Worms & Germs - Thanks to our readers!
The Worms & Germs blog has officially been active for one year, and look how far it’s come! Just last week we surpassed 100 000 unique hits since our launch. We now regularly have over 1000 unique hits on the site per day during the week, and the numbers are still growing. The current swine flu outbreak has emphasized once again the importance of zoonotic diseases in the world today, and the diminishing division between human and animal health. It's great that we're able to provide a reliable source of information about zoonotic infectious diseases to such a wide and diverse audience.
Everyone involved in Worms & Germs would like to take this opportunity to thank all the visitors who come to our site, and especially those who keep coming back for more! Please continue to help us spread the word about zoonotic disease control and safe, responsible pet ownership. Questions, comments and suggestions are always welcome! -Scott & Maureen
Updated H1N1 (swine) influenza outbreak numbers from WHO
The World Health Organization (WHO) has provided the latest update about H1N1 influenza numbers internationally. (People are still often calling this "swine flu", but it has yet to be found in pigs and is clearly being transmitted human-human now, therefore some have recommended it be called "Mexican flu" or "North American flu" instead. This also decreases the negative associations with pork products, which are totally unfounded because the virus is NOT a food safety concern). Regardless of the name, this pathogen continues to move across the planet. The WHO is reporting 148 laboratory confirmed cases. Ninety-one have been confirmed in the US with 26 confirmed in Mexico.
It's important to remember that confirmed cases are very much the "tip of the iceberg". It's likely that there are thousands of cases in Mexico, despite only 26 having been confirmed by laboratory testing. For a case to make this list, the sick person has to go to a doctor AND samples have to be collected for testing AND the testing has to be appropriate for identification of swine flu versus other types of influenza. Areas with more diagnostic testing capacity and public health infrastructure (like some places in the US) will end up reporting more cases, even if they actually have fewer sick people. So, we shouldn't become complacent when reading about relatively small numbers of confirmed cases, and we must take care when comparing regional rates.
Confirmed cases have also been reported in Austria (1), Canada (13), Germany (3), Israel (2), New Zealand (3), Spain (4) and the United Kingdom (5). Deaths have only been reported in Mexico and the US, with the single (to date) US death being a child that was visiting from Mexico.
Swine flu: What about the pigs?
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We've been talking a lot about the swine flu outbreak the last few days, but so far all we've really talked about are the human aspects. The reason we're blogging about it on this site is that it's a zoonotic disease - so where do the pigs fit in?
There's a distinct lack of information about where this strain of the influenza virus actually came from. I heard on the news this morning that one person who was interviewed by a CNN reporter was even trying to blame Canada for the outbreak, claiming that it was Canadian tourists that introduced the disease to Mexico in the first place! While I'm sure there will eventually be a great deal of investigation into how the outbreak got started (for the moment I think everyone's more worried about trying to just keep it under control), it's quite possible that we'll never find the "index case" or know exactly from where it came. But one thing's for sure: somewhere along the way, there has to be some pigs involved.
Pigs are the great "mixing pot" of influenza viruses, particularly with regard to avian, human and swine versions of the pathogen. Pigs can be infected by strains of all these different types, and coinfections (infection with more than one influenza virus at the same time) provide the viruses with a prime opportunity to trade RNA and recombine to form new influenza strains with new properties - more infectious, more virulent, or perhaps better able to infect another species, for example. In this case we appear to have a swine influenza virus that is not only capable of being spread to people (as occasionally happens with "regular" swine influenza viruses), but also between people, and hence the developing human outbreak.
But what about the pigs? There isn't a lot of information out there at the moment, with all the focus on the human aspect, but so far Mexican authorities have found no infected pigs in Mexico (at least no where they've looked - so far). Influenza in pigs is really nothing new, and other swine influenza strains are commonly found in pigs around the world. Highly pathogenic strains, like those that cause massive devastation of poultry flocks, don't occur in swine. If an influenza virus gets into a pig barn, however, it's like putting a person with the flu in a crowded room - the virus spreads very quickly through the air over short distances and soon everyone (or every pig) has the flu. Thankfully the virus generally also moves on quite quickly, and after a few days the animals generally start to recover. While such an outbreak certainly affects their growth efficiency, very few (if any) pigs die.
Yesterday the Canadian Veterinary Medical Association (CVMA) distributed a fact sheet on swine flu from the Canadian Food Inspection Agency (CFIA) for all Canadian veterinarians and swine producers. The CFIA is encouraging increased vigilance with regard to monitoring and diagnosing disease in Canadian pigs, to prevent the disease from spreading through the swine population. In addition to emphasizing vaccination, good hygiene practices and biosecurity, particularly around sick pigs, they also point out that it's equally important (especially now) for anyone who may have the flu to avoid contact with pigs (be they Canadian pigs or pigs in any other country), in order to avoid spreading the virus to them. Hopefully people in other countries will take the same precautions.
Another very important point is that swine influenza is NOT a food safety concern. The virus does not survive well in the environment for very long, and therefore cannot survive on pork products, and certainly cannot survive proper cooking (which is always very important for any kind of meat). The fact that some countries are banning pork imports is really not going to do anything to help control the outbreak - the concern should only be about live pigs (and people). So you can still have pork sausages at your next spring barbeque, just ask anyone who's feeling "under the weather" (or a little flu-ish) to please stay home!!
Interactive swine flu map
GoogleMaps has an interactive swine flu map that is quite interesting. The map indicates where cases of the disease have been diagnosed or are suspected, and it's updated frequently. Clicking on a marker gives you more information about what is happening in that particular location. Many of the pink "suspected" markers will probably turn out to be negative, but I fear the map's going to get a lot more crowded over the next couple of days. The picture below is a captured image of the map, but click here for the live interactive version.
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Pets and household quarantine
A few years ago, I wrote a commentary in the journal Emerging Infectious Diseases about pets and household quarantine. It was written after SARS (severe acute respiratory syndrome) had caused tremendous problems in many areas, including Toronto. The point I was trying get across was that while there was a strict household quarantine implemented for exposed people, there was no consideration of pets. We now know that cats can become infected with the SARS coronavirus, and can transmit it to other cats. However, when people were quarantined, there were no recommendations for pets - pets could interact with quarantined people, then visit non-quarantined family members, or interact with other animals or people outside. From my standpoint, this was a significant concern. If cats had become infected with SARS, they could have been a source of transmission in households and potentially beyond. If SARS had infected the feral cat population in Toronto, it might have been very difficult to eliminate. I encouraged groups to ensure that pets are included in household quarantine guidelines.
The topic is front and centre again with swine flu. We don't know whether dogs and cats can be infected with this particular swine flu virus, but we DO know that cats can become infected with H5N1 avian flu and shed the virus. In my mind, that means that we should consider pets susceptible until proven otherwise.
So what should we do if people are being quarantined?
- If you are quarantining the family, quarantine the WHOLE family, including pets.
- Quarantined cats must be kept in the house. Quarantined dogs must be kept in the house as much as possible. They should only be taken outside to urinate/defecate, and this should be in a "remote" area where they can't have contact with other people or animals. They should always be under physical control (e.g. on a leash) when outside.
- If a quarantined pet gets sick, a veterinarian should be called first. That way, it can be determined if the pet needs to be examined, and if so, the clinic can know when it's coming and have protocols set up to handle it with infection control precautions.
EU recommends avoiding US/Mexico travel
The European Union's Health Commissioner has recommended that Europeans avoid all non-essential travel to the US and Mexico (Canada's apparently under the radar so far) as a measure to contain the spread of the emerging swine influenza virus. This has been met with some disdain by US officials, who emphasize the small number of cases (so far) in the US, and the much, much larger numbers of people that die in various countries every year from classical human influenza.
It's hard to say what type of restrictions are appropriate at this point in the outbreak. In general, it's better to be prudent and excessive (within limits) when dealing with a developing problem. The lack of information about the true scope of the problem, and the delays from transmission to definitive diagnosis of new cases, complicate assessments about whether the problem is truly contained, or containable.
Swine flu was most recently confirmed in Spain, and it has probably reached many different countries. It is also suspected in a group of students in New Zealand that recently visited Mexico. Considering the massive volume of travel between North America and much of the world, and the wide geographic range of cases in North America, it's hard to envision keeping this localized.
The fact that this outbreak is going to be difficult to contain, however, should not be taken as an excuse to not try to contain it. Even if this virus spreads to many different countries, good infection control and surveillance measures can help limit the impact of the disease.
Photo: Chichen Itza, one of the major tourist attractions on the Yucutan Peninsula in Mexico (credit M. Anderson)
Swine flu confirmed in Canada
Not surprisingly, swine influenza has been confirmed in Canada: 4 cases in Nova Scotia and 2 cases in British Columbia. More cases are certain to follow. As in the cases reported from the US so far, all Canadian cases have been mild.
The 4 cases from Nova Scotia were from the same high school. One of the affected students had been on a school trip to the Yucatan Peninsula in Mexico recently. Presumably, he or she picked up swine flu in Mexico and other students were infected by that student or others that went on the field trip. This is similar to a cluster of cases from a high school in New York. Eight students from that school were diagnosed with swine flu while more than 100 students had flu-like disease (it's unclear how many of these were tested). The two cases from BC were both in people who recently returned from Mexico themselves.
I imagine that we're going to see almost hourly reports over the next few days describing swine flu cases in people in various regions. Lets hope the pattern of mild disease that has characterized the Canadian and US cases persists.
US government declares public health emergency over swine flu
In response to increasing numbers of confirmed or suspected cases of swine flu in the US, plus a still relatively unknown number of cases and at least 81 deaths in Mexico, the US government has declared a public health emergency.
This H1N1 swine influenza virus has many of the hallmarks of a virus with pandemic potential. It is of animal origin but has a unique combination of gene sequences that has not been found previously in swine or human influenza strains. People don't have pre-existing antibodies because they have not been exposed to it before, which leads to the chance for widespre
ad disease. A big concern is that it seems to spread at least somewhat efficiently between people (unlike the H5N1 avian flu virus which is not efficiently transmitted between people). Fortunately, while it can cause death, this swine flu virus does not seem to be as deadly as avian flu, which kills approximately 50% of the people it infects. Therefore, while swine flu appears to be much more transmissible, it's probably not as fatal. (However, the large number of reported deaths in Mexico and early stage of the outbreak at this point means we need to be cautious making such statements).
It is clear that this swine flu strain is spreading in the US. It's been found in multiple US states and it is probably going to be found throughout the country. Mild cases have already been confirmed in Canada, and there are suspected cases in other countries. The number of cases in different regions and the amount of international travel makes containment of a reasonably-transmissible virus very difficult.
Some tips to reduce the risk of catching (or spreading) swine flu:
- Wash your hands regularly, particularly after contact with other people or common-contact sites (e.g. public door handles, public transit).
- If you are sick, STAY AT HOME. The era of "sucking it up" and going to work when you are sick should be over. All you're doing is putting others at risk.
More information about swine influenza can be found on the CDC's swine influenza website.
Image from http://www.nydailynews.com
Sandbox worms
I received this question the other day:
I just bought sand for a sandbox that I bought new 3 weeks ago. My granddaughter and I were playing in it and I came across some 2 inch long worms. I had a cover on my sandbox from day one so no animals got into it. I would like to know how to treat the sand without infecting my grandchildren and are these worms harmless.
We often use the term "worm" loosely when referring to different types of parasites. An important point, however, is not all worms are parasites, and not all parasites are worms. Most worms that you find outside are just worms that have no relevance at all to human or animal health.
When it comes to concerns about "worms" and sandboxes, we're worried about roundworm eggs and hookworm larvae from the feces of infected animals. It's these microscopic eggs and larvae that are the problem, not any large worms you'd be able to see with the naked eye. Covering sandboxes is recommended to keep animals from defecating in them and contaminating the sand, but various types of non-parasitic worms can still certainly find their way into some outdoor sandboxes, even if they're covered. I don't know of any human or animal health concerns regarding these kinds of non-parasitic worms. (I don't recommend snacking on worms from the sandbox to prove the point, but I would not be concerned about having worms in a sandbox).
More information about sandboxes can be found on the Worms & Germs Resources page.
Songbird fever: Salmonella in birds and cats
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.
Climate change and pet health
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.
MRSA strains found in pets
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Methicillin-resistant Staphylococcus aureus (MRSA) is an important (and high profile) cause of disease in people, and an emerging problem in animals. Evaluating the types of MRSA that we find in pets can help us understand what is happening with MRSA in pets and why.
A few different studies have evaluated the types of MRSA found in pets, using different molecular typing methods. The common result from all these studies is that the MRSA types found in pets are typically the same as those found in people in the same area. Even in different countries where there are different MRSA strains, the strains most commonly found in people are the same as the ones most commonly found in pets. Also, as the types of MRSA found in people in different regions change, so do the types found in pets. For example, USA300 (which can be a particularly nasty strain of MRSA) emerged a few years ago as a leading cause of MRSA infections in people in the general population (i.e. community-associated MRSA) in the US. Shortly thereafter, we started to see this strain in pets too. As USA300 began to crop up in people in Ontario, we also started finding it in pets. These results strongly suggest that MRSA in pets is closely related to MRSA in humans, and that most MRSA infections in pets ultimately started off in a person. Remember, though, that pets can still transmit MRSA once they've been infected.
It's inevitable that we will see more changes in MRSA types in people in the future, and it's almost certain that these changes will then be reflected in animals. In some ways, we can use humans as sentinels for what we are going to see in pets. By monitoring what is happening with MRSA in people and how it is being addressed, we can perhaps figure out the best (and worst!) ways to address the problem in animals.
More information about MRSA in pets can be found on the Worms & Germs Resources page. Information about MRSA in horses can be found on our sister site, equIDblog.
Rabid rat attack
Cab drivers have to put up with a lot of risks, but attacks from marauding rats probably aren't high on their list of concerns. However, a Ukrainian cab driver was recently attacked by a rat, and the rat was subsequently killed and found to be positive for rabies. The cab driver is now undergoing post-exposure treatment, and authorities are vaccinating pets and trying to eliminate mice and rats in the nearby neighbourhoods.
This is another good example of why it's important not to ignore a bite from any mammal, because rabies can affect any mammal. People often don't consider rodents a concern when it comes to rabies transmission, because most rodents would die from an attack by a rabid animal, thus preventing them from becoming infected and passing on the virus. This is probably true in most circumstances, but there have been enough reports of rabies in rodents, and potential human exposure from contact with rabid rodents, that we have to pay attention to this risk. Overall, the likelihood of acquiring rabies from a rat bite is pretty minuscule, and much less than the risk of contracting other diseases such as rat bite fever, but it's not zero. Since rabies is almost invariably fatal, even seemingly low risk situations need to be carefully assessed. In the case of this cab driver, there was definitely a risk of rabies exposure. If the rat had not been caught and tested, the potential for rabies exposure might have been dismissed, which could have had catastrophic consequences for the cabbie.
More information about rabies can be found on the Worms & Germs Resources page.
Rabies quarantine in Flagstaff, Arizona
Quarantining animals that have potentially been exposed to rabies is a standard practice, but quarantining a whole town is new to me. Because of a large increase in rabies cases in the Flagstaff, Arizona area, a rabies quarantine was established on April 8th by the Coconino County Board of Supervisors. The quarantine requires all dogs and cats to be enclosed or secured on their owner's property. When off the property, animals must be on a leash that is no longer than six feet in length. All dogs and cats must be vaccinated, and low-cost rabies vaccine clinics have been held to help increase compliance with this requirement. Vaccination of wildlife using baits containing an oral form of rabies vaccine will also be performed. The quarantine also restricts feeding and interacting with wildlife. Also, people cannot leave pet food outside after sunset and all compost piles must be completely enclosed.
This is an aggressive approach to rabies control in an area experiencing a wildlife outbreak of the disease. They've implemented comprehensive but still quite practical measures that should help reduce the risk of exposure of domestic animals (and people) without a significant negative impact on pet owners. I've mentioned my concerns about rabies vaccine clinics in the past, but this is a situation where I think it's a good idea.
It's always hard to evaluate the effectiveness of outbreak measures, because you never know what would have happened if nothing had been done. Regardless, it will be interesting to see how well this quarantine works, both in terms of the number of new rabies cases they see and the response of citizens to these restrictions. It would be very useful if Coconino County personnel provide information about how things went when the quarantine is over - the information might be useful for management of future rabies outbreaks.
Plague in a rabbit: New Mexico
Plague has been diagnosed in a dead rabbit found on a private residence in New Mexico. Plague, also known as the black death, is a highly fatal disease of humans and many animals caused by the bacterium Yersina pestis. While often considered a disease of mainly historical interest - having killed a large percentage of people on the planet during a few pandemics over the centuries - plague is actually still alive and well in some regions. In North America, most cases occur in New Mexico, Arizona, Colorado and California.
Yersinia pestis primarily lives in wild rodents and is transmitted by fleas. Many different animal species, including cats, dogs, rabbits and people, can be infected if bitten by a flea from an infected rodent (hence the historical association of the disease with rats). Predatory species (like dogs and cats) can also become infected by eating infected animals. Dogs are relatively resistant to plague and usually only develop mild disease, while cats and rabbits are as susceptible as people, and can develop bubonic, septicemic or pneumonic plague. Transmission of plague from pets to people can occur, and most often involves cats. People can become infected by close contact with sick pets, or being bitten by a flea from such a pet.
Preventing plague in animals involves flea control and reducing exposure to infected wildlife. In areas where plague is active, all pets should be on a flea control program. Cats should be kept indoors to reduce the risk of exposure (e.g. keeps them from hunting infected rodents). Dogs and cats should not be allowed to have contact with dead animals of any kind. Measures to reduce rodent infestations in and around the house are also important.
More information on plague is available in the Worms & Germs archives.
By the book: Rabies vaccination, titres and exposure
Rabies vaccination is supposed to be given at regular intervals - typically every 1 or 3 years, depending on the vaccine. Some people don't want to vaccinate their pets on a regular basis, but they may not understand all the implications of this decision. Often, people ask whether antibody levels (titres) can be checked to determine if repeated vaccination is necessary or if it can be delayed longer. However, rabies is covered by very straightforward government regulations in Canada (and presumably in many other regions). According to these regulations, checking vaccine titres is not considered an acceptable alternative to regular vaccination. Knowing this, here are two scenarios to consider:
1) Your pet bites someone.
After a pet bites anyone, it must be monitored for 10 days to ensure that it does not develop signs of rabies. It makes no difference whether the animal is vaccinated or not. However, if you do not have proof that your pet has been properly vaccinated, in Ontario, it is theoretically possible that you could be charged under the Health Protection and Promotion Act.
2) Your pet is exposed to a rabies suspect.
If your pet was vaccinated, you'd have two options. Most commonly, your pet would receive a booster vaccine and would be observed at home for 45 days. Alternatively, if you wanted to avoid a booster, you could take a blood sample to check the rabies titre. If a protective titre (>0.5 IU/ml) was present, there would be a 45 day observation period. If a protective titre was not present, the pet would be treated as unvaccinated.
If your pet was not vaccinated, it would be subject to a strict six-month quarantine or euthanasia.
If your was vaccinated at some point, but not vaccinated according to the vaccine manufacturer's guidelines (i.e. it didn't receive the appropriate 1 or 3 year booster), it would be considered unvaccinated, and be subject to the same 6 month quarantine. It would not matter if the rabies titres had been checked and a protective titre had been present in the past.
From this, it should be clear that there are serious implications of not vaccinating your pet, at least in Canada. There are some circumstances where you may be rightfully hesitant to vaccinate your pet, such as if your pet previously had a severe vaccine reaction. However, if you choose not to vaccinate, you must be aware of the implications of this decision. Neither a letter from your vet stating that vaccination would be risky nor annual rabies titre checks are going to be of any help at all because of the rules that are currently in place.
More information about rabies and rabies vaccination can be found on the Worms & Germs Resources page and in our archives.
Exotic animals in daycares... another bad idea
One more post about illogical and dangerous activities associated with animals and young children and I'll hopefully get off the subject for awhile. I came across this daycare's website today. Keep in mind (again) that the the Centers for Disease Control and Prevention (CDC) recommends that children less than 5 years of age not have contact with reptiles, and that the Compendium of Measures to Prevent Disease Associated with Animals in Public Settings published by the National Association of State Public Health Veterinarians states that wild or exotic animals may not be appropriate in school settings. The photo gallery from this particular daycare included some great pictures of things that you should NOT do with young children. Some of the more striking example are below:
1) Letting a large snake wrap its body around the neck of a young child.
2) Letting a young child kiss a snake.
3) Letting a child touch a turtle.
4) Letting a young child pet a pygmy hedgehog. (Like reptiles, hedgehogs very often carry infectious pathogens, including Salmonella.)
I wonder...
- whether anyone made sure these children immediately washed their hands after they touched the animals.
- how may kids but their hands in their mouths before they washed their hands. (Probably almost all of them, considering the "animal visit" probably went on for quite a while.)
- whether this activity took place in the same area where the children later ate lunch or a snack.
- whether the parents knew that this was going to happen.
I'm not against young children having contact with animals. I think pet contact can be very rewarding for young children. However, these individuals are at higher risk for infection and it is our responsibility to protect them. Putting them in high risk situations like these is inappropriate. Animal visitation in daycares is not necessarily a bad thing, if it involves animals that are a low risk species (e.g. dogs and cats), that are healthy, and that have been temperament tested (to show they are at low likelihood of biting). It is also important that parents provide consent for their children to participate, that good hygiene practices are used (and enforced), and that the people bringing in the animals know what they are doing.
Weil's disease from a pet rat
A recent edition of the Veterinary Record contains a case report of Weil's disease in a person that adopted a feral (wild) rat (Strugnell et al, 2009). Weil's disease is a severe disease of the kidneys, liver and other body systems that can develop after acute leptospirosis (infection by Leptospira bacteria). This group of bacteria can infect a wide range of animals and is typically shed in the urine. The person that was affected adopted the rat after it was caught by her neighbour's cat. The paper says that the rat was "urinary incontinent" - not something we usually notice about rats since they are not typically litter or house trained. I presume this means the rat was urinating frequently when out of its cage, including when it was being handled. Because of this, the owner reported that she "aimed" to wash her hands after every time she touched the rat.
A couple of weeks after adopting the rat, the woman was admitted to hospital because of lethargy, muscle aches, mild abdominal pain, cough and a bloody nose. Blood tests showed that she had decreased levels of white and red blood cells, as well as liver and kidney disease. After further testing she was diagnosed with leptospirosis. She had to be treated in the ICU, but eventually made a complete recovery. The adopted rat and the other rat that she owned were euthanized by the owner's partner shortly after she was admitted to hospital. Testing of the adopted rat identified Leptospira in the kidneys.
This is another example of why wild animals should be left in the wild, and another case highlighting the need for veterinarians, physicians and public health personnel to work together.
More information on Leptospira and leptospirosis can be found on the Worms & Germs Resources page and in our archives.
Baby chicks in preschools
Just last week I blogged about concerns regarding young children handling baby chicks in classrooms. Baby chicks are high-risk animals because of the potential for transmission of Salmonella. The Centers for Disease Control and Prevention (CDC) recommends that children less than 5 years of age not have contact with baby chicks for this reason. Unfortunately, few people seem to know this (or at least pay attention to it). If I have a problem with baby chicks in kindergarten classrooms, you can imagine the conniption I have about chicks in preschools. These pictures illustrate my concerns in phenomenal fashion.
If you look closely at this first picture (right), you can see the plop of "chick poop" on this child's sweater (which he seems all too happy about). The picture is from a blog written by the child's mother - she gives absolutely no recognition that this is an infectious disease concern.
The second picture (left) is from a news article about a preschool. The preschool obviously has no clue about infectious disease risks because they allowed this c to put the chick on his head and were apparently proud enough of it to have the reporter take a picture.
And last but certainly not least, we have a great picture (below) of a child either kissing a chick or eating very undercooked poultry. Either way, it's a bad idea. This picture is from another parent's blog, who apparently thought it was cute.
Baby chicks should not be in preschools - ever. The novelty factor of having chicks in the facility does not supercede the infectious disease risks and recommendations from public health agencies.
Batty decision? Changing rabies exposure recommendations
The British Columbia Centre for Disease Control (BCCDC) has changed its rabies exposure guidelines and gone against established protocols used elsewhere. Typically, anyone who has slept in a house where a bat was present at the same time is considered to have been exposed to rabies if the bat was rabid or the bat's rabies status is not known. This is because bats can bite people while they are sleeping and the bite wounds can be so small that someone may not even notice after they wake up. People who get rabies from a bat bite almost always die. Because of the severity of this disease, the general rule has been to err on the side of caution and consider anyone even possibly bitten by a bat as exposed to rabies.
Yes, rabies is a very rare disease in people in this part of the world... but you don't want to be the rare person that gets it. I understand that risk analysis may indicate that there is, overall, low risk from sleeping in the same house with a bat, and that almost all people that receive post-exposure treatment didn't actually need it. However, for a fatal disease with the potential for uncertain exposure in such a situation, I think this is important to err on the side of caution. It's always difficult to reconcile risk analysis data with human lives. The BCCDC estimates that this new policy will only result in one (1) additional rabies death every 675 years. That's not a lot, but how would you like to be that one person?
I hope this isn't a decision influenced by cost. Post-exposure treatment costs about $1500 per person, and they expect that this protocol will result in "hundreds" of fewer people receiving treatment. The treatment of all people sleeping in houses with bats actually costs a huge amount of money to prevent a small number of cases. However, what is the cost (financial and otherwise) of even a single case of rabies that could have been prevented? That's a lot harder to incorporate into a risk analysis. Personally, if I had a bat in the house overnight and my kids were potentially exposed (again!), I'd go for post-exposure treatment without any hesitation. Call me a paranoid parent if you will, but I'd sleep much better at night (for years, since the incubation period following exposure can be a long, long time).
The full BCCDC report can be found here. More information on rabies can be found on the Worms & Germs Resources page and in our archives.
Doctors, pets and vets
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.
For example:
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.
For example:
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.)
Raccoon roundworm in New York
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ProMed mail has a report about 2 cases of Baylisascaris procyonis infection in people in Brooklyn, New York. Baylisascaris is the raccoon roundworm and is very commonly found in the intestinal tract of healthy raccoons. Raccoons shed this parasite in their stool, and after a short period of time, the parasite larvae become infective to other animals and people. Infective larvae can survive for a long time in the environment. People become infected by swallowing the larvae that can be found in dirt or on any object contaminated by raccoon stool. Disease in humans due to this parasite is rare but can be extremely severe.
The first case in this report involved an infant with neural larval migrans, a condition caused by migration of the roundworm larvae through the brain. Despite treatment, the child now has permanent brain damage because of this disease. Unfortunately, this is not uncommon consequence, as the infection is not usually identified until severe and irreversible damage has already occurred. The child had a history of eating soil, and swallowing soil contaminated with raccoon feces is the most likely source of infection.
The second case involved a 17-year-old with ocular larval migrans, which is caused by migration of the parasite larvae through the eye. The parasite was killed using laser therapy, however the patient lost all vision in the affected eye before the infection was identified. There was no mention of where or how the teenager may have been exposed. Infection of someone of this age is very uncommon, as most 17-year-olds are much less likely in ingest (intentionally or accidentally) raccoon stool. It would be useful to know whether this patient had a developmental disability which results in an increased likelihood of swallowing dirt or feces, or whether there may have been some other type of exposure.
Baylisascaris infections in people are extremely rare, despite the fact that a large percentage of raccoons carry this roundworm. This report of two cases occuring in the same area within a few months of each other is surprising. Hopefully it's just a bad coincidence, and not an indication of some change in the incidence of this disease. Avoiding Baylisascaris means avoiding ingestion of raccoon stool. Sounds simple enough, but this is of particular concern with young children and people with developmental delays who are more likely to swallow contaminated dirt or stool, or put dirty/contaminated hands or objects in their mouths.
More information about Baylisascaris and preventing transmission of the infection can be found in our archives, as well as information about cleaning up raccoon latrines.
Chicks in classrooms: Salmonella shouldn't be a sign of spring
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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.
Rabid fox comes knocking
The Cherokee Scout reported a story about a North Carolina man that was attacked by a rabid fox in his own home. It seems he was awakened one morning by scratching at the front door. Thinking it was his cat, he opened the door, only to be greeted by a rabid fox that bit "plumb through [his] big toe", rampaged around the house, then bit his other foot. He killed the fox using a mop handle (definitely self defence), and it tested positive for rabies (no surprise here!). This was the sixth confirmed case of rabies in the county since March 16, 2009, indicating that people in that area should be particularly cautious. Marshall Duggan, the man that was attacked, was treated for his bite wounds and is now undergoing rabies post-exposure treatment. The morals of the story are:
- Be wary of rabies, particularly when an outbreak is underway. Make sure, as in this case, that animals are tested if there has been potential exposure (e.g. a bite).
- Make sure your pets are vaccinated against rabies.
- Keep your cats indoors. Mr. Duggan is lucky his cat wasn't exposed to rabies or killed by the rabid fox.
- Don't trust foxes that knock on doors.
More information about rabies can be found on the Worms & Germs Resources page.
Suspected psittacosis in a pet shop worker
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.
Image from: http://www.cbc.ca/health/story/2009/04/01/parrot-fever.html
Ban the Easter bunny?
As Easter approaches, so do the annual commentaries about concerns with people buying "Easter bunnies" (the real variety, not the chocolate version) without knowing what they are getting into. It's a big problem because a lot of spontaneous Easter bunny purchases end up abandoned at humane societies (or worse) after a few months.
In general, rabbits can be great pets. However, they have special management needs, and they can live for a relatively long time (years), so people need to think about whether a rabbit is the right pet for them, and whether they can (or will) look after it properly for the duration of its life.
Rabbits are pretty low risk in terms of zoonotic disease transmission. There are a few concerns but these are typically quite manageable with pretty basic hygiene measures. Knowing how to properly handle a rabbit is very important to prevent scratches (and bites) to the handler, and potentially serious injuries to the rabbit. For more information and a video about safe rabbit handling, see the previous Worms & Germs post entitled "Safe Rabbit Handling - For You And Your Rabbit".
Easter may be as good a time as any to get a rabbit - if it's not a spontaneous decision and you've really put some serious thought into it. Part of that process needs to include finding out about ways to reduce the risk of illness and injury associated with rabbits. This type of information can be found in the rabbit information sheets on the Worms & Germs Resources page.
Pet therapy and patients with multidrug resistant bacteria
I received this question on hospital visitation animals today...
For patients who are on contact precautions for a multidrug resistant organism, what other than hand hygiene could be suggested? I am currently rewriting our hospital infection control policy related to pet therapy and visitation with clients with a MDRO [multidrug resistant organism]. I was thinking that visitation of clients with a MDRO should not be allowed??? Any advice?
I am surprised at how often I get asked about pets and patients with multidrug resistant infections. These patients are typically isolated and managed with "contact precautions". The goal of these precautions is to reduce the amount of contact between the infected patients and other people (staff and patients) and includes the use of barriers (e.g. gowns, gloves) to reduce the risk of disease transmission when contact must occur. If the goal is to reduce contact, we shouldn't be allowing patients with these infections to have contact with pets. Pet therapy animals usually visit a large number of patients in the hospital, and we don't want them transmitting an infection to the other patients they visit. Pets are also accompanied by people (their owners), who we don't want to expose to infection and/or to transmit infection to other patients. So, visitation of these high-risk patients by animals should not be allowed. Animal visitation can have very positive effects and its unfortunate that people with multidrug resistant infections should be restricted from these programs, however it's for the greater good of other patients in the hospital, as well as the pet and its owners.
More information about pet therapy programs can be found in our hospital visitation archives.
Image from: http://www.thewholechild.us/integrative_/2006/04/pet_therapy.html
(It's a cute cartoon. I just have to ignore the fact that the dog is on the bed (i.e. the patient's living space) without being on a barrier such as towel or drape.)
Helicobacter and pets... Is there a link?
Helicobacter species are a fascinating group of bacteria. They live in the stomach of humans and many animals, an environment that was previously thought to be completely inhospitable to bacteria. We now know that Helicobacter bacteria are beautifully adapted for survival in the stomach and are very common. In people, Helicobacter pylori is an important cause of gastritis (inflammation of the stomach), stomach ulcers and stomach cancer.
Studies looking at bacteria in the stomachs of dogs and cats have found that Helicobacter species are extremely common, with some studies finding one or more species of Helicobacter in every dog or cat that was tested. Since Helicobacter is an important problem in people, does that mean that we need to be worried about pets as a source of infection? Probably not. Here's why:
It could be a problem because:
- A few studies have found the same Helicobacter species in infected people and their pets.
It's probably not a problem because:
- Studies looking at risk factors for Helicobacter infection in people have not identified pet ownership as a risk factor.
- A study comparing one Helicobacter species that has been mentioned as a possible zoonotic concern, H. heilmannii, reported that H. heilmannii strains from people were generally different than those from animals.
- While other Helicobacter species are common in dogs and cats, H. pylori (the main cause of problems in people) is rare in pets.
- While finding the same Helicobacter species in a person and his or her pet raises concern, studies have yet to demonstrate whether such findings are due to animal-to-human transmission, human-to-animal transmission, or infection of both person and pet from the same source.
Overall, the risks of pet-associated Helicobacter infection are probably very, very low. If there is any involvement of pets in this disease in people, it's probably sporadic at most. Avoiding contact with stool from pets and paying good attention to handwashing should decrease the risk even further.
One question that is currently unanswered is whether the mouth of a dog or cat can be a source of Helicobacter infection, because the bacterium can be found in saliva. We really don't know whether this is a risk - it's probably minimal at most, but avoiding contact with pet saliva (e.g. no sloppy wet dog kisses!) is a good idea anyway.
Dirty hands, Dirty therapy dogs?
A study published recently in the Journal of Hospital Infection (Lefebvre & Weese, 2009) looked at contamination of the haircoat of animals used in hospital visitation programs. In the study, Dr. Lefebvre petted animals that were going into a hospital and we cultured her hands. Then when the dogs finished their visits she petting them again and we re-cultured her hands. We tested for MRSA and Clostridium difficile, two important causes of hospital-associated infections. The goal was to see if the dogs' coats could become contaminated, presumably by patients' hands, during regular visits. The dogs' paws were also tested before and after to see what they picked up walking around the hospital.
After being in the hospital, one dog (4%) was found to have C. difficile on its feet. The strain that was recovered (ribottype 027/NAP1) is a strain of great concern, being it has caused outbreaks of illness internationally. The fact that there was C. difficile on the dog's paws, which was presumably picked up from the floor in the hospital, isn't exactly surprising. It shows that contact with dogs' feet (e.g. shaking a paw) could be a source of exposure to people in hospitals, and at home, and that dogs could be exposed to C. difficile after hospital visits by licking their paws. We previously demonstrated in another study that visitation dogs are at high risk for picking up C. difficile during visits.
The more important aspect of the study was what ended up on Dr. Lefebvre's hands after petting the dogs - a very common type of contact with dogs in hospitals and at home. She picked up MRSA from the coat of one dog (4% of dogs overall) after it had been in the hospital. The dog was not an MRSA carrier, and it did not have contact with anyone known to be carrying MRSA during its visit. Presumably, there was someone in the hospital that was an unknown carrier. If MRSA was on the person's hands, they could have transfered the MRSA to the dog's coat. The important part is that this MRSA was then able to spread to someone else's hands (Dr. Lefebvre's, in this case). This is a potential route of transmission of MRSA to patients during hospital visitations, and to other people these dogs might encounter outside of hospitals. The same thing could presumably happen with other infectious agents, including bugs like norovirus and influenza. These can't infect dogs, but dogs could potentially be short-term vectors of these viruses and spread them around a hospital.
The good thing about all this is that some basic guidelines can greatly reduce the risk of transmission:
- Patients should wash their hands or use an alcohol-based hand sanitizer before (to reduce the risk of depositing something on the pet's coat) and after (to reduce the risk of picking something up from the pet's coat) touching a pet.
- Pets should be kept off beds unless a disposal/washable barrier (e.g. drape, towel) is kept between the pet and the bed sheets, to prevent dirty feet from infecting the patient's living space/clothes/sheets.
- People should not "shake-a-paw" with pets in hospitals.
All these precautions can be taken without compromising the benefits of hospital pet visitations. More details about guidelines for hospital visitation aniamls can be found in an earlier post. More information about Clostridium difficile and MRSA can be found on the Worms & Germs Resources page.
Fatal needle phobia: Rabies in Bali
ProMed mail reports two more rabies fatalities in an ongoing outbreak in Bali, Indonesia. The first person was bitten by a stray dog, which always must be considered a potential rabies exposure, especially in an area where an outbreak is underway. He received one rabies shot but did not undergo the whole post-exposure series because of a fear of needles, and he died.
The second person was bitten by both a stray and a pet dog, another clear indication for post-exposure treatment. She refused treatment because of a fear of needles, and also died of rabies.
These were two completely preventable deaths. The decision to forgo treatment almost certainly cost these people their lives - rabies is preventable with appropriate and timely post-exposure treatment. These cases also highlight the need for proper education of the public when it comes to rabies, both in terms of avoiding strays and the need for prompt attention when there's potential exposure to the disease. I have no idea how forcefully medical or public health personnel explained the need for proper treatment. For people that want to decline treatment, aggressive and comprehensive education is needed. Ultimately, people are allowed to make bad decisions, but we need to make sure they at least make informed bad decisions.
There are various other concerning issues with this outbreak, particularly the government's response to it. Multiple sources have apparently advised the government that aggressive vaccination and halting of dog movement between the peninsula and the mainland could contain this outbreak. So far, this has not been done. Amazingly, importing rabies vaccine into Bali was illegal until December 2008, and it is still illegal to vaccinate dogs outside of the outbreak area! The cost of vaccination has been used as an excuse not to do so. Certainly, financial issues are important in developing countries. However, the estimated cost is only about $0.50 US per dog. When one considers that this area is highly dependent on the tourist industry, they need to consider this as an investment to maintain their economy. Would you like to spend your vacation in an area with an ongoing rabies outbreak?
Possible E. coli O157 infections from dogs
Escherichia coli (E. coli) O157 is a particularly important bacterium that can cause very serious disease in people, including diarrhea and a severe kidney disorder called hemolytic uremic syndrome (HUS). Infection in people typically results from ingesting the bacterium from contaminated food products. The main reservoir of E. coli O157 is in the intestinal tract of cattle. There have been a few reports of suspected transmission of E. coli O157 from pets, but overall pets are thought to play a very minor role in the spread of this disease.
However, minor role does not mean no role. A recent report in the journal Veterinary Record described suspected transmission of E. coli O157 from dogs to people. Three children and two adults in a household developed diarrhea, and E. coli O157 was isolated from their stool, as well as from the stool of a healthy sibling in the house. Molecular testing showed that all the people were infected with the same strain of E. coli. An "outbreak response" was initiated by the UK's Health Protection Agency to determine the source of infection. One of the affected children, the first to get sick, visited a farm five days before developing diarrhea, so the investigation focused on that farm.
The same E. coli strain was found in 7/29 samples collected from the farm: three samples from calves, two from dogs, one from a manure pile and one from a calf pen gate. Finding E. coli in samples from the calves was not surprising, as it is commonly found in healthy cattle. However, the visiting child did not have direct contact with the calves. Finding the bacterium in the dogs was somewhat surprising. Since the child had contact with both dogs, this was thought to be the most likely source of infection. Cattle were probably the source that infected the dogs, the dogs were then probably able to transmit the infection to the child, and the child then infected other people in the house. Infection from contact with E. coli in the environment is also possible, but considering there was confirmed contact with dogs who were carrying the same strain, the conclusion that the dogs were likely the source is reasonable.
Like many of the other bacteria we worry about, E. coli is transmitted by the fecal-oral route - infection is spread by swallowing feces/stool/manure (even in minute quantities) that contains E. coli. This can occur more easily than people think, as low-level fecal contamination of hands and other surfaces is common. Identifying animals that carry this bacterium is not practical. The most important protective measure is close attention to handwashing after contact with animals, especially farm animals or pets exposed to farm animals.
This study provides more information about dogs as potential sources of E. coli O157 and the need to include testing of pets during outbreak investigations. However, dogs are probably still a minor source of this important pathogen, and it's most likely only of concern in dogs with close contact with cattle.
