Cryptosporidiosis from wildlife centre lambs
The May 2010 edition of Emerging Infectious Diseases contains a report about an outbreak of cryptosporidiosis in Scotland (McGuigan et al. 2010). Cryptosporidiosis is a common parasitic disease caused by Cryptosporidium, a protozoal parasite. It causes diarrhea, which is usually annoying (to say the least) but self-limiting in healthy people, but the infection is potentially fatal in people with compromised immune systems.
An investigation was launched after a single case of cyrptosporidiosis was diagnosed by a Scottish laboratory. The reason a single infection caused such concern is that it was suspected to have originated from contact with lambs at a wildlife centre, so there was potential for exposure of many people. The concerns were valid, since a total of 128 cases of cryptosporidosis were uncovered during their investigation, and 117 of the people affected had visited the wildlife centre. Another 252 unconfirmed cases were also identified.
The investigation suggested that direct contact with diarrheic lambs was the source of infection. Lambs (and calves) are high risk for shedding Cryptosporidium, even when they're healthy. Diarrhea increase the risk of transmission from these animals even more, because diarrheic animals are more likely to (1) shed the parasite and (2) have fecal staining of their haircoats, which increases the likelihood of fecal contact for every person and animal around them. That's why young ruminants (e.g. lambs, calves) as well as young poultry are considered inappropriate for petting zoos and other similar public animal contact events. This outbreak is yet another example of why these recommendations are in place.
At the wildlife centre in this study, children were apparently encouraged to pick up the lambs, despite visible diarrhea. No handwashing facilities were near the lamb petting area and it took "considerable effort" to find a location to wash your hands anywhere on site. Alcohol hand sanitizers were available, however Cryptosporidium is resistant to alcohol. Handwashing is a critical component of disease prevention, but unfortunately it is very underused. In general, people are becoming much more aware of the need for handwashing, but even so, if handwashing facilities are not conveniently located, people tend not to go to much effort to find them. That leads to increased risk of infections, as was the case here.
Control measures at the wildlife centre implemented after the investigation included removal of the lambs (who should never have been there anyway), disinfection of the premises with bleach (although disinfecting a farm environment is very difficult, and Cryptosporidium is also resistant to bleach), and stopping direct contact between animals and visitors.
As we enter the season when there are more fairs, petting zoos and other animal contact events, facility managers need to pay attention to important factors like:
- Readily available hand hygiene facilities
- Good design to control the types of human-animal contact and to steer people towards hand hygiene stations
- Appropriate animals: no calves, lambs or chicks
- Proper supervision of people and animals
A little common sense goes a long way. The goal is to set up these events so that there is still a beneficial impact of seeing and interacting with animals while reducing (but never eliminating) the risk of disease transmission. A 100% safe petting zoo is not achievable (there's always some risk in life), but some pretty simple measures can greatly reduce the risks while still providing excellent entertainment and educational opportunities.
Rabid calf at educational centre
Rabies has been diagnosed in a 6-week-old Jersey calf at a Maryland educational centre, raising concerns about exposure of farm visitors, particularly groups of school children. At least 70 kids and an unstated number other visitors had recently visited the farm.
Fortunately, the farm in question is not open to the public, so they should have an easier time identifying people who have been there (e.g. school groups). Contact tracing is underway to try to identify people that had contact with the calf. Simply petting the calf or being in the general area does not pose a risk. The main risk would be from contact of open wounds with the calf's saliva, or a bite. We don't typically associate bites and calves, but it can happen when calves are allowed to suck on someone's fingers - if the person sticks their hand in too far he/she may get chomped by the calf's sharp molars. Public health personnel are trying to identify people who had contact with the calf, then they'll determine whether there was a chance of exposure to the virus. People that were potentially exposed to rabies will undergo post-exposure prophylaxis, consisting of a shot of anti-rabies antibodies and four doses of vaccine over the course of a month. Not fun, but much better than getting this almost invariably fatal disease. At least nine students have started treatment so far.
Petting zoos and similar events are a concern in terms of disease transmission because of the large number of people that can be exposed to animals and the high percentage of children that are involved. Rabies is uncommon in petting zoo animals, but it is periodically identified at such a facility/event, often resulting in the need for post-exposure treatment of large numbers of people. Vaccination of petting zoo animals against rabies should be a standard practice. This calf, being only six weeks old, was too young to vaccinate, but if the calf's mother was vaccinated the risk of rabies would be lower (because the calf would get antibodies from the mother). There's no information about the cow's vaccination status or much else about the calf, apart from it being a recent acquisition.
The fact that a recently acquired young calf was allowed to have contact with the public is questionable management, because young calves are a high risk group for certain infectious agents like Cryptosporidium and Salmonella. The CDC recommends that children less than five years of age not have contact with young calves. Since young kids are frequent visitors of places like this, having calves (or at least letting people have direct contact with them) is quite questionable as well. Hopefully there will be a good review of vaccination, animal acquisition and animal contact protocols for this facility to reduce the risk of future exposures to rabies or other infectious diseases.
Child+reptile zoo - (infection control+hand hygiene) = lawsuit
Gurnee's Serpent Safari is being sued by the family of a two-year-old boy who allege the child contracted salmonellosis from a snake at the zoo. The child became ill and was hospitalized three days after visiting the zoo and petting a snake. The boy's mother got sick shortly thereafter. It's unclear if the same Salmonella strain was found in the snake or what degree of proof is present that the zoo was the source, but contact with reptiles is a huge risk factor for salmonellosis.
Exposure to zoonotic infections like Salmonella is an inherent risk of animal contact. We accept some degree of risk in everything that we do. The question is "Did the zoo take reasonable precautions to reduce the risk of disease transmission?" Based on the information in the Chicago Tribune news report, the answer is pretty clearly no.
There are standard guidelines for animal contact events that should be followed. These include:
- Children less than five years of age should not have contact with reptiles.
- There should be good, convenient access to hand hygiene (handwashing stations or alcohol hand sanitizers).
- Signs should be present to encourage people to wash their hands after animal contact and discourage high risk people (e.g. two-year-olds) from having contact with high risk animals (e.g. snakes)
The family alleges that the zoo is negligent because it:
- Did not have notices regarding handwashing after contact with reptiles.
- Did not provide hand sanitizers for patrons.
- Did not provide warnings regarding the risk of Salmonella for high risk groups.
- Allowed and encouraged the child to touch the snake.
We live in a pretty litigious society, but people need to assume responsibility for their (and their childrens') health and safety. However, exhibits that allow people to have contact with animals have a moral and legal responsibility to provide as safe of an environment as reasonably possible. Risk will never be zero and people can get sick from the best run events, but there is no excuse for failing to implement basic measures to reduce the risks.
Vancouver petting zoo outbreak numbers climb
Five more E. coli O157 infections have been linked to the Pacific National Exhibition's petting zoo, bringing the total to 18. It's very likely that the true number of infected people is higher, since mild cases are often missed because they don't go to the doctor or because testing is not performed. This situation follows a very large outbreak linked to a UK public farm and closure of some other UK petting zoos because of E. coli O157. Clearly, more effort needs to be put into proper management of these events, design of petting zoo facilities, scrutiny of animals and education of the public about infection control practices. Petting zoos shouldn't be banned, but they should be regulated and run responsibly. .jpg)
Fergus Fall Fair folly
Considering all of the disease outbreaks that have been attributed to petting zoos, including an outbreak in the UK this month that has sickened dozens and another in Vancouver that has affected at least 13 people, you would think that people who operate petting zoos would start to take the hint. Unfortunately, that's clearly not the case.
My family and I went to the Fergus [Ontario] Fall Fair today. Apart from the petting zoos, it was a great day, but the potential for ending up in hospital with a life-threatening infection shouldn't have to be a concern for fair attendees.
This fair had two petting zoos. One was also associated with a pony ride. We went there first and while my kids were looking at the animals, I noticed there was a table and a sign saying to use a hand sanitizer after touching the animals, but there were not actually any hand sanitizers available. I asked the attendant and he immediately started looking. They eventually found some, but we gave up after waiting a few minutes and went to the other petting zoo location because a handwashing station was set up there. Despite a large crowd around the first petting zoo, I didn't see anyone following our actions so presumably almost no one washed their hands after petting the animals. The good thing about this first petting zoo was they at least had a clean facility, appropriate animals and no major problems apart from the forgotten sanitizers.
Petting zoo number two was not as good. There were numerous problems, some of them very major.
- Inappropriate animals #1: As we walked in, someone held out a baby chick and tried to give it two my 2-year-old daughter to handle. Standard guidelines are that children under 5 should not handle young poultry, so these animals are inappropriate for any petting zoo.
- Inappropriate animals #2: The next thing we passed was a young calf. Calves are also considered a high-risk animal and should not be present in petting zoos.
Inappropriate animals #3: The calf had diarrhea (see the diarrhea staining and hair loss probably associated with prolonged diarrhea in picture). It's very likely that this calf was shedding one or more infectious agents in its diarrhea, such as Cryptosporidium.- Food for sale: Food was being sold and consumed inside the tent where the petting zoo was. This is inappropriate.
Petting zoos can be great events for kids. They can also be sources of large and serious outbreaks of infectious diseases. Hopefully nothing bad will come from this and we won't hear reports of illness in petting zoo participants. But, as I've said before, hope is not a proper infection control program.
Anyone running a petting zoo MUST know the issues, risks and proper preventative measures to take. Reading the Compendium of measures to prevent disease associated with animals in public settings would be a good start.
Petting zoo outbreak investigation continues
The investigation into a large E. coli O157 outbreak linked to a UK petting zoo continues, and the number of potentially exposed people is astounding. There are a couple of reasons that I write a fair bit about petting zoos, and they are highlighted here: the potential for exposure of a large number of people and the predominance of children. In this outbreak, it is feared that tens of thousands of people may have been exposed since problems started in August. The exact number of infected people is currently unclear but is in the "dozens," including some with hemolytic uremia, a severe kidney disorder. One report says there are 36 sick people, including 12 children under the age of 10. It's pretty likely that these numbers will increase, and that even more cases will go undiagnosed because they were mild and people didn't get tested.
This week, testing has been performed on animals and environmental areas on the farm to look at sources of E. coli O157. I'm not sure why this wasn't done a while ago. However, at this point, it's mainly going to be useful to confirm that the E. coli strain infecting people is also present in animals on the farm. Finding or not finding the bacterium at various environmental sites at one point in time really doesn't say much about where it was when people were getting infected. If E. coli was in the animals, it's likely to contaminate various environmental areas. If petting zoo design and hygiene were not optimal, this could result in contamination of visitors' areas.
Some parents have complained that the farm was allowed to remain open for more than two weeks after the first cases of E. coli were reported. That's a very valid concern and one that should be clearly addressed. Once there was reasonable suspicion of the farm being involved, measures should have been taken to reduce further exposure. A good synopsis of these events is available here. It certainly depicts a less-than-stellar response to a potential outbreak. Although you don't want to over-react and close a facility that was not actually the source, given the potential severity of disease and massive number of people that could be exposed, public health concerns need to supercede economic concerns in situations like this.
Petting zoos will never be "no risk." There is an inherent risk of infectious disease transmission any time you interact with an animal. That being said, there are standard recommendations that are in place to greatly reduce the risk of disease transmission. I don't know much about the quality of infection control practices on this farm, but it's likely they could be better. One writer to timesonline describes how kids are allowed to climb in with the animals and chase after herds of pigs, which certainly suggests a lack of proper control.
People running petting zoos need to take their role in protecting the public seriously. That includes protection from infectious disease and injuries such as bites. Public health authorities need to take a more proactive role. Instead of the standard approach of just providing documents or signs, these events need to be inspected and any problems need to be identified and addressed. The key is to use basic, practical measures that reduce the risk while maintaining the positive aspects of the petting zoo. It's getting better in many areas, but there's clearly still room for improvement.
Petting zoo improvements
The last time I visited the Aberfoyle (Ontario) Fall Fair, the petting zoo was so bad that I ended up writing to the fair organizers and the Wellington-Dufferin-Guelph Public Health Unit. (Neither group replied). It was pretty bad. Young poultry are inappropriate petting zoo animals because of the risk of transmission of bacteria like Salmonella, yet baby chicks were being passed around to young children. One chick was injured by rough handling and the petting zoo supervisor just threw it (still alive) in the garbage. There was a diarrheic calf, poor hand hygiene facilities, and other problems.
We went back to the fair yesterday and I was quite pleasantly surprised: no chicks, no calves, all appropriate and healthy-looking animals, a clean facility and good hand hygiene stations. There were still a couple of suboptimal things, like not having hand sanitizers by one exit, and having a "supervisor" who was staring off into the wilderness and smoking inside the tent filled with kids and straw, but it was night-vs-day compared to the last time. I doubt my letter had much to do with it, but you never know. I think it's important that people not accept inadequacies that put the public (particularly children) at risk. People need to raise a stink when they see a problem. I wrote earlier today about a child who had her finger bitten off by a petting zoo zebra that had bitten other people. The previous bites may not have been reported because they were minor, but we need to report apparently minor problems so they don't escalate into major injuries, disease outbreaks or other bad scenarios.
Anyway, it was great to see an improvement, and people in the petting zoo appeared to be having a good time. Now if they'd just work on "Big Ned's" food concession, where the only sink seems to be a storage area with no soap or paper towels, and which appeared to be in need of a serious cleaning, or on the little midway, where they were hand cranking the questionable kiddie ferris wheel to get kids off when all the rides stopped working. Baby steps, I guess.
Petting zoo zebra bites off finger
The finger was not able to be re-attached. It was also reported that the girl is receiving a series of seven rabies shots. That doesn't make a lot of sense. The animal that bit her is clearly identified and can be monitored to see if it develops rabies. We don't have clear guidelines for duration of monitoring of animals apart from cats and dogs (10 day observation), which may be why they are not simply observing the zebra for signs of rabies. However, it's extremely unlikely that the zebra is rabid, and having the child undergo post-exposure treatment is questionable in the absence of any signs of disease in the animal. Regardless, the zebra should have been vaccinated against rabies beforehand. The owner of the park apparently stated that what happened to the girl is "highly unusual." Severing of extremities shouldn't be a regular event at a petting zoo. It's rather disturbing to hear that this zebra has bitten other children and a volunteer over the past couple of years. A responsible petting zoo operator would not keep a "known biter," or would at least only have the animal on display in an area where no one could touch it. It's irresponsible to put an animal that has been known to cause injuries in close contact with young children. Hopefully local officials will take a close look at this operation, however their ability to act may be limited because often petting zoos can operate with little or no oversight. A lawsuit is probably the most likely way to control such irresponsible behaviour, because the fear of being sued may be the only effective motivation for some people to clean up their operations. I'm pretty opposed to the way society is becoming increasingly prone to suing when anything bad happens, but this is a case where it's not hard to argue that the petting zoo operator's action (or rather, inaction) directly led to a serious and lifelong injury to a child. I'm sure there are some lawyers in North Carolina lining up to talk to the parents. The TV report about this from WCNC can be found here..jpg)
A zebra in Buffalo Beal's Animal Park in Maiden, North Carolina, bit the hand of a nine-year-old girl, severing her finger. The girl was feeding the animal when it bit off most of her right pinkie finger. Her father had to hit the zebra a few times to get it to release her hand.
HIV/AIDS, kids and pets
The Centers for Disease Control and Prevention (CDC) has released updated Guidelines for the Prevention and Treatment of Opportunistic Infections Among HIV-exposed and HIV-infected Children. A small but still important part of this document involves recommendations for contact with animals. It's a nice, balanced document that acknowledges the risk but doesn't make unnecessarily restrictive recommendations.
Among the important recommendations regarding animals:
- When getting a new pet, avoid dogs and cats less than 6 months of age or strays: These animals are at higher risk for shedding various infectious diseases and are more likely to have problems with biting and scratching.
- Avoid contact with animals that have diarrhea.
- Wash hands after handling pets.
- Avoid contact with pet feces.
- Avoid contact with reptiles, chicks and ducklings: These are very high risk for Salmonella.
- Avoid contact with calves or lambs at farms or petting zoos: These animals are high risk for various infectious diseases such as Cryptosporidium and Salmonella.
These recommendations also largely apply to other high-risk groups, including people (of all ages) with compromised immune systems and young children (especially less than 5 years of age). A key point is normal contact with common household pest using basic hygiene practices is considered a low risk. Infection control isn't rocket science. It involves basic and practical measures that can reduce risks associated with animal contact.
Testing petting zoo animals
I received the following comment in response to a recent E. coli O157 and petting zoos post, and thought that it merited a post of its own.
"Why doesn't the petting zoo owners have a fecal swab sample taken from each animal in the petting zoo and submitted for STx PCR screen testing. If a positive is found isolate the animal and continue to monitor it. I would assume The University of Guelph's extension service would have some information about this."
That's a great question. When we start talking about infectious disease risks, people often ask about testing. However, testing is not always useful and I think that's the case here. Here's a few reasons why:
- Animals don't shed E. coli O157 all the time. It's been shown in cattle that if you sample animals regularly, you will find the bacterium in the manure some days but not others. Therefore, a single negative result does not mean that the animal is definitely negative.
- No test is 100% accurate. While current tests are quite good, it cannot be stated with absolute certainty that an animal that is negative on a test for E. coli O157 is truly negative.
- Even if the animals are all truly negative for E. coli O157, they may still be shedding other potentially harmful microorganisms (e.g. Salmonella, Campylobacter, Cryptosporidium ) for which people need to take the same kind of precautions as for E. coli.
- If petting zoo operators had to pay hundreds or thousands of dollars a year per animal for diagnostic testing (a reasonable estimate if they had to do multiple tests on each animal, possibly for multiple organisms), there wouldn't be many petting zoos around.
For any test, whether it's being used for screening or to make a diagnosis on a sick animal, it's critical that it be thought of in terms of "what will I do with the results." In this case, negative results would not change recommendations for running or visiting a petting zoo. I'd assume that animals could still be shedding E. coli O157 intermittently, or that they could be shedding various other pathogens, and I'd still recommend use of good infection control practices like hand washing. Efforts are best spent working on petting zoo design and hand hygiene, rather than testing the animals, because these are more likely to have a positive impact by reducing the risk of disease transmission.
Photo source: http://www.microvet.arizona.edu/Faculty/songer/diag.htm
Verotoxigenic E. coli in petting zoo animals: UK
I’ve written several posts about petting zoos, mainly about the potential negative aspects, although I still think they’re valuable if run properly. A major concern with these events is exposure of people to zoonotic infectious diseases, particularly harmful bacteria that can be carried by healthy animals. One of the more common pathogens that causes disease outbreaks associated with petting zoos, including severe or even fatal infections in people, is verotoxigenic E. coli, particularly E. coli O157.
A recent study by Pritchard et al. in the Veterinary Record highlights some of the concerns with this pathogen. Samples were collected from various animals on 31 different farms in the UK. They found verotoxigenic E. coli on 61% of premises. The premises selected were evaluated due to suspicion that they may have been sources of infection for people, so it’s possible that the numbers reported in the study are higher than they would be for all such farms overall, nonetheless the numbers are impressive. Risk factors for finding verotoxigenic E. coli on a given farm were the presence of young cattle and (surprisingly) adult pigs. Verotoxigenic E. coli were most commonly identified in cattle (29%). It wasn’t surprising that cattle, especially young cattle (calves), were the most common carriers based on what we know about the bacterium. However, it was impressive how commonly it was found in other species, including sheep (24%), donkeys (15%), pigs (14%), horses (12%) and goats (10%). On most farms where verotoxigenic E. coli was found, the same strain was identified in multiple animal species, indicating that the bacterium can be wide spread on the property. This may be because different animal species in petting zoos are often mixed together, as opposed to the situation on conventional farms where they are usually housed separately.
Does this mean we should consider petting zoos biohazardous and avoid them? Well, the answer really is "yes" and "no". We should consider petting zoos as potential sources of harmful bacteria. High-risk people (e.g. very young, very old, weakened immune system) should probably avoid them. We should also think about ways to reduce the risks, such as using lower risk species, having good petting zoo design and, most important, encouraging and enforcing hand hygiene on the part of all petting zoo visitors. As the authors of this study stated “It is also necessary to balance this small risk against the undoubted benefits of allowing the public to interact with farm animals. The risk of people acquiring an infection from animals depends more on the degree of contact and the precautions adopted than the prevalence of infection in a particular species. ”
If you get verotoxigenic E. coli on your hands but you promptly and properly disinfect them (before contaminating something or putting your fingers in your mouth), you’ll be fine. The quality of petting zoos varies quite a lot, as we showed in a previous study, and pressure should be put on petting zoo operators to have well-designed and well-run events.
More information about petting zoos can be found on the Worms & Germs Resources page.
E. coli outbreak at a petting zoo
The latest edition of the CDC's Morbidity and Mortality Weekly Reports describes an E. coli O157:H7 outbreak associated with a petting zoo. The outbreak, which occurred at a day camp in Florida in 2007, involved 7 infected individuals. Two children were hospitalized. The same E. coli strain affecting the people was found in the stool of goats at the petting zoo.
During the investigation of the facility, it was noted that many of the general recommendations for petting zoos were followed, including providing handwashing stations, promoting hand hygiene compliance, prominent signage, and restricting eating and drinking in the zoo area. This shows that outbreaks can occur even at facilities that seem to be doing a reasonably good job of infection control. However, several key issues were identified:
- Campers were not instructed how to wash their hands properly.
- Handwashing was not carefully monitored.
- There was unlimited (and presumably not completely supervised) contact with animals throughout the day.
Numerous outbreaks of disease associated with petting zoos have been reported, often involving E. coli O157, a strain of E. coli that can cause serious or even fatal disease. This E. coli strain can be found in healthy cattle, sheep and goats. Other potentially harmful microorganisms can also be found in healthy animals of these, and other, species (particularly in their manure). Because you never know whether an animal is “potentially infectious,” taking measures to reduce the risk of disease after possible exposure is critical, particularly meticulous hand hygiene. Restricting high-risk animals (e.g. calves, baby chicks, pregnant sheep and goats) from petting zoos is also important.
Petting zoos can be great events, but carry any inherent risk of disease. More information about petting zoos and the diseases associated with them can be found in a new information sheet on the Worms & Germs Resources page. The National Association of State Public Health Veterinarians has also just released its revised Compendium of Measures to Prevent Disease Associated with Animals in Public Settings, a comprehensive document about measures to reduce the risks associated with petting zoos and other animal contact events.
Lambing season and Q fever
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I have a small flock of Soay sheep and lambing season started today (too early, but better than the -30C weather from a few days ago). For someone like me, lambing season inevitably triggers thoughts about Q fever, a zoonotic disease that is most commonly associated with contact with small ruminants like sheep and goats (especially sheep). The disease is caused by the bacterium Coxiella burnetii. This organism is highly infectious - very few bacteria are required to cause infection - and is considered a potential bioterrorism agent. Coxiella burnetii can be transmitted by direct contact with an infected animal, or by inhalation of organisms in dust or dirt that get blown into the air. It can be carried by healthy animals several species, but the greatest risk of transmission is from sheep and goats around the time of birthing (lambing and kidding, respectively). At that time, large numbers of C. burnetii can be shed with the placenta and fetal fluids, and can also be found on the newborn animals. Close contact with the animal and these tissues during lambing, such as with our first lambing this morning - a stillborn lamb that was stuck at the shoulders and required some manipulation to free it - can result in transmission of C. burnetii.
On a happier note, the second lambing in our flock was unassisted, although I still handled the little guy to make sure he was okay.
Q fever can affect people of any age or health status. Disease can range from mild to life-threatening. More information on Q fever can be found on the websites of the Ontario Ministry of Health and Long-Term Care and the Centers for Disease Control and Prevention (CDC), as well as the previous Worms & Germs post entitled "Q Fever - From Goats to People (and Pets!)". The disease can cause miscarriage in pregnant women. People with heart valve disease or vascular grafts are also at high risk for serious disease from this infection.
- It is prudent to consider all sheep and goats Q fever-positive unless proven otherwise (which is difficult to do).
- Contact with newborn lambs and kids, placentae and fetal fluids of sheep and goats, and any area contaminated by these tissues should be avoided as much as possible. If contact is necessary, it should be done by low-risk people, and careful attention should be paid to hygiene, especially handwashing.
- Pregnant sheep and goats should not be used in petting zoos. Unfortunately, this is actually a common occurence.
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- Live birthing exhibits, where sheep or goats give birth in public during fairs or similar events, should not be held. If they are held, they should be in an area where there is no direct or indirect contact with the public, unlike this picture (right).
- While we focus on sheep and goats, many different species can shed Coxiella burnetii, including cattle and cats. It is reasonable to consider all animals a risk around the time of giving birth, and ensure that hygiene practices are optimal.
- At my place, Q fever control consists mainly of careful attention to hygiene around newborn lambs and their ewes, and not allowing my kids to handle newborn lambs.
- Like most zoonotic diseases, hand hygiene is a critical infection control measure.
E. coli O157 outbreak tentatively linked to livestock show
An outbreak of E. coli O157 - the particularly nasty strain of E. coli that can cause hemolytic uremia (a serious kidney disease) and death - has been identified in Colorado, and signs are pointing toward a livestock show as the source. So far, 20 people have been identified as infected, including 19 children. The exact source of the infection is not clear, and could be food, water or contact with animals. However, considering the high percentage of children, the petting zoo is a likely source.
As we've discussed previously, petting zoos can be fun and educational events (particularly for children) but are always associated with some degree of infectious disease risk. Petting zoos are often poorly equipped to handle these risks, as we reported in a paper in Clinical Infectious Diseases a little while ago. Petting zoos are a risk because animals that appear healthy can still carry infectious diseases. This is particularly true for E. coli O157, which can be carried by perfectly healthy cattle. Despite the possibility of exposure to E. coli and other potentially harmful microorganisms, the potential for disease can be greatly reduced with some very basic measures, like handwashing, not eating in the petting zoo, handwashing, keeping baby bottles and other items out of the petting zoo, handwashing, and having signs encouraging people to wash their hands. The people in charge of this event stated that they had a well organized petting zoo with handwashing stations available, and that may very well be true. Having access to handwashing facilities is a critical step, but it doesn't do anything if people don't use them. Unfortunately, poor compliance with handwashing is very common and is one of the weakest links in infection control at petting zoos.
- Always wash your hands after leaving a petting zoo.
- Don't eat in a petting zoo area.
- Don't take items into the petting zoo that will go into a child's mouth, like bottles, cups and soothers.
Petting zoos: What's wrong with this picture, Part II
Recently, my family went to an Ontario aviary/animal park. It was possible to touch many of the animals, and contact was encouraged because they sold food for the animals. The kids enjoyed having contact with animals, but this facility was an example of completely inadequate (or negligent) infection control practices. There's actually not much wrong with the picture in this post. The problem is that there was absolutely no means for people to wash or disinfect their hands after touching the animals. This is truly astounding in this day and age, with the increased awareness of the need for hand hygiene in these situations. Even at small, temporary animal exhibits and local fairs, handwashing facilities have become standard. I can't fathom why a large, permanent animal park wouldn't be set up properly. (It was even possible for people to touch aquatic turtles, which are very high risk for Salmonella transmission, but that's another story. More information on turtles can be found on the Resources page). What do you do if you want to have contact with animals but don't know whether you'll be able to wash your hands? Bring your own alcohol-based hand sanitizer. They're cheap, easy to find and effective, and it never hurts to have them on hand (pardon the pun).
Discussion of other petting zoo issues and links to other resources can be found in our Petting Zoo archives.
Petting zoos: What's wrong with this picture?
Petting zoos can be great activities, providing entertainment and education to kids and adults alike. However, contact with animals at these events does come with some degree of risk, and numerous infectious disease outbreaks associated with such contacts have been reported. Because of these risks, most petting zoos are improving their infection control precautions, particularly with respect to handwashing by participants after touching animals. Yet some high risk behaviours continue to occur. The picture at the right was recently published in the York Daily Record. While cute, this picture raises the ire of someone like me (especially since I have young children). My main concern: the goat is licking this baby's bottle. Where do you think the goat's mouth just came from? The ground, along with manure from various animals.
What might the bottle have been contaminated with? E. coli O157, Salmonella, Campylobacter, Clostridium difficile...
Where do you think this bottle is going next? The baby's mouth.
What will probably happen to the child?: Nothing.
What might happen to the child?: Disease caused by one of the above-named microorganisms (or others), ranging from mild diarrhea to fatal infection.
While there is good information available about precautions that should be taken for petting zoos, such as from the National Association of State Public Health Veterinarians, not all petting zoos take adequate precautions. A recent study pointed out common deficiencies.
Some important points to consider:
- Petting zoos are safe for the vast majority of the population if common sense measures are used.
- Items that will end up in the mouth of a child should never go into a petting zoo.
- Children should be closely supervised in petting zoos.
- Uncontrolled animal contact should be prevent.
- Hands should be washed after contact with animals or the petting zoo environment.
Reptile shows....wash your hands!!
Petting zoos and similar animal contact events carry an inherent risk of infectious disease transmission. Outbreaks of various infectious diseases have been reported, mainly associated with farm animals. Reptiles are a particular concern because they can have high rates of Salmonella carriage. Terrestrial reptiles like bearded dragons and pythons are lower risk than species like aquatic turtles, but these animals can still be the source of salmonellosis in humans. Petting zoos can be entertaining and educational, and fairly safe if run properly. However, deficiencies are often present. At this facility, there were multiple hand hygiene stations, consisting of alcohol-based hand sanitizers, which are very effective. Food and drink were banned in the area and there were staff supervising all animal contacts. These are all good things, however the best measures are useless if they are not used or enforced. While I made sure that my family carefully cleaned their hands, we were definitely in the minority. The hand hygiene stations were not particularly easy to access and there was't one present at the exit, so if you weren't looking for it you would probably just leave. Further, despite the signs, staff allowed people to eat and drink in the area where they were handling reptiles. Allowing people to eat and drink, and not providing easy access to the hand sanitizers (two pretty basic measures) were major problems and greatly increase the risk of disease transmission.
I'm not suggesting we should avoid petting zoos. My kids enjoy them and we will surely attend a few this summer. The key with animal contact exhibits is common sense....avoid high risk animals, keep you hands out of your mouth and wash your hands thoroughly when leaving (even if you didn't touch an animal since you probably touched other surfaces). Some animal species are particularly high risk, including young poultry and young ruminants (e.g. calves, lambs, goats). Reptiles fit into this high risk group, which is why I had more concern about this event than a standard petting zoo. People with compromised immune systems should avoid animal contact, particularly with calves, chicks, lambs and reptiles.
And above all, WASH YOUR HANDS.
A good source of information about animal contact events and infectious diseases is available from the National Association of State Public Health Veterinarians.
Information Sheets for Pet Owners
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.
| Animals | Diseases | Other |
| Dogs | Rabies | Litter Boxes |
| Cats | Giardia | Sandboxes |
| Turtles | Toxoplasma | Cat Bites |
| Hamsters | Leptospira | Raw Meat |
| Rabbits | Clostridium difficile | Petting Zoos |
| Pet Birds | Cryptosporidium | Needlestick Injuries |
| Reptiles | MRSA | |
| MRSP | ||
| Salmonella | ||
| Ringworm | ||
| Campylobacter | ||
| Bartonella henselae | ||
Please Remember:
- 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.
