The risk of disease is pretty low for most people, and we are potentially exposed to many of those bugs on a daily basis. The risks increase with higher ingested doses (so direct-deposit of poop is a much greater concern that inadvertent contamination of your hands) and in people with compromised immune systems. It's unlikely but not impossible that someone would get sick from exposure to pigeon feces, and don't eat poop is a good general philosophy for life.
Peritoneal dialysis is used to treat some people with chronic kidney failure. Infection is a major concern, particularly peritonitis (infection of the lining of the abdomen) because peritoneal dialysis involves having an indwelling catheter that goes through the skin and body wall directly into the abdominal cavity.
Infections can occur from bacteria that inadvertently get flushed into the abdomen during dialysis treatment or potentially migrate along the side of the catheter. Accordingly, most infections associated with peritoneal dialysis are caused by bacteria that are found on peoples' skin, such as Staphylococcus aureus.
While the vast majority of peritoneal dialysis infections are human-associated, infections from pets have been reported. Multiple different pet species have been implicated, even hamsters - one case report described an infection in a child that was thought to be caused by a hamster that slept in the same bed as the child (Campos et al 2000).
A recent study in the journal Seminars in Dialysis (Broughton et al 2010) involved a review of the scientific literature for reports of pet-associated peritoneal dialysis infections, as well as a review of records from the authors' peritoneal dialysis unit.
In their review, they identified 124 reported infections caused by zoonotic microorganisms in the literature, involving 12 different microorganisms. The most common microorganisms were Campylobacter, Pasteurella, Zygomycetes, Neisseria, Rhodococcus, Listeria, Mycobacterium avium complex, Capnocytophaga spp, Salmonella, Brucella and Bordetella bronchiseptica. However, only a subset of these were probably associated with pet contact, and retrospectively determining the sources is quite difficult for some. For example, Campylobacter and Salmonella could as easily (or more easily) come from contact with raw meat as from pets. Infections were fatal in 13.5% of cases, demonstrating why this is an important issue.
The most common bacterium causing convincing pet-associated infections was Pasteurella, which can be found in the mouths (and other places) of healthy pets. It is a common cause of pet bite infections and it makes sense that Pasteurella could contaminate pet owners' hands or the dialysis catheter site. In the study of their own hospital's cases, the authors found similar findings, with a low rate of zoonotic infections and a predominance of Pasteurella among those.
Literature reviews aren't a great way of determining the true scope of a problem, because they require people to:
- identify the infection
- identify a pet as a possible source (often the weak link; furthermore, identifying an infection caused by a potentially zoonotic microorganism doesn't necessarily mean a pet was the source)
- decide to write a case report
- get that case report accepted by a journal
Studying medical records has limitations as well, since steps 1 and 2 still need to be performed (with the weak link again being thinking about a pet-association). So, care should be taken when interpreting the results of this study. However, while the results indicate that pet-associated peritoneal dialysis infections do occur, they are probably relatively uncommon.
While pet-associated infections are likely uncommon, any peritoneal infection can be a major problem, so common sense measures that would likely reduce the risk should be used:
- Avoid contact of pets with the dialysis catheter and catheter site
- Wash hands after having any contact with pets
- Don't let pets sleep in the bed
- Wash hands before touching the catheter
- Physicians should be aware of the potential for pet-associated infections, and pet contact by their patients
- If a pet (usually a cat) bites the tubing, this should be reported to a physician ASAP and preventative treatment for infection might be indicated
- Initial antibiotic therapy choices should cover common pet-associated pathogens if there is a history of contact of pets with the catheter or tubing.
People with peritoneal dialysis catheters shouldn't fear their pets, and there is no need for these people to get rid of pets (although they should avoid high-risk pets like reptiles). Pet owners are presumably at somewhat higher risk than non-pet-owners, but the risk appears to be fairly low. In most situations, the positive aspects of pet ownership probably outweigh the risks.
Image: Schematic diagram of peritoneal dialysis (click image for source)
A 62-yr-old Italian woman has died from psittacosis, an infection caused by the bacterium Chlamydophila psittaci. Sometimes called "parrot fever," psittacosis is an uncommon but important disease linked to contact with birds, particularly psittacines (e.g. parrots, parakeets, cockatiels). In people, C. psittaci usually causes flu-like respiratory disease, but severe pneumonia and encephalitis (inflammation of the brain) can occur in some individuals. With prompt diagnosis and treatment, mortality (death) rates are very low (<1%), however mortality rates are higher when diagnosis and proper treatment are delayed. It's not clear in the this case whether psittacosis was considered early in disease nor when treatment was initiated.
Chlamydophila psittaci can cause illness in birds, but it's also carried by a variable percentage of healthy birds, mainly psittacines. This complicates control of the disease, since you can't tell which birds are carrying the bacterium without testing them all. In this case, the woman's parrot died a few days before she became ill. It's not clear from the brief report whether the bird was diagnosed with C. psittaci infection, however this is a good reminder of the need to consider pet and owner health in parallel. It also indicates why diagnostic testing is important when pets are sick, or even after they've died.
If a pet becomes sick, knowing what caused the disease might be of relevance to human health. Also, if physician's ask about illness of any other individuals in the house, this should include pets, as they might get some relevant information.
In a case like this, if the bird was diagnosed with C. psittaci infection and the owner developed flu-like illness shortly thereafter, it should have been a strong indication that the person might have psittacosis, allowing for early treatment. Alternatively, even without a diagnosis, knowing that the person had a pet parrot (a risk factor for psittacosis), and that the bird had died shortly before the woman got sick, could lead to recognition that both diseases could be linked, and could lead to earlier consideration of psittacosis.
This unfortunate event should be taken as yet another reminder of the need for veterinary personnel and human physicians to communicate more effectively, and that physicians need to know about pet contact and pet health when evaluating their patients.
Image: African Grey Parrot (Psittacus erithacus erithacus). (Photo credit: Eli Duke)
I heard this on the radio yesterday morning, I kid you not: Butterball has a "Turkey Talk" toll-free helpline, which naturally gets busy around turkey holidays like Thanksgiving and Christmas. Like many helplines, they get stories of every kind, and this year apparently one person called in and asked if it was alright that she thawed her frozen turkey in the bathtub - while her kids were in it taking a bath!
Anyone who has read anything about food safety hopefully knows that raw meat can potentially be (and usually is) contaminated with many different pathogens - that's the biggest reason why observing proper cooking times and temperatures is so important. Raw poultry in particular should basically be treated like it's contaminated with Salmonella and/or Campylobacter until proven otherwise. You can just imagine the field day that these bacteria could have in a nice warm, wet bathtub - it's just the way they like it, and it's exactly what we try to avoid in the kitchen, where food is ideally kept either nice and cold or nice and hot in order to prevent (or at least minimize) bacterial growth. Then of all things to put young children in this veritable cesspool of bacteria - turkey and all - it's just a gastrointestinal disaster waiting to happen. You also needs to consider what the turkey could become contaminated with sitting in bathwater. Even children who don't have diarrhea can be shedding intestinal pathogens - human pathogens which are obviously transmissible to other people. If you really cooked that bird well (maybe deep-fried it) I suppose that should ultimatley eliminate any surface contamination anyway, but I don't think I'd be able to get past the "ick" factor. Don't throw the baby out with the bathwater, but of there's a turkey in there (as far as I'm concerned) that can go.
I realize this is primarily a food safety issue, but it made me think about what else this person (or others) may put in a bathtub. In previous posts in which we've talked about reptiles kept as pets (all of which should be treated as Salmonella carriers), we've mentioned that ideally (if they need a bath) they should be bathed in their own designated container (like a big rubbermaid) and not in the bathtub. If there is no other option and the bathtub must be used, it should be thoroughly cleaned and properly disinfected (keeping contact-time with the disinfectant in mind) before it is used again by a person (especially children).
Ideally the same precautions should be taken if you bathe a dog in the bathtub, but the risks are not as high as with reptiles (unless the dog is very dirty, has skin lesions, or has (or recently had) diarrhea). We've talked about the limited risks of allowing dogs in backyard swimming pools (but of course there is even less chlorine in bath water). I hope no one ever bathes their dog with their kids - we could debate the risks, which likely aren't high anyway, but in the end the risk is simply unnecessary. The pool is one thing, but there's no reason for a dog to be in the tub at the same time as the kids (and really, how clean are the kids going to get with a dirty dog in the tub?). If you're trying to save water you can always throw the dog in after the kids are out.
If you're attempting to bathe a cat in the tub... well, based on most feline behaviour I'd say your primary risks are bites and scratches more than enteric bacteria and parasites. Proceed at your own risk!
A happy (and hopefully healthy) American Thanksgiving to all of our US readers!
The recent discovery of H1N1 influenza in a pet ferret has led to another round of concern about the potential impact of H1N1 on pets and pets as a source of human infection. Finding H1N1 in a ferret is not particularly surprising, considering ferrets are susceptible to various (including human) influenza viruses. We shouldn't dismiss the potential that certain pets could become infected by this virus or transmit, it but the overall risks are presumed to be very low. There have obviously been many, many cases of H1N1 influenza in pet owners, yet there is just this one report in a pet (although it's certainly possible that other pets have been infected but not diagnosed). Ferrets may be the biggest concern. Pet birds and pot-bellied pigs may also be at higher risk considering this virus can clearly infect pigs and birds. Cats are probably a bigger concern than dogs because of what we know about cats' susceptibility to (and ability to shed) H5N1 (avian) influenza.
The risks are low to pets and pet owners, but there's rarely a no-risk situation with infectious diseases. A few basic measures should be taken to reduce the risks associated with this pandemic virus:
- If you have (or think you may have) influenza, treat you pet like other people in your family. Avoid contact with them, especially their faces, and pay close attention to hygiene (especially handwashing). This should help reduce the risk of exposing your pet to H1N1.
- If you have influenza, or your pet has been exposed to anyone with influenza, and your pet becomes ill (e.g. respiratory disease, fever, lethargy), contact your veterinarian. Avoid close contact with your sick pet (especially the face) and wash your hands after you handle it.
- Relax and enjoy the company of your pet. The risks of influenza are low.
Just when all those turkeys that managed to survive Thanksgiving weekend thought their troubles were over, there's new issue: H1N1 influenza (formerly known as swine flu) has been found in an Ontario turkey flock. The H1N1 virus was first reported in birds in Chile in late August.
This is not a reason to panic. No one can get the flu from eating a properly-cooked Thanksgiving turkey (nor from any other type of properly-cooked turkey). The producer has voluntarily (and very responsibly) quarantined the affected flock, and no birds or eggs have left the facility. There is no risk to the food chain.
Pigs can be infected by human, pig and bird flu viruses, and multiple infections can result in viruses trading genes and producing new viruses that can infect more species. So it's not too surprising that H1N1can infect people, pigs and now birds as well. This incident serves as an important reminder that we need to remain diligent about infection control and hygiene, even around animals. It's highly unlikely that these turkeys had contact with infected pigs - most likely the virus was spread to this flock by a person. Poultry producers may therefore need to consider getting vaccinated for H1N1 flu not only to protect themselves, but also their flocks, and anyone who may have the flu should definitely stay off these farms. Hopefully the virus does not become established in wild bird populations (like H5N1 has in some areas), as this would make it much harder to control.
Recommendations for avoiding the flu (H1N1 or other) remain the same:
- Wash your hands and/or use alcohol-based hand sanitizer
- Sneeze into your elbow
- Disinfect commonly touched surfaces
- Stay home if you are sick
- Get vaccinated!
As public awareness of zoonotic diseases increases, some new marketing opportunities are created. One is offering screening of pets for "protection" of the family. One company, Healthgene, offers a Family Protection Program that involves screening pets for selected zoonotic pathogens. Unfortunately, it involves the use of non-validated PCR tests for pathogens for which screening of healthy animals is not considered useful. They make various unsupported, illogical and sometimes downright incorrect statements such as "If, by chance, any positive results should occur, not only should the animal be treated immediately, but the client and anyone having contact with the animal should also notify their family physician." Despite the fact that the tests themselves are of questionable quality and the results are essentially useless, I'm sure they are developing a market.
Also, it's pretty concerning that this company misspells the names of various microoganisms for which they test on their website - they even misspell "protection" in one of their Family Protection Plan info sheets! Inability to spell isn't necessarily linked to inability to test properly, but it shows a lack of care and attention to detail that raises further red flags in my mind.
Zoonotic diseases ARE a concern. We need to pay attention to them and try to reduce the risks of transmission to people. Screening healthy animals is almost never a component of this. Save your money when it comes to "routine" screening of healthy animals - talking to your vet about potential problems and washing your hands are much better ways to reduce the risk of infection.
In the same edition of Emerging Infectious Diseases as a report on Campylobacter jejuni in macaroni penguins in Antarctica, there is a report about vancomycin-resistant enterococci (VRE) in glaucous gulls in Point Barrow, a remote area of Alaska.
Vancomycin-resistant enterococci are an important problem in human medicine, mainly in hospitals where they can cause sporadic infections and outbreaks of infection. These infections can be difficult to treat because VRE is resistant to many antibiotics, including vancomycin. VRE is not very common in animals in North America at this time, but there is concern that it could be an emerging problem, because as VRE rates in people increase the bacterium gets spread more commonly to animals. There have been many more reports of VRE in animals in Europe. This has been largely attributed to the widespread use of avoparcin (a drug related to vancomycin) as a growth promoter in food animals in Europe, a practice that was common until the mid 1990s, but is now banned in many countries.
This study demonstrates that organisms like VRE can be spread to wildlife in one of the most remote regions of North America. As the authors state "This spread suggests that few (if any) places on earth may be protected against the spread of such resistance, and the dispersal mechanisms are far more efficient than previously thought."
These two reports show how well (and expectedly) infectious agents can travel. They are also good examples of why we need to be thinking globally, ecologically and truly in the mindset of “one medicine” if we really want to understand infectious diseases.
...Macaroni penguins, that is. There is a report in a recent edition of Emerging Infectious Diseases about isolation of Campylobacter jejuni from Macaroni penguins in Antarctica. Campylobacter is a bacterium that can cause diarrhea in people and animals, and which can also be found in the intestinal tracts of a wide variety of animal species, even when they’re healthy. Researchers typed the Campylobacter isolates from a group of penguins in Antarctica and found that many were a strain that commonly affects people. They had a few different ideas about how the penguins became infected. One possibility is contamination from toilet wastes that a nearby research station dumped into the surrounding water. They thought that ships discharging sewage into the ocean near the penguins' feeding grounds could also be a source of the bacteria, as could migratory birds like albatrosses that spend part of the year closer to people. Whatever way it got there, a penguin colony provides an exceptional opportunity for Campylobacter to spread, since huge numbers of penguins live in very close proximity to each other. Fortunately, Campylobacter rarely causes disease in birds, and we hope that's true with this strain in penguins as well.
This report shows how closely linked humans and animals can be, even when we usually live far apart. It also shows why we keep saying that a global ecological approach to infectious diseases is needed - we need to look at the big picture.
More information about Campylobacter can be found on the Worms & Germs Resources page.
Recently, I wrote a post about the need for vets and physicians to communicate more, and about concerns that zoonotic diseases get missed because vets deal with animals and physicians deal with people, but few people pay attention to the interface between them. A reader (my father, actually) wrote this comment.
“...is the opposite also true? If I take my sick cat to the local vet, will he advise me to see my physician if I begin to feel ill effects? Are vets trained to know that pets can transfer disease to their owners or in this an emerging part of vet. science?”
It’s a good question and one that doesn’t have a straightforward answer. Vets certainly do get educated regarding zoonoses. From what I understand from talking to colleagues in the human medical field, there is much more emphasis on zoonoses in the veterinary medical curriculum compared to the human medical curriculum. However, a lot of the focus is on foodborne and waterborne zoonoses, with much less information about companion animal (e.g. dog, cat, horse) zoonoses. Different vets have quite variable knowledge in this area, ranging from excellent to poor. It’s a huge field (I’m still learning more about it all the time), and vets and physicians alike have busy schedules and many other areas where they need to stay current as well, so it’s not unfathomable that zoonoses could get neglected.
So, to answer the question, if you take your sick cat to the vet, it’s unlikely he/she will initially ask about your health. However, if the vet suspects a zoonotic disease, hopefully he/she would tell you what it is and possibly what signs for which to watch out. Providing additional information would also be useful, which is why we're developing the information sheets that are available on our Resources page). At that point, the vet would typically (and reasonably) leave it up to you to determine whether you should see your physician and what should happen from there. In the grand scheme of things, it would be very useful for vets and physicians to have some form of dialogue or at least an understanding of each other's roles and a willingness to call each other when appropriate.
Both human and veterinary medicine have a long way to go to get to the "one medicine" concept that people like to talk about. I think we’re slowly moving in the right direction, but vets and physicians need to talk more to properly cover this important area of overlap between their professions.
A new trend in the back-to-nature/all-natural (or whatever the catch-word of the day is) movement is urban chickens. These chickens are raised in small numbers by city slickers (i.e. urban residents) in their yards, and are typically used as a source of fresh eggs. Not surprisingly, this concept has met with some controversy. Some people are strong supporters of the idea, while others have serious objections. Different jurisdictions have begun passing bylaws regarding urban chickens - some have implemented pilot projects and others don't allow it at all.
- It's a cheap, sustainable and "all-natural" source of eggs
- It allows people to "get back to nature"
- It's a more humane way to raise chickens
- Watching chickens roam around the yard is enjoyable
Opponents counter with:
- Farm animals should be on farms
- Chickens smell: Very true, especially in large numbers and/or confined spaces.
- Chickens are loud: Many places that allow urban chickens ban roosters to decrease problems with crack-of-dawn wake-up calls.
- Chickens carry infectious diseases: Also true, but the same can be said for any animal. The main concerns with chickens specifically are Salmonella and Campylobacter, which are both bacteria that cause diarrhea. They can be passed in the droppings of healthy chickens and can be on eggs. Common sense practices such as keeping the chickens away from areas where people eat (e.g. the backyard picnic table), proper handling of eggs and good general hygiene should reduce the risks greatly, as long as the number of chickens kept is small. Avian influenza (bird flu) is another concern, although currently it's not a major issue in North America. Anything that increases contact between birds and people can increase the risk of influenza transmission. If bird flu entered a particular region, urban chickens could be a big problem.
- Chickens attract undesirable and potentially dangerous wildlife like coyotes, skunks and foxes: That's certainly a possibility, and might be more of a concern in suburban regions that have ongoing issues with things like coyote attacks.
- Most people don't have a clue how to raise chickens: That's why some animal welfare agencies are opposed to urban chickens. Some humane societies also object because they can end up being the recipients of abandoned chickens, with which they are not equipped to deal and which cannot be easily adopted.
Here are some important points to consider if you're thinking about getting some urban chickens:
- Is it legal in your town?
- Do your neighbours like the idea? A few chickens isn't worth a neighbourhood spat.
- Do you know how to take care of chickens? If the answer is no (as for most people), are you willing to learn before you get your first chicken?
- Do you have a easily accessible source of feed? If you have to drive 100 km to get chicken feed, the project is bound to fail.
- Do you have any high-risk individuals in the house? This would include the very young, very old and people with weakened immune systems, who are more prone to developing disease if exposed to infectious agents. These individuals should not be exposed to chickens.
- Are you in for the long term? Commercial layer hens are generally productive for about 12 months, but some chickens can live for years.
- If you decide to get rid of the chickens, what will you do? Where will they go? Setting them free or dumping them off in the country is not an ehtical option. Adult hens don't make good roasting chickens, so even if you get them butchered for meat, you're probably left with stewing chicken at best.
- Remember that backyard eggs are not necessarily safer than commercial eggs. Consumption of raw eggs and improper handling of eggs are risk factors for diseases like Salmonella, no matter where they come from. Don't be fooled by the "all natural means safe" myth.
As is common this time of year, outbreaks of Salmonella infection in wild birds have been widely reported in parts of the US. Salmonella circulates regularly at low levels in the wild bird population, and sporadic outbreaks involving large numbers of sick and dead birds are periodically encountered. These are often noticed in urban areas when dead birds are found around bird feeders.
Salmonella can infect a wide range of species other than birds, including cats (and people). Cats can be exposed to Salmonella during these outbreaks from catching and eating sick birds, or healthy birds that are carriers of the bacterium. In fact, one name for salmonellosis in cats is songbird fever, a testament to the role of birding in feline salmonellosis. An example of the potential effect of wild bird Salmonella outbreaks on cats is described in the The Daily Journal from International Falls, Minnesota. In this report, a local veterinarian explains that he has seen an increase in salmonellosis cases in pets at his practice, mainly in cats. In the past 2 weeks, he has diagnosed approximately 20 cases, which is a pretty impressive number. Most of the infected cats had known contact with wild birds or areas around bird feeders.
If your cat goes outside, it is at higher risk for Salmonella. If there is an outbreak of salmonellosis in wild birds in the area (or you're seeing dead birds around the feeder), then the risks are probably much higher. While Salmonella is usually associated with diarrhea, not all cats that are infected develop diarrhea. Some develop mild disease without diarrhea (e.g. fever, lethargy), some get serious systemic infections (septicemia), and some may show no signs of illness at all but still pass Salmonella in their stool. In any case, the bacterium can still be transmitted to and infect people.
Any outdoor cat that develops diarrhea should be considered a Salmonella suspect. Really, Salmonella should be considered in all outdoor cats with fever and signs of illness that are not specific for a particular disease. Stool culture can be used to diagnose Salmonella.
Avoiding wild-bird associated salmonellosis in cats is pretty easy - keep your cat indoors. A cat that can't catch birds or hang around contaminated areas surrounding bird feeders won't be exposed to Salmonella from wild birds. At a minimum, cats should be kept inside if there is an outbreak of Salmonella in wild birds in the area, or if dead birds are found around your bird feeder. Ideally, they should be kept inside all of the time, for many reasons.
More information about Salmonella in pets can be found on the Worms & Germs Resources page.
Recently, I made a few comments about climate change and the potential impact on infectious diseases in horses on our sister site, equIDblog. A recent news article in New Scientist discussed concerns about climate change and pets. The main infectious disease concern regarding climate change is changes in patterns and spread of insect-borne diseases, because different insect vectors may expand their normal ranges or change their seasonality in response to climate change. Some of the examples cited in the article include:
- Babesiosis, a blood-borne disease spread by the European dog tick, is being found in areas of Europe where it was previously rare.
- Increasing populations and ranges of ticks have been reported in many countries, which is a significant concern based on the number of different diseases these ticks can carry and transmit.
- Leishmaniasis has been identified in dogs in the southern UK. If climate change allows sandflies (the insect vector of this disease) to become established in the UK, then spread of this disease could become a major problem.
- Milder winters may result in longer periods of activity of some insects that transmit disease, thereby extending the times of the year when there is a risk of disease. In some areas, year-round risk could develop for diseases that were previously seasonal.
Climate change is a complex and still rather controversial topic. Predicting the infectious diseases implications of climate change is difficult. Information that is already available for some diseases, combined with general knowledge about microorganisms and their hosts, can help us make some educated guesses about what may happen. While the full scope of the impact cannot be predicted, it is almost certan that climate change will result in infectious disease challenges in both veterinary and human medicine.
Over 50% of households in Canada and the US have pets, and the numbers are probably similar in many other countries. Pets are often considered part of the family socially but we need to consider them part of the family biologically as well. It's clear that diseases that be transmitted between people and pets - in both directions. Unfortunately, it's also clear that physicians and vets don't do a very good job talking to each other.
Pet contact (and animal contact, in general) should be part of the standard history obtained by any physician. In my perfect world, every medical record would include a permanent record of contact with pets or other animals. This information is potentially useful because certain diseases that are not a big issue for non-pet owners may need to be considered (or may be higher on the list of possibilities) in pet owners. Knowing about pet contacts up front could help speed up diagnosis and proper treatment.
I have a flock of rare breed sheep. The other day, I had to assist with a lambing. Contact with newborn lambs and fetal fluids is the main source of the organism Coxiella burnetti, which causes Q-fever. If I became infected, the illness would start off with vague signs like fever and malaise. If I went to a physician at that point, I'd probably be told to go home, rest and take anti-inflammatories as needed (the old "take two aspirin and call me in the morning" type thing). If the physician knew I had sheep, he/she might ask about the risk of exposure for Q-fever. Upon hearing that I had a high risk exposure a few days earlier, Q-fever would be considered right away and appropriate measures could be taken.
Also, as strange as it sounds, in my utopian world physicians would ask about pet health. Yes, it may seem strange if your doctor were to ask "So how are you doing today? And how's your dog been feeling lately?" - but it might be important. Illness in your pet may be associated with illness in you or other members of your household. Knowing that a pet is sick might give some indication of that (a) certain disease(s) are more likely in a person. Also, if the sick pet has been to a veterinarian for testing, those results might be useful to the physician. There's no guarantee that a pet and owner that are sick have the same thing, but a general principle of medicine is that a single cause is more likely than co-incidental independent problems.
Similar to the case of psittacosis in a pet store employee that I reported about recently, let's say that you own a bird and it's been sick for a week or so. It's weak and not eating well. You then come down with a fever and cough - something that's not uncommon. However, when your astute physician asks about the health of your pets, he/she gets concerned about the fact that your bird is sick. Your doctor contacts your bird's veterinarian, and it becomes clear that the bird could be infected with Chlamydophila psittaci, the cause of psittacosis in people. Your doctor therefore puts psittacosis on top of the list of potential problems, and instead of telling you to go home and rest, he/she takes some blood samples to try to diagnose it the infection and may even start treatment right away. Because your physician identified a higher risk situation with your sick bird, you get prompt treatment, you start to feel better in 24 hours and it's unlikely you'll have any major problems. (The mortality rate from psittacosis is < 1% in people that are treated properly. If the diagnosis is missed, the mortality rate increases to 20%, and you also run the risk of complications such as heart valve damage.)
An annual "ritual" in some schools is hatching chicken eggs in the classroom. This can be a great educational experience for children as they learn about eggs and incubation, watch them hatch and see the baby chicks. It can also be a great source of infection for children if certain precautions are neglected. The picture on the right, from an article in the Ilkley Gazette, shows a good example of a bad idea. This four-year-old boy has a newly hatched chick on his shoulder. Why does this bother me?
- Chicks are a great source of potentially harmful bacteria, particularly Salmonella.
- You can't litter train a day-old chick. I wouldn't be surprised if it left a little biohazardous "present" on the child's shoulder.
- Outbreaks of salmonellosis in people associated with baby chicks have been reported.
- The Centers for Disease Control and Prevention (CDC) recommends children under five years of age should not have contact with chicks.
If there are going to be chicks in a classroom:
- They should only be in classrooms with older students.
- Contact with chicks should be restricted and always supervised.
- Careful attention must be paid to handwashing. Everyone who handles chicks or comes in contact with their environment (e.g. box, cage, incubator) should immediately and thoroughly wash their hands.
- Chicks should never be allowed to roam free in the classroom.
- Chicks should never be handled during lunch or snack time.
- Immunocompromised children should not be present in the class.
It's common sense, but it's amazing how uncommon "common sense" seems to be sometimes.
People that work with animals are at increased risk for certain infectious diseases. That's pretty clear. Pet shop employees fit into this group as well, and they may be at particular risk for specific diseases because of their close contact with young animals, birds, rodents and reptiles. A suspected case of psittacosis in a Toronto pet shop worker is an example of this.
A bird in the pet store where this person worked supposedly died of avian chlamydiosis in mid-March (although the initial test results have been called into question). Avian chlamydiosis is caused by the bacterium Chlamydophila psittaci. This organism is relatively common in psttacine birds (parrot family), especially in breeding colonies, but can also be found in other types of birds. It can cause serious disease in birds, but it is also commonly carried by healthy birds. People can become infected from breathing in the bacterium, often from aersolized dust containing dried bird droppings. The disease in people is called psittacosis. The pet store worker developed signs that could be consistent with psittacosis: cough, lethargy and difficulty breathing. However, these signs are still fairly non-specific and could also be caused by numerous other respiratory pathogens. Test results are still pending.
People that have close contact with pet birds, especially psittacines, need to know that they may be at increased risk of psittacosis. They also need to ensure that their physicians know about their increased risk. This is important because early signs of psittacosis are very vague, such as fever and cough. Psittacosis would presumably not be high on the doctor's list of possible diagnoses for the average person coming in with fever and a cough. If the doctor knows a person has contact with birds, hopefully psittacosis would be considered earlier so prompt diagnosis and appropriate treatment can be given. This disease is readily treatable if diagnosed early, so awareness of the possibility on the part of the patient and physician are important.
This report also demonstrates why determining a final diagnosis for sick or dead pets is critical. While the diagnosis may not help the animal (especially if it's already dead), it may play an important role in protecting the health of people or other animals. If the bird in this case was not tested, it's hard to say how long it would have taken for psittacoiss to be considered in the case of the pet store worker.
More information about psittacosis can be found in a document from the National Association of State Public Health Veterinarians. More information about good management practices to reduce the risk of disease transmission from birds can be found in the information sheets on pet birds on the Worms & Germs Resources page.
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.
As you undoubtedly know, a large Salmonella outbreak has occurred in the US, associated with contaminated peanuts. The scope of this outbreak continues to expand in unexpected areas, including pets. The latest development is a voluntary recall of bird seed. The recall affects 20-pound packages of Wild Birds Unlimited Wildlife Blend bird food (produced by Kentucky-based Burkmann Feeds) with the manufacturing date code 81132200 2916 08124.
The contaminated bird seed was linked to the deaths of several birds in North Carolina, and it was confirmed that the bird seed manufacturer received peanuts from the Georgia facility that was implicated in the Salmonella outbreak.
People that have used this bird seed should clear out their bird feeders, ideally while wearing gloves. The feeders should be thoroughly cleaned and then disinfected (although this may be easier said than done). Hands should be washed after handling the bird seed, potentially contaminated feeders or any other potentially contaminated items.
The risk to people is presumably quite low, but people handling the bird seed could potentially contaminate their hands with Salmonella and then inadvertently swallow some of the bacteria. Concerns are greatest in people with compromised immune systems, the very young, the elderly and people taking antibiotics, as they are more likely to get sick following exposure to small numbers of Salmonella.
More information about Salmonella can be found on the Worms & Germs Resources page.
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.
My oldest daughter is in Grade 2, and last year her class hatched chicken eggs in the classroom. As a parent, I was somewhat torn about the idea. My main concern was the risk of exposure to Salmonella. A recent article in Morbidity and Mortality Weekly Reports described outbreaks of salmonellosis associated with contact with live poultry. Most cases were associated with handling baby chicks obtained from agricultural stores or by mail order. Infections from classroom and petting zoo-associated contacts were also reported.
Salmonella contamination of eggs and carriage by baby chicks is very common. The CDC recommends that children less than five years old do not have any contact with baby chicks, and that older individuals pay close attention to hygiene in order to prevent transmission of Salmonella. Being six years old, my daughter was just over this age cutoff (although there's nothing magical about going from five to six years old, so I'd still consider her at somewhat higher risk). So, as long as good infection control practices were used (e.g. hand hygiene), the risk to the children was probably quite low. Were the benefits of hatching eggs in the classroom worth the risk? I don't know, but she enjoyed the experience and did learn a few things along the way. Concerns about infectious diseases are often dismissed, which is a problem, but sometimes excessive concern gets in the way of life. There's rarely a clear answer as to what is acceptable and what is too risky, given the potential benefits.
- Eggs and chicks should not be kept in classrooms where children under five years old will be present, or if there are immunocompromised children in the class. It's unclear whether all teachers would know if they had a high-risk child in the class. Parents of immunocompromised children should make sure teachers know about their child's increased risk.
- It is prudent for teachers to send home a note to inform parents if eggs/chicks will be in the classroom, or if similar activities involving animals are undertaken.
- Eggs and chicks should be kept in a complete enclosure, in an area that is always supervised when children are around.
- Chicks should always be kept in their enclosure. They should never be taken to areas (e.g. a student's desk) where food might be consumed.
- Direct contact with eggs and chicks (and their environment) should be kept to a minimum.
- Hands should be thoroughly washed or an alcohol hand sanitizer used immediately after contact with eggs, chicks or their environment.
- Appropriate thought should go into the use of eggs and chicks in classrooms. They should be there for more than the "novelty factor". There should be a clear teaching plan associated with them so they provide the maximum educational value possible.
- Testing eggs and chicks for Salmonella isn't practical. A negative result cannot guarantee that Salmonella is not there. As well, there are other infectious diseases that are of concern. Consider all eggs and chicks Salmonella-positive and handle them appropriately.
As an illustration of some of the points made in the recent Worms&Germs post on animal smuggling, an outbreak of psittacosis was recently reported in Russia, which has been linked to illegally imported decorative birds. Since December 30, 21 cases of psittacosis have been reported in the Petuhovsky district of the Kurgan region. The source of the infections was reportedly a large group of illegally imported parrots and canaries. In late 2008, another group of 15 cases were reported in the Orenburg region of Russia, which were also associated with a large group of 1500 smuggled birds. Compare this to statistics from the CDC, to which only 125 cases of psittacosis were reported from 2000 through 2006.
This report reiterates the infectious disease risks than can be associated with illegally imported animals, as well as some of the welfare issues (a second article reported that some of the birds in the illegal shipment were found dead when they reached the border). It's also important to be aware of zoonotic pathogens that can be carried by even healthy pet birds.
Psittacosis, also known as ornithosis or "parrot fever," is caused by the bacterium Chlamydophila psittaci, which is commonly carried by psittacine (pronounced "sit-a-seen") birds, often without making them sick. These birds may shed large numbers of C. psittaci in their feces. When the feces dry they become dusty, which can result in people inhaling the bacteria as they work around the birds. This is the most common way for people to become infected, and can result in pneumonia. The infection can be treated with antibiotics if it is caught in reasonable time, but it can be very serious in some cases. The bacterium can make birds sick as well in come cases, in which case the disease is called avian chlamydiosis.
More information on psittacosis is available in the National Association of State Public Health Veterinarians' Psittacosis Compendium and in the Worms & Germs archives.
Animal smuggling is a surprisingly big problem. A report in the Canberra Times quotes an Australian customs officer as saying animal smuggling is a $20 billion industry and the third largest criminal activity in the world (after drugs and weapons).
Animal smuggling can range from someone trying to sneak an exotic pet into the country, or large- scale smuggling by certain individuals (like the guy who tried to smuggle 300 poisonous frogs onto a plane). It can also consist of massive organized crime ventures.
There are many concerns associated with animal smuggling:
- Animal welfare: High death rates are not uncommon among animals during illicit transportation. Smuggled animals are often wild-caught, and even if they survive the stress of transportation, they may die soon after arrival. Particularly when you hear about animals being smuggled sewn up in giant teddy bears, or stuffed into pockets and pouches, it's a wonder as many of them survive as they do. The customs office in the Canberra Times article sums it up nicely "'People who smuggle animals don't care about the animals ... They actually see dead animals as an overhead.'"
- Introduction of foreign diseases: Smuggled animals have been blamed for introduction of serious diseases like avian influenza into areas where these diseases don't normally exist. This can be a huge problem, as it creates the potential for large outbreaks amongst indigenous animals or people whose immune systems are completely naive to the diseases.
- Transmission of disease to new owners: Smuggled animals certainly have not undergone good health examinations and quarantines, and can carry a host of potentially harmful microorganisms. This can put buyers and their families at risk.
Despite being a huge industry, there are things that everyone can and should do to reduce animal smuggling:
- Don't buy animals that you know were or may have been illegally imported. Doing so contributes to the death of countless other animals for every animal that survives.
- Don't buy wild-caught animals like birds and reptiles. Wild caught doesn't mean smuggled, but it may be hard to tell the two apart. Some of the disease risks, particularly to individual buyers, are the same with legally and illegally imported wild-caught animals. These days there are good, reputable and ethical breeders of many animal species around that can supply animals. If the species is so rare that there aren't any good breeders around, then don't buy it. It might be rare because the animals don't survive well in captivity, or are hard to find in the wild. You don't want to contribute to either of those situations. In some instances, you can find both wild-caught and captive-bred animals for sale. While the captive-bred version will almost certainly be more expensive, the extra cost is not so great when you consider the overall lifetime costs of the animal. And how much money do you really save if you end up with a sick or dead animal?
- If a deal sounds too good to be true, it probably is. That animal that you're getting for such a "great deal" might have been smuggled or be otherwise unhealthy.
- If, for some reason, you are determined to get a wild-caught animal, make sure that it comes from a reputable source who imported the animal legally. Ask how it was caught, stored and transported. A good supplier should be able to tell you everything that happened from the time of capture to its arrival, or at least be able to find that out. If they don't know or don't care, walk away.
A recent article in the journal Avian Pathology describes a case of Mycobacterium tuberculosis, the cause of tuberculosis (TB), in a pet bird (African Grey parrot) and its owner. Mycobacterium tuberculosis mainly causes disease in people, but can sometimes be found in other animal species, including birds. In this case, the bird was presented to a veterinarian because it had a decreased appetite and nodules under its tongue. The bird was wild-caught in Africa 11 years earlier. The owner was treated for TB two-and-a-half years earlier. Apparently, the owner usually fed the bird pre-chewed food (don't ask me why), and the vets suspected TB because of this close exposure. Because of the severity of the disease, the bird was euthanized and TB was confirmed by culture and PCR.
Often, we get to a point like this where both an animal and person have been diagnosed with the same disease, and can't go any further in terms of determining how each of them got the disease, and if it was transmitted between them. Fortunately, the Mycobacterium tuberculosis isolate from the owner had been saved, and they were able to compare it with the strain found in the bird. They were same. This strongly supports the theory that TB was transmitted between the owner and the bird. However, that's as far as we can go with confidence. The authors hypothesized (reasonably) that since the owner was diagnosed first, and since TB is mainly a human issue and is rarely found in birds, that the person acquired TB from some source then infected the bird. Additionally, two other reports of TB in birds also stated that the owners pre-chewed the birds' food.
TB in birds (and pets in general) is rare, and people shouldn't panic about it. However, it is apparent that transmission between species can occur. Transmission from an infected person to a pet is more likely than the other way around, but both are certainly possible. It's a good reminder that people with TB who are considered infectious should take precautions around their pets, just like they do around other people.
...and pre-chewing food for your bird is probably not a good idea, either.
It's amazing where infectious disease discussions can develop (at least for strange people like me). I was having a conversation with Dr. Mike Taylor (an avian and exotics specialist at the Ontario Veterinary College) after hockey the other night, and we started talking about infectious diseases.
Mike has done a lot of work with proventricular dilatation disease (PDD), a serious disease of psittacine birds. Recently a virus (avian bornavirus) has been identified as the cause of the disease. One of Mike's observations during field investigations was that avian facilities that used a two-bowl cleaning system seemed to have a lower incidence of disease. In this type of system, the feed bowl in each bird enclosure is removed each day and replaced with a clean one. The dirty bowl is then cleaned, disinfected and allowed to dry until it is used again the next day. The system is quite easy to implement and allows for thorough disinfection of bowls. Cleaning and replacing the same bowl each day presumably results is a quicker and less thorough disinfection, and does not allow for a period of drying. Bornavirus is fairly easily killed with proper cleaning, disinfection and drying, but can survive in a bowl that is not adequately cleaned. This two-bowl system may have helped kill more of the virus that was deposited in the bowls.
This simple management tool might be useful for controlling PDD (and other diseases) in birds, and perhaps could indirectly reduce the risk of transmission of certain pathogens from birds to people. Avian bornavirus itself does not infect people.
Infection control isn't rocket science. Simple, common-sense measures (like hand washing) are often the most important factors in the success or failure of disease prevention programs. Simple management tools such as this should be considered as part of routine activities to reduce the risk of various infectious diseases.
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.
A recent report in the Medical Journal of Australia described the case of a woman who was pecked in the leg by her daughter's pet magpie. The woman was otherwise healthy (i.e. she did not have a compromised immune system), but the wound became infected by the fungus Saksenaea vasiformis, which rarely causes disease in people or animals. The infection became so severe that the woman's leg had to be amputated.
Saksenaea vasiformis can be found in soil all over the world. There are a few possible routes by which the fungus may have infected the woman's leg in this case. The fungus could have been on the person's skin, and been carried into the deeper tissues by the pecking. It also could have been on the bird's beak. Alternatively, it could have contaminated the wound after the pecking, through contact with soil or dirty hands.
This is an example of an infection that would be difficult to anticipate, since it occurred in a healthy person as a result of contact with a healthy bird, and with minor trauma, but potentially could have been avoided. Although the bird may not have been the source of the fungus, the break in the protective barrier of the skin was the critical event. Basic wound care is always important, and any injury from an animal should be taken seriously and properly addressed. Wounds should be carefully cleaned and monitored for signs of infection. A physician should be consulted as soon as possible if there are any concerns. A physician should always be consulted for any wound that is:
- on the hands
- over a joint
- over a tendon (e.g. wrist, ankle)
- in the genital area
- over a prosthetic device
- sustained by a person with a compromised immune system (e.g. HIV/AIDS, transplant or cancer patient)
More information on bites can be found in the Cat Bites information sheet on the Worms & Germs Resources page). It's unclear whether any of these precautions would have prevented the serious fungal infection that occured in this case, but these measures can reduce the risks of infection.
There was an interesting article in USA Today about the increasing recognition of the positive role that pets can play in patients recovering from serious disease, and how contact with pets can sometimes conflict with disease transmission concerns in these same patients. The attitude towards pet ownership among physicians is highly variable - some recognize the strong human-animal bond and its positive effects, while others see pets as unnecessary infectious disease risks. The infectious disease concerns are heightened in patients with compromised immune systems, to the point that sometimes people are told to get rid of their pets if they are severely immunocompromised. However, more and more pet owners, veterinarians and physicians are beginning to question if this is truly the best approach.
The USA Today article describes the experiences of a cancer patient whose greyhounds were "banished to a caregiver on doctors’ orders". Considering she was at high risk for (potentially fatal) infectious disease because of chemotherapy, bone marrow transplant, stem cell transplant and immunosuppressive drugs, it’s not surprising that there was concern about the pets. After researching the risks, and measures she could take to reduce those risks, the patient convinced her doctors that the risks from her dogs were not as great as the benefits from having them around, and so the dogs returned home. While everyone’s relationship with their pets is different, the patient felt that the return of her dogs was an important step in her recovery, stating "There's no question that having (the dogs) with me these past few months made a huge difference in my recovery".
Infectious disease transmission from pets to people is certainly a real issue, and it is of particular concern in people with weakened immune systems. There is not, nor will there ever be, a "no-risk" pet. Every contact with a pet, just like every contact with another person, carries with it some degree of risk of disease transmission. What needs to be considered is the trade-off, the risks versus the benefits. In some people, the risks are greater than the benefits because of the severity of disease, type of pet, the person's ability (or more likely inability) to interact with the pet. In other people, especially those who have a very strong bond with the animal, the positive social and emotional benefits of pet ownership may greatly outweigh the associated disease risks. The article contains a great quote from Dr. Ray Pais, a pediatric hematology/oncology specialist, saying "Our young patients have already given up so much, I see no reason at that moment for them to also lose the dog."
People that have compromised immune systems need to have a serious discussion with their physician, veterinarian and family about the best thing to do with their pets while they are sick. While there is very little research in this area, taking a few common sense precautions should reduce the risks of disease transmission. These include:
- Avoiding contact with stool
- Frequent handwashing
- Preventing licking of the person by the pet
- Proper training to reduce the risk of bites and scratches
- Keeping cats indoors
- Following a good preventive medicine program for the pet
More information about Immunocompromised Pet Owners will be available soon on the Worms & Germs Resources page. The CDC also has useful information on its website about this topic.
Thanks to Dr. Doug Powell of Barfblog for forwarding this article.
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.
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!
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.
Typically, psittacosis causes flu-like disease and is easily treated, if diagnosed properly, however more severe disease can develop. Infected birds can shed the bacterium through feces and nasal secretions. People usually become infected by inhaling aerosolized bacteria from dried feces or nasal secretion.
Psittacosis is an uncommon disease. Only 125 human cases were reported to the CDC in the US between 2000 and 2006, however many more cases probably occurred. The risk of acquiring psittacosis from a pet bird is very low.
- Bird owners should make sure that their physician is aware that they have contact with birds. Psittacosis should be considered in people with flu-like disease that have bird contact.
- Do not buy birds that look unhealthy (lethargy, nasal or eye discharge, ruffled feathers...).
- If you have other birds, isolate new birds for 30 days before allowing them to have contact with existing birds.
- Reduce aerosolization of materials when cleaning cages. Lightly wetting cage paper will reduce the risk of aerosolization.
- Wash your hands after handling birds or cleaning their cage.
- Try to prevent your pet from eating/touching dead birds.
- If your pet develops diarrhea after eating a dead bird, it is probably not a health concern for anyone else but Salmonella infection is possible, so consider taking your dog to the veterinarian. This is especially important if the dog appears sick (i.e. besides vomiting and diarrhea, the dog also is not acting like itself) or if there are people in the household that are at higher risk for getting sick from bugs like Salmonella (i.e. infants, people with weakened immune systems). All diarrhea should be considered potentially infectious to other animals and people. Extra care should be taken around affected pets and their stool, including extra attention to hand washing, and disinfecting the site of any "accidents" that occur in the house.
- In some areas where bird testing is performed for West Nile virus or avian influenza surveillance, public health personnel will collect dead birds. Contact your public health department if you are unsure what is done in your region.
- Do not touch dead birds with bare hands.
- Use heavy-duty, leak-proof gloves to place the bird in a leak-proof plastic bag. Alternatively, fold two bags over your hand and use the bag to cover your hand when picking up the bird (like people do when poop-scooping), or use a shovel to place the bird in a bag.
- Double bag the bird.
- If the bird is not being collected for testing, contact your local waste management agency regarding disposal instructions.
- Always wash your hands with soap and water as soon as you're done.
This disease is another good example why people should make sure their physician knows what types of animals they own or have contact with.
INFORMATION SHEETS specifically for KIDS, for VETERINARIANS, for PHYSICIANS and for PUBLIC HEALTH PERSONNEL are also available on the Worms & Germs RESOURCES page!
Click on the highlighted topics below for information sheets. Topics that are not highlighted are in development and coming soon. Sheets for other animal species and diseases are also under development and will be added when they are available.
- Your veterinarian and physician are your ultimate resource for information about the health of your pets or your family.
- Information provided here is accurate to the best of our knowledge, but infectious diseases can be unpredictable and these sheets are for general information purposes only.
- There can be great variation in disease risks in different geographic areas. The information provided was developed for Ontario, Canada, but most of the information is relevant for other regions as well.