Orange County CA is currently experiencing a major outbreak of West Nile infection in people. Since January 94 cases have been confirmed, three of which were fatal, representing nearly a quarter of the 400 cases reported across the country so far this year. The number of cases of infection with a mosquito-borne virus like West Nile (or EEE, which we’ve been seeing over the last month in Ontario horses) can be affected by a lot of factors, including climate/weather, flooding or drought, bird populations and movements, mosquito populations and local mosquito species, and population density of those affected, be they people or animals.
Often we associated wet weather and flooding with increased incidence of diseases like West Nile, but this year California is experiencing a drought. How does that make sense? It’s been suggested that the dry weather is driving birds into more populated areas to look for water. More infected birds in the area provides more opportunity for mosquitoes to bite the birds and then transmit the virus to a person. The number of mosquito pools testing positive in Orange County (80%) is the highest its been since West Nile first hit California a decade ago, and 6.5 times more dead birds (260 total) have tested positive for WNV compared to 2013.
Most of the human cases in California included some signs of illness. When you consider that 80% of people infected with WNV show no signs of the disease, that means there has actually been an even larger number of people actually infected.
The impact on the local horse population has not been mentioned, but it is unlikely that horses will escape this outbreak unscathed. After a relatively slow year for WNV in 2013, I wonder how many horse owners in the area may have decided to forgo vaccinating their horses this year, and may now be regretting it. It’s easy for us to get complacent about infection control when things are going well. In the case of West Nile, people may stop taking precautions to avoid mosquitoes, to remove standing water from their property, and vaccinating their horses. It’s important to remain vigilant though, because there are so many different factors involved in the cycles of various diseases that predicting their resurgence can be extremely difficult, if not impossible. Taking some simple preventative steps, and making basic infection control practices habit can help reduce the impact of unexpected outbreaks, and help keep everyone (people and animals) healthier and safer.
A couple days ago, I was talking to a vet who's trying to manage a strangles outbreak on a farm. In many outbreaks, the biggest hassles are dealing with horse owners, not the disease itself. Strangles, infection by the bacterium Streptococcus equi subsp. equi, is a highly contagious disease but one that is relatively easy to control if things are done right.
The critical variable is whether people will do things right.
There are many issues that result in prolonged outbreaks at single facilities or spread of strangles from farm to farms, but two are quite common, recurrent problems.
1. Unwillingness of people to skip shows during the outbreak. I understand the desire to go to shows, since the show season may be short and shows are what people look forward to all year. However, despite the fact that it's clearly unethical for people to take a horse to a show from a barn where a strangles outbreak is underway, it happens all the time. That's probably one of the most important ways strangles is spread during the show season.
2. People moving horses to other barns. It's not uncommon for there to have already been one or more people flee the barn by the time I'm involved in an outbreak investigation, and I've seen multiple situations where one-farm outbreaks have turned into regional outbreaks because of this. This response is sometimes because individuals want to try to avoid the outbreak (although their horse may have already been exposed, making it too late), or to avoid any restrictions that might be put on the barn and movement of horses therefrom.
Both situations are common, but ethically are unacceptable. If a person knows that his/her horse is on a farm where strangles is present, the animal is considered infectious until proven otherwise.
How can these problems be prevented?
1) Boarding contracts that stipulate owners will stay on the farm in the event of an outbreak (maybe not easy to enforce, but at least addresses the issue up front).
2) The carrot: Emphasizing that with a good infection control response, if a particular horse has not been exposed, it probably won't be, and if it has been exposed, it's a risk to others. Either way, keeping it on the farm is the best for it and for others.
3) The stick: Reminding owners that they know their horses might have been exposed to strangles. If they take a horse somewhere and infect other horses, they might be (or should be) liable for any costs and losses associated with those subsequent cases. Infectious diseases are an inherent risk of life and are not always preventable, but when someone knowingly creates a high risk situation (and that situation was avoidable), legal consequences may ensue.
Not surprisingly (since bacteria don't respect borders), the Salmonella Cotham outbreak in the US associated with bearded dragons has also affected people in Canada. Nine cases of human salmonellosis associated with this rare Salmonella strain have been identified, many with a link to bearded dragons.
It's not particularly remarkable, but should be yet another reminder of the need to take care with reptiles, because they are such common carriers of Salmonella. Remember that basic hygiene and common sense (like keeping reptiles away from any and all food preparation areas, like the kitchen) go a long way to reducing the risk of disease transmission from these critters. High-risk individuals (young children, elderly, pregnant or immunosuppressed) need to be extra careful, or ideally just stay away from reptiles and other high-risk animals.
Hint... if you like time off during the summer, don't get into equine infectious diseases.
Vesicular stomatitis (VS) has been identified in five (so far - probably more to come) horses in Kinney County, Texas. The case is shown on the Worms & Germs Map, and more details are available in the news release from the Texas Animal Health Commission.
Vesicular stomatitis is a viral disease that causes blistering and sores of the mouth/muzzle of infected animals, as well as on the udder and coronary band (around the hooves) in some cases. The disease is certainly uncomfortable, and can cause animals to stop eating, but the lesions gradually heal and the infection resolves on its own in a few weeks. Part of the reason VS is such a big deal is because it can also infect cattle, sheep, goats and pigs, and in these species the lesions look just like those caused by Foot and Mouth Disease, which is a very serious foreign animal disease to Canada and the US.
In some ways, it doesn’t surprise me because it’s happened many times before. However, you’d think that, at some point, things would start to improve.
The US CDC is reporting yet another outbreak of salmonellosis associated with contact with feeder mice, that is, mice produced commercially to feed to pet reptiles. Sadly, this outbreak is quite similar to previous outbreaks. Multiple people (37 confirmed so far) in multiple US states (18 so far) have become ill, and 15% of affected people were hospitalized.
As I mentioned a few days ago about a salmonellosis outbreak linked to a company that sells eggs for hatching chicks, there seems to be no ability or effort (not sure which one is the case) to do anything about the source of these outbreaks. The FDA has issued a notice that “In the absence of a voluntary recall from Reptile Industries, Inc, FDA issued a warning to pet owners who have purchased frozen rodents packaged by Reptile Industries, Inc since 11 Jan 2014 that they have the potential to be contaminated with salmonella. Reptile Industries, Inc packages frozen rodents for PetSmart stores nationwide and are sold under the brand name Arctic Mice.”
The issue may be that these mice are not being sold as human food, so there’s no ability to mandate a recall. Yet, people are clearly getting sick from them, so it makes no sense that a recall and careful investigation of the facility and its practices is not underway. People purchasing feeder rodents need to remember:
- Freezing doesn’t kill Salmonella.
- Frozen rodents can be (and often are) contaminated with Salmonella and presumably various other pathogens.
- All feeder rodents should be considered contaminated and basic hygiene practices should be used when handling them at all times. This includes storing them away from human food, thawing them in sealed containers in a manner that won’t contaminate human food or food-preparation surfaces (including the kitchen sink), and hand washing after contact with rodents or packaging.
April showers bring May flowers.
…and I can’t come up with a good rhyme for salmonellosis.
Nonetheless, it’s Salmonella season, courtesy of cute but biohazardous baby poultry.
You can buy chicken, turkey and other bird eggs to hatch every spring. Our local feed mill had the order forms out a while ago, and you can also buy them over the internet. Some schools still buy them.
The problem is baby poultry are high risk for shedding Salmonella (and Campylobacter, another problematic bacterium). Every year, outbreaks of disease in people occur from contact with hatching chicks, so the message isn’t getting around or getting through to people.
In the latest CDC report, 60 people in 23 US states have been diagnosed with salmonellosis linked to a single hatchery that "has been associated with multiple outbreaks of salmonellosis linked to live poultry in past years, including in 2012 and 2013." (How many outbreaks does it take to tell you your company is probably doing something wrong, or in the wrong business?)
The figure of 60 infected people is probably an underestimate, since it’s expected that many people were probably sick but didn’t go to a doctor or submit a stool sample for testing. Of the 60 diagnosed cases, 31% ended up hospitalized, re-enforcing that fact that this is a serious problem.
While the hatchery said they are “working collaboratively with authorities at the Ohio Department of Agriculture and CDC as they proceed with their investigation,” the Ohio Deptartment of Agriculture tellingly stated “The more accurate description of our relationship with that company has been we have tried to provide guidance through the years, but I don't know how many of the recommendations that we have brought to them have actually been implemented.”
Sadly (and bizarrely, from my standpoint) the agiculture department doesn’t have any authority to require the hatchery to implement recommended changes. "We're trying to tell them what they need to do in order to keep this from happening every year." How many people does one company need to sicken before they are forced to do things right (or shut down)?
This report shows a few things.
- Some people just don’t learn (sellers and buyers alike)
- Regulation of animal production for sale to the general public is horribly lax
- Contact with young poultry is a major risk factor for salmonellosis.
- The industrial scale of production of eggs for hatching chicks (and some pet species) means that a problem with a single facility can lead to widespread disease.
- It’s a "buyer beware" world. Don’t trust that the critter you just bought is pathogen free, and take measures to protect yourself.
- High-risk individuals should not be around hatching chicks because of the risk of salmonellosis. This includes kids less than 5 years of age (a key target group for sellers), elderly individuals, pregnant women and people with compromised immune systems.
Photo copyright: piep600 / 123RF Stock Photo
The US CDC is reporting yet another multistate Salmonella outbreak linked to reptiles. This one is an outbreak of Salmonella Cotham that, as of April 21, has infected at least 132 people in 31 states.
The story is pretty similar to other reptile-associated Salmonella incidents.
58% of infected individuals are kids five years of age or younger.
- That’s presumably a result of both higher risk contact by young kids (especially kissing reptiles) and the fact that young kids are at increased risk of getting sick when exposed to the bacterium.
42% of infected people have been hospitalized.
- That’s a pretty high number compared to many other outbreaks. However, the actual overall hospitalization rate is probably lower, since it’s likely that many people had mild infections that were not diagnosed. Fortunately, no one died.
This Salmonella type is pretty rare, which makes it easier to trace it to a specific source. The investigation in this case traced it back to bearded dragons purchased as pets from a variety of stores in different states. Further investigation of the source is ongoing, and breeders that supplied the pet stores are being identified.
Of particular concern here was the presence of resistance to ceftriaxone, an important antibiotic, in a strain from at least one person. That’s something we don’t want spreading, since ceftriazone is often used to treat people with serious Salmonella infections.
Bearded dragons have a lot of personality (for reptiles), and are interesting little critters, so they’ve become popular pets. Like all other reptiles, they pose a risk of Salmonella exposure, and they shouldn’t be in households with high-risk individual (i.e. kids less than five years of age, elderly individuals, pregnant women, immunocompromised individuals). People who own "beardies" should use good hygiene practices and a solid dose of common sense to reduce the risk of salmonellosis.
More information about Salmonella and reptiles is available on the Worms & Germs Resources - Pets page.
A few questions were sent in by a reader regarding a recent post about rabies in a Texas animal shelter. They’re good ones so I thought I’d cover them here.
I'm a little confused by this. Weren't these shelter dogs vaccinated?
- Probably not. Many shelters don’t vaccinate against rabies. There are a few reasons for this:
- One reason is cost. From a shelter standpoint, rabies vaccination may even be considered of less importance compared to vaccination against diseases that are more common causes of illness in shelters (such as parvo).
- A big reason is that in most regions, rabies vaccines must be given by a veterinarian, and many shelters don’t have much veterinary involvement.
- Another consideration is that even if animals are vaccinated in the shelter, they are not considered protected until 28 days after vaccination.
- Yet another thing to consider is whether vaccination would have changed anything. Vaccinated dogs would still require a 45 day observation period. That’s much easier than a 6 month quarantine but still problematic and could lead to euthanasia for logistical reasons.
How exactly were these dogs exposed?
- Good question. It depends how the shelter was run and whether dogs were mixed together or socialized in groups. Sometimes, all dogs end up being considered exposed unless shelter personnel can definitively state that they know a particular dog didn’t have contact with the rabid dog. It’s often hard to say that with confidence, so by default they consider all dogs exposed.
What about vaccinated pets (dog and cat) that live in homes but go outside in suburban or rural environments? How do we know, for instance, that an indoor/outdoor cat hasn't come into contact with a rabid wild animal or feral cat? Do owners of indoor/outdoor cats really know where their cats go and what they do or who they associate with when they're out all day long? And, what about dogs that go out for their last potty break, unattended, in the fenced backyard at night when the wild critters come out? How do we know, really, that our pets haven't been exposed to rabies?
- We don’t. That’s an inherent risk in life, and a reason that we push for vaccination of all pets. Vaccination isn’t 100% but it will greatly reduce the risk of an animal developing rabies.
- This is also one of many reasons to make sure animals aren’t allowed to wander outside unsupervised.
There have been a few reports of equine herpesvirus (EHV-1) neurological disease over the last couple of weeks and some other cases that have been less well publicized. Hopefully it’s all just been a blip on the radar and not a sign of things to come as equine events start to ramp up at this time of year. However, it would be good for racetracks to take these cases as reminders of the ever-present risk of EHV and the need to try to prevent problems.
Some tracks have taken this issue seriously and are working on infection control and outbreak response plans. In response to one outbreak, a Minnesota track is building an isolation area for infected horses and implementing a variety of infection control measures.
Too often, the response to EHV-1 is only reactive: when there's no immediate problem, people don’t do anything, and when there is a problem, people freak out (and it’s hard to do things right when people are freaking out).
We need a happy middle ground that includes a reasonable response plan (effective and realistic) and proactive measures to both reduce the risk of an outbreak and to facilitate response.
Racetracks are starting to understand the need, although the response is variable. The number of outbreaks and the potential implications of them (e.g. sick or dead horses, cancelled racing, horses banned from going to certain tracks) means that it is in the horse owners’ and tracks’ best interests to do things right. What constitutes "right" is a moving target, though, and some people just don’t want to bother.
You can virtually guarantee that there will be EHV-1 outbreaks at racetracks this summer. A limited number of horses will die but there will be massive disruption based on quarantines (sometimes reasonable, often excessive) and other fall-out.
While there’s no way to completely eliminate the risk of EHV in horses, there are many things that can be done to reduce the risk of an outbreak. Some are relatively cheap and easy, such as
- Ensuring that horses with signs consistent with EHV-1 are promptly examined and isolated
- Avoiding shipping horses from sales directly into racing barns
- Cohorting groups on tracks as much as possible to contain incidents to individual barns
- Fostering routine infection control practices by people who frequently move between barns like veterinarians, farriers and riders/drivers
Other measures may take more time, effort and planning, such as creation of isolation areas and development of clear outbreak response plans. One of the most important things that can be done, however, is improving communication and trust. Often the biggest challenges in outbreaks involve poor communications, such as unwillingness to report cases, egos and agendas that get in the way of effective and timely response, and various other related problems that can be fixed by people thinking and talking to each other.
Some tracks are doing a good job of thinking proactively. Many are taking the "head-in-the-sand" approach. Any track could run into a problem, but my money’s on bigger problems occurring at the tracks that don’t take this problem seriously.
Unfortunately, we’ll be talking more about EHV-1 outbreaks this summer.
Surprisingly (at least to me), I don't hear much about individuals suing other people because of infectious diseases in their horses (apart from sporadic situations involving veterinary hospitals). I'm not saying the increasingly litigious nature of society is a good thing, but I can see how lawsuits could happen given the costs associated with infectious diseases, the emotions that can be involved and the lack of a well-defined standard of care.
The potential for liability isn't necessarily a bad thing IF it motivates people to do what's right. While ideally it wouldn't take the threat of financial loss to properly motivate someone, it can be a useful argument. Our first strangles poster touched on social influences as a motivator (i.e. if you do something that causes other peoples' horses to get sick, you're not going to be popular). Our second poster (below) addresses the potential for liability, which I think is particularly real when people knowingly move horses from a farm with strangles, especially when they don't notify the new farm about the potential for strangles exposure and take appropriate precautions.
An outbreak of equine herpesvirus type 1 (EHV-1) neurological disease has occurred on an Oregon farm. At last report, five horses had tested positive for the virus (though it's not clear if all of them had neurological disease) and one had died.
EHV-1 outbreaks are not exactly rare these days. There's certainly more reporting of sporadic disease and outbreaks, but it also seems like there's been a true increase in outbreaks over the past 10-15 years. During my residency, we saw EHV-1 neuro cases not uncommonly, but almost always as single cases. Now, clusters like this are more common, for no clear reason.
Anyway, this outbreak appears to be contained, and it's good that there's been no movement on or off the farm in a while. This will likely end up being a sporadic, contained cluster on a farm with no broader implications. Since EHV-1 is very common, being found in the majority of horses, there's always some risk of disease occurring. That's one of the main challenges we have in understanding and controlling this virus.
Tracking of EHV-1, and other equine (and dog and cat) diseases will soon be available on Worms & Germs MAP. Stay tuned.
There's been a lot of press about strangles (Streptococcus equi) outbreaks in Ontario lately, including a biosecurity update from the Ontario Ministry of Agriculture and Food (OMAF). In some ways, it's surprising since this is an endemic disease and strangles is pretty much always causing trouble somewhere in the province. However, a little press is never a bad thing, if it can help get people to do what they need to do (but often don't do) to control this highly contagious equine disease.
A big problem with strangles control is the unwillingness of some people to admit they have cases and/or people knowingly taking exposed horses off the farm, thereby spreading the bacterium to other farms.
Along that line, here's our latest educational poster. As with all of our materials, feel free to print, copy, post or disseminate at will. A higher resolution version can be downloaded from the Worms & Germs Resources - Horses page.
An outbreak of equine herpesvirus type 1 (EHV-1) neurological disease (also known as equine herpes myeloencephalopathy (EHM)) is underway in a currently undisclosed location in New Zealand. It appears that at least 12 horses have been affected with 6 deaths, all on one farm.
This is being described as the first outbreak of the neurological form of EHV-1 in New Zealand. That's pretty surprising to me, since this virus in endemic in the horse population throughout the world, and although the neurological form of disease is sporadic it's certainly not a rare occurrence. I imagine there have been periodic cases and maybe small clusters, but perhaps they mean that this is the first large outbreak to be identified (but that’s a guess). We do seem to be seeing more large EHV-1 neurological outbreaks in recent years, and I don't think it’s just because we're recognizing them more.
Fortunately, there is now much more willingness amongst most sectors of the equine industry to take these outbreaks seriously and act much more quickly and comprehensively than in the past (when getting people to admit to an outbreak was a challenge, let alone getting any action).
Hopefully this one's been contained on the farm and no further spread will be encountered.
Stay tuned for the launch of WormsAndGermsMap, a real-time disease mapping site to track cases like this. Coming soon.
For the third time in the past year, Macon-Bill Animal Welfare in Georgia (USA) has a problem with canine parvovirus. The shelter is closed for two weeks in response to a puppy testing positive for this highly contagious virus that can cause serious disease in dogs (almost exclusively in unvaccinated puppies). At first glance, it may seem like an overly-aggressive response. A single parvo case isn’t too surprising in a shelter, and if appropriate routine precautions are followed, there are sound protocols to isolate parvo suspects and a good vaccination program, the risk to other animals can be contained.
In this outbreak, 14 puppies have been euthanized (though some reports differ). Again, the news reports are pretty crappy and it’s unclear whether all the puppies were sick or whether they were euthanized because they were exposed. The statement that parvovirus infection is "most times fatal for dogs" is wrong, since it’s usually treatable, but it certainly takes time, effort and money - things that may be of limited availability in a shelter. Also, if the shelter has inadequate facilities or personnel to properly treat and contain parvo, euthanasia gets considered more readily that in better equipped facilities.
The first report also says that the shelter refunded adoption fees of people who adopted puppies that subsequently died from parvo, so it does sound like there was probably a real (and possibly large) outbreak.
Closing a shelter is an extreme move but it’s sometimes required. It helps reduce the number of animals in the facility in order to make isolation of sick animals, separation of groups, management of exposed and infected animals and many other aspects of the infection control response easier. It also stops adding fuel to the fire, by halting admission of new susceptible animals that can get sick and thereby propagate the outbreak.
Some shelter outbreaks are the result of poor routine management (and some incompetence). Some are the result of inadequate response to an infectious animal. Some are an over-reaction to a limited and containable problem. Some will occur despite the best practices in the best facility. That’s the nature of infectious diseases. Any time there’s an outbreak, a shelter needs to figure out which of the above categories they fit in so that they can reduce the risk of future problems.
(For tracking of selected infectious diseases and outbreaks, stay tuned for the launch of WormsAndGermsMap. More information to come!)
Pet aquatic turtles have been implicated in three outbreaks of salmonellosis involving 43 US states over the past year and a half. Disappointing, but not surprising.
Disappointing, obviously, because people are getting sick. Disappointing also because these outbreaks have occurred over and over, despite availability of good information on how to reduce the risks.
It’s not surprising, though, because it’s happened so often.
Why? It’s a combination of people not researching these animals properly before buying them, pet stores not providing information, turtle farmers in denial that there is a problem, people flouting the small turtle ban, and poor overall awareness (and application) of basic infection control measures (more on that in a minute).
The Michigan Department of Community Health (MDCH) has reported that 5 people from Michigan have become ill as part of these outbreaks. As is typical, most were kids.
So, if you own a pet turtle, what do you do?
“We don’t recommend that they release them into the wild. Instead, we recommend that you contact a pet retailer, a pet store, to talk to them about it. Also, you can speak with a local animal shelter or a veterinarian for other options as well.” said MDCH spokesperson Angela Minicuci.
That’s not bad advice. However, the pet store and vet probably aren’t going to take the turtle. The humane society might (and those that do might try to find it a home or might just euthanize it right away). There’s another step here that’s forgotten: doing a risk assessment.
Are there high-risk people in the household (kids less than five years of age, elderly, pregnant women, people with compromised immune systems)?
- If yes, the turtle should be re-homed.
- If no…
Are you willing to accept some degree of risk, risk that can be mitigated with some basic practices?
- If no, the turtle needs a new home. (There’s always some degree of risk with turtle (and any animal) ownership).
- If yes…
Are you willing/able to take some basic measures to reduce the risk of Salmonella exposure, on the assumption that your turtle is Salmonella positive?
- If no… (take a guess here) the turtle needs a new home.
- If yes...
A local county newspaper had a front page headline about a zoning amendment that was approved to allow for a feeder rodent facility that will produce about 10 000 rodents a week (I know, apparently there aren't a lot of big things happen around here). Co-incidentally, a couple days later, I received an alert and fact sheet from the Ontario Ministry of Health and Longterm Care and the Office of the Chief Veterinarian of Ontario about Salmonella and feeder rodents because of an increase in human Salmonella Typhimurium infections in people in Ontario and a link to feeder rodents in some cases.
It’s not really a surprise. Large and sustained outbreaks of salmonellosis associated with feeder rodents have been reported for a while. These rodents are often produced at large facilities with hundreds of thousands of rodents, and if Salmonella gets in the facility, thousands (or millions) of biohazardous small-and-fuzzy snake snacks can get shipped around the world.
The fact sheet is attached here, and it contains good information about the standard reptile and rodent handling practices that I always keep coming back too: wash your hands, keep high risk people away, prevent cross-contamination of snake food with people food (e.g. don’t thaw frozen rodents in an open container in the fridge (yuck… but it happens) or cross contaminate kitchen surfaces) and other basic hygiene practices.
Infection control isn’t complicated, it’s often just ignored.
I’ve been holding off on writing about this one for a while since it’s been unclear what’s happening, but a strange disease situation appears to be ongoing in Ohio dogs.
There’s old adage in medicine: an uncommon presentation of a common disease is much more likely than presentation of an uncommon (or new) disease.
- aka common things happen commonly.
While this is certainly true, emerging diseases continue to just that. This one seems like it really is something new, and something to which we need to pay attention.
Reports have been coming in for a few weeks about severe and sometimes fatal gastrointestinal disease (e.g. vomiting and diarrhea), and deaths were occurring, particularly in dogs that were not treated early in disease. The usual suspects were ruled out, and eventually there was suspicion that the cause might be a circovirus.
Until recently, circovirus was only known to be a problem in pigs (where it’s a very big problem). Then, in 2012, a canine circovirus was reported in dogs in California with severe gastrointestinal disease, as well as some healthy dogs. Circovirus wasn’t proven to be the cause of illness, but it was quite suspicious that this could be a canine pathogen.
Because of the similarity in disease signs in the Ohio dogs and the ones from California, circovirus testing was done and apparently the virus has been detected.
This doesn’t mean that the virus is what's making the dogs sick. Since the virus can also be found in some healthy dogs, its role in disease is unclear. Certainly, it’s not a virus that causes disease in every dog that is exposed. So, at this point, we’re still a bit (or more than a bit) in the dark. Yet, there’s enough evidence to indicate that we need to investigate this virus, see where it is, where it’s going and figure out how to control it.
How can you protect your dog?
It’s not really clear, but basic infection control practices are probably the key at this point in time. The virus is spread through contact with feces of infected dogs.
- If your dog is sick, keep it away from other dogs and places where other dogs go (e.g. the dog park).
- If your dog is sick, take it to the vet. (Make sure they know why you’re coming in so that they can take appropriate precautions to isolate your dog, rather than having you hang out in the waiting room with other dogs while waiting to see the vet.)
- Keep your dog away from sick dogs.
- Pick up your dog’s feces. Always. Even if it’s healthy.
Nothing fancy or really anything beyond what people should normally be doing, but this situation is a good reminder of why we should use basic infection control practices routinely.
I haven’t heard of any concerns about this disease in Canada, but rapid investigation and communication are important, so any concerns about possible cases will hopefully be sent my way.
Hastings Racecourse cancelled racing last Saturday because of an outbreak of equine influenza in horses at the track. A recent CBC news report indicates that things started a week and a half earlier, with 150 horses affected when the race cancellations were announced. That's a pretty impressive outbreak.
There's no information about the response, beyond cancelling racing. In some ways, flu is quite easy to control because animals do not become long-term carriers of the virus and infected horses only shed the virus for a short period of time. This makes it easier to contain an outbreak with good infection control precautions, since you only need to implement them over a fairly short period of time. However, the downside is flu is highly infectious and can spread easily and quickly.
I have no first hand knowledge of this outbreak so I can't say anything about what was done or what was missed. However, from a generic standpoint, these are the main problems I see with this kind of outbreak.
There's no response.
- This is too often the problem. This can occur because people don't realize something is happening or the snow-balling of issues that can result. Education is needed to help prevent this.
- Lack of response can also occur because people don't want to tell anyone about an infectious case or don't trust the authorities. This sometimes happens if horsemen are worried about being stigmatized or prevented from racing or showing. Again, education is needed.
- Sometimes, there's mistrust of track or regulatory personnel. If people are worried that the other group doesn't understand or care about their situation, or they don't realize the benefit of communicating, they might try to hide a problem.
There's a late response.
- Another common problem. This usually occurs because people try the "I hope it will go away" approach to infection control first. This rarely works.
- If you get infection control measures in place early, you can contain things much more easily. You're much more likely to contain an outbreak if you only have one horse, or a few horses, affected. It's also easier to contain the disease if you can keep it localized to one barn. Once it spreads to many horses and gets into multiple barns, it can be tough to stop.
- This is why protocols that require reporting of fevers other other basic, early signs of infectious disease (and how to respond to them) should be commonplace.
The response is half-hearted.
- Yet another common problem. Even when people get moving and try to contain an outbreak, it's often not done effectively.
- One reason for this lack of efficacy is people often don't want to do what's recommended. Infection control measures always make life more difficult, and they take time, no doubt. They're important though. Skipping important measures and just trying to do the more convenient ones isn't a good response.
- Another reason for an inffective response is not knowing what to do. Sometimes, I get involved in outbreaks after there's been an initial response and see lots of effort being put into relatively (or completely) useless activities, while the key control measures are ignored. Getting the input of experts as early as possible is critical.
There's inconsistent response.
- This may be similar to 'half-hearted," but by this I mean an outbreak where some people do everything right, and some do little or nothing. Sometimes this is a result of poor communication, and therefore everyone doesn't understand what's happening. Better communication and education can help.
- Other times, this can be caused by simple belligerence: "I don't want to do it so I'm not going to do it!" Sometimes good communication and education can help with this too, by showing people that it's to their own benefit. However, willful neglect is not uncommon and it's hard to handle.
The common themes to preventing these issues are communication and education.
An outbreak of equine herpesvirus type 1 (EHV-1) has resulted in implementation of a quarantine at Woodbine, a major Thoroughbred track in Toronto. This outbreak is unrelated to the recent outbreak at an Ontario Standardbred training facility.
The Ontario Racing Commission has issued the following release:
The Ontario Racing Commission (ORC) announced that there have been five confirmed reports of the neurotrophic form of EHV-1 in thoroughbreds residing in Barn 1 at Woodbine Racetrack. One horse was euthanized on June 10 after becoming recumbent with a fever. A second horse in the same barn (Barn 1) also had a fever and showed neurological signs. The second horse was transported to the Ontario Veterinary College for further evaluation and treatment.
Thoroughbred racing will continue at Woodbine. However, due to the infectious nature of this disease, the ORC has ordered the implementation of various infectious disease protocols to protect our equine athletes.
In order to determine any further spread of the disease to horses in other barns, no horses are to exit Woodbine Racetrack without ORC approval for the next 7 days (June 19). This restriction may be reviewed based on the progression of the disease.
In addition, no horse is allowed in or out of Barn 1 or Barn 3 for the next 7 days, including training. This restriction may be reviewed, based on the progression of the disease.
All horses stabled at Woodbine must have their temperatures taken and recorded visibly on the horse’s stall door for inspection. Trainers with horses that have clinical signs consistent with EHV-1 infection (including fever (101.5 F/38.5 C or above), respiratory signs (cough, nasal discharge and/or neurological signs) must report these findings to their veterinarian immediately.
Horse people who had horses at Woodbine Racetrack within the last 7 days should monitor their horses for any signs of illness. Standardbred horses are not stabled at Woodbine Racetrack. As well, the standardbred racing meet concluded at Woodbine on May 20, 2013 and moved to Mohawk Raceway on May 23. Therefore the June 15 North American Cup at Mohawk will not be impacted by these measures.
As with most outbreaks, the next few days are critical to see how far the virus has spread. Early on, you never know whether it's confined to a specific barn or group, or whether it's widely disseminated across the facility. An outbreak that just affects one barn is still a problem, but it's much easier to contain than one that's already moved beyond the initial group. Without knowing how the first horse was infected (something that's rarely identifiable), time and testing are needed to determine the extent of the spread and how hard it will be to contain it.
Several dogs at a Miami humane society were quarantined last week because of concerns (or possibly panic/over-reaction) about methicillin-resistant Staphylococcus aureus (MRSA). MRSA in dogs is a concern because it's an important cause of infection in both people and animals. However, it's an opportunist, meaning it typically doesn't cause disease when it encounters a normal, healthy person or animal. In fact, a small percentage (~1-3% probably) of the human and pet populations carry this bacterium in their nose without knowing it, and the vast majority never suffer any consequences.
It's often tough to strike the right balance when dealing with an MRSA issue. We want people to realize that it's an important cause of disease and that it needs to be taken seriously, but we also want people to keep it in perspective and not freak out.
The Miami shelter report seems to be on the "freak out" side, particularly on the part of the local media.
It's not really clear what's happening based on this fairly poor article. The shelter's Chief Medical Officer, Dr. Maureen Swan, is quoted as saying there's a routine respiratory disease cluster in the shelter, but MRSA rarely causes respiratory disease in dogs. The article then adds Dr. Swan said it was "not the highly contagious MRSA virus." I have no idea what that means, and MRSA is not a virus.
My suspicion is that they have respiratory disease caused by the typical bacterial and/or viral pathogens that are commonly found in shelter dogs, and that they isolated a methicillin-resistant staph that just happened to be hanging around in that particular dog (since such bacteria normally live in the mouth, nose and skin). It's also not really clear whether this is MRSA. The article says MRSA, but the first thing I ask when I get an advice call about MRSA is "what staph species does the report say was isolated?". Most often, it's Staphylococcus pseudintermedius or another staph. These bugs can still be relevant, but they don't carry the same human health risk as MRSA, so it's important to know exactly what's been found.
Finding MR staph, including MRSA, isn't unheard of in a shelter. It's just one of many reasons that good general infection control practices are needed in these facilities. When MRSA is found, taking some extra precautions is reasonable because of the potential for disease and transmission to people, but too often people panic. It's understandable based on concern about MRSA and the scary stories people can find with a quick Google search. Not uncommonly, there's a combination of an short-term overly aggressive response while at the same time failing to improve basic infection control practices, which are the most important.
More information about MRSA can be found on the Worms & Germs Resources - Pets page.
I’ve written about the African dwarf frog and Salmonella issue before, but it’s worth a recap since an overview of the 2008-2011 outbreak was recently published in the journal Pediatrics (Mettee Zarecki et al 2013). The fact that reptiles and amphibians can carry Salmonella is nothing new, nor is the fact that outbreaks of disease can occur in people who have contact with them. However, the scale of outbreaks associated with pets can be impressive.
Here are some highlights from the paper:
- Between January 1, 2008 and December 31, 2011, 376 people were diagnosed with salmonellosis caused by the outbreak strain, a type of Salmonella Typhimurium.
- As is common in pet-associated outbreaks, kids bore the brunt of this one. The mean age of infected individuals was 5 years, and 69% were children under the age of 10.
- Severe disease wasn’t uncommon - 29% of people were hospitalized, half of those being kids less than 5 years of age. Fortunately, no one died.
- During a preliminary study, when they compared people who got sick with a group of healthy controls, they found that people who reported exposure to any aquatic pet were almost 5 times as likely to have salmonellosis. When that was narrowed down to exposure to just frogs, the risk went up to 12.4 times higher than healthy controls.
- When they looked at people who were sick and reported exposure to frogs, only 27% reported having touched a frog, with 46% reporting having fed a frog, 59% having had contact with a frog’s habitat and 60% having had contact with water from a frog’s habitat. Twenty-three percent (23%) reported cleaning the frog’s habitat in the kitchen sink, and 35% in the bathroom sink. This tells us some very important information. It tells us that direct contact with frogs or their environment is a high risk behaviour. However, direct contact isn’t required to get sick. While the frog may stay in its habitat, Salmonella may not. Cleaning habitats in kitchen or bathroom sinks is a high risk activity, because it can result in contamination of common human-touch surfaces and items that go into peoples’ mouths (e.g. toothbrushes, cups).
- Often, disease occurred not long after a new frog was obtained. The median time from purchase of a frog to disease was 30 days (range 5-2310 days).
- Only 17% of people interviewed reported knowing that frogs can carry Salmonella. Over twice as many knew there was a risk from reptiles. This shows there needs to be more education of people who buy animals such as frogs. Pet stores should be required to provide some basic public health information. Pet owners should also take initiative and research potential new pets, including how to care for them and how to reduce the risk of zoonotic infection.
- The outbreak Salmonella strain was found in the environment of some patient homes (not surprisingly), an African dwarf frog vendor (potential source of infection), a large-scale African dwarf frog distributor (a great way to spread an outbreak across the continent) and a daycare centre (that never should have had an amphibian in the first place!).
- One breeding facility in California was the likely source. With centralized, large-scale breeding and warehouse-style distribution of pets (of various species, not just frogs), we’re seeing more large-scale outbreaks like this.
More information about African dwarf frogs can be found on the Worms & Germs Resources - Pets page.
Lately there has been a run of pet treat recalls due to Salmonella contamination (with the latest one courtesy of "Diggin' Your Dog"), but it shouldn't come as much of a surprise. Salmonella contamination of raw animal-based pet treats has been reported for years. It's not just a risk to dogs, since outbreaks of salmonellosis in people from handling treats have also been reported. Despite some good moves by the industry to improve the situation (e.g. better manufacturing practices, more products being irradiated), treats still need to be considered high-risk for being contaminated with Salmonella and other bacteria.
So, what can be done to reduce the risk?
- Buy individually wrapped or pre-packaged treats. Treats from bulk bins are higher risk because one contaminated item can cross-contaminate many others. Also, bins are often continually topped up without cleaning or disinfection so contamination can persist.
- Choose products that have been irradiated. There are still some baseless fears about irradiation, but there is absolutely no evidence that irradiation of food is harmful and it can effectively kill pathogenic microorganisms.
- Avoid feeding raw animal-based treats that have not been irradiated to animals at higher risk of becoming sick or having a serious infection. This includes elderly animals, puppies, pregnant and nursing dogs, dogs that are immunocompromised (e.g. undergoing chemotherapy) or dogs that have chronic intestinal disease. Also, they should not be fed to dogs that have contact with high risk people, such as those that live in households with infants, elderly individuals, pregnant women or immunocompromised individuals. Also, they shouldn't be fed to dogs that visit human hospitals. One study showed that dogs fed raw animal-based treats had a 12-times greater likelihood of shedding Salmonella (Lefebvre et al 2008).
- Wash your hands after handing pet treats.
If in doubt, or if your dog or family fits into one of those high risk groups, stick with processed treats that have been cooked or make your own cooked treats.
In Canada (like most places), there's no semblance of a formal surveillance program for infectious diseases of companion animals. We're left with anecdotes and whatever short-term research projects we can put together to try to figure out what's happening in our companion animal populations. Not ideal, but better than nothing.
Over the past month or two, I've been hearing more rumblings about canine parvovirus infections in dogs in Ontario. Nothing too dramatic, just a spike in calls and emails about cases, mainly typical parvo cases (e.g. disease in young and un- or inadequately-vaccinated puppies, outbreaks in groups like shelters and breeding kennels) with some cases that seem more severe and some in dogs that seem to have appropriate vaccination history or in older dogs. It doesn't seem to be due to a focal outbreak, since these may be occurring in a few different regions in Ontario. This type of anecdotal information is far from definitive but enough to start asking questions.
I'm not the only one who's been hearing this. The Ontario Veterinary Medical Association has had enquiries and has been receiving more information from Ontario vets, so they have put out a press release indicating that something might be going on with regard to parvovirus in the province, and emphasizing the need for proper vaccination and preventive medical care for dogs.
So is something happening in Ontario? I'm still not sure. Sometimes situations like these are just because people are talking and we're hearing more about little clusters that go on all the time under the radar. However, this could be real and caused by a variety of factors such as decreasing vaccination rates, increased parvovirus circulation in some regions or a change in parvovirus strains.
The only way to truly figure out what's happening is to get more data. That's not an easy proposition since surveillance networks aren't established and there's no money to do any disease surveillance like this. However, Ontario veterinarians who are seeing parvo cases can feel free to provide more info and to send samples for typing.
A proposed Florida bill would require shelter operators to produce monthly and annual euthanasia reports. The reported goal of the effort is to "reduce euthanasia of unwanted animals." But how? The idea has various pros and cons.
Potential good points
More transparency: Euthanasia rates are often considered the "dirty secret" of the shelter world. In reality, it's not the shelters' fault that animals are being euthanized. It's society's fault because of overpopulation. Shelters should be reporting these numbers (and ensuring they are accurate), not as part of a "we kill fewer than you do" competition, but to highlight the challenges, increase public awareness and to work toward improving the shelter system.
More data: The more we understand the epidemiology of adoption, euthanasia, disease and other events in shelters, the better. Knowledge helps us figure out better ways to run things.
Potential bad points
Animal welfare: Will shelters resist euthanizing sick or injured animals that would otherwise be euthanized to keep their rates lower? If an animal is very sick, will there be the temptation to let it die rather than euthanize it, if deaths are not reportable but euthanasias are?
Overpopulation in shelters: If shelters try to avoid euthanising animals because the rates are reportable, there will be more animals in the shelters - likely more than they can actually handle. More animals in a shelter does not mean more adoptions. Overcrowding leads to many problems such as increased disease risk, deceased quality of care, decreased human contact and increased shelter operation costs.
Outbreak potential: Yet another issue related to overcrowding is when you cram in as many animals as possible (often using carriers and other temporary housing stashed anywhere there's spare space) and decrease the time you spend with each animal, you create great potential for a disease outbreak. The more animals are present, the more likely the outbreak will take hold and the harder it will be to control.
Needless transfers: Will shelters try to transfer animals that are unadoptable to areas where this law is not in effect, simply to be euthanized outside of the recording system? Beyond the humane aspects of putting the animal through the stress of a transfer for no real reason, shipping shelter animals is notoriously high risk for shipping diseases along with them.
Cherry-picking: This already happens with some shelters, but one way to keep euthanasia rates low is to refuse to admit animals that are not likely to be adopted. Turning them away doesn't help the animal or society (and may result in more animal suffering, among other things, if the animals are simply abandoned), but it keeps euthanasia numbers low.
Will this work?
Shelters don't euthanize for fun. They do it because there is a finite number of homes available and the number of animals coming into shelters (especially cats) is way beyond that. This bill will not magically create millions of new homes for shelter animals. So, how will it "reduce euthanasia of unwanted animals"?
A representative of a group working to reduce shelter euthanasias added "We do not believe that it is the conscious will of the people of the state of Florida to kill over 50% of the lost and homeless shelter pets each year." It's not their conscious will but what can/will they do about it? Euthanasia numbers might help spur interest in adopting from shelters, and if so, that would be great. But the fact is that if 50% of animals in shelters are being euthanized, it's because they don't have homes.
Probably a well-intentioned but poorly thought-out approach to the pet overpopulation problem.
I'm just back from vacation (luckily, with no infectious disease stories to write), but now I have to catch up on a few posts. One easy one that was waiting for me in my inbox was about Salmonella and hedgehogs.
I've written before about biohazardous hedgehogs, and more details about the US 2011-2013 multi-state Salmonella outbreak were reported in a recent edition of CDC's Morbidity and Mortality Weekly Reports. The outbreak was identified through recognition of a cluster of infections in people caused by the same, historically rare strain of Salmonella Typhimurium. Finding a cluster of the same strain, especially a rare one, suggests that there might be a common source, so an investigation ensued. Here are some highlights:
- Twenty people from 8 states (Alabama, Illinois, Indiana, Michigan, Minnesota, Ohio, Oregon and Washington) were affected, although (as is typical) it's almost guaranteed that many more people were affected but not tested.
- Young people were more often affected, with the average age being 13. The age range spanned from less than 1 year to 91 years of age.
- Four people were hospitalized and one died.
- 14/15 (93%) people interviewed reported direct or indirect contact with a hedgehog. That's a pretty strong indication that hedgehogs might be involved, since that number is wildly disproportionate to the percentage of people in the general population that have contact with hedgehogs.
- Hedgehogs were obtained from various breeders, not from a single source.That's not uncommon since breeders often get animals from other breeders or suppliers and a point-source of infection further up the supply chain is likely.
For some reason, hedgehogs are high risk pets when it comes to Salmonella. High Salmonella shedding rates have been identified in studies of healthy hedgehogs and it's clear that contact with healthy carriers can lead to human infection. Hedgehogs should be considered alongside reptiles in terms of pets that should not be present in high risk households (households with kids less than 5 years of age, elderly individuals, pregnant women or people with compromised immune systems). Hedgehog owners should take care to avoid direct and indirect contact with feces and use good hygiene practices to reduce the risk of infection.
Yes, the title's a bit misleading. Equine herpesvirus (EHV) is everywhere, since the virus circulates widely in the horse population internationally and lies dormant in the bodies of a large percentage of healthy horses. However, cases of EHV-1 neurological disease get attention because of the severity of disease and the potential for outbreaks (for reasons we really don't fully understand). Seeing a report of a new case isn't surprising, since they are always occurring somewhere, but it's worthy of note for horse owners in the area or those who might have visited the area recently.
The latest incident, reported by TheHorse.com, involves a Standardbred horse that raced at Sports Creek Raceway, a small track in Michigan. The animal raced on December 22nd and started showing signs of neurological disease on December 23rd. It presumably didn't pick up the virus at the track, because 24 hours is on the very low end of the potential incubation period, so the main concern is that the horse might have been shedding the virus while at the track. It's possible that EHV could have been transmitted to other horses via aerosols (virus on small particles released when the horse was breathing, shorting or coughing), contaminated items that were used for multiple horses (e.g. buckets), or on the hands or clothes of people. That's why good general infection control practices are needed at tracks and other horse competitions at all times - to reduce the risk of transmission when an infectious but currently healthy animal is present (and there's room for a lot of improvement).
Typically, the incubation period of EHV-1 in a neurological disease outbreak isn't very long: about 4-6 days or so. If anyone had a horse at the track on the 22nd and it's still healthy today (January 4th), odds are it won't be affected. However, there are some instances when the incubation period can be longer, particularly with abortions in pregnant mares. Also, horses could have been infected and not gotten sick, but still be able to spread the virus to other horses with which they subsequently have contact. For this reason, several racetracks have imposed temporary entry restrictions on horses that were at Sports Creek in December. It's probably a low risk situation, but you can never put an outbreak "back in the bottle," and a little short term inconvenience is much better than the major hassles (and deaths) that can come with an outbreak.
The affected horse was in pretty rough shape neurologically but ultimately recovered, as can occur with EHV-1 neurological disease. If your horse has to have a neurological disease, this is probably one you want since full recovery is possible. EHV-1 will probably live within this horse's body for a while, if not lifelong, but that's true of a large percentage of other horses as well, so after a few weeks (when the likelihood of him shedding the virus decreases), he probably poses no more risk than any other horse.
This story's a couple of weeks old, but Sonoma County (California) residents have been warned about an outbreak of salmonellosis in songbirds. Outbreaks of salmonellosis occur occasionally in songbirds such as finches, and can result is lots of sick and dead birds. There are also risks to other species, including cats and people.
Why cats? Cats can be exposed to Salmonella from eating infected songbirds, and sick birds are typically a lot easier to catch than healthy ones.
Why people? People can be exposed to Salmonella from areas the birds have contaminated, particularly bird feeders and their vicinity. People have been advised to remove bird feeders or clean them regularly, and to promptly remove dead birds from under feeders.
- Removing bird feeders temporarily might help keep birds (including sick birds) farther away from people. It's not going to hurt the birds since other food supplies are typically abundant.
- Washing feeders can reduce the Salmonella burden but it could also increase the risk to people if they contaminate themselves while washing them. Certainly, people should not wash bird feeders inside the house, especially not in the kitchen sink. They should also take care to avoid contaminating their clothing and make sure they wash their hands thoroughly after finishing with the feeder.
"Songbird fever" is a colloquial name for salmonellosis in cats - a testament to the potential for feline infection. It's uncommon but can be severe, and cats can act as a bridge between sick birds and people by bringing Salmonella into the household. This is just one of many reasons why domestic cats are better off living indoors.
I haven’t written much about equine herpesvirus type 1 (EHV-1) outbreaks lately because I have a hard time getting excited about them (from a blog writing standpoint… if one occurs here, that will be a different story). Outbreaks of neurological disease caused by this very common equine virus (one that doesn’t spread to people or non-equids) continue to occur, and it’s hard to say whether we've been seeing more of them over the past couple of years or whether we’re just hearing about them more often. It does seem like outbreaks have truly become more common and more virulent in the past 10 years or so, but I’m not sure it’s continuing to get worse.
The latest EHV-1 outbreak has affected 5 of 7 horses on a central Minnesota farm. At last report, one horse had been euthanized and one was hospitalized at the University of Minnesota. The hospitalized horse is presumably receiving supportive care, such as intravenous fluids and general nursing support. Affected horses may become very weak and sometimes they need to be managed in a sling (see photo), since horses don’t tolerate being unable to stand for long (laying down for prolonged periods of time can damage muscles and nerves, simply because they are crushed by the horse's own weight). Sometimes the bladder becomes paralysed and needs to be drained using a catheter. Numerous other problems can occur since the way this disease affects each horse can be quite variable. Fortunately, the prognosis tends to be reasonable (at least compared to other neurological disorders) if the horse is not severely infected and stays standing or is able to remain upright with the support of a sling. The clinical signs are the result of inflammation of the blood vessels in the brain and spinal cord, and the key is to get that inflammation down and keep the horse alive in the meantime.
In the past, we didn’t worry too much about these horses in equine hospitals. EHV-1 neurological disease tended to occur sporadically, not in the form of outbreaks, and dogma was that once the horse was sick, it wasn’t at much risk of shedding the virus. In fact, for a long time our best stall in the main hospital for neurological cases (which had padded walls, and a ceiling anchor for a sling) was right at the front of our main equine ward. A large outbreak in the US in the early 2000s changed that, and now we take much more aggressive measures to contain this virus, including housing affected horses in isolation and using strict infection control measures. With these precautions, the risk of spreading the virus in an equine hospital is low.
Image: A horse with neurological disease being managed in a sling (source: http://coloradodisasterhelp.colostate.edu)
It's perhaps a good sign for public health when I don't tend to come home from a local fair and write a rant about the sorry state of the petting zoo. Around here, things seem to have improved at most events over the past few years, probably largely because of the efforts of local public health personnel. However, some establishments still fall through the cracks and regardless, even with optimal management, there's always some degree of risk with contact between animals and the public.
Welsh authorities are investigating a small (so far... and hopefully to remain that way) outbreak of E. coli O157 that has been tentatively linked to Cantref Adventure Farm. The two children became ill after visiting the farm. Two family members of one child have also tested positive for the bacterium, and it's believed that one of them was infected via contact with child (as opposed to direct contact with animals at the farm). Since both kids visited the farm in the days before they got sick, and since petting zoos are a prime source of E. coli outbreaks, it's logical to assume the farm was the source. Even though this has not yet proven, the reason to make this early assumption before a link can be definitively established is to get the word out to others that may have visited the petting zoo, in case there are more cases of illness. Authorities are telling people who visited the farm since the beginning of August to contact their physician. It's not clear whether they want to test everyone (by collecting a stool sample) or just have them checked out to make sure they are okay.
Meanwhile, the investigation at the farm is ongoing. Presumably, stool samples from animals on the premises and environmental samples have been collected to see if the same strain of E. coli is present. All direct contact between the public and animals on the farm has been stopped, and the site is being thoroughly cleaned. That's a pretty standard response overall, and hopefully if the petting zoo was the source, transmission has ceased.
Petting zoos can be fun and educational and we don't want to over-react and assume they are all inherently dangerous. There's always some degree of risk of infectious disease exposure, and the key is making sure petting zoos are run optimally to reduce, as much as possible, the risk to the public. The public also has to play a role, by following rules, supervising children and (probably most importantly) actually using hand sanitizers and handwashing stations that are provided.
The Guelph Humane Society has re-opened after a temporary closure to manage a potential ringworm outbreak. The shelter took an aggressive, proactive approach to the issue, including testing and treatment of all animals and thorough disinfection of the facility.
Looking back on a proactive outbreak response like this one, it's always hard to say if a bad outbreak didn't develop because it wasn't going to, or because of the early aggressive response (i.e. did it get better because of what they did or despite what they did). However, if you sit back and wait (or remain in denial), you can be sure that it's much more likely that badness will develop.
Once things have settled down, people sometimes complain that an aggressive response was unnecessary because nothing bad happened, but they're often the same people that complain that not enough was done when an major outbreak occurs. An ongoing challenge in infection control is fighting complacency, since successful infection prevention and control programs sometimes lead to people forgetting about the bad things that can happen and why such programs are in place to begin with. We should applaud facilities that "suck it up" and accept the negative PR, time and financial consequences of an appropriate response in order to protect the health and welfare of the animals for which they care and all the people (employees and public) who have contact with them.
When I give talks about pet therapy animals, I talk about appropriate and inappropriate animals. On one slide I have a picture of a hedgehog, and I use it as an example of an animal that sometimes makes its way into pet therapy programs, despite standard guidelines to the contrary. This is a species that raises significant infectious disease concerns because hedgehogs can carry an impressive array of microorganisms that can be spread to humans. A big one is Salmonella.
So, it doesn't come as too much of a surprise that the CDC is reporting a multistate outbreak of salmonellosis associated with hedgehogs. Here are the highlights:
- Fourteen infections have been reported between December 2011 and August 2012. There are probably many more because in most outbreaks, only a minority of affected people get tested.
- People have been infected in six states (Alabama, Indiana, Michigan, Minnesota, Ohio and Washington), all with the same strain of Salmonella Typhimurium.
- All 10 people that were interviewed reported contact with hedgehogs or their environments. Considering the rarity of hedgehogs as pets, that's a pretty good indicator that hedgehogs were the source. The outbreak strain of Salmonella was detected in two households, in areas where the hedgehogs lived or were bathed.
- No one has died, but three people were hospitalized.
- As it typical, a large percentage (50%) of affected individuals were children 10 years of age or under.
The fact that this outbreak appears to have occurred over a long period of time and a large geographic area strongly suggests that this might be ultimately traced back to a common breeder or intermediary source. Many small pets like these are mass produced by large breeders and shipped across the country, creating the potential for a problem at a single breeder to have far-reaching consequences in other breeder colonies and in households. This has been shown repeatedly with species like hamsters and mice.
This report doesn't mean that hedgehogs shouldn't be kept as pets. However, hedgehogs do seem to be a higher-risk species than average, and households that include high-risk individuals (e.g. young children, elderly persons, immunocompromised individuals, pregnant women) should probably avoid them. More importantly, the potential for transmission of Salmonella and other pathogens indicates the need for good basic, routine hygiene practices, such as washing hands after handling a hedgehog, keeping them out of the kitchen, not bathing them in kitchen or bathroom sinks, and supervising contact between hedgehogs and kids.
I'm not really sure what to think about canine norovirus. Is it a rare, oddball infection or is it an important, overlooked and/or emerging problem?
- There are only a few reports of norovirus infections in dogs, but I doubt many people are looking for it.
- I've looked for it a few times during outbreaks, but not enough to convince me it's not here.
- Most outbreaks of canine gastrointestinal disease are not investigated, and norovirus testing isn't commonly available.
So, I think it's hard to say much about this bug at the moment.
However, another outbreak report involving canine norovirus (Mesquita and Nascimento, Transboundary and Emerging Diseases 2012) has been published, increasing concern that this might be an overlooked or developing issue. This latest report from Portugal describes an outbreak in a kennel that started after the introduction of some dogs imported from Russia (yet another example of the problems that can occur with dog importation, especially in the absence of good quarantine and infection control practices).
The outbreak started after two dogs from Russia were brought into a Portuguese kennel. Both had diarrhea at the time of arrival (strike 1 - introduction of new dogs, particularly sick dogs, is just asking for an outbreak) and were put into the general dog population (strike 2). Two days later, the other five dogs in the kennel developed diarrhea (not surprising). All were positive for canine norovirus (ok, that's surprising) and within one week, all the dogs appeared to have fully recovered.
There's no mention of whether testing for other causes of diarrhea was performed, but I assume that's the case. The sudden onset, rapid transmission and relatively short, self-limiting course of disease is consistent with norovirus infection.
Canine norovirus has been found in Portugal before, and the virus found in these dogs was very similar to previous Portuguese isolates. Whether that means the dogs acquired the virus in Portugal en route to the kennel or whether this virus is widely disseminated internationally isn't clear (in large part because so few people have looked for canine norovirus).
Much more remains to be learned about this virus. It should be considered in outbreaks of diarrhea in dogs, especially outbreaks involving rapid transmission between animals. A major obstacle to obtaining more information about this pathogen is the general failure to investigate outbreaks in which it may be involved. While outbreaks are often dramatic, testing is usually limited because of the cost. That's especially true when dogs aren't dying. Often, testing for rare or potentially new problems only occurs when there's a complete disaster and/or if an interested researcher or diagnostic laboratory gets wind of it and is willing (and able) to do some testing at no cost. That's not often an option. I do testing as much as I can, but I don't have any money dedicated to outbreak investigation so it depends on whether I have spare resources to put into an investigation at the time.
The risk to people from canine norovirus is not known, but is probably limited. There is some evidence of potential transmission of noroviruses from pigs or calves to people, but the risk from canine norovirus isn't clear. Common sense practices to avoid contact with diarrhea (from any animal) should be used, as much to prevent exposure to the pile of other pathogens that can be in dog poop, as to prevent potential exposure to canine norovirus.
On my way to Beth's soccer practice yesterday, I heard a blurb on the radio about how Frank Klees, MPP (Member of Provincial Parliament) told the legislature that the Newmarket OSPCA was going to euthanize all their animals because of a ringworm outbreak, and that three employees had been fired because they objected to the number of euthanasias. His statement that "We have a repeat now, at the same shelter, of what took place nearly a year and a half ago" was pretty concerning, given the severity of the earlier "ringworm" debacle. Klees, the veteran PC party MPP, has been a vocal critic of the OSPCA in the past.
Later that night, I found a little more information, which was mainly centred around complaints about the number of animals being euthanized for various reasons, and a subsequent statement by the OSPCA that there was no outbreak.
Now, it appears that a protest is being planned for today (Friday), although it's not really clear to me what they are protesting. Maybe there's more to it than is being reported and an outbreak or cull is actually underway. However, in the absence of that, their protest is better directed at the state of the animal population rather than OSPCA euthanasias.
While I don't have a lot of confidence in Newmarket OSPCA management at this point, it's hard to blame the them for euthanizing a lot of animals. It's a function of supply and demand, as well as limited capacity.
North America wide, the euthanasia rate for cats entering shelters is about 50%. That's a staggering number, but it's not usually the fault of the shelter system - it's because of the massive overpopulation of cats. When twice as many cats come in as there are available homes, something has to give. You can either build new shelters every year (obviously unrealistic), pack current shelters to the ceiling with cats crammed into crates in every corner (a perfect situation for a large outbreak and hardly fair to the cats) or euthanize many and focus efforts and resources on the most adoptable animals. As much as the "no-kill" concept has market appeal, it's completely unrealistic for cats at this time because of the simple fact that millions of new cats are born every year with no hopes for a home. A small shelter can run as a no-kill shelter, but that just means that they limit their admissions and/or don't accept cats with limited adoption potential. A large shelter like Newmarket that takes whatever cats arrive will euthanize many of them, even without an outbreak going on. In fact, to do things right, a large shelter has to euthanize lots of cats to allow them to properly care for and find homes for other cats. Sad but true.
So, while euthanasia is obviously undesirable and it gets people worked up, yelling at the OSPCA doesn't do anything. They're not going to stop euthanizing cats, because they can't. Efforts are better spent helping deliver care to stray animals and preventing the cat population from expanding.
One of the most important things anyone can do to help the problem is make sure to (as Bob Barker used to say) have your pet spayed or neutered (and pass the message along to those you know as well!).
'Tis the season for ringworm, I guess.
The Guelph Humane Society has closed to visitors, and adoptions have been suspended in response to concerns about the potential for a ringworm outbreak. Implementing a proactive response, all animals are being tested for ringworm and all cats are being treated. While the scope of the problem isn't yet clear (and hopefully it's minimal), this type of response is the optimal approach because waiting to "see what happens" and waiting for culture results (which can take a long time) before deciding to take aggressive measures results is a much greater chance of things getting out of hand.
In an outbreak like this, the first week or so is critical. Introduction of an animal that's carrying ringworm is hard to prevent, as is limited transmission within a shelter (even with good routine infection control practices) from that first case. That's the non-preventable component of shelter diseases. However, it's the 2nd generation of transmission (transmission of ringworm from that initial animal or group of animals to the broader population) that leads to things getting out of control. That's the preventable fraction of infections, on which we can have the biggest impact. It's during this early phase where intervention is critical It's always better to have an overly aggressive response and simply tone it down after a few days, than to have an inadequate response that lets things spiral out of control.
More information about ringworm can be found on the Worms & Germs Resources - Pets page.
The scope of the outbreak isn't really clear from press reports, but "a couple" of other animals now have signs of the skin disease. Investigation of the timing and likely sources of exposure of new cases is crucial. They may just be animals that were infected early, before the problem was recognized (the best case scenario) but investigating these "new" cases is very important because if these animals were exposed after the outbreak was identified, then there are problems with containment.
Shelter personnel have declared that they aren't planning on euthanizing more animals, but the shelter remains closed for adoptions. Stray animals will continue to be accepted. This creates a tricky situation where new animals (e.g. fuel for the fire, if things aren't under control) come in and can actually propagate the outbreak. It also creates overcrowding issues since the shelter was probably pretty full to start with, and continuing admissions with no adoptions can't be maintained for long. The shelter is looking at renting units in which to put animals - this is a relatively common approach for creating more contained spaces, and one that can be useful if good infection control practices are in place (although I've seen too many outbreaks where the offending pathogen quickly makes its way into the new units). Clear policies, sound training, careful supervision, exquisite planning and good communication are critical for making a situation like that work.
While the shelter has gone from an unrealistically optimistic time frame to a warning about long-term efforts, as with most things in life, the middle ground is usually the most accurate. Ringworm outbreaks can't be declared over in a few days (it's possible to contain it in a short period of time, but not declare an outbreak over). A few days isn't even enough time to get culture results back to figure out exactly what's happening. Testing, isolation, cohorting, mass treatment, evaluation of training, evaluation of infection control practices, and similar measures are needed, but if done right, an outbreak can be contained in a reasonably short period of time. Given the need to repeatedly treat all animals (affected animals are being bathed every three days with a medicated solution) and the time lag for ringworm culture, it's going to take at least a few weeks, but let's hope this outbreak ultimately gets measured in weeks rather than months.
The facility was closed to the public on August 4th because three cats and one dog were showing unspecified signs of ringworm.
Samples were collected for testing, but they decided to euthanize the 4 animals.
"You’re kind of under the gun to decide what you want to do,” said their operations manager. I can certainly empathize. It's not easy to deal with an outbreak. However, from my standpoint, if you feel like you're under the gun in that kind of situation, you're likely to make (or to have already made) mistakes. If you're managing the situation well, getting advice and following standard practices, you may be stressed, exhausted, humbled and concerned, but you shouldn't feel "under the gun." Maybe euthanasia was warranted here, but with a small number of infected animals, the ability to potentially isolate and treat them, and lots of information about how to manage ringworm to avoid further spread, it's important to avoid a panic response that leads to premature euthanasia decisions.
The three cats that were euthanized apparently did not have ringworm, but the shelter is "certain" (not sure how) that the dog had ringworm. Sudden onset of skin lesions in dogs and cats at the same time is certainly suggestive of ringworm, and if the dog was truly infected, it's hard to believe the cats were not (especially since cats are most often affected in ringworm outbreaks compared to dogs). So I wouldn't be too quick to rule out ringworm in the cats. Ringworm culture can take a couple of weeks, so it's not clear to me whether this interpretation is based on culture results or not.
"With the results being better than expected, the humane society will not have to move larger numbers of possibly infected animals to a different facility — the usual procedure in an outbreak." While I can't say too much from a distance, I can say that moving animals to another facility is certainly not a typical outbreak response measure. It's an effective outbreak propagation measure, since it can easily disseminate ringworm to other places, so it's good to hear that they are not planning on moving animals. It's much better to manage things well at one site than to have to manage things at multiple sites.
They state that "the situation now appears to be under control." Hopefully that's true, but it's way too early to say. You can't declare an outbreak over a few days after you declare that it started. There hasn't even been enough time for any animal or environmental ringworm culture results to come back. Closing, testing, treating all exposed animals and thorough cleaning and disinfecting of the environment can be a great start, but trying to say "we won" too early often leads to inadequate response and continuation of the outbreak.
"We’re keeping our fingers crossed and hoping that everything comes back negative so we can be open for business sometime next week" Again, I'm not involved and I'm working with sparse information, but this seems to be way too early to reopen the shelter. You need to make sure things are really under control before you get out of "outbreak mode" and before you can be "open for business" again. That's especially true with a disease like ringworm that is highly transmissible and can be spread to people. Too often, a small outbreak is identified and declared over prematurely, only to be followed by a big mess in short order. Let's hope that's not the case here.
Image: Photo of a dermatophyte-positive culture specimen, which can take two weeks or longer to grow.
A short distance down the road from here, the Kitchener-Waterloo Humane Society has been quarantined because of an apparent ringworm outbreak. There's no information on the facility's website and information in the press has been pretty vague (both concerning aspects), but it sounds like a ringworm outbreak. Adoptions have been ceased and the Humane Society will apparently "reassess its safety protocols by the end of the week." The outbreak appears to have been going on since at least last week, so hopefully they're getting on this and have a strong outbreak investigation and control plan in place.
I haven't been involved in this outbreak so I know nothing more than what is in the press, but ringworm can be a big problem in shelters. It's a controllable disease, but the situation can get completely screwed up with a poor outbreak response. It's also sometimes an overblown problem (or not a true problem at all) in some situations, so it's critical that the outbreak is properly investigated and managed. That's not always the case, and the consequences can be serious.
There are a lot of factors that go into good outbreak management that are hopefully being done at the KW Humane Society. These include:
- Good communication both internally and externally.
- Sound containment practices.
- Getting good advice.
- Actually listening to the good advice (and not bad advice).
- Taking the time to do it right.
- Ensuring one is acting on correct information.
- Spending money where it needs to be spent, be it testing, treatment, personnel or other factors. Trying to save money during an outbreak response often ends up costing much more in the end.
The independent report of the 2010 ringworm debacle at the Newmarket OSPCA should be important reading for any shelter trying to figure out what to do, and what not to do.
The outbreak stretched over a long period of time, from 2007-2009, and involved a strain of Salmonella called Salmonella Java. During the course of the investigation, 75 people with S. Java infection were identified, although there were probably many more infected since diagnosed cases are usually the minority of the true total.
Individuals affected ranged in age from 1 month to 60 years, but the median age was only 2 years, which means the majority were very young children. The investigation started to focus on playgrounds and ultimately 207 sand samples were collected from 39 locations. Thirty-five isolates of S. Java were found, all from 6 playgrounds. These playgrounds had all received sand from the same depot over the preceding year, but Salmonella wasn't found in samples from the depot.
To try to find a source, they started testing critters living in the area of parks, and found S. Java in 34 of 261 animals, mainly from long-nosed bandicoots (a marsupial indigenous to Australia).
It's possible that this Salmonella strain is widely present in bandicoots (and other critters) in the area. I don't know their defecation habits, but if they have a preference for pooping in sandboxes (like cats do), they could be contaminating play areas. The other possibility is that the sand was contaminated from some other source and the bandicoots were infected from the sand just like the people. There's not really any easy way to figure that out.
Sandboxes have been associated with various disease outbreaks, but the overall risk is low and it's certainly not a reason to keep kids away from them. Some things that can be done to reduce the risk of potential disease transmission from things in the sand include:
- Supervising kids to prevent them from sticking things in their mouths.
- Making sure they don't eat or drink in the sandbox/playground.
- Making sure they wash their hands after playing in the sand.
- Covering the sandbox whenever it's feasible (not always an option but good if it can be done) to help prevent animals from defecating in the sand.
More information about sandboxes and potential disease risks can be found on the Worms & Germs Resources - Pets page.
Image: Long-nosed bandicoot from Eastern Australia (Perameles nasuta)(click image for source)
Q-fever, a serious disease caused by the bacterium Coxiella burnetii, is an important concern at petting zoos because small ruminants (sheep and goats) are commonly present at these events and they are the major source of this pathogen. The risk is greatest around adult animal at the time of birthing, and around the new lambs and kids (baby goats), because this is when large numbers of highly infectious Coxiella can be shed. That’s one of the reasons why pregnant small ruminants shouldn’t be part of any petting zoo, but unfortunately this particular recommendation is widely disregarded.
Other than petting zoos, the general public can also have contact with small ruminants through various other routes. An outbreak of Q-fever in the Netherlands (a country with serious Q-fever problems) was reported in association with one of these atypical events, namely "lamb viewing days" on a farm (Whelan et al, Epi Infect 2012).
This farm was open to the public every year during lambing season, and attracted about 12000 visitors from the area annually. Visitors could watch lambs being born (if the timing was right) and interact with young lambs. After finding a cluster of Q-fever cases in the region, an investigation ensued, which compared people who were diagnosed with Q-fever in the region to a group of people without Q-fever. Here are some of the highlights:
- 21% of people with Q-fever reported visiting the farm compared to just 1% of controls.
- When various other factors were controlled in the analysis, having visited the farm meant someone was 43.3 times as likely to have Q-fever compared to someone who didn’t visit the farm.
- Coxiella burnetii was identified in numerous sheep, as well as from 7 of 8 air samples collected on the farm. (Coxiella is a very small, hardy organism that can resist drying, and it can therefore often be found in the dust in the air in areas that have a lot of environmental contamination, like pens where goats and sheep give birth.)
- Specific contacts (e.g. holding a lamb, witnessing a birth) were not identified as risk factors, but the small sample size of people that reported what types of contact they had may have limited the ability to detect a difference.
Visiting farms and having contact with farm animals shouldn’t necessarily be considered a high-risk behaviour. In fact, in some ways it’s a good thing. Greater contact between people and animals and a better understanding of farm animals can be very beneficial. However, we’ve known for a long time that some situations pose an increased and unnecessarily high risk. People organizing farm encounters or petting zoos need to take some basic precautions to reduce the risk to visitors. These are pretty simple and can be done without significantly affecting the visitors' experience. Visitors also need to take some responsibility themselves and follow recommendations, like practicing good hand hygiene and keeping food and drink out of animal areas (just to name a couple). Additionally, the more visitors know about risks and preventive measures, the more they can pressure facilities into doing things right. Public health personnel can work hard to try to improve petting zoos and other events, but nothing will change things quicker than an informed public withholding their money from places that put them at unnecessary risk.
It's not the first, and it's a safe bet it's not the last, but a lawsuit has been filed against Diamond Pet Foods in response to a case of salmonellosis in a New Jersey infant. The lawsuit claims (probably correctly) that the infant acquired Salmonella from contaminated dog food that was in the household. The infant was hospitalized for three days but recovered. The lawsuit, one of at least eight that have been filed, claims negligence and fraudulent representation, and is seeking over $75000 in compensation.
In reality, it's hard to consider a company liable simply for Salmonella contamination. Various practices can be used to reduce the risk and to detect contamination when it occurs, but these will never be 100% effective. Standard hygiene practices that are recommended to reduce the risk of exposing people (especially high risk people) to any pathogens that might be found in pet food must therefore always be used. It's hard to say what degree of responsibility needs to be placed on consumers versus companies, since companies need to do their best and people need to use common sense.
From my completely non-legal standpoint, the issues of negligence and liability come in when:
- A company has inadequate facilities that do not conform to standard requirements to reduce the risk of contamination (e.g. duct tape and cardboard in food processing equipment, as per the FDA report).
- A company has an inadequate quality control program.
- A company knows there's a problem and doesn't take prompt and appropriate action to correct it.
Based on what information has been released (including the relatively damning FDA report that cited lack of microbial analysis of certain ingredients, lack of hand hygiene facilities and the use of duct tape, cardboard and other non-cleanable materials in the plant) combined with some questionable communications strategies, it certainly seems like a case can be made here.
While I guess it's getting beyond the point where Hendra virus infections in horses in Queensland, Australia are considered "news," it's still a highly concerning situation. Infections caused by this fruit bat-associated virus continue to occur in the region and there's no sign that this problem is going to go away any time soon.
In the latest report, two horses from a farm where a horse recently died of Hendra tested positive for the virus. In another location, a dog is being re-tested after a weak positive test. This situation brings back memories of the debate that occurred last year after a healthy dog that tested positive was euthanized as a precautionary measure, despite no information about whether the dog could actually be a source of infection.
Hendra is resulting in profound changes in the horse industry in Queensland. Beyond being a major problem in horses, this virus can be passed from horses to people, resulting is tremendous concerns amongst horse owners and veterinarians. Many veterinarians are refusing to work with horses because of the risk and I assume that some people are selling horses for similar reasons.
Infection control practices can presumably reduce the risk of transmission of Hendra virus between horses and from horses to people, but there's no way to completely eliminate the risk. Fruit bat control strategies get discussed, ranging from removal of fruit trees from horse pasture to reduce fruit bat exposure (logical) to fruit bat culls (highly unlikely to have any longterm effect). At a minimum areas under fruit trees should be fenced off from horses, and it has also been recommended to keep water troughs covered to prevent contamination with excrement from the flying foxes. Ultimately, everyone's holding out for an effective vaccine, which has yet to appear, but work on the vaccine is well underway and the hope is that a commercial vaccine could be released as early as next year.
The title from Food Safety News' latest report says it all: "After eight expansions, how big is the Diamond Pet Foods Recall?" It's disturbing that we can't answer that question, considering the contamination stretches back to 2011 and now it's apparent that there are problems with another one of their plants.
Accordingly to Food Safety News, the FDA has indicated Salmonella contamination has been found in Diamond's Meta, Missouri plant, in addition to the South Carolina plant that's been at the heart of the recall. However, the Missouri Salmonella contamination is from Salmonella Liverpool, a different strain from the South Carolina plant where Salmonella Infantis has been involved. So, there's no evidence that the two recalls are linked, although you have to wonder whether deficiencies that were found by the FDA at the South Carolina plant might also be present at other plants, thus creating an increased risk of Salmonella contamination.
Anecdotal information about sick animals and people associated with this recall abounds, in stark contrast to information from Diamond Pet Foods. It would be nice to have some clear communication from the company about this outbreak, and some information about what they are doing to control it and prevent it from happening again. The continued expansion of the recall and contamination is concerning, and in the absence of clear communication from the company it's hard to have confidence in the safety of any more of their products.
There have been various news reports from different parts of North America describing distemper outbreak in raccoons. Distemper is a viral infection caused by canine distemper virus, which is related to the human measles virus (but the canine version can't infect people). A variety of animal species in addition to dogs can get distemper, most notably raccoons.
Distemper outbreaks are not uncommon in raccoons, and one big problem with distemper is that the neurological signs cannot be distinguished from rabies. Yes, there may be some general trends in how a raccoon with distemper behaves that differ from one with rabies, but it’s far from definitive. That creates issues because distemper is of absolutely no human health concern while rabies can be transmitted to humans and is almost invariably fatal.
A Windsor-Essex (Ontario) outbreak of distemper in raccoons highlights some of these issues and the care that must be taken with regard to public communications.
Authorities are “urging the Windsor-Essex public not to worry about a rising number of incidents with strange-acting raccoons: The poor scavengers are suffering from distemper, not rabies.”
- This is bad communication in my opinion. I’d rather see something like authorities are "urging the public the avoid raccoons because of the risk of rabies exposure, but to be aware that a raccoon that is behaving abnormally probably has distemper, not rabies." Telling people not to worry is okay, but making it seem like there's no issue whatsoever is another. No one can say for sure that all of these affected raccoons have distemper, not rabies.
A good statement appears later in the article ”(Executive Director of the Windsor-Essex County Humane Society Melanie) Coulter stressed that although the disease is highly contagious among animals, it can't be passed to humans. But she added that raccoons with distemper are still capable of sudden aggression, especially if they feel cornered. As well, the symptoms of distemper are similar to those associated with rabies -- and the difference can't be determined without lab testing.”
- That’s much better. It highlights the problem and explains that it’s probably not a risk to people, but also makes it clear that you can’t be sure it’s not rabies.
The key thing is avoiding contact with raccoons all of the time, with particular attention to raccoons that are acting abnormally, since they are more likely to have rabies and they can be unpredictable. Some other things to consider:
- Don’t keep raccoons as pets (common but illegal, at least here).
- Don’t encourage raccoons to live around your home.
- Keep pets away from wildlife.
- Ensure dogs (and cats) are vaccinated against rabies and distemper, in case they have an unexpected incident with a raccoon.
I'm getting a lot of questions now about canine aspects of this recall, so I've addressed my take on some of the important issues below.
Can Salmonella cause disease in dogs?
Absolutely. The common myth about dogs being immune to Salmonella (mainly found on raw food sites) is just that: a myth. Dogs can and do get Salmonella infections, and it can make them sick.
Are dogs getting sick because of the recalled food?
I don't know but I suspect they are. There's no reason to think that the strain of Salmonella involved here would infect people but not dogs. The reason that there are reports of human but not canine cases could simply be because there is a formal surveillance and reporting system for humans but not dogs. Also, testing is not commonly performed on dogs with diarrhea, so large numbers of cases could go unidentified.
What would a sick dog look like?
The most common presentation of salmonellosis in dogs is diarrhea. Vomiting, lethargy and lack of appetite may also be present. Diarrhea can range from mild to severe and bloody. Chronic diarrhea can also develop but is less common. Other types of infections such as bloodstream infections can occur, with or without diarrhea, but these are pretty rare.
How do I know if my dog has salmonellosis?
The only was to know is to try to detect the Salmonella bacterium. This usually involves testing of stool samples. Culture is the standard and preferred approach, and is best done by a lab experienced with Salmonella testing and one where selective culture methods will be used. PCR, a type of molecular test, can also be used to detect Salmonella DNA. The quality of these tests (and the labs that offer them) is quite variable, but some of these tests are quite good. The downside is that all you find out with PCR testing is whether Salmonella is present or not. With culture, the bacterium can be tested further to see if it is the outbreak strain, and it can be tested for its susceptibility to antibiotics in the uncommon event that antibiotic treatment is needed.
My dog is healthy but has been fed recalled food. Should he/she be tested?
I don't recommend that. I only want to do a diagnostic test if I have a clear plan regarding how to use the results, which wouldn't be the case is a situation like this. If the dog was positive for Salmonella, I wouldn't do anything special except remind you to avoid contact with its poop (which you should be doing anyway). We don't treat Salmonella carriers - dogs that are healthy and shedding Salmonella will eliminate it on their own, usually within a couple weeks. A negative result also doesn't guarantee that the dog is truly negative. Usually we want multiple negative cultures to rule out Salmonella since it can be shed intermittently and can be hard to detect.
My dog is healthy but has been fed recalled food. Should he/she be treated with antibiotics?
NO. That's the last thing I want to do. Antibiotics are not very effective (or effective at all) at eliminating Salmonella that's living in the intestinal tract. A healthy animal shedding Salmonella is an indication that the body is handling it. It doesn't mean that disease won't occur, but one critical aspect for preventing intestinal infections is the protective effect of the gut microbiota - the trillions of bacteria that are in the gut helping suppress "bad" bugs like Salmonella. My concern with prophylactic treatment is that we might make things worse by suppressing this protective bacterial population and letting Salmonella overgrow in a situation where it otherwise would not have been an issue.
Why the fuss?
VS is a viral infection that can affect a range of animals species. In addition to horses, it can infect cattle, pigs and sheep (and a few others). It produces painful blisters in the mouth and other areas that can result in decreased eating and drinking, lameness, severe weight loss and secondary infections. In food animals, it can cause severe economic losses. Another issue is that in cattle and sheep, it looks like the dreaded food and mouth disease. Lab tests can distinguish the two, but there can be a lot of angst when sorting out what causes vesicular diseases in cattle.
VS is a reportable disease in Canada and was last identified in the country in 1949. Import restrictions are a routine measure in response to the periodic US cases that occur.
In this case, the following restrictions have been implemented:
- Horses cannot be imported from New Mexico.
- Canadian horses that are in New Mexico must either get an import permit and supplemental USDA health certificate, or must be moved to another state for at least 21 days prior to returning to Canada. The supplemental certification indicates they've been evaluated by a veterinarian, have not been on a farm where VS was present over the past 60 days, and have a negative VS blood test. Horses that are moved to another state require a USDA certificate indicating that they've lived in that state for at least 21 days. (This may be complicated by restrictions implemented by other states on accepting horses from New Mexico.)
- All other horses coming from the US must be certified by the USDA as not having been in New Mexico in the past 21 days.
Image: Ulcers on the tongue of a horse infected by vesicular stomatitis (VS) virus. Image source: Colorado State University Extension
After starting off like a simple recall of potentially Salmonella-contaminated dry pet food, the Diamond Pet Food problem has now expanded into a multistate outbreak of salmonellosis in humans linked to exposure to the contaminated pet food. At last count, there were 14 affected people from 9 US states, including 5 who required hospitalization. These numbers could increase since so far they only include people who got sick up to April 1 (because it takes time for Salmonella to be grown in the lab, sent to CDC for testing and the result investigated, later cases may not have been reported yet).
This outbreak involves Salmonella Infantis, a strain that is uncommonly identified in people. Finding an increased number of infections caused by an unusual strain makes it easier to identify an outbreak, as was presumably the case here. This strain has also been isolated from various types of pet food that were produced at the Diamond Pet Foods' South Carolina plant. Despite the name, this strain of Salmonella is not more likely to infect infants, and people ranging from less than 1 year to 82 years of age have been infected.
Details about the types of contact people had with the pet food are limited. 70% of infected people reported having contact with a dog the week before getting sick. How the other 30% could have been exposed is unclear. Sometimes peoples' recall is poor, especially if they had transient contact with a pet. Individuals could have been exposed from environmental contamination when visiting a household where contaminated pet food was fed, without having direct contact with a pet. It's also possible some cases are not directly related to the outbreak and co-incidentally were exposed to the same strain from some other source.
Since we see periodic outbreaks associated with dry pet food, does that mean that other types of pet food are safer? Not really. Canned food is ultimately the safest because of the heat processing, but it's not practical for all animals.
Typically, after a report like this, I get a barrage of emails from people saying "See... we don't have large outbreaks from raw food diets so they are safer." Unfortunately, that's not the case. High pressure pasteurization (HPP) of raw food, a process that uses pressure with minimal heat to kill bacteria, is an effective method for reducing contamination of such products with harmful pathogens like Salmonella, and HPP is now being used by a couple of companies. These raw diets should be quite safe from a Salmonella standpoint. Otherwise, the risk of Salmonella contamination of raw pet foods is still very high, and if anything, the dry food outbreaks show how people can be infected from contaminated pet food.
Why don't we see large outbreaks associated with raw food? Outbreaks get detected because certain patterns or unusual findings are identified. Raw pet food associated outbreaks probably occur but are not as readily identifiable since raw meat contamination is common but involves variable Salmonella types that regularly change. In a situation like that, you can potentially have lots of people getting Salmonella from raw food, but if there is limited commonality in strains and products, it doesn't get picked up as an outbreak. That's particularly true when the strains that are involved are the common ones found in food, since they would often be dismissed on the premise that the person likely got it from some unknown food source. Without large numbers of cases in an area or a cluster of unusual strains, the investigation wouldn't likely get very far and nothing would be reported.
How do reduce the risk of getting Salmonella from pet food (or your pet)?
- Don't feed pets in the kitchen. This practice has been associated with an increased risk of disease in a previous outbreak of salmonellosis in children.
- Wash your hands after handling pet food.
- Don't let young children have contact with pet food.
- Use common sense when handling pet feces.
More information about both Salmonella and issues pertaining to raw diets (including how to reduce the risk) can be found on the Worms & Germs Resources - Pets page.
Botulism has been in the news lately, with numerous outbreaks involving different species and some human food recalls. Botulism outbreaks are often pretty dramatic because of the number of individuals that can be involved, the severity of disease and the fact that it's often difficult to do much beyond damage control once the problem is recognized. Recently, there have been reports of widespread duck deaths along with a couple of different recalls and warnings in Ontario about potentially contaminated smoked salmon and improperly eviscerated salted fish.
On the equine front, there's also been a large botulism outbreak that is believed to have killed 23 horses in Maine (USA). The outbreak occurred over the last month and, as is typical, has been devastating because of the profound susceptibility of horses to botulinum toxin and the inability to do much to save the animals once it was realized that botulism was present.
In adult horses, botulism is caused by ingestion of food that's been contaminated with toxins produced by the bacterium Clostridium botulinum, as it grows. This relatively widespread bacterium doesn't normally grow and produce toxins in horse feed since it requires an oxygen-free environment and other specific conditions, but when these occur, the incredibly potent neurotoxin can be produced. Equine outbreaks are often associated with haylage or silage (which if improperly fermented allow for C. bolulinum to grow) or contamination of round bales (e.g. an smaller animal that died of botulism gets accidentally incorporated into the bale, where the toxins can persist and/or the bacterium can grow if the right environment is present deep within the bale). In this outbreak, silage is suspected to be the cause. The silage is being tested to confirm this suspicion.
You can never 100% prevent botulism, since strange sources are sometimes found, but avoiding high risk feeds (e.g. silage, haylage, moldy round bales), trying to ensure that dead animals do not get caught up in hay bales during the baling process and taking exceptional care when baling if botulism is present in wildlife in the area can help greatly. A vaccine is available but it only protects against certain types of botulism. If those types are the main types that cause disease in a given area, vaccination can be useful, but good feeding practices are the most important preventive measure.
Image: Horses at a round bale feeder (source: www.omafra.gov.on.ca)
The CDC is investigating CDC is investigating more cases of salmonellosis associated with feeder rodent contact, caused by the less-than-catchy-named Salmonella I 4,,12:i:-. This strain is the same one that was implicated in a large and prolonged outbreak in the US and UK in 2009-2010 which was also associated with frozen feeder rodents (rodents sold frozen as reptile food) from a single US supplier. The current outbreak has affected people in 22 US states from August 2011-February 2012, and involvement of the same strain from the same source certainly leads to suspicion that this is actually an ongoing problem.
In the latest outbreak:
- 46 people have become sick. As is common, kids have borne the brunt of this outbreak, with the median age of affected persons being 11 years.
- 37% of affected people were kids five years of age or younger. Since this outbreak involved feeder rodents, clearly people aren’t heeding the guidelines that kids of that age shouldn’t be in households with reptiles.
- No two affected people reported buying rodents from the same store. This shows how widespread the problem is and that it must be originating from the place where the rodents are bred and/or distributed, not a focal pet store issue.
Record-keeping at the pet stores complicated figuring out the source. However, two breeders that supplied pet stores received mice from the company that was the source of the 2009-2010 outbreak. This suggests that not only were people exposed from frozen feeder rodents in the earlier outbreak, but that breeding colonies in different areas were infected from that source. This may have allowed wide dissemination of this Salmonella strain into numerous rodent breeding colonies, creating many possible sources of exposure for members of the public purchasing feeder rodents. The large-scale commercial nature of rodent breeding and wide distribution network creates a great opportunity for widespread outbreaks, as is apparent here and with various other outbreaks (including salmonellosis outbreaks from guinea pigs and baby poultry).
If you are going to buy feeder rodents:
- Treat them as if they are carrying Salmonella, because they just might be.
- Keep them away from human food. Keep them in a separate freezer or fridge, or in a sealed container if they have to be in the same fridge as human food.
- Don't handle them in the kitchen.
- Wash your hands thoroughly after handling.
- Keep them away from young children, as well as people with compromised immune systems, elderly individuals and pregnant women. None of these groups should have contact with reptiles either.
Image: A package of frozen rats, as sold commercially for feeding reptiles.
It's amazing how one little email comment can make a mess of my week.
Here's the story: I sent an email to a colleague that works for an agency in Ontario. At the bottom of the email, I gave an FYI about an Ontario dog that was found to have antibodies against canine flu, but that wasn't sick. At the time, I didn't realize that my colleague was no longer at the aforementioned agency.
- Astoundingly, instead of cancelling my colleague's email account, the agency had left the account active - and the CEO of the agency reads her emails!
- In this case, not only does the CEO read the email, she forwards it to other people in the agency.
- Not only do the others read it, they create a release that they send out to associates of their agency throughout the province and some other groups... without contacting me to get details, understand the full story or get permission to use the information I provided. Not exactly a good communications strategy.
In an amazingly short period of time, I was contacted by two provincial Ministries about Ontario's canine flu status, since incomplete information was forwarded to them, and veterinary clinics in the province are now asking questions about our "canine flu case" or "canine flu outbreak."
So, to set the record straight (and decrease the number of phone calls I'm getting today):
- We found a dog that had antibodies against canine influenza as part of an outbreak investigation. The outbreak was not caused by canine flu.
- The dog had the same antibody level on two blood samples taken two weeks apart. This is not consistent with disease caused by flu. Rather, it indicates that the dog has been exposed to the virus.
- The fact that the dog has been exposed to the virus is noteworthy. The only other seropositive (i.e. antibody positive) dog that we have seen in Ontario was a greyhound from Florida, and we assumed it was infected in Florida. That was a few years ago, and we haven't seen anything since. Initial information indicates that this dog has not left the province, but I'm working to confirm that before I can be confident that this is evidence that canine flu is present in Ontario.
This is an important topic because if/when canine flu hits a region, it certainly has the potential to cause big outbreaks. The outbreak at a Texas racing facility that I wrote about yesterday is a good example of the bad things that can happen when flu hits a susceptible population. Knowing if the virus is in the area is important for things like vaccination programs and making recommendations for management of respiratory disease cases in veterinary clinics and in the community.
We currently have no evidence of canine flu activity in Ontario, but we are actively looking because we assume that it will make it here sometime, if it's not here now. Identifying it early and communicating that properly are critical control measures for canine flu and other emerging infectious diseases, but there's nothing to worry about at the moment.
As canine influenza continues it's rather gradual, patchwork movement across North America, an outbreak at a greyhound racetrack southeast of Houston highlights some of the concerns about this virus. Canine influenza has been active in the Houston region for some time, causing sporadic infections as well as outbreaks in pet dogs in the community and in veterinary clinics.
Greyhound tracks are a great place for influenza transmission because they have a lot of dogs in close quarters, and racetrack outbreaks can be large and severe. In this outbreak, approximately 100 dogs have been affected so far, with six deaths. It sounds like there are 600-700 dogs on the track, and given how transmissible the virus is, unless they have very tight infection control practices in place to separate groups of dogs (unlikely), it's reasonable to assume that many more dogs will be infected, or have already been infected but weren't recognized because they had mild disease. The ~6% mortality rate is not surprising, as dogs can die from severe influenza or because of bacterial pneumonia that develops afterwards. Higher death rates are talked about, and were features of the early reports of canine flu in Florida, but this lower rate seems to be more typical.
Local Humane Society personnel are rightly warning pet owners to be on the lookout for canine flu. Public awareness is critical, although I'd argue with some of their advice:
"The only protection is the dog flu vaccine."
- Not really. It's part of the infection prevention plan but not the only thing. Vaccination is an effective way to reduce the incidence or severity of disease, but it's not 100%. Vaccination should be considered the last line of defense that comes into play when efforts to avoid the virus have failed. If the dog doesn't get exposed to canine flu, it won't get influenza, regardless of vaccination status. Dog owners need to be aware of high-risk situations and avoid contact with dogs that are or have recently been sick. That being said, in an area where canine flu is active, vaccination is a good idea, since you can never completely guarantee your dog won't be exposed to the virus if it's exposed to other dogs.
"Dog owners were warned if they noticed any flu-like symptoms in their dog to take them to a vet immediately for antibiotics and the vaccine and not to take their dog to the park or doggie daycare."
- I agree with the last part. If your dog is sick, keep it away from areas where other dogs mingle while it's sick and for about 10 days after it gets better. So, if that's the case, why take all potentially sick animals into the vet right away? It might just result in exposure of other dogs to the virus. If you have influenza and you're not very sick or at high risk for complications, the recommendation isn't to immediately go to the doctor. It's to rest and stay away from other people. The same applies for dogs.
- Calling a veterinarian to see whether the dog should be examined makes sense. This also helps ensure that if the dog does go to the clinic, it can be handled properly. By that, I mean instead of showing up, checking in at the front desk and lingering in the waiting room with other dogs for a while, a dog with suspected flu should be admitted directly into isolation or an exam room. This can be done by calling the front desk on arrival or by checking in without the dog, so that the dog can be taken directly to a contained area to avoid other dogs.
- Antibiotics are rarely needed. Antibiotics don't kill influenza virus, so they are indicated only if there is evidence (or very high risk) of secondary bacterial disease, which doesn't happen in most cases. We don't want every coughing dog on antibiotics, since few need them.
As we've discussed previously, rabies has been a big problem in Bali since 2008. Previously rabies-free, this densely populated island has been struggling with a large and persistent canine rabies outbreak that has resulted in numerous deaths and much debate about control measures.
- Dog bites are very common on the island, with a daily average of nearly 100 bites reported over the study period. Since many bites don't get reported, even this large number is an underestimate.
- The average age of affected people was 36 years, with a range of 3-84 years. All 104 died.
- Most of the cases (57%) were male. This is common, although whether it is because men are more likely to be bitten (because of greater exposure or greater provocation) or less likely to seek medical care after a bite is not known.
- There was a history of a dog bite in 96/104 infected people. It's likely a bite occurred for the others as well, but in those cases the patient was unconscious at the time rabies was suspected and family members did not know of any bites.
- The incubation period ranged from 12 day to 2 years. It was less than 1 year in 98% of cases. Very short incubation periods, like the 12 day one reported here, are almost always associated with bites to the head or neck, since it's a shorter distance for the virus to travel up nerves to the brain.
- Early signs of disease are often vague. Pain or numbness at the location of the bite (37%), nausea or vomiting (30%), fever (22%), aches (17%), headache (16%) and insomnia (7%) were most common.
- 81% of people that developed rabies did not undergo any type of treatment. 11% washed the wound themselves. Only 6% went to the hospital on the day of the bite. The people who went to the hospital received a course of rabies vaccines but did not receive rabies immunoglobulin (RIG, which is anti-rabies antibodies). So, while they were treated, they didn't get the full recommended treatment. This is incredibly frustrating since rabies is almost 100% preventable if people get proper medical care. Failure of most of these cases to even seek care is a huge issue, and inadequate treatment of people who sought medical care compounds the problem. Not all of the vaccinated people completed the full vaccine course before developing signs of rabies. These were individuals who had short incubation periods because of bites to the head and neck.
These results are not surprising but demonstrate a few important concepts, including:
- the need for education of the general public to seek medical care after a bite.
- the need for proper education of healthcare providers so that people who are bitten get proper medical care.
- the need for adequate supplies of rabies vaccine and immunoglobulin. It wasn't stated whether people didn't receive RIG because it wasn't offered or (as is common in some regions) it wasn't available.
- rabies may not be considered initially when signs first start appearing, as many of these people ended up being treated for various other potential problems before rabies was considered. While rabies is almost always fatal, there have been very few "successfully" treated individuals (meaning they didn't die, but they can still have long-term neurological impairment), but to have any chance at success, treatment needs to be administered as quickly as possible.
- control of canine rabies is a key part of controlling human rabies.
The CDC has announced an investigation of three multistate outbreaks of salmonellosis linked to pet turtles. At last report, 66 affected people had been identified, and since most outbreaks like this only identify a minority of cases, it's safe to assume there are many others.
- Three different types of Salmonella have been implicated; S. Sandiego, S. Pomona and S. Poona.
- Infected people have been identified in 16 US states (see map).
- 11 people have been hospitalized, but no one has died.
- Most cases (55%) have involved children under the age of 10.
- Almost all infected individuals who provided information about turtle contact with said the turtles were less than 4 inches long.
This ongoing outbreak, dating back to September 2011, has all the hallmarks of a pet turtle-associated outbreak: a large number of cases over a wide area and prolonged period of time, a predilection for young children, and the potential for severe disease. While far from novel, this outbreak also highlights some recurring themes.
The potential for widespread outbreaks from mass production and distribution of pets has been repeatedly demonstrated with a range of diseases, including recent examples involving chicks and guinea pigs. That doesn't mean that mass production is necessarily higher risk (although it certainly can be), but when something goes wrong, it can go very wrong because of the large number of infectious animals that get sent out.
Sale of turtles with shell lengths under 4 inches has been banned in the US since 1975. This is because small turtles are more likely to be handled (and potentially put in the mouth) by young kids. Despite extensive lobbying by US turtle breeders, the law remains in effect, but it's widely flaunted. It's surprising more efforts aren't put into enforcing this regulation given the number of people who are sickened every year from contraband turtles. (It's also surprising that infected people in the US haven't started large lawsuits against people distributing small turtles.)
Anyway, this is yet another reminder about the risks associated with reptiles and high risk individuals (i.e. young children, elderly, pregnant, immunocompromised) and the need for pet turtle owners to follow basic hygiene and infection control practices. More information about turtles - for owners, veterinarians and healthcare professionals - can be found on the Worms & Germs Resources page.
An outbreak of strangles (Streptococcus equi infection) has led to cancellation of the racing program at Saratoga Raceway in New York State. In a ripple effect, other racetracks in the region have taken measures to protect their horses, including banning horses from Saratoga, banning horses from surrounding tracks, not allowing horses that leave the grounds to come back and/or requiring that horses have a health certificate before entering the grounds.
As with most outbreaks, details are sketchy, including information about the number of exposed horses and specific outbreak response measures. Strangles is a highly infectious disease but it's also one that we know a lot about, and one for which containment of an outbreak is certainly possible with good infection control practices, screening to find carriers and a big dose of patience. Unfortunately, the latter is often the limiting factor, especially when money is on the line. The fact that Saratoga has initiated a quarantine and other tracks are taking precautionary measures is a good sign. Not long ago, most of these situations were met with silence and the hope that concealing the problem would make it go away (not usually an effective approach). We've come a long way in both our knowledge of strangles control and the industry's willingness to take control, so hopefully Saratoga (including officials and horsemen) is taking a good, evidence-based and patient approach to this outbreak.
At this time of year, I start to see ads from local feed supply stores about annual chick sales. Overall, it's not a big deal and most people that buy chicks don't have problems. However, it can be a particular concern for certain high risk groups, particularly young children, and outbreaks of salmonellosis are a recurring issue.
Contact with young poultry is considered very high risk for Salmonella exposure, since Salmonella shedding rates amongst the little guys are pretty high. Most outbreaks of salmonellosis disproportionately involve young kids, due to a combination of increased handling, poor hygiene and inherent increased susceptibility of young kids to infection. The problem is that sometimes people buy chicks because their young kids want to raise and handle them. Outbreaks associated with sales of young chicks, as well as hatching chicks in schools and daycare, have been reported.
A recent CDC report describes yet another multistate outbreak of Salmonella, this time associated with a mail-order hatchery.
The outbreak occurred from February to October 2011 and was first noticed through lab-based identification of clusters of Salmonella Altona and Salmonella Johannesburg. Ultimately, 68 cases of S. Altona and 28 of S. Johannesburg infection were identified in 24 states. Here are some highlights:
- 32% of people with S. Altona and 75% with S. Johannesburg were kids 5 years of age or younger.
- 74% of people with S. Altona and 71% of people with S. Johnannesburg reported recent contact with young poultry.
- Most people that had poultry contact reported purchasing chicks or ducklings at local agricultural feed stores. These stores got the chicks and ducklings from a single mail-order hatchery.
Mass production of animals for widespread distribution, whether it's guinea pigs like I wrote about the other day, or chicks and ducklings here, increases the risk of widespread outbreaks because a single focus of infection can have far-reaching effects.
Mass production and mail-ordering of chicks isn't likely to stop, so what can people do to reduce the risk?
- Keep high-risk people (that is kids 5 years of age or less, elderly individuals, pregnant women and people with compromised immune systems) away from young poultry. This includes keeping chicks out of schools, where hatching chicks is still performed in some areas.
- Use good hygiene practices when handling chicks or anything in their environment. Assume that all of the chicks are shedding Salmonella and treat them accordingly. By that I mean use good general hygiene practices, particularly hand hygiene, to reduce the risk of exposure.
- Stores selling chicks should also provide basic safety information to inform and remind people to use appropriate practices to reduce the risk of infection.
Guinea pigs are relatively benign pets in terms of zoonotic diseases, but like any animal, they can carry some pathogens that are transmissible to people. This was highlighted in a poster presentation at the recent International Conference on Emerging Infectious Diseases in Atlanta. The poster (Bartholomew et al) described a CDC investigation into an outbreak of Salmonella Enteritidis infections in people in multiple states in 2010.
Here are some highlights:
- The first affected person was a child who purchased a guinea pig from a pet store. The animal looked "frail" and was housed with the child's existing guinea pig. Later that month, both guinea pigs developed diarrhea and died. Shortly thereafter, the child developed diarrhea, fever, cough, chest and back pain, a rash and some other signs. Ultimately, a Salmonella infection of the sternum was diagnosed, indicating that Salmonella had traveled from the intestinal tract to the child's bloodstream and set up an infection in the breast bone.
- The CDC investigation focused on other people who had been diagnosed with the same strain of S. Enteritidis. They identified 10 such cases who also reported guinea pig exposure, scattered over 8 US states.
- The same Salmonella strain was also identified in guinea pigs, including one from a Texas guinea pig broker, around the same time as these cases were occurring.
- Most of the affected individuals were children. Three had purchased guinea pigs from the same pet store chain as the first child. Three other affected people were employees of stores from that pet store chain.
- Testing of the environment in pet stores from that chain did not identify Salmonella. However, since sampling was done well after people got infected, it doesn't mean it wasn't there earlier.
- No common guinea pig source supplier was found, but one Pennsylvania breeder was identified as a possible source for the cases associated with that pet store chain.
This is pretty strong evidence that the infections were guinea pig-associated.
Some take-home messages:
- Any animal can be a source of potential infection, and general hygiene practices should be used all the time to reduce exposure to pet feces.
- Sick animals might mean the potential for sick people. While it's sometimes tough to convince people that testing dead animals (especially dead animals that don't cost much) is useful, it might have had a great impact on the care of the first child. If physicians knew that the child was exposed to Salmonella, they might have been able to make the diagnosis much quicker.
- Pet stores are not uncommonly implicated as sources of outbreaks, and there are also risks to their staff. Pet stores need to have good infection control, hygiene and disease reporting practices.
- The nature of pet rodent distribution, with large breeders sending animals to brokers where large numbers of animals get mixed and sent on to pet stores, creates the potential for widespread disease transmission, as has been repeatedly shown in the past.
Kennel cough, also (and more properly) referred to as canine infectious respiratory disease complex (CIRDC), has been in the news lately. This condition is a syndrome, not a specific disease, being potentially caused by a range of bacteria, viruses and Mycoplasma, including canine parainfluenza virus, canine influenza virus, canine respiratory herpesvirus, canine adenovirus, distemper virus, Bordetella bronchiseptica and Streptococcus zooepidemicus. Regardless of the cause, it's still a highly infectious disease characterized by a hacking cough. Serious illness, including deaths, can occur but is uncommon.
Here are a couple of kennel cough issues have hit the press lately:
- Mandatory kennel cough vaccination is now required for dogs competing in the Iditarod Trail Sled Dog Race. It's easy to see how this disease is a concern in these sled dogs, given the stress and rigours of competing and the mixing of many dogs from different areas. Kennel cough vaccination doesn't prevent all cases, since it only protects against Bordetella bronchiseptica +/- parainfluenza virus, but it's a useful infection control tool in high risk populations. The requirement has been implemented in part due to cases of kennel cough that were encountered in the 2011 race, along with the publicity that was generated (including the attention of PETA).
- In Rocklin, California, a dog park was closed for two days because of a kennel cough outbreak. It seems the closure was in response to the diagnosis of kennel cough in two dogs, and it's an unusual move given the apparently low number of cases. The issue isn't the park environment itself being biohazardous - rather, the park provides an opportunity for dog-dog transmission. Given that, it's a questionable control measures since it's unlikely that people will keep their dogs at home. Rather, they'll probably just go to another park, where the same risks will be present. It's a bit like the debate around school closures with pandemic influenza. On the surface, it seems like a good idea, since kids won't pass around flu at school. However, in reality, what happens is kids congregate at the mall and other places if schools are closed, so it just moves the site of transmission somewhere else and probably doesn't have any net benefit. Here, a better response would probably be an educational campaign to get people to keep sick dogs at home, have people keep their dog away from other dogs at the park and encourage vaccination of high risk dogs (which would include those that go to a park and interact with other dogs).
- A kennel cough outbreak was reported in Bozeman, Montana, with veterinarians asking owners to be on the lookout for disease. Local veterinarians reported a spike in the number of cases, with one clinic reporting around 20 cases in the past month, which is a pretty remarkable number for your average vet clinic.
- And locally... nothing specific, but I keep getting reports of clusters of respiratory disease in dogs. We often don't get a chance to investigate small clusters to figure out the cause, since information often gets to me after the fact, but it's a recurrent problem in Ontario. Most of the reports are rather poorly defined clusters of sick dogs, with occasional severe outbreaks involving fatalities (including one I'm dealing with at the moment).
TheHorse.com has reported on an outbreak of Rhodococcus equi that has claimed the lives of seven ponies at an equestrian facility on the island on Mayotte (a French protectorate off the coast of Madagascar). Local agriculture officials report that two other horses are also affected, but recovering, and the facility has been quarantined
There are a few strange aspects of this report. Rhodococcus equi is an important cause of respiratory disease in foals, in which it can cause serious abscesses in the lungs. However, it's extremely rare in mature horses, and it seems that the horses affected in Mayotte were adults. It's not impossible, but an outbreak of Rhodococcus in adults would be incredibly surprising, indicating either something that made these horses remarkably susceptible to the bacterium, or the presence of a strain of Rhodococcus more able to cause disease in adults. A more likely explanation is that it's not actually Rhodococcus. There's no mention of what type of disease the horses had or for what other infectious agents tests were done. A Department of Agriculture official stated that the diagnosis was made by blood tests, but blood testing is pretty useless for diagnosis of Rhodococcus. So, I'd consider the diagnosis highly questionable without further information.
Whatever the cause, something that kills seven horses on a farm is remarkable and thorough testing is needed to determine exactly what's happening. In the unlikely event that this was caused by Rhodococcus, more work needs to be done to explain why the outbreak occurred and why it was so severe. If (as is likely) it wasn't Rodococcus, knowing the actual cause is important for controlling further spread and preventing problems in the future.
Fortunately, the remote nature of this location makes it rather unlikely that whatever's happening there will spread to another region soon.
Image: Location of Mayotte (click image for source)
An article from NBCMontana.com describes a kennel cough outbreak in dogs in Bozeman, Montana. It's a pretty basic article that outlines a rather typical presentation of kennel cough (now largely referred to as canine infectious respiratory disease complex - a respiratory infection that can be caused by a range of viruses, bacteria and Mycoplasma).
As part of the story, they state that if you have a sick dog, the "best course of action is to call your local veterinarian and get medication." I realize it's a quick statement, perhaps tossed in without much consideration, but there are some important issues to consider.
Should someone call a veterinarian and get medication, or should a veterinarian actually see the dog?
- Sometimes dogs just need to be given time and rest. Viruses are often the cause of this condition, and it just takes time for the infection to resolve (just like person with a cold virus). If that's the case, a little over-the-phone veterinary advice might be fine. If drugs are needed, then the dog needs to go to a veterinarian. Affected dogs might need something to control cough, which need to be given by prescription, and occasionally antibiotics are needed, but in either case a veterinarian needs to see the dog first. If the dog is sick enough that it needs additional treatment above and beyond this, then of course it needs to be seen by a veterinarian.
Are there any problems with a dog like this going to the veterinarian?
- Here's where the ball often gets dropped. The last thing we want to see is someone walking through the from door with a hacking, biohazardous dog who goes nose-to-nose with other dogs in the waiting room, breathes on half of the surfaces in the room, sits there for ten minutes while waiting for the appointment, and gets handled by every staff member before they realize the dog might be infectious. A situation like that can turn a veterinary clinic into a source of infection for many other dogs, and help an outbreak spread.
A very basic but well coordinated approach can greatly reduce the risk of dogs infecting other dogs in the clinic. These would include:
- Not taking a biohazardous dog into the waiting room. The owner can call from the car upon arrival or come in without the dog to let the clinic know they're there.
- The dog can be admitted directly into isolation or an exam room, thereby avoiding contact with other animals in the waiting room or elsewhere in the clinic.
- Veterinarians and techs that are going to work with the dog can know in advance and come in prepared, wearing appropriate protective outerwear (e.g. gloves and a labcoat or gown that they use for only that appointment) to prevent contamination of their clothing or body.
Very easy to do. Probably very effective too, but often not done.
No, not gravy made from bearded dragons (a type of reptile), but foodborne Salmonella with a link to the reptile.
Reptiles are an important source of Salmonella, which is why standard guidelines recommend that high-risk people (e.g. children less than 5 years of age, elderly individuals, people with compromised immune systems, pregnant women) not have contact with reptiles or have them in the house. A report in Zoonoses and Public Health (Lowther et al 2011) highlights another possible risk.
The report describes a Salmonella outbreak that was traced back to a potluck dinner. Nineteen cases were identified, 17 primary cases (people that attended the dinner) and two secondary cases (household members of people that attended the dinner). Overall, 29% of people that attended the dinner got sick. A further 18 people had some intestinal disease but strictly speaking didn't fit the definition for a case (however it is suspected that they were part of the outbreak). Salmonella subspecies IV (a type mainly associated with reptiles) was isolated from the stool of five people, confirming the occurrence of an outbreak.
As is typical, food consumption history was evaluated. Sixteen of the 17 primary cases reported consuming turkey gravy, which was a statistically higher proportion than that of people who did not get sick. The gravy was made at the private home of a person who didn't attend the dinner. This was the only home of the people involved where reptiles were kept. Two healthy bearded dragons lived in the house, in a terrarium in the living room.
The investigation focused on the reptiles, since the Salmonella strain found is typically associated with reptiles, and the turkey (the source of the gravy) had no evidence of Salmonella contamination based on testing. Samples from the environment of the household where the gravy was made were collected, and two types of Salmonella were identified. One of these Salmonella types (Salmonella Labadi, which was different from the outbreak strain) was isolated from one of the bearded dragons, as well as the inside and outside of the terrarium glass, other terrarium surfaces, surfaces around the terrarium, the bathroom sink drain and kitchen sink drain.
A common question that comes up when people have reptiles and high risk people in the house is "If I don't take the critter out of the cage, I should be ok, right?" Unfortunately, that's not true. Human Salmonella infections have been clearly identified in situations where reptiles don't leave the terrarium because (as was the case here), while the reptile may not leave the terrarium, Salmonella often does.
The person who made the gravy said that the bearded dragons had not been out of the terrarium when food was being prepared. A child was responsible for feeding the reptiles and cleaning the terrarium, and was supposed to use the bathroom for terrarium cleaning. However, it was reported that the reptiles' dishes "might have" been cleaned in the kitchen sink during the the day period when food was being prepared for the party.
The overall conclusion was that this outbreak "probably resulted from environmental contamination from bearded dragon faeces." It's a reasonable conclusion. Even though the same Salmonella strain wasn't found in the reptile, it makes sense because the reptiles were the most likely source of environmental contamination in the household, and that was the most likely source of the foodborne contamination. Reptiles can shed various Salmonella strains and they can shed intermittently. It takes multiple samples over time to get a real idea of the scope of Salmonella shedding, and I assume that one or both of these reptiles were shedding the outbreak strain at some point.
How can something like this be prevented, since the standard recommendation of having high risk people avoid contact with reptiles doesn't apply to this type of situation?
- Good hygiene practices should be used when handling reptiles and their environments. In particular, there should be proper attention to hand hygiene after contact with reptiles or their cages.
- Reptiles should not be allowed in the kitchen. Ever.
- Food and water bowls should not be cleaned in kitchen sinks. Terrariums should not be cleaned in kitchen sinks. Ideally, they shouldn't be cleaned in bathroom sinks either. (If possible they should be cleaned outdoors with a hose.)
- Good food handling practices are critical. Here, gravy wasn't re-heated to a high enough temperature to kill the contaminating Salmonella. Adequate re-heating would have prevented this outbreak.
The Redlands Animal Shelter in California is looking into bird control measures after blaming Giardia infections in dogs on exposure to wild bird poop. On Facebook, Redlands Friends of Shelter Animals have declared "We have a serious problem with birds at the shelter. They land on the kennels and poop goes into the water bowls and give the dogs giardia - which is a parasite that gives them explosive diarrhea."
Giardia is a protozoal parasite that can cause diarrhea in dogs and other species. It can also be carried by healthy dogs, at relatively high rates in some groups. The scope of the problem at the Redlands shelter isn't clear since the news article only talks about one case. Whatever the scope, shelter management is blaming the birds.
Apparently, discussions are underway with different companies about a solution to the bird problem, something that is anticipated to be expensive. However, it's all too common for people to jump the gun on expensive interventions when there's an outbreak and overlook the root causes. While news reports don't always give the whole story, I'd be wary about blaming birds without much more evidence.
Can wild birds carry Giardia? Yes. However, there's more to the Giardia story than that. It doesn't sound like they've actually tested the bird feces to determine whether Giardia is there. Additionally (and critically) it doesn't sound like they've determined the type of Giardia that's infecting the dogs. There are different types (assemblages) of Giardia and most have a limited range of species they can infect. The vast majority of dogs with Giardia in most regions are infected by Assemblage D, a dog-specific strain that comes from other dogs and poses no risk to people. I'm not aware of Assemblage D being found in birds. Dogs can also be infected by Assemblage A, a type that infects people, and also can infect birds.
So, if Assemblage D is involved, they need to look at transmission between dogs within the shelter. If Assemblage A is involved, they still need to focus on dogs but could investigate birds as a potential source.
Overall, Giardia transmission is much more likely due to breakdowns in cleaning, disinfection, hand hygiene and general shelter practices rather than birds pooping in water bowls. It's a lot cheaper to address these shelter management practices (which will also help control various other infectious diseases) rather than dumping a lot of money into controlling bird exposure when in fact that may not be causing the problem. Trying to reduce exposure to bird poop is a good thing as a general practice, but it's important to focus efforts and resources on finding and addressing the true root problems during an outbreak.
More information about Giardia can be found on the Worms & Germs Resources page.
It's been a while since I wrote about petting zoos. Part of the reason is that the state of petting zoos in this area has improved quite a bit over the past few years, so I haven't been coming home from fairs or other events with a need to vent. However, improvements are not universal, and even with improved conditions, there are always going to be disease risks associated with petting zoos and other events where people have contact with animals.
This week's edition of Morbidity and Mortality Weekly Reports (a rather gruesomely named but very interesting publication by the US CDC) describes a 2011 outbreak of E. coli O157 from a North Carolina State Fair. After receiving reports of infections in four people who had attended the fair, an investigation was launched. Here are the highlights:
- A total of 25 suspected cases were ultimately identified. (Usually, there are many more milder cases that go undiagnosed). Stool samples were collected from 19 of these individuals and the same strain of E. coli O157 was confirmed in 11 of them.
- Affected people ranged from 1-77 years of age.
- Eight people (32%) were hospitalized. Four of those had hemolytic uremic syndrome (HUS), a severe form of disease caused by E. coli O157.
- When compared to people who did not get sick, having visited one of the buildings were sheep, goats and pigs were housed for livestock competitions was the only risk factor identified. While the public was not supposed to have contact with animals in those buildings, 25% of people reported having had direct contact with animals anyway.
An investigation like this often can't determine the source of the pathogen with 100% accuracy, because the investigation occurs after the fact (sometimes long after). That means the animals aren't around anymore for testing, the area/fair may have been cleaned up already, and people may not completely (nor accurately) recall exactly what they did. Regardless, it's quite suspicious that contact with this particular building was the root of the problem. How people became infected isn't clear. Some had direct contact with animals, and that's an obvious potential source. Cattle are the most common source of E. coli O157, but it doesn't appear that any were present in the building. Sheep and goats are a more likely source than pigs. Other people could have been infected through contact with contaminated surfaces in the building, something that has been documented in other outbreaks.
After a large 2004 petting zoo outbreak at this same fair, the state passed a law (named Aedin's Law, after a child who became seriously ill) that set strict requirements for animal exhibits where contact with the public is intended. This facility was not subject to Aedin's Law because animal contact was not intended (even though it was apparently common) and a multiagency task force is looking into additional measures for exhibits where animal contact might occur.
Cost/benefit is an important issue when it comes to infectious disease control. There will always be some risk of disease when interaction with animals is allowed. We can take measures to reduce the risk, but never eliminate it. Therefore, the key is maximizing the benefit and minimizing the risk. Animal contact at fairs and similar events can be very rewarding for some people, so most people will accept some degree of risk. This outbreak involved a relatively small number of people, particularly when you consider approximately 1 million visitors attended the fair. The infection rate was really very, but with a potentially life-threatening disease, it's not something that should be ignored.
As is the case here, infection control is often reactionary, with changes only taking place after problems occur. However, it's good to see that actions are being taken (at least in NC) to reduce the risk of this happening again.
A parvovirus outbreak has been identified at the Occupy San Francisco camp, with at least three dogs affected by the highly contagious and potentially very serious viral disease. The San Francisco SPCA has visited the camp and their temporary clinic was attended by "dozens" of dog owners (indicating lots of dogs at the camp). This is a nice proactive step to help contain the parvo outbreak and hopefully reduce the risk of transmission of various other infectious diseases amongst the animals. Some people appreciated the help. Others (probably the subset that complains about everything) accused the SPCA of spreading bad publicity to help shut down the camp. (I guess they'd rather have good press than healthy dogs.)
In many ways, it's not too surprising. "Occupy" camps are just asking for infectious disease outbreaks, more so in people, but the same risk factors are there for dogs. Whenever you mix together lots of different individuals from different sources, put them in close and prolonged contact and have hygiene challenges, you set the scene for infectious diseases. From a canine parvovirus aspect, heavy fecal contamination from dogs defecating in a small, concentrated area and unvaccinated dogs feed the fire even more. (I don't know for sure that the affected dogs were un- or incompletely-vaccinated, however given the excellent effectiveness of parvovirus vaccines, it's highly likely that sick dogs were not adequately vaccinated.)
Parvo isn't the only infectious disease problem at the camp. Kennel cough (now known as canine infectious respiratory disease complex, CIRDC) has also been identified. This syndrome, caused by a mix of bacteria, viruses and Mycoplasma, has greater potential to spread widely because some of these bugs are highly contagious and vaccination coverage in the population will be lower than for parvo. A large-scale kennel cough outbreak is quite likely if there is kennel cough activity at the camp.
What can you do to reduce the risk, whether it's while "occupying" or during your daily activities?
- Have your puppy vaccinated as per your veterinarian's recommendations.
- Don't take unvaccinated puppies to areas where there will be lots of other dogs. "Unvaccinated" includes puppies who have not had their full initial series of vaccines.
- If your dog is sick, don't take it out in the public, especially to places where other dogs will be present.
- If your dog gets sick during a public event, take it away promptly to reduce the risk of it infecting other dogs.
- Don't let healthy skepticism grow to paranoia, and don't let political squabbles interfere with proper healthcare... both human and veterinary.
Canine influenza continues its rather puzzling spread through the US. After emerging years ago, it has spread sporadically, causing some large regional outbreaks but sparing many areas, and it has moved about in a pattern that's pretty unusual for a highly contagious virus.
There have been various reports of canine influenza activity in the New York and New Jersey areas over the past few months, and an outbreak has now been reported in a PetSmart doggie daycare in Farmingdale (NY) . Eight dogs have been diagnosed with canine flu (though not sure how or whether it's a lab-confirmed diagnosis) and the PetSmart doggie daycare has been closed since November 14. It was supposed to have re-opened on the 22nd, but dogs that had been there won't be allowed back until two week after their last visit, due to the potential that they were infected at the facility and are still infectious.
Like human influenza in people, canine flu is a viral infection that's readily transmissible between dogs. It typically causes mild disease, with coughing as the main sign, but can cause serious (and sometime fatal) pneumonia in some cases. A vaccine is available but it's not considered a "core" vaccine and is largely reserved for dogs in areas where the virus is active and/or in dogs whose lifestyle makes them more susceptible to exposure (e.g. contact with doggie daycare or boarding facilities, contact with many other dogs, travel to areas where the virus may be active).
Interestingly, PetSmart is paying for treatment of the infected dogs. That's pretty surprising, and may set a precedent they might want to avoid. Infectious diseases are a fact of life. We can do things to reduce the risk of exposure, but we can never completely eliminate the risk that our pets (or ourselves) will get an infection. Usually, infectious diseases that happen in facilities are considered an unfortunate fact of life (especially when it's a vaccine-preventable disease) and facilities rarely cover any costs associated with such outbreaks. In reality, this would be a reasonable approach assuming the facility used standard and reasonable practices to reduce the risk of disease.
If a facility has an infection control plan and adheres to it, whether it's a boarding facility or a veterinary hospital, it's hard to expect them to cover the costs of infections, since not all infections are preventable. In contrast, if there is no infection control program or if things aren't done right, it's easier to assign blame and expect some financial support. Sometimes, costs are covered purely on a public relations basis, which is perfectly reasonable as well. There's no indication why costs are being covered here, but it raises some interesting, broader questions about infection control in facilities like this and their role in covering any costs that are incurred from any type of infectious disease exposure.
A Kitchener, Ontario family is dealing with a household outbreak of ringworm, likely contracted from a new pet guinea pig. Ringworm is a fungal infection cause by a few different types of fungi. Some ringworm fungi are able to infect both people and animals, and those can be spread in households from direct contact with an infected person or pet. In this case, the Gross family purchased a new guinea pig from a local pet store, and unfortunately, ended up bringing ringworm home as a bonus.
As is common, the new pet was the centre of attention when it got home, and the Gross' three children, ages 8, 5, and 2, had very close and frequent contact with it. The next day, the family noticed an area of hair loss on the guinea pig, at which point they took it back to the store. Ringworm was subsequently diagnosed, though there's no mention of how this was done, nor is there any mention of what actually happened to the little critter afterward.
The big problems started a week later, when a red lesion was seen on their youngest child's back. This was also diagnosed as ringworm, though again there's no mention of how, or whether it was definitively confirmed as ringworm. The newspaper report goes on to say "More spots kept appearing on Matthew’s skin as Gross was given different steroid creams to try and contain the infection." You always need to take media descriptions of medical issues with a grain of salt. Hopefully, the child was treated with anti-fungal cream, not steroid cream, as the latter not only won't treat ringworm, they may make it worse if used alone. Steroid creams are often prescribed for non-specific skin issues (particularly if the skin is very itchy, which can certainly happen with ringworm), but in a case like this where there was known contact with an animal with ringworm, I have to hope that the physician was treating with an antifungal cream instead of, or in addition to, a steroid cream.
Anyway, whether despite or because of the treatment, more skin lesions kept appearing on the child. Then skin lesions were found on the family dog, and both the dog and cat ended up being treated for ringworm. The treatment for dogs and cats is relatively straightforward, but it's still a hassle and can be somewhat expensive, and often takes several weeks.
The family has contacted the pet store about paying for cleaning supplies, air purifiers and veterinary bills, but the company did not respond to the newspaper reporter's inquiries, citing an ongoing investigation. It's hard to say whether the company should be held responsible. It largely depends on the measures they take to reduce the risk that they are selling pets at increased risk of transmitting infectious diseases. There's always a chance of picking up something from a pet, so an infection does not necessarily indicate incompetence or liability. If a store had reasonable practices in place, it's probably the purchaser's responsibility to take proper precautions when they take the pet home, and it's an example of why prompt veterinary examination of new pets is always a good idea. It's rarely done, particularly for species that cost less than the price of a veterinary exam, and you never know whether it would have helped prevent anything in this case, but in many instances it can help identify potential issues and address them before problems occur.
Preventing outbreaks like this can be difficult. Ringworm can be found on animals in the absence of any skin disease, so you can't always tell an animal is infected by looking at it. (However, in this case if a large patch of hair loss was noticed by the owners the day after the guinea pig came home, it's likely that something was evident the day before). Ringworm is spread by direct contact, which is common between pets and kids, especially new pets that often get smothered with attention in the first few days. Good hygiene practices, particularly attention to handwashing, can certainly help, but some degree of risk will remain.
Overall, guinea pigs are relatively low risk for zoonotic diseases, but this report shows that even "low risk" pets can be sources of infection. Fortunately, while controlling ringworm outbreaks can take time and be frustrating, it's not a serious disease and it is controllable.
More information about ringworm can be found on the Worms & Germs Resources page.
Canine influenza continues to be a problem in some areas of Texas, most notably in the Austin area. A recent news report indicates 30 confirmed cases and 70 suspected H3N8 canine influenza cases since September.
It's hard to say what the scope of the problem really is, but something's definitely happening. Getting good data about infectious diseases of companion animals is difficult because there is no central surveillance program and government animal health agencies tend to have little interest in non-food animals. Data tend to be assembled by word of mouth, which can lead to either over- or under-estimation of the problem. As highlighted by the number of "suspected" cases, lack of diagnostic testing is also an issue. Since dog owners have to pay for the testing themselves and since, for influenza, test results rarely change what's done for initial treatment of the dog, many people are reluctant to have the tests done. That leaves us with large numbers of unconfirmed cases, as is this situation. When there is documented flu activity in the area, a suspected case could quite likely be influenza. The bigger problem is in areas where flu is not common or hasn't been found, because canine flu looks no different than several other causes of respiratory disease, and knowing whether it's really flu is important for making vaccination decisions, as well as implementing certain infection control measures.
Avoiding exposure to canine flu is tough in areas where flu is active, just like it is for people when human flu is circulating. One of the big problems is that infected dogs start shedding the influenza virus from their respiratory tract before they get sick. Therefore, staying away from sick dogs and keeping your dog at home if it has signs of disease can't completely prevent exposure. However, these steps are still very important as they can help reduce the risk. Vaccination is another measure to reduce the risk. Vaccination is not 100% protective but it is an important part of influenza control in dogs that might be exposed to the virus.
There have been a few large outbreaks of dead birds around Ontario lately, with botulism being the main suspect. In one area alone, up to 6000 dead birds have washed up on Georgian Bay beaches. While dramatic, it's not a rare situation at this time of year, and typically relates to birds ingesting fish that died of botulism. When birds eat enough fish with enough botulinum toxin inside them, they can develop botulism themselves and die. This pattern can continue if dead birds are eaten by other animals.
In response to these events, I often get calls about risks to dogs and people. When thinking about it, it's important to consider how botulism occurs. There are two main forms of botulism:
- Toxicoinfectious botulism involves growth of the Clostridium botulinum bacterium in the intestinal tract, and as the bacterium multiplies it produces toxin which can be absorbed into the body through the intestinal wall. This type of botulism is rare in adults (both people and animals), since the mature intestinal bacterial population usually prevents C. botulinum from overgrowing. It's mainly a risk in young individuals. )This is why you're not supposed to give honey to babies, since C. botulinum spores that can be present in honey can pose a risk to them.)
- The other form of botulism in from ingestion of botulinum toxin that's already been produced. This is the most common form. When birds eat fish that have died of botulism, they ingest both the bacterium and its toxins, but it's the toxins that make them ill and ultimately lead to death. Dead birds will probably have some C. botulinum in their intestinal tracts, but the main concern is the botulinum toxin in the rest of their tissues.
Dogs (and cats) are quite resistant to botulinum toxin, and reports of botulism in these species are rare. It would take a pretty large amount of toxin to cause disease (at least compared to many other species) but it's not impossible. Casual contact with areas where birds have died is of basically no risk. Eating dead birds could pose some risk to the dog, depending on the amount eaten and how much toxin was present in the bodies. Ingestion of some C. botulinum bacteria in the birds is of limited concern.
So, walking in an area where birds have died is very low risk. People should ensure that their dogs don't have uncontrolled access to areas where birds have died, so that they can't eat lots of dead birds.
I also get questions about whether dogs that get exposed to beaches where birds have died pose any risk:
- Even if a dog ate a lot of dead birds and got botulism, a person could only be exposed to that toxin by eating the dog - an unlikely event. The dog could ingest some C. botulinum bacterium, but this also poses minimal risk since the bacterium is pretty widespread and people can be exposed to it from many different sources. Even if a dog had some C. botulinum in its intestinal tract, avoiding contact with feces will reduce the risk of exposure. Even if there was some ingestion of C. botulinum from the feces, there's little risk, especially to adults. Perhaps the main public health concern (which is still very low) would be exposure of infants to C. botulinum from dog feces or perhaps from a dog's contaminated haircoat.
Bottom line: Keeping dogs and cats away from dead birds is a good idea, for several reasons, including botulism exposure, but there's limited public health concern.
Image: Dead birds washed up on the shore of Georgian Bay, on the eastern side of Lake Huron (click for source)
Infectious diseases are continuous challenges for animal shelters. Unfortunately, outbreaks are not uncommon. Sometimes they're the result bad luck and the inherent risks involved in bringing together lots of animals of questionable health status from different sources. However, if you compound these risks with things like inadequate facilities, overcrowding, poor training of personnel, poor adherence to protocols, bad protocols, lack of awareness about infectious diseases and failure to get expert help early in any outbreak, the likelihood of "badness" increases.
A few shelter outbreaks are underway at the moment, and they highlight some of the infectious disease challenges posed by different diseases in animal shelters.
- The Oakville and Milton Humane Society (in Ontario) is closed because of a ringworm outbreak that's been going on since early September. Ringworm, while of limited health consequences, is an important shelter problem because it's common, highly transmissible, can be hard to control and can infect people. At last report, 22 cats were confirmed or suspected to have ringworm, along with at least four staff members. It's not clear who's coordinating the outbreak response, but hopefully they're getting good advice and they've read the comprehensive report from the Newmarket OSPCA ringworm debacle.
- 72 kittens were euthanized in the Miami-Dade County Animal Services because of "cat plague," which is a common name for feline panleukopenia. This viral disease is preventable by vaccination, but it's a serious concern in shelters were there are often lots of unvaccinated or inadequately-vaccinated cats and lots of susceptible kittens. In this shelter, all cats with clinical signs consistent with panleukopenia are being euthanized. Euthanasia is always a tough decision, but with a serious disease like this, it's a reasonable response. Outbreaks like this highlight the need for excellent infection control practices to reduce the risk of spread of pathogens like this once they make it into a shelter.
- Upper respiratory tract infections have resulted in suspension of adoptions at the Bergen County Animal Shelter in New Jersey. News reports are calling it a canine influenza outbreak, and canine flu is definitely on the list of possibilities, but it doesn't sound like it's been confirmed. Respiratory infections are a common cause of problems in animal shelters because some causes (e.g. canine parainfluenza virus, canine influenza virus) are quite transmissible. Canine flu poses extra challenges when it moves into a new area, since few if any dogs have antibodies against the virus and therefore it can spread rapidly. The report also mentions transmission by dogs not showing signs of disease. That's a problem with some infectious agents. For example, with canine flu, dogs tend to be able to shed the virus before they show signs of illness. Therefore, there's a period of a couple of days after infection but before disease where you can have a silent reservoir of infection. That's why quarantine of new admissions is critical, since it gives animals a few days to show signs of diseases they may be brewing at the time of admission. (Unfortunately, it's not easy to find space in which to quarantine an animal in an overcrowded shelter.)
A common denominator in all of these outbreaks is the potential that something could have been done differently to prevent the problem. It's possible (although unlikely) that everything that was done perfectly, however it's a rare outbreak where you can't find multiple areas for improvement. A key aspect of outbreak management is, once the crisis is over, performing an investigation of what really went wrong and why, and taking measures to reduce the chance of it happening again.
Image: Ringworm infection in a cat is not always readily apparent, but in some cases can cause obvious patches of hair loss.
An outbreak of canine influenza is occurring in San Antonio, TX, as this virus continues its strange and unpredictable movement through the North American dog population. In an article published on a local San Antonio news website, Dr. Michele Wright, a San Antonio veterinarian, reports 20 confirmed and 70 suspected cases over the past month. It's not clear whether these are all from her clinic, nor is there any information about possible sources of the virus or the severity of disease. Dr. Wright also states that the virus has been identified in Austin and Dallas.
It's not particularly surprising that canine flu has been found in Texas. It's now been identified in at least 38 US states, as well as one Canadian province. An outbreak is not particularly surprising either in this case, because when a virus reaches a new area, it can easily cause widespread disease since it encounters a population of animals that don't have any pre-existing immunity (i.e. antibodies) against it.
What's strange about canine flu is how it has spread across North America. When it was first identified in Florida greyhounds in 2004, it seemed like it was going to spread widely across the dog population. It spread quickly at greyhound tracks and in clusters in Florida and in other states, but it's subsequent spread across the continent was quite patchy - it caused only localized outbreaks in different states, instead of the catastrophic continent-wide epidemic that was anticipated. Whether this relates to the amount and type of direct contact between dogs (e.g. dogs are only infectious for a short period of time and an infected dog has to meet a susceptible dog during that time to continue transmission of the virus, otherwise it dies out), specific aspects of the virus in dogs (e.g. how long it is shed) or lack of recognition of disease in some areas (e.g. mild disease that doesn't get diagnosed) is unclear.
We've been looking for canine flu in Ontario for a few years now, with no "success" (that is, we haven't found it yet).
Are we flu-free at the moment? Probably not. I suspect it's lurking out there, but it's possible that it really hasn't made it to Ontario - yet.
If it's not here now, will it make it here eventually? Almost certainly. It's taking longer than I expected but all it takes is one infected dog entering the country. With the amount of cross-border dog movement, it's probably inevitable.
What about vaccination for canine flu? It comes down to risk of exposure and risk aversion. If flu is in the area, vaccination is a good idea. If flu is in adjacent areas, it's also a good idea. If flu isn't recognized in the area, it's a matter of how much risk people are willing to take and thinking about higher risk situations, as described below.
What about vaccination in Ontario, or other places where the virus doesn't seem to be present? It's hard to say when to recommend canine flu vaccination. Certainly, vaccination of dogs traveling to areas where canine flu is or has been present is a good idea. Vaccination of dogs that engage in high risk activities such as going to shows or kennels is also prudent, since these are the places where we may see the firsts outbreaks if/when canine flu makes it here. Vaccination of low-risk dogs in the province is probably not necessary at the moment (unless people are very risk averse and don't want to take any chances).
Why vaccinate? It's just "the flu"... This is an attitude that the human public health field battles all the time. Most people who get human influenza (humans can't get the dog version of the virus) feel crappy for a few days and get over it. The perception that it's only and always a mild disease keeps some people from getting vaccinated. However, thousands of people die from flu complications, particularly the very young and elderly individuals. Vaccinating everyone helps reduce the chance that these high-risk people will get sick. Also, while rare, serious (including fatal) infections can occur in otherwise healthy people. In dogs, there's probably actually more indication to vaccinate if there is a realistic risk of exposure. Canine flu can cause classical flu-like disease, akin to the typical human case. However, severe (often fatal) pneumonia can also occur in otherwise healthy dogs. High rates of severe disease were reported initially when canine flu was first identified. It seems like severe disease rates have dropped, but it's still a concern. I wouldn't be surprised if severe disease is more common in dogs with canine flu than in people with human flu.
Whether or not to vaccinate is a discussion dog owners should have with their veterinarian, considering the risk of exposure, risk of severe illness and risk aversion. At the same time, people in areas where flu has not been identified need to be on the lookout for it, to ensure that it gets diagnosed promptly if it emerges, and that information gets communicated to veterinarians and the dog-owning public so that appropriate responses can be made.
Neil Fearon and his family have lost three horses to Hendra virus, and are concerned about one other. They are now dealing with the implications of their dog, a Kelpie named Dusty, having tested positive for Hendra virus antibodies in its blood. As I mentioned in yesterday's post, the presence of antibodies in the blood of this dog, detected during voluntary testing as part of the outbreak response, only indicates that the dog was exposed to the virus. Viral shedding was not identified, suggesting that the exposure was a prior event and that an active infection was not present. Despite this, government authorities are requiring that the Hendra antibody-positive dog be euthanized.
Poor communication and mixed messages are often the cause of problems during outbreak management, and this seems to be the case here. Based on the news reports, there are some pretty concerning issues.
Testing of the dog was voluntary and the owner was not notified that euthanasia would be required if the dog tested positive.
- This is rather unethical. People need to understand the implications of outbreak control measures. It's not fair to have such an aggressive response to a voluntary test without proper notification.
Mixed messages are being given about the risk the dog poses to the family.
- Authorities want to euthanize the dog, indicating they must believe there is some risk. However, the owner is very concerned about his 11-year-old son who has slept with the dog in his bed for the last few weeks. Yet, ABC news indicates authorities reassured Mr. Fearon that the risks are minimal. If the risks are minimal from that type of prolonged, close contact during the period when the dog may have been actively infected, it's hard to justify euthanasia after the fact on the basis of the dog posing a risk to people or animals (especially when the virus is endemic in the bat population in the area).
- Why euthanasia is being required seems to be unclear. While fear of Hendra virus shedding makes the most sense, Queensland's chief vet has stated that the dog will be euthanized as a precaution because "As a result of that infection, it may make it aggressive." It seems rather strange to euthanize a dog because of concern that an infection (which may not be active) might cause aggression, with no evidence that disease will occur or that it can cause aggression in dogs. Quarantine and observation would make more sense. There are a lot more dogs that are prone to aggression wandering around Australia.
This type of action drives things underground.
- When overly-aggressive actions are used, and people either don't agree with them or don't understand them, faith in the system decreases. What's the likelihood that people are going to allow their pets to be tested now? I assume it's a lot lower now that they've seen what will happen. So, the ability to determine exposure of other species and the potential risks from other species will be impacted.
Hendra virus is not something with which to play around. It's a very serious disease and one must err on the side of caution. How far you err on the side of caution is the question, and it's a hard thing to determine. It's easy to be very strict when setting rules, and fear of liability or fear of making a subjective decision often override logical thought and discussion.
As a somewhat informed outsider, I have a hard time supporting mandatory euthanasia for a dog that has evidence of previous infection but no evidence of active viral shedding. Yes, no test for virus shedding is 100%, but a pretty high level of assurance can be obtained and the dog can be quarantined for further testing. There's no indication from laboratory studies that I know of that dogs (or other non-bat species) can become longterm carriers of the virus. The owners should be involved in the decision making process and be given enough information to understand the implications of keeping the dog, the risks that might be present, and what they can do to reduce the risks. Government authorities need to clearly state their concerns and the evidence supporting them. With that, it's easier to make a logical plan that protects the public but is also appropriate for the animal and its owners. If the risk is deemed to be real and/or the owners are not willing to accept some degree of risk, then euthanasia is reasonable.
"Kill the dog" is an easy knee-jerk response. I simply don't see the evidence supporting it. Is it possible that authorities have a true reason to be concerned? Sure, but if so, that indicates another communication problem. If there is really evidence that this dog is a concern, this needs to be clearly communicated so people understand what's happening and why such drastic actions are being taken.
This Worms & Germs blog entry was originally posted on equIDblog on 27-Jul-11.
The US CDC is investigating yet another multistate outbreak of salmonellosis associated with contact with chicks and ducklings. As of June 18, 39 people have been diagnosed with Salmonella Altona infection (with a large number of others presumably infected, since only a minority of cases tend to be diagnosed). People in at least 15 states have been affected, as indicated by the map on the right.
Reported cases so far occurred between February and the end of May, but the outbreak could still be ongoing. Of all the affected individuals, 28% have been hospitalized but there have been no deaths.
Outbreaks like this lead to investigation of possible sources, starting with the usual suspects of high-risk foods and animal contact. In interviewing people that became sick, 81% of them reported having contact with live poultry before getting sick. In people that identified the type of poultry, all reported contact with chicks, ducklings or both. All 19 people that provided information about the source of chicks or ducklings reported getting them from different locations of a nationwide agriculture feed store (which is not being identified). The same strain of Salmonella was isolated from ill people and chick/duckling displays in two store locations. A single mail-order hatchery was then identified as the source of the animals.
Large distributors of animals, especially high-risk animals like chicks and ducklings, can be the sources of large outbreaks since they can supply large numbers of infected animals to a large region. While cute, chicks and ducklings are high risk for carrying Salmonella and they can shed large numbers of Salmonella in their feces without showing any signs of disease. That's why standard recommendations are that high risk persons (e.g. children less than 5 years of age, immunocompromised or elderly individuals) should avoid contact with baby poultry.
In the context of this outbreak, since the store is not being named (and since it's possible the hatchery sent chicks to other sources), anyone who has had contact with chicks and ducklings needs to be aware of the potential for Salmonella exposure. In reality, this is also true outside of the context of this outbreak, since Salmonella exposure needs to be considered after any contact with chicks and ducklings. It doesn't mean that people who have had contact with baby poultry should go to the doctor, get tested, or do anything different. However, it is important that people notify their physician about poultry contact should they get sick. For more information about reducing the risk of Salmonella exposure from poultry, click here.
As many of you know, there was a large ringworm "outbreak" at the Newmarket (Ontario) OSPCA shelter in 2010 that led to a public outcry in response to plans to depopulate the shelter. In the aftermath of the event, an independent investigation was launched, headed by Mr. Patrick LeSage (former Chief Justice of the Ontario Superior Court) and Dr. Alan Meek (former Dean of the Ontario Veterinary College). The investigation involved a comprehensive examination of activities pertaining to the outbreak and shelter operations, in conjunction with relevant experts (disclosure: I was one of those).
The report of the investigation is now available, and covers important aspects such as whether an outbreak was actually present (short answer: no) and whether there were major problems in shelter operation (short answer: yes). Most importantly, it provides a comprehensive set of recommendations to improve the operations of the Newmarket shelter and OSPCA as a whole.
The report, in its entirety, was released today by the OSPCA and is available for download on their website. The report is on the site in multiple files: the main report is listed as "Index" and contains the ~90 page overview and recommendations. The expert reports, which might also be of interest, are tables D1-3, E, F and G.
As I mentioned in an earlier post, there's been a large and ongoing outbreak of salmonellosis in people across the US associated with pet aquatic frogs (such as African dwarf frogs). A recent edition of Morbidity and Mortality Weekly Reports provides an update on this large and concerning outbreak. Here are the highlights regarding infections reported between April 1, 2009 and May 10, 2011.
- 224 infections with the unique outbreak strain of Salmonella Typhimurium have been identified in 42 US states. Since it is estimated that only ~3% of Salmonella infections are laboratory confirmed, this means that the number of true cases is probably much higher (e.g. >8000, if the 3% estimate is accurate).
- The median age of affected people was 5 years, with a range of <1-67 years. The young age bias may be because of increased susceptibility to infection, increased likelihood of severe infection (which would more likely result in testing) or more common exposure.
- 30% of affected individuals were hospitalized. There were no deaths.
- 65% of affected people reported contact with frogs in the week before illness. 18% of those occurred outside the home (which is why we need to make sure that even non-pet-owners are educated about zoonotic disease risks associated with pets).
- The median time from acquiring a frog to onset of disease was 15 days. This means people often got sick fairly soon after acquiring their new pet.
- One breeder in California has been implicated as a common source of infected African dwarf frogs. As with many kinds of small pets (e.g. rodents, reptiles), this is a large breeder that sells to distributors who then sell to pet stores and elsewhere. This type of mass production and distribution system means that a problem with a single breeder can result in widespread disease. This has been clearly shown previously in various other outbreaks, especially with pet rodents.
What should the average pet owner know?
- High-risk households - those including kids under the age of five, elderly individuals, pregnant women or individuals with a compromised immune system - should not have pet aquatic frogs.
- High-risk people (as describe above) should not have contact with aquatic frogs in other places.
- People with aquatic frogs should consider the frogs to be infected with Salmonella until proven otherwise. Since we don't know how to prove otherwise, that means treat all pet aquatic frogs as infectious.
- Frog owners should avoid direct contact with the frogs and their water. Hands should be washed thoroughly after contact with frogs or their environment.
- Frog owners should never dump aquarium water into kitchen or bathroom sinks.
- Any spills of water during aquarium cleaning should be promptly and thoroughly cleaned up.
- Other pets should be kept away from aquaria (I remember when I used to have aquatic turtles and a cat. The cat used to drink from the aquarium and occasionally bat at the turtles. Not something I'd endorse now, but that was in my pre-DVM era).
This outbreak doesn't mean that aquatic frogs can't be good pets. It means that they shouldn't be pets for certain people, that good routine infection control practices need to be used by frog owners and that consideration needs to be given to whether mass production of pet frogs (and other species) is appropriate.
Photo: An African dwarf frog (Hymenochirus boettgeri) (photo credit: James Gathany, CDC Public Health Image LIbrary #11831).
Like any animal, disease outbreaks can occur in wild birds. Unless they are large outbreaks they often go unnoticed, but smaller outbreaks can sometimes be encountered by homeowners with bird feeders. Because bird feeders are mixing sites for birds, they are also sites of disease transmission and a place where deaths can be identified. In an outbreak, feeders can contribute to the spread of infection between birds, and potentially be a source of infection for people or pets.
A classic example of this is Salmonella infection in songbirds. Outbreaks occur periodically and are often identified by people with bird feeders who start to find the odd dead bird in their yard. Some birds can be healthy carriers of the Salmonella bacterium (and therefore be a source of infection for others), while other birds may get sick and potentially die from the infection. If you have noted dead birds around a bird feeder, consider the potential for a disease outbreak, particularly salmonellosis.
The risk to people and pets from Salmonella outbreaks in birds is reasonably low, and probably greatest in cats. Most reports of songbird-associated salmonellosis (songbird fever) are in cats, because cats are more likely to catch and eat songbirds. Sick birds are easier to catch, further increasing the likelihood of exposure during an outbreak. Exposure is also possible through scavenging already-dead birds and perhaps from exposure to heavily contaminated surfaces or spilled feed around feeders.
General recommendations during an outbreak of salmonellosis in songbirds include:
- Keep cats indoors. This is a good idea at any time, but if you have an indoor-outdoor cat, keep it indoors if there might be an outbreak underway.
- If your pet has been exposed to a sick bird or an area where sick or dead birds have been found, and your pet gets sick, make sure you tell your veterinarian about the birds.
- Clean the bird feeder and then disinfect it by soaking it in 10% bleach for 30 minutes. Rinse it after the bleach treatment. If the feeder is difficult to properly disinfect (or you don't want to try), get rid of it by double bagging it and putting it in the garbage.
- When cleaning the feeder, do it outside so that you don't contaminate any household surfaces. When handling the feeder, wear disposable gloves and wash your hands after you remove the gloves.
- Keep the feeder down for 1-4 weeks. This reduces the concentration of birds in the area and may help reduce mingling of sick and healthy birds.
- Remove any dead birds by burying them at least two feet deep in a flowerbed (not in a vegetable garden!). This is not very easy or practical however - alternatively, double bag the bodies and put them in the garbage, avoiding direct contact with the birds and washing your hands afterward.
The investigation started off with the identification of the bird-associated disease in three people at a local hospital. All three were hospitalized with respiratory disease, and all had attended the bird fair.
- A critical step in diagnosis of psittacosis and recognition of outbreaks is knowing about bird contact. If bird contact isn't questioned, psittacosis is unlikely to be considered. Too often, physicians don't inquire about animal contact, which limits their ability to detect zoonotic diseases. In this case, a survey on psittacosis was underway, which may have helped.
This finding led to an investigation of the fair to determine what happened and make sure there were no other unidentified cases.
The fair lasted one day, and had 83 exhibitors, 1500 birds and around 600 visitors. The investigators ultimately identified two confirmed cases of psittacosis in people who attended the fair, along with two probable and 44 possible cases. (Possible cases were people who developed respiratory disease and were exposed at the event, but did not necessarily have any diagnostic testing done to confirm the cause).
The reported disease characteristics were pretty typical:
- Fever in 96%
- Pneumonia and cough in 63%
- 98% visited a doctor
- 23% were hospitalized
- No one died (psittacosis can be fatal, but is quite treatable if identified in a reasonable time)
Thirty-eight percent (38%) of exhibitors and organizers got sick. That's a very high attack rate for people casually interacting with a group of (presumably) healthy birds. Poor ventilation may have played a role. The fair was held inside, windows were closed and there was no mechanical ventilation. This might have helped the bacterium build up in the air in the building and result in wider, heavier exposure.
The source of infection wasn't determined. They were only able to obtain samples from birds from six of the 83 exhibitors, and all 64 tested birds were negative. Chlamydophila psittaci can be shed by healthy birds, and identification of the source isn't always easy.
It's not guaranteed that everyone who got sick after the fair had psittacosis. You can't rule out the possibility that there were only a couple people with psittacosis and a large number with the flu or another disease, but the incidence of disease, type of disease and timing of disease are all quite suggestive.
How do we prevent outbreaks like this in the future? It's tough to prevent them completely, because you can't tell that a bird is shedding the bug just by looking at it, and testing every bird before a show is impractical. Risks can probably be reduced by ensuring proper ventilation, limiting crowding of areas, limiting unnecessary direct contact between birds and people, and improving general hygiene practices.
Thanks to Dr. Doug Powell of BarfBlog for sending the article.
More information about psittacosis is available in our archives.
Yesterday, I wrote an equIDblog post about an outbreak of unexplained neurological disease in horses in the Murray River region of Australia. Today, a ProMed report indicates that Murray Valley encephalitis is now being considered as a possible cause of death in a man from the area.
Murray Valley encephalitis (MVE) is one of the possible causes of the equine neurological disease outbreak, and it's quite likely that if it caused disease in one species in the region, it did the same to another. This rare mosquito-borne disease hasn't been seen in decades in the region, but it's possible that high mosquito numbers following heavy rainfall and flooding have increased the risk of transmission.
While this virus poses a risk to both humans and horses, humans and horses pose no risk to each other. Both acquire the disease the same way - from mosquitoes - and neither can pass it on to the other. This is also true of other insect-borne viruses such as West Nile virus and Eastern Equine Encephalitis (EEE) virus.
This is a good example of why human and animal disease surveillance need to be linked, and why governments need to put resources into testing of animals beyond food animals. Rapidly identifying a disease in horses or other animal species can help determine whether there is any risk to humans, and hopefully lead to preventive measures being taken earlier.
Prevention of this disease is focused predominantly on mosquito avoidance. It's impossible to completely prevent mosquito exposure, but some basic practices can help reduce the risk. Click here for some practical tips on protecting yourself and your horses from mosquitoes.
Image: Location of the Murray River in Australia (click for source)
This Worms & Germs blog entry was originally posted on equIDblog on 13-Mar-11.
You can probably tell from various posts that I'm a fan of the CDC's journal Emerging Infectious Diseases. It's a great journal containing interesting infectious disease reports about people and animals (it's free too, which is a nice bonus). In addition to the ferret infection I wrote about, the last edition also has a very interesting report about tuberculosis (TB) in people associated with an elephant sanctuary.
Tuberculosis is a big problem in elephants. It is relatively common in captive elephants in North America (2-12% are thought to be infected), and it It can be a tricky infection to diagnose, so it's very hard to know who's infected an who isn't.
Beyond being a problem for the elephants (because infection can be fatal), elephants with TB pose a risk to people, and there have been reports of human infections associated with elephant contact. Close and prolonged contact is most often associated with transmission of TB from elephants to people, but this recent report shows that indirect transmission may also be a concern.
The report in question deals with an elephant sanctuary in Tennessee. Problems were identified in July 2009 when routine TB skin testing of some workers at the facility indicated exposure to TB. Further investigation revealed that a quarantined elephant had tested positive in December of 2008. The elephant was diagnosed by culture of a trunk wash - to do this, the elephant is trained to suck water into its trunk and then "exhale" it into a plastic bag. The sample is then cultured for Mycobacterium tuberculosis. Animals with positive trunk washes are considered infectious, just like people with positive sputum (spit) cultures.
The TB history at this facility goes back further. In 2004, they took in two elephants that were known to be infected with TB. They were handled as per USDA Guidelines for the Control of Tuberculosis in Elephants (yes, such a document exists). One died of TB and the other was later released from isolation after treatment, according to the guidelines. In 2006, they took in eight more elephants from the same facility. All were considered high-risk for TB and were tested annually. All samples between 2006 and 2009 were negative, except for that one December 2008 sample. There's concern that since the elephants tested negative, people might have become lax with infection control practices. It's a problem beyond elephant facilities, where compliance slips over time since people may not see the need to continue to do what's required.
After being notified of the the 2009 human TB test results, Public Health personnel launched an investigation. They eventually determined that 9/46 people whom they were able to contact had positive TB skin tests during the 2006-2009 period, despite having negative tests before then (confirming that they were truly exposed during this period). The strange thing was that it wasn't only the people with prolonged, close contact who were infected. People who worked in the quarantined area in 2009 were significantly more likely to be positive, but of the 13 people that worked in the quarantine area, only one had close contact with any elephant. Furthermore, three of the people who were infected were administrators.
This is where is gets interesting. Normal cleaning practices included the use of high-pressure washing to clean the barn. We know that this increases the risk of spreading bacteria in the air over long distances, and it's generally frowned upon from an infection control standpoint. People in the quarantine area wore respirators to reduce the risk. However, the administrative area was attached to the quarantine area and investigators subsequently determined that there was airflow from the quarantine area into the administrative area. So, when people were cleaning the quarantine area with high pressure washing, they were creating infectious aerosols that spread into the administrative building. That presumably accounted for infection of the people who had no contact with elephants. Furthermore, one of the investigators was also exposed during time spent in the administrative area before the risk was identified.
This highlights a few issues:
- Infectious diseases continue to surprise us. We may know what they tend to do, but new transmission patterns and new concerns can develop.
- Power washing can contribute to the spread of infectious diseases. This is a concern in many types of facilities.
- Infection control compliance needs to be maintained over time, even if it seems like the risks have dropped.
- Captive elephants continue to pose a risk to people around them, and careful precautions are needed to reduce the risk of exposure to TB.
We've known for a while that cats and ferrets are susceptible to many human influenza viruses, something that was again demonstrated last year through sporadic (and often fatal) reports of H1N1 influenza in both species. Since H1N1 is still in circulation in the human population, there's still a risk of exposure of cats and ferrets, as was seen in an outbreak at a ferret shelter in Kentucky that began last month.
Over a few weeks, starting in early February, all 17 ferrets at the Ferret Villa Shelter in Erlanger, KY, developed influenza. As expected, coughing, sneezing, fever and lethargy were the first signs of disease, with more severe respiratory disease developing in some. One ferret died, and H1N1 was diagnosed through post mortem testing. Presumably, all of the other sick ferrets had influenza as well. Fortunately, the other 16 ferrets survived with supportive care and should presumably suffer no long-term effects.
There's been no mention of the source of the virus, but it almost certainly came from an infected person. Given the susceptibility of ferrets to influenza and the potential for severe illness, ferret owners should be aware of the risk and restrict contact between their ferrets and anyone with flu-like disease. Ferret shelters or breeders, with larger numbers of ferrets, should take extra precautions.
The risk of transmission from ferrets to people isn't known, but it's logical to assume that there is some degree of risk. An infected ferret could quite plausibly shed enough virus to infect a person under the right circumstances. However, since influenza in a pet ferret most likely came from its owner, and most ferrets don't meet many people outside of their households, the risk to other people in most households is probably limited - most people would probably be exposed via the person who was originally sick before they had a chance to get it from the ferret.
(Photo credit: Luke Rutherford)
Glanders, a very serious disease of horses, donkeys and mules caused by infection with the bacterium Burkholderia mallei, has made the news again in a rather unusual manner – it has been reported as the cause of an outbreak in lions and a tiger at an Iranian zoo in Tehran.
The story goes that two Amur tigers arrived at the Tehran zoo from Eastern Russia in April 2010 as part of an exchange program between the two countries. The tigers were supposed to be used to help restore the tiger population in northern Iran on the Miankaleh nature reserve, but their living quarters there were apparently still not ready, and thus they were being kept at the zoo. One of the tigers died in December 2010.
And that’s were the story starts to get a little dicey. The Iranians claim the tigers were imported already carrying the disease, and that the last case of glanders at the zoo was 50 years ago. The tigers had already been at the zoo for eight months - although the incubation period for glanders can be months in some cases, it is normally only weeks. The Russians of course insist that the tigers were completely healthy when they were transferred – they’d been thoroughly examined and quarantined prior to being moved. (This makes the most sense to me, since transporting an animal such a long distance is a major stress and increases the risk of illness, and transporting an animal that is already sick would be even more risky. Not a chance I would take with two members of a species of which there are fewer than 900 individuals left in the world.) They also pointed out that a sick tiger from the cold regions of Russia would be much more likely to succumb to illness during the very hot Iranian summer, not during the winter.
Another report said that three lions at the zoo also died from glanders in the last two months, and subsequently another 14 lions were diagnosed with the disease, all of which were put down by the authorities. The main concern seemed to be the spread of the disease from the big cats to the feral cat population, and then to the human population. This second report states that “the tiger died after being fed contaminated meat, though it is possible it could also be related to the glanders.” Yet another report said that the tiger was infected with feline immunodeficiency virus (FIV - the feline equivalent of HIV).
Facts to keep in mind:
- Glanders is an highly contagious disease, and highly fatal (B. mallei is even classified as a Class B bioterrorism agent).
- Animals that do recover from the disease can become long-term carriers of B. mallei, and are a risk to other animals (and people). Prompt euthanasia of affected animals is therefore often the primary means of controlling outbreaks (but the bacterium is susceptible to antibiotics).
- The infection can be transmitted to other animals (and people), usually through close direct contact or contact with oral and nasal secretions and discharge from skin ulcers. It can also be transmitted by eating tissues from infected animals.
- The bacterium is killed by most disinfectants, and UV radiation (sunlight).
Glanders can affect species other than equids, including people and cats, however there is very little information available about glanders in any felids, let alone lions and tigers. Theoretically it might be possible for the disease to spread from the zoo animals to feral cats and then to people, but I don’t know how many feral cats are brave (or stupid) enough to wander into a lion enclosure. There’s also a possibility that a glanders-positive feral cat may have infected the zoo cats (but again, it would have to be very brave, or very stupid). It is also unclear what tests were used to confirm that the big cats were infected with glanders, and it is unknown if other animals at the zoo have been tested. Since this is typically a disease of equids (and has also been found in goats and camels), I would certainly be checking these animals first.
The big question is, where did the glanders come from in the first place? It seems unlikely that the tigers brought it from Russia, when the disease is actually endemic in Iran (even though they’d had no diagnosed cases at the zoo for many years). Is there a carrier animal in the zoo? Were the animals infected by eating contaminated meat? Was it brought in by feral cats? The source needs to be identified and addressed or animals will continue to be infected, which is particularly bad news for the kinds of rare species that may be found in a zoological collection. Some more details about the testing would also be appreciated – given the severity of this disease, and the severity of the consequences for positive animals (euthanasia), one needs to be as sure as possible that these animals are infected with B. mallei and not something else.
Photo: Amur Tiger (Panthera tigris ssp. altaica) (click image for source)
Petting zoos are very common in the UK (as in many other regions), where approximately 2 million people visit 1000 different petting zoos every year. While the vast majority of petting zoo visits are simply pleasant outings associated with no problems, some people leave with more than just memories... they leave with an infectious disease. A letter in the latest edition of Emerging Infectious Diseases (Gormley et al 2011) describes one of the diseases people can pick up at petting zoos: cryptosporidiosis.
From 1992-2009, 55 outbreaks of intestinal infections associated with petting zoos were reported in England and Wales. (There were presumably many more unidentified cases or even outbreaks.) Of these, 55% were caused by E. coli O157. The second most common cause was Cryptosporidium, a protozoal parasite that is commonly found in feces of calves and lambs, which was responsible for 42% of the outbreaks and affected 1078 people. (Again, this is probably an underestimation of the true numbers because typically there are many undiagnosed or unreported cases of illness for every case that is identified). The number of people involved ranged from 2-541 per outbreak. Twenty-nine people were hospitalized due to the infection.
Factors associated with outbreaks were things that we know are issues with petting zoos:
- Contact with young lambs, calves or kids
- Inadequate hand hygiene facilities
Cryptosporidium outbreaks were also more common in the spring, as opposed to E. coli outbreaks which were more common in the summer. This may be explained by the association of the pathogen with contact with young calves, lambs and kids, since these animals are mainly born in the spring.
Alcohol-based hand sanitizers, while excellent for most bacteria, are ineffective against Cryptosporidium. This can also be a contributing factor to outbreaks of cryptosporidiosis, particularly if hand washing stations are replaced with hand sanitizers. While alcohol-based hand sanitizers are certainly better than nothing, their usefulness is limited when resistant pathogens (such as Cryptosporidium) may be present, and when peoples' hands might be contaminated with large amounts of dirt or other debris (e.g. feces).
Petting zoos can be great events, particularly for kids. However, kids, especially young kids (less than five years of age), are at high risk for certain infectious diseases they may encounter at such venues. While petting zoos seem to be improving and governments are paying more attention to making them safer, visitors need to look out for themselves.
- Make sure a hand hygiene station, preferably a hand washing station, is available. Do this before you touch animals.
- Always wash your hands after leaving the petting zoo, regardless of whether or not you touched an animal (since other surfaces you touched may have been contaminated).
- Do not have contact with young calves, lambs, kids (i.e. baby goats) or poultry.
- Do not have contact with diarrheic animals, or animals that appear to have any other health problems.
- Don't take food, drink or anything that might go into a child's mouth (e.g. baby bottles) into the petting zoo area.
- Closely supervise children.
- If you see a poorly equipped or run event, don't be afraid to contact your local public health office. While most petting zoos seem to be improving, some are still pretty bad and may need to be forced to do things right.
Recently, I wrote about a potential outbreak of respiratory disease in dogs in Ottawa, Ontario. That "outbreak" seems to have died down (as is common, since outbreaks typically burn out over a period of time). However, I had a call today about a similar situation that might be occurring in the Whitby (Ontario) area. A few veterinarians are reporting a spike in "kennel cough" cases, including some dogs with severe disease. Whether this is truly an outbreak, and whether it's related to the Ottawa situation are both unclear, but it's concerning to get two similar reports over a relatively short period of time.
Situations like this can be caused by a variety of factors, including
- Movement of a known pathogen into a new area. Emergence of canine influenza in Ontario is my main concern in this category.
- Increased disease caused by typical pathogens that are present in the area.
- Hyper-awareness (and increased reporting), as opposed to a true outbreak.
Veterinarians and dog owners should be aware that something different may be going on in different Ontario regions, and consider more thorough diagnostic testing should respiratory disease be encountered. Including testing for canine flu would be a good idea. The two most common and effective ways to test for this disease are:
- Seroconversion: Detection of an increase in antibody levels against canine influenza virus in blood samples taken 10-14 days apart.
- Detection of virus by PCR: This molecular test looks for viral RNA. Testing can be done by certain labs on deep nasal swabs.
Testing does cost money (not much, but free testing isn't available) and it's sometimes hard to convince people that testing is useful, since it may not change the treatment for an individual dog. However, it is important to find out what caused the disease in order to explain why disease happened, to help prevent further disease in the individual dog, to determine optimal vaccination programs, and to provide important information for protection of other dogs in the community.
I had a call from a colleague in Ottawa (Ontario) the other day, asking if I'd seen an increase in kennel cough in dogs lately. Kennel cough is a respiratory infection of dogs that can be caused by a variety of different viruses and bacteria, or combinations thereof, but is often associated with the bacterium Bordetella bronchiseptica. Apparently, this colleague's clinic has seen a large number of cases compared to normal, and he was wondering if the trend was more widespread and/or if there's something new out there to be concerned about.
Informal reports like this are often the key to identifying new problems. There are only a few reportable diseases of companion animals (such as rabies), and existing federal and provincial public health and animal health agencies tend to have little mandate regarding non-reportable infectious diseases of companion animals. That means that there is no centralized reporting or investigation for all these other diseases (in other words: we're on our own).
Most often, reports of higher disease rates or suspected outbreaks don't end up leading to anything. Things tend to revert back to baseline fairly quickly without any explanation of what happened. Sometimes, however, reports like this are the first in a series that can flag the emergence of a new disease or a change in existing disease patterns.
Is anything actually going on with kennel cough in Ottawa? It's hard to say. A report like this could be due to:
- A focal outbreak caused by exposure at a single kennel, park or event.
- A local outbreak of "run-of-the-mill" kennel cough that is being spread from multiple sources, but which involves the normal kennel cough bacteria and viruses.
- Increased reporting of the normal baseline rate of disease, with increased awareness leading to the appearance of an outbreak.
- A new disease (either a brand new disease or, more likely, the first instance of an existing disease in the area).
Whenever I hear reports like this in Ontario, I think about canine influenza. This virus is present in dogs in many regions of North America, but we have yet to identify it in Ontario (at least from the last data I have. We also couldn't find any evidence of canine influenza virus in a surveillance study we did a while ago). It is certainly possible that this virus could make it to Ontario, and I would not be surprised at all if canine flu caused a readily detectable cluster of respiratory disease cases when it arrived.
Should dog owners in Ottawa be worried? No.
Should dog owners and veterinarians in Ottawa pay attention? Sure. It's always good to be aware of things that are happening locally. Dog owners need to be aware of the risk of exposure to a variety of infectious diseases. Veterinarians should consider testing for canine influenza (and dog owners need to be willing to pay for the testing) if they see changes in respiratory disease patterns in their area.
How can dog owners reduce the risk of exposure of their dogs to respiratory diseases? Common sense. The more dogs that a dog meets, the closer they get to them and the less vaccination in the population, the greater the risk. Kenneling and other situations where many dogs get together increase the risk, and preemptive kennel cough vaccination should be considered in such cases. This vaccine doesn't protect against all causes of respiratory infection, but it can protect against some of the most likely causes. People should keep their dogs away from other dogs that look sick (especially dogs that are coughing), and if they have a sick dog, they should keep their dog away from other dogs for a few weeks.
A somewhat strange report from MSN News India describes measures that are being considered following an outbreak of salmonellosis that killed 3 tigers at Bannerghatta Biological Park. The zoo authority is investigating whether tests used by the Indian army to detect Salmonella in milk and milk products could be used to detect Salmonella in meat.
Testing of meat for Salmonella is a reasonable consideration, but it really depends on how often meat samples are contaminated.
- If most meat samples have Salmonella, what will be done with the results and the meat? The cats have to eat, and unless they have a plan to throw out all positive food or do something to it eliminate Salmonella (like cooking it), testing might be of limited use.
- Also, if Salmonella is usually there at low levels and problems only occur with sporadic high level contamination, or contamination with particularly virulent strains, then using a test that just says "Salmonella yes" or "Salmonella no" may not help much.
It is also reported that "the authority is also in talks with some firms to come up with a microwave which has the capacity to kill microbes in 300-400 kg of meat at a time."
- This is questionable since it's probably a lot of expense to develop a large microwave, and particularly since microwaving is not a reliable method of killing Salmonella. If there is a need to treat the meat to kill Salmonella, there are more reliable measures, such as cooking in a conventional oven, irradiation or high pressure pasteurization.
Another bizarre aspect is someone from the zoo authority stated "In Canada, when 7,000 pet dogs died on being fed infected beef last year, some firms there came up with a microwave with the capacity to kill microbes in 500 kg of beef in three to four minutes. We are exploring the possibility of similar technological innovation being implemented here, for which we are in talks with some technicians".
- I have no idea what this guy is talking about. I am not aware of any outbreak killing 7000 dogs in Canada (and if it really happened, I'm pretty sure I'd be well aware, if not in the middle of it).
On the positive side, all of the tigers that survived have now completely recovered and no new cases have been identified.
An investigation is underway regarding mysterious deaths of dogs that have been walked in public areas of Sandringham, the Queen's 20 000 acre estate in Norfolk. Gastrointestinal disease, consisting of vomiting, diarrhea and lethargy, has afflicted an unknown number of dogs. One area veterinarian reports five deaths and four dogs with serious illness. No cause has been identified, but it's unclear how much testing has been done to date. There was also a cluster of sick dogs last year, but that outbreak was written off as a one-time event caused by a virus.
Outbreaks like this can have a wide variety of causes, including viruses, bacteria, parasites or toxins. Determining the cause of a diarrhea outbreak is often difficult, because of the numerous potential pathogens/toxins, significant gaps in knowledge about what's normally part of the dog's intestinal bacterial population, and limitations of existing diagnostic tests.
(Another possibility is that this isn't really an outbreak, but rather increased reporting of disease that has always been there. I doubt that's the case here, but it is a possibility - dogs get sick all the time. If the baseline level of gastrointestinal illness is just now being scrutinized, and public awareness is increasing because of news reports, you can get a spike in cases that have nothing to do with an outbreak.)
The Animal Health Trust has been called in to investigate. This will presumably involve several approaches, including getting more detailed information about the number of sick dogs, identifying any common links among sick dogs, comparing activities of sick dogs with those of healthy dogs, and testing of feces for various potential causes of disease.
There's no word about whether the Queen's corgis are being restricted from the area.
The UK's Health Protection Agency is warning families who own reptiles about the risks of Salmonella, following the diagnosis of salmonellosis in 9 Merseyside children in the past 6 months. All the affected kids had direct or indirect contact with reptiles. Three of them (all less than three years of age) were hospitalized. One of them, an infant who was infected at four weeks of age, is still sick five months later.
Salmonella is commonly found in or on healthy reptiles. All reptiles should be considered Salmonella carriers, and handled accordingly. Standard guidelines are that children under the age of five, along with immunocompromised individuals, the elderly and pregnant women, should avoid contact with reptiles. The reason for this is clearly evident here, with the bacterium having caused serious illness in these young children.
Thinking that you can eliminate the risk in a high-risk household by making sure the high-risk person never handles the reptile isn't adequate. There are numerous reports of Salmonella infections in people who never had direct contact with the reptile. Salmonella can be spread from the reptile's enclosure to other parts of the house, resulting in indirect infections.
Reptiles can make great pets (I used to have tortoises and turtles). However, reptiles are responsible for a large and disproportionate number of Salmonella infections in people, and high-risk households should not have reptiles. People with reptiles need to take basic infection control measures seriously, including:
- Washing hands after contact with reptiles.
- Never cleaning aquaria or terrariums in kitchen or bathroom sinks.
- Never bathing or soaking reptiles in the bathtub, or kitchen or bathroom sinks.
- Keeping reptiles confined to their enclosures and not allowing them to roam the house.
More information about turtles and Salmonella can be found on the Worms & Germs Resources page.
A large whooping cough (pertussis) outbreak has been ongoing in people California in 2010. This bacterial infection, caused by Bordetella pertussis, is a highly transmissible disease that can result in serious problems (including death) in young infants. At last report, there were over 6000 cases of whooping cough, making this the largest outbreak in 60 years. Over 200 infants have been hospitalized, and there have been at least 10 deaths. Nine of the 10 deaths were in infants less than two months of age. Infants in this age group have little to no immunity to the disease because they haven't been vaccinated, and they are more prone to severe complications.
Bordetella pertussis is a human bacterium. It does not infect animals and animals are not direct sources of infection. (Actually, experimental infection of neonatal puppies with large doses of B. pertussis can result in shedding of the bacterium by a small percentage of dogs, but that's not particularly relevant to the normal household situation). Therefore, people don't need to worry about infecting their pets and pets passing the infection on to other people. However, it's not impossible that pets could play an indirect role in transmission. A pet's haircoat could possibly become contaminated with the pertussis bacterium from someone coughing around it, or touching it with contaminated hands. The bacterium could survive on the haircoat for a while (probably days), and someone could potentially get the bacterium on their hands by petting it, and subsequently become infected.
What are the odds of this happening? Who knows. It's not something that anyone has investigated, as far as I know.
Could dogs and cats be important sources of pertussis in households? Probably not. I assume that if there is a person with whooping cough in a household, that person is more likely to be the source of infection for other people than a pet.
Could pets spread pertussis outside the home? That might be a more realistic concern. People with pertussis might keep themselves away from others and stay at home, but if they contaminate their dog's coat and the dog meets people on a walk or at the park (or at a veterinary clinic, or anywhere else), I have to wonder whether there could be the potential for spread of the disease.
What should we do about this? Common sense should prevail, and itt's important for pertussis as well as other diseases. If someone in the household has an infectious disease that is transmissible and for which a pet could potentially be a vector, some basic precautions should be taken. Good attention to hygiene might help reduce contamination of the pet's haircoat. This includes regular handwashing (especially after coughing and before petting an animal), avoiding coughing close to the pet and not letting the pet sleep close to the person's head. Keeping the pet away from people outside the house, or at least limiting it's contact with high-risk people might also be useful. In particular, keeping pets that might have been contaminated away from infants would be wise.
Overall, the risks are very low. We don't need to fear dogs and cats as potential pertussis vectors. However, in the absence of proof that there's no risk, and with a highly transmissible and potentially serious disease, use of some simple infection control measures makes sense.
A Salmonella outbreak at the Bannerghatta Biological Park in Bangalore, India, has resulted in the death of three tigers. The latest victim, a four-year-old female tiger named Minchu, had been critically ill for the past two weeks and died of kidney failure. (Kidney failure is a potential complication of severe intestinal bacterial infections like salmonellosis.) This followed on the deaths of Minchu's older sister Divya and a 45-day-old tiger cub. Fifteen of the remaining 41 tigers are sick, and more deaths would not be surprising.
The source of the outbreak at the Bannerghatta Biological Park hasn't been reported. Likely, it originated from Salmonella in raw meat. Whether the large outbreak indicates a highly contaminated batch of meat, a particularly virulent strain of Salmonella or widespread transmission of Salmonella from an initial case or two is not clear. Regardless, good infection control practices are going to be critical, since the animals' environment is certainly highly contaminated. This poses a risk to all animals and people exposed to the environment. Good infection control is also needed to prevent Salmonella from spreading to other parts of the park. Spread is most likely to occur via peoples' hands or clothing, or through contaminated equipment.
Large Salmonella outbreaks can be very hard to contain. Aggressive infection control, including testing of animals, isolation, thorough cleaning and disinfection, restriction of movement, and re-assessment of various management practices are key aspects of any outbreak control program. Hopefully this outbreak is now under control and Salmonella doesn't "escape" and affect other animals or people at the park.
The Public Health Agency of Canada (PHAC) has issued a public advisory regarding salmonellosis linked to frozen rodents used as pet (reptile) food. The rather vaguely-worded advisory states that there have been seven reported cases of Salmonella caused by a specific strain that has been linked to frozen rodents. No details about the cases or the origin of the rodents are provided, however it presumably involves the large international Salmonella outbreak associated with Mice Direct, a mail-order rodent company. The advisory reminds people to take basic precautions when handling rodents that are used for reptile food.
Basically, the key is to consider all such frozen rodents biohazardous, and handle them accordingly. Remember to:
- Limit contact with the rodents as much as possible.
- Thaw them in a sealed container, preventing any contact with human food.
- Keep them away from kitchen countertops and other food handling surfaces.
- Wash your hands thoroughly after handling them.
An article released today in the journal Pediatrics (Behravesh et al, 2010) provides more information about a salmonellosis outbreak linked to pet food. The outbreak itself is old news - I commented about it almost two years ago. What is new is the detailed epidemiological analysis of the outbreak, and there is some interesting information in the paper that is worth reporting. Here are the highlights:
Almost 50% of people who were infected were kids two years of age or younger.
- That's not too surprising considering kids less than five years of age are a high-risk group for getting sick after being exposed to Salmonella.
Households with sick people were almost 7 times as likely to have recently purchased the affected food.
- This provides good evidence of the link between the contaminated food and disease.
The Salmonella strain that was found in people was also found in bags of pet food at the manufacturing plant, samples from the manufacturing plant environment, and fecal samples from dogs that had eaten the food.
- This is pretty convincing evidence that the food was the source. Because they were able to type the Salmonella strain in people and it was an uncommon strain, and they then found the same uncommon strain in food, animals and people, it paints a pretty clear picture of what happened.
Illnesses occurred over a 3 year period.
- This is pretty concerning. This was more than a little lapse at a plant that led to contamination of a single batch of food or a short term event. This was a major failure in quality control that was undetected for a long period of time, resulting in at least 79 human infections in 21 US states.
A cluster of infections caused by the strain involved here, S. Schwarzengrund, was identified early in the outbreak. However, a link with pet food was not considered until the following year.
- That's unfortunate but maybe not surprising. There are a lot of other more likely sources of infection that were probably focused on initially. "What kind of pet food do you feed your dog?" was unlikely to be a routine question asked of people with infections. Identification of outbreaks caused by uncommon events is difficult and typically takes more time.
People that fed their dog in the kitchen were 4 times as likely to have an infection.
- Feeding a pet in the kitchen presumably increased the chance of cross-contamination with human food or contamination of the food preparation environment.
The cause of contamination was never identified. The authors of the paper suspected that contamination occurred after extrusion (the process during which the kibble is formed), which makes the most sense. The extrusion process results in high enough temperatures to kill bacteria like Salmonella. Possible causes of contamination include contaminated equipment used after extrusion, cross-contamination of pre- and post-extrusion food and contamination of substances (e.g. flavour enhancers) sprayed on kibble after extrusion. The fact that Salmonella was found in the room where materials were sprayed on the kibble supports this further.
In general, dry pet food is quite low-risk in terms of Salmonella contamination, but just like with other non-raw-animal products such as lettuce, tomatoes and sprouts, contamination can occur and human infections can result. The best way to reduce the risk is to use good general hygiene practices, particularly washing hands after handling food, keeping pet food and pet food bowls out of kitchens and limiting contact of young children and other high-risk individuals with pet foods.
MiceDirect, a company that sells frozen mice, rats and chicks as reptile feed, has issued a recall because of Salmonella contamination of their product. Contaminated critters have been sold across the US (except Hawaii) through mail order and pet stores, and recalled product codes can be found in the FDA recall notice. Contamination isn't a big deal for the reptiles, since carriage rates for Salmonella are already high and they are usually healthy carriers. The concern is for people who handle the frozen rodents/chicks (or who can be exposed indirectly from contaminated surfaces in the home). There have been previous outbreaks of human Salmonella infections associated with contaminated frozen rodents.
Unlike many other recalls where the product is recalled because of contamination but without evidence of human illness, human illnesses suspected to be linked to contaminated reptile food have been identified in 17 states. In reality, reported cases may be the tip of the iceberg, and I suspect that if cases in 17 states are confirmed, there will be (or may already be) many more. Other details regarding these cases and the recall, such as the strain of Salmonella involved, haven't been released.
In response to this problem, the FDA report and the company website indicate that products from MiceDirect will be irradiated. It's not clear if this will be a standard protocol from now on, or whether it's a short-term response to the contamination problem. Considering the repeated outbreaks associated with frozen reptile food, irradiation sounds like a good standard practice. Perhaps the best way to help make (or keep) it a standard practice industry-wide is for consumers to vote with their wallets: ask for irradiated or otherwise treated (e.g. high pressure pasteurization (although I'm not sure what that would do to a mouse)) feeds to reduce the risks of contamination.
Because of recurrent problems with contaminated frozen reptile feed, if people are not buying products that are treated to eliminate contamination, they should assume that all such feed is contaminated and handle it accordingly. That means using basic practices such as:
- keeping frozen reptile feed away from human food
- if defrosting it in the refrigerator, keep the reptile feed in a sealed container that is not used for human food and that is disinfected afterward
- washing hands after handling the feed
- disinfecting any potentially contaminated surfaces that come in contact with the feed
- discarding uneaten food promptly, since Salmonella can multiply as uneaten food sits in the open, especially in a nice, warm reptile terrarium
A link to more information about MiceDirect is available through a post on Barfblog.
A study we just published in the journal Veterinary Record (Floras et al 2010) described an MRSA outbreak in a dog breeding kennel. That's a little unusual in itself, but considering how MRSA is spreading amongst the dog population, it's not really astounding. What was unique about this outbreak was the strain of MRSA that was involved, sequence type 398 (ST398).
ST398 MRSA is commonly referred to as livestock-associated MRSA, since this strain seems to have originated in pigs, and is commonly found in pigs and calves in some regions of the world. It can also infect people, and high rates of carriage of this MRSA strain can be found in pig farmers, pig vets and other people with close contact with livestock. In some areas of Europe, this strain is a big problem, accounting for a large percentage of human MRSA infections. Interestingly, it seems to be a rare cause of illness in people in North America (at least at the moment).
Dogs seem to be innocent bystanders when it comes to MRSA. The vast majority of MRSA strains found in dogs are common human strains, indicating that, ultimately, MRSA in dogs originated in people. There are only two other reports of dogs with ST398, both from Europe. One was a dog with a skin infection. The other was a healthy dog (a carrier) who was owned by a pig vet.
This kennel outbreak involved a larger number of dogs, including both healthy carriers and sick dogs. Overall, MRSA was isolated on at least one occasion from 23/42 (55%) dogs in the kennel. In a couple of litters, most of the puppies were identified as carriers, but fortunately most stayed healthy. MRSA caused skin infection in one puppy and mastitis in a mother dog, and was also found in the respiratory tract of a puppy that died (although it may or may not have been the cause of death).
The source of the ST398 was not identified. One of the owners worked on a pig farm, but MRSA was not isolated from either owner. It's most likely that the owner did bring MRSA home from the farm, either as a transient carrier (in their nose) or as a contaminant on their skin. Regardless, once it got into the kennel, it was able to move between dogs, either from dog-dog contact or with the help of human hands. Fortunately, ST398 MRSA carriage by dogs seemed to be transient in this situation, which is consistent with what we know about carriage of other strains. MRSA is not really adapted for long-term survival in dogs, so they only carry it for short periods of time. That's a big advantage when it comes to trying to control this pathogen.
While we have to be careful to not over-interpret data from only a few studies, this report indicates that ST398 can cause disease in dogs and it can be present in apparently healthy dogs. It can also be spread relatively easily amongst dogs in a breeding kennel situation. While a pig-link was not confirmed, it's reasonable to suspect that dogs with contact with pigs (and perhaps other livestock) might be at higher risk of developing ST398 infections, as is the case with people.
This is a perfect example of the one medicine concept, and why we need to think about infectious diseases in broad terms, not just focusing on specific populations or species. This situation involved a pig Staphylococcus aureus that somehow acquired methicillin-resistance, spread widely around the world (most likely in pigs, initially), spread to people, and then likely spread to another species, in this case dogs.
An Indianapolis area shelter recently put out a public call for foster homes to help deal with an outbreak of respiratory tract disease in cats. They were trying to find homes for sick cats, presumably as part of a plan to depopulate the humane society to help control the outbreak. This is what a lot of people have said that the OSPCA should have done in the recent ringworm outbreak in Newmarket, Ontario. But these are two completely different issues.
The main difference is the nature of the infection. Feline upper respiratory tract viruses only infect cats. Therefore, foster homes that don't have cats can take them safely. Ringworm can affect people and other animals. Every household has some individuals that are susceptible to ringworm. Therefore, cats with respiratory tract infections pose no risk to appropriate foster households, while the same can't be said about ringworm. Reportedly, six staff members and two volunteers have contracted ringworm so far in the Newmarket outbreak.
Fostering a cat with viral respiratory tract disease is relatively easy. You just treat it like any cat and watch for signs of worsening disease or secondary infection. Fostering a cat with ringworm is not as easy. You need to keep it isolated to keep it from spreading the infection through contact with people and animals, and to prevent contamination of the household environment. You need to wear proper protective clothing when handling it. You probably need to treat it, such as giving it a bath twice a week and/or oral medication every day. It's not rocket science, but it takes a lot of time and commitment. Importantly, it takes long-term commitment, since you need to do this for weeks or months. You can't get into a situation when foster homes get bored and want to return the animal before it is considered non-infectious.
In all outbreaks, one of the most important steps is to figure out what happened and why. A detailed (and ideally arms-length) investigation needs to be performed to identify problems with animal management, medical care, general protocol, communications and other areas, and to make any required changes to reduce the risk of it happening again.
The OSPCA has changed their plans for management of the ringworm outbreak that is ongoing in a Newmarket, Ontario shelter. Now, some (hopefully all) remaining animals will be fostered out to local veterinarians while the situation is being brought under control.
One question that has been asked widely in the press and by the public is why these animals haven't simply been sent to foster homes. Particularly now, with all the attention, there would presumably be many people willing to take in these pets. However, putting animals infected or potentially infected with ringworm into foster homes is a controversial and potentially problematic situation, because ringworm can be spread easily to people and other animals in the household. Sending out an animal that is or may be shedding a zoonotic disease is a tricky situation, and one that can't be taken lightly. Additionally, proper management of these animals can take significant time and effort.
A better approach is to send the animals to places where they can be properly, safely and humanely isolated and treated. Veterinary clinics are a logical option, and a request has been sent to clinics in the area to take animals for quarantine and treatment. The reason veterinary clinics are being solicited is that many clinics have the ability to properly house these animals in isolation units and have the expertise and commitment to properly treat them.
Nonetheless, this is no small favour to ask of these veterinary clinics. Just as taking an infected pet into a household carries some risk, taking these animals into a clinic is also associated with some risk of transmission to people and other animals. However, with proper facilities and protocols, and the donation of sufficient personnel hours to implement those protocols, the risks should be minimal. To facilitate this, we have developed an information sheet with infection control and treatment recommendations for veterinary clinics. For anyone else who is interested, the document can be found here and on the Worms & Germs Resources page under Information Sheets For Veterinarians.
Image: Ringworm lesions on the paws of a dog. Although this is how "classic" lesions tend to appear, clinical signs of ringworm in pets can be highly variable. (click image for source)
The recent ringworm outbreak in a Newmarket, Ontario shelter has focused a lot of attention on shelter outbreaks, outbreak prevention and management. A common question that I've been getting in the last couple of days is "Why do these outbreaks occur?"
There are many reasons why an outbreak can develop. I have no first-hand knowledge of the Newmarket outbreak, and don't know what prompted that outbreak, but here are some general causes of outbreaks.
- Shelters need clear and logical protocols for all things dealing with animal care. This needs to include aspects like where new animals go, what types of evaluation and monitoring are performed, vaccination and deworming plans, when animals need to be tested or treated, when they can be released from quarantine, how to record and report infectious diseases, how to clean and disinfect areas and items, personal hygiene, and protective clothing, among other things. These protocols need to be in writing and accessible to all personnel.
- Shelters often have large numbers of staff, many with minimal training in animal husbandry or medicine. Proper training is required to ensure that they know what to do and why. (The latter is important because if people know why they need to do something, they are more likely to do it.) Training programs need to be well-structured and formal, not casual, follow-someone-around-and-see-what-they-do training.
- Even with good protocols and training, the facility managers need to ensure that protocols are followed. They need to enforce protocols and address problems with compliance. They need to make sure their protocols are up-to-date and consistent with best practices.They need to monitor disease rates and concerning trends of illnesses, so that problems can be identified early. They need to know when to get advice and who to ask (see below).
- Some facilities (or actually, most facilities) are not well designed in terms of infection control. That makes it harder to prevent disease transmission and contain problems. Limitations in isolation/quarantine areas may result in mixing of new (and more likely infectious) animals with those ready for adoption. Few sinks may reduce handwashing, a key component of infection control. A facility that is too small for the animal load results in cramming in too many animals.
- If staff (from management on down) don't understand the issues, they may not act appropriately. Proper routine preventive measures and outbreak response measures may not be convenient, easy or cheap. There must be motivation to implement them. If there is little awareness of the problem, people are less likely to do what is needed.
Failure to act appropriately when the first cases are identified:
- It is much easier to contain a problem when you act early. If only a few animals have been infected or exposed, it's much easier to take aggressive measures. Once you get a large number of infected or exposed animals, it's much harder to do things like properly separate different groups (e.g. infected vs potentially infected vs non-infected). The more animals affected, the greater the chance of further transmission. Keeping your head in the sand and hoping things will go away can result in a small containable outbreak becoming a facility-wide, difficult-or-impossible-to-contain outbreak.
Failure to get good advice:
- People working in shelters can't be expected to be experts in all aspects of infectious diseases and infection control. That's why getting good advice (and following it) is critical. Sometimes, people don't ask for advice or don't go to the real experts. This can happen because they don't really understand the problem, don't know who to contact, don't want to admit they don't know everything or don't realize they are in over their heads. A little good advice, especially early, can make a world of difference.
- Ultimately, you can have an exceptionally run facility and still get an outbreak. By the nature of what shelters do, they bring in a lot of animals with potentially infectious diseases and have many animals that are at higher risk of getting sick if they get exposed. It's much less likely to occur with a good infection control program, but you can never 100% guarantee nothing bad will happen. You can't do much about this. All you can do is make the best program possible, and try to limit any problems that develop.
Never a dull moment...
This morning the Toronto Star published an article about the intended euthanasia of 350 animals at a humane society in Newmarket due to an ongoing ringworm outbreak. This was quickly followed by another article about the same event that gave a few more details, including some comments from the OSPCA chief executive officer Kate MacDonald, who confirmed that the euthanasias had begun. A "very aggressive strain" of ringworm and "human error" (related to a breakdown in protocols) are currently being blamed for this morning's actions. A lot of people are (understandably) very upset. No one ever wants to see an infectious disease outbreak come to something like this.
I’m hesitant to comment too much at this stage, because we still don’t have all the facts - apparently even the duration of the outbreak is unknown. No one has said if all 350 animals are infected (or what percentage of them are), nor how many other animals are present at the shelter. We also don’t know what’s already been tried in terms of controlling the outbreak.
A few facts about ringworm (dermatophytosis) that people need to remember:
- Ringworm is a skin infection that can be caused by several species of fungi. It is not a "worm" at all. It is also very easily transmitted by direct or indirect contact with infected animals - their fur, their cages, their blankets, or anything else that may be contaminated with infected skin cells or hair. Such infectious material can even be spread over short distances (e.g. room to room) in dust that is stirred up into the air.
- Ringworm is transmissible to people, so with a large outbreak there are also issues with staff safety, and concerns with adopting out infected animals. For most people ringworm infection may cause itchy, uncomfortable skin lesions, but for higher-risk people (e.g. very young children, the elderly or immunosuppressed individuals) the infection can be much more serious.
- There are also a lot of animals (particularly cats) that carry ringworm without showing any signs of infection. If the Newmarket shelter has 350 animals with clinical signs of ringworm (a detail about which we have no information right now), that’s pretty bad, but even the animals who don't appear to be infected may be carrying the fungus and could spread it to others.
- Crowding, close contact and warm, humid environments are all factors that increase the risk of ringworm transmission. These are also all factors that are very hard to control in a crowded animal shelter.
- Ringworm is treatable, but it is not cheap or easy. Animals typically require systemic therapy (usually oral medication, which can be very expensive particularly in large dogs) as well as whole-body topical therapy (e.g. dips, shampoos, sprays), and they need to be treated for several weeks. Decontamination of the environment at the same time is critical to prevent reinfection.
Cleaning up a ringworm outbreak at a shelter with at least 350 animals is no small undertaking. The second article in the Star also describes personnel at the shelter this morning wearing "white hazardous material suits, latex gloves and plastic covers over their shoes", which would be considered reasonable precautions for entering a highly contaminated environment.
I'm sure we'll hear more about this in the days to come, and hopefully that will include more details about why the mass euthanasia was deemed necessary by the OSPCA.
Photo source: yorkregion.ontariospca.ca via www.thestar.com
In 2007, there was a massive equine influenza outbreak in Australia. A large number of horses were infected in this country that was previously equine influenza-free, and there was tremendous economic disruption caused by containment measures. It turns out horses weren't the only animals infected. A report in the April edition of Emerging Infectious Diseases describes influenza infections in dogs associated with the equine outbreak.
In some ways, it's not too surprising. Canine influenza in North America is caused by H3N8 influenza that moved from horses to dogs. Similarly, H3N8 influenza of equine origin has been identified in dogs in the UK. So, while it's an uncommon event, we know that in some situations, the "standard" equine H3N8 influenza virus can infect dogs.
The first dog that was diagnosed lived near a large horse stable. The dog developed typical signs of influenza: decreased appetite, lethargy, nasal discharge and cough. After the first dog was identified, other dogs were noted to have similar signs, including dogs whose owners had contact with infected horses and dogs that had contact with other sick dogs. Some dogs had severe infections. Influenza was diagnosed through detection of antibodies in their blood, and the influenza virus was isolated from one dog. The virus that was isolated was the same as the one present in horses (and different from that in US dogs).
For influenza to jump between species a few things have to happen.
- First, the virus has to be able to infect the other (non-natural) species. This can happen because the virus is inherently able to infect different species or because of a random viral mutation that allows for infection of the new species.
- Second, the virus must encounter that host (in this case, dogs). It must then be able to multiply within the new host.
All this can happen with or without development of disease. For the virus to truly establish itself in the new species and spread (like canine flu did in the US):
- The virus must be able to multiply well in the new host, and adequate virus levels must be produced for the new host to be a source of infection to other individuals.
- The new host must come into contact with other susceptible individuals.
- The virus must be able to infect new hosts readily enough to maintain infection in the population, instead of dying out after a couple transmission cycles.
In these Australian cases, while it is apparent that equine flu was able to infect dogs, there was no clear evidence that perpetual dog-to-dog transmission occurred. Influenza virus was rarely detected in nasal secretions from infected dogs, making it unlikely that the virus would spread between dogs. Therefore, the virus was not able to establish itself in the dog population. This means it ended up being only an interesting situation that affected a limited number of animals, instead of the creation of a new, self-propagating infection that could continue to circulate in dogs in the country.
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.
In response to ongoing problems with rabies in raccoons in New York's Central Park, a vaccination program is now underway. Raccoons are being trapped, vaccinated, tagged and then released. This is a logical response to the outbreak and one that will hopefully have a significant impact.
Trap, vaccinate and release programs can help in a few different ways. Firstly, they protect the individual raccoons that are vaccinated. However, in the bigger picture, mass vaccination is designed to protect humans and animals beyond those that are vaccinated (this is referred to as "herd immunity" - click here for a good video about this concept from a previous post). As the number of vaccinated (and therefore immune) individuals in a population increases, there's less risk of ongoing transmission of the disease (in this case, rabies), since an infected animal is less likely to encounter a susceptible (unvaccinated) individual. If, on average, an infected individual does not have a chance to infect another individual, the outbreak will eventually die out. The key is getting a high enough percentage of the population vaccinated.
For eradication of dog rabies, the World Health Organization recommends vaccinating at least 70% of dogs in a population. I'm not sure what the critical number is for raccoons, but it's presumably a similar, and reasonably high, number. Since a high vaccination rate is needed, there needs to be a concerted effort to do more than just a token vaccination program. It also helps if there's good information about raccoon numbers and distribution in the area. As long as the Department of Health is serious about this program and puts the required time and resources into it, the odds are very good that it will be successful.
The latest edition of the journal Emerging Infectious Diseases contains a paper describing the 2008 Australian Hendra virus outbreak in horses and people.
In this outbreak, there were five horses infected and two humans infected. The horses predominantly had signs of neurological disease, not respiratory disease like some other reports describing this disease. Four horses died. One recovered but was euthanized for public health reasons.
Two people became infected after working with the sick horses, which represents 10% of the total veterinary staff that were exposed to the infected horses. Both people started off with influenza-like illness, which seemed to improve initially, but then signs of severe neurological disease developed. They were treated with ribavirin, an antiviral drug, as part of an experimental treatment. One of them died after 40 days of illness, the other person survived.
The authors stressed that the effectiveness of ribavirin could not be determined, but they recommend it nonetheless because of the severity of Hendra virus infection and lack of other options. Ribavirin was also used in the 2009 outbreak, but it is clearly not 100% effective since one person died there also.
A number of concerning activities occurred that put people at risk of infection, including a "percutaneous blood exposure while euthanizing an infected horses" (they didn't explain exactly what this was, but it could have been a needlestick), low use of personal protective equipment, and contact with potentially infectious body fluids. This is unfortunately not surprising since the approach to infection control (particularly in terms of zoonotic infections) is often lax in equine medicine. That certainly has to change, particularly in areas where Hendra virus may be present.
Much more information about how to control this potentially devastating virus is needed. Fortunately, infections are uncommon and it is restricted to a fairly small geographic range in Queensland, Australia.
Image source: http://animalphotos.info/
This Worms & Germs blog entry was originally posted on equIDblog on 27-Jan-10.
The CDC is investigating an apparent multistate outbreak of salmonellosis associated with contact with frogs. As of December 7, 48 infected people had been identified from 25 states - a pretty remarkable distribution. People got sick between June 24 and November 14, 2009. As is normal for Salmonella outbreaks linked to animals, young children have been more commonly affected, with kids under 10 accounting for 77% of cases. Fortunately, no one has died.
As part of the investigation, contact with animals was investigated and their preliminary analysis indicates contact with water frogs like African Dwarf frogs is the likely source of infection.
Amphibians often get ignored when it comes to zoonotic diseases. The risk of salmonellosis associated with reptiles is fairly well known, but not too many people think about the risk associated with amphibians. The same general guidelines for keeping and handling reptiles should be used for amphibians:
- Children under the age of five should not have contact with amphibians, nor should people with compromised immune systems.
- Hands should be thoroughly washed after handling frogs or having contact with their environment (terrarium/aquarium).
- Frogs should not be allowed to roam freely in the house.
- Aquarium/terrarium water should not be dumped out in the kitchen sink. Ideally, amphibian habitats should be cleaned outside. Care should be taken to prevent contamination of the household environment.
- Amphibians should not be kept in childcare facilities or kindergarten classrooms.
A very poorly-written and confusing report suggests that another Streptococcus zooepidemicus outbreak is underway in dogs in a shelter in Ohio. Five of 175 dogs on the premises died suddenly of hemorrhagic pneumonia. The report variably mentioned a "virus that mutated from horses," that it's thought to be "not contagious" despite multiple dogs being affected, and that it's a "rare form of streptococcus" (a bacterium). Presumably, they are dealing with a group of dogs with Streptococcus zooepidemicus pneumonia (technically, Streptococcus equi var. zooepidemicus). This bacterium predominantly lives in horses but periodically causes infections in other species. Outbreaks in dogs are uncommon but have been reported in other shelters. I assume that cultures from the dead dogs identified the bacterium, otherwise other possible causes such as canine influenza would also have to be considered.
The statement about it not being contagious is bizzare. Obviously, it is contagious between dogs. It may have been referring to dog-to-human transmission, but while that's rare it has been reported.
The shelter is apparently treating all dogs with penicillin prophylactically (i.e. to prevent any more dogs from getting sick). There's no clear guidelines regarding management of S. zooepidemicus outbreaks in kennels. It's now known whether mass antibiotic treatment does anything helpful, but it has been used in other outbreaks. I think it's likely that these outbreaks stop on their own, rather than penicillin having a major impact, and that there's probably another underlying cause such as a viral infection to account for outbreaks of this rare disease. However, that's just speculation for now. Hopefully this outbreak will cease with whatever treatment and infection control measures they put in place (or on it's own). Hopefully a good review of routine infection control practices will be performed at the same time, as routine practices (or lack thereof) are often a major problem in shelters.
A large number of rabies cases in Santa Cruz County, Arizona has lead to the rare practice of implementing a county-wide rabies quarantine. Fifty-four cases of rabies have been diagnosed so far this year, mainly in skunks. That's about twice as many as normal.
Quarantine is probably not the best description of what they are doing, but they are taking measures to improve vaccination of pets, reduce roaming pets and discourage human-wildlife interaction.
For the next 60 days, the following rules are in place:
- Dogs and cats must be vaccinated against rabies.
- Dogs must be confined to the property or on a leash.
- People are not allowed to feed wild animals.
- Pet food must not be left outdoors after sundown.
Those are all pretty standard measures that should be used anytime. It sounds like these rules already exist in Santa Cruz County but their "quarantine" means that they will be aggressive in enforcing them. Increasing enforcement is a good idea, but ongoing efforts after this quarantine period are also needed because rabies will continue to be a risk in that area.
Image source: www.acmeanimalremoval.com
You'd think, after countless outbreak of salmonellosis associated with pet turtles, that people would learn and things would start to improve. I guess not. A paper published this week in Pediatrics (Harris et al) described a large outbreak of Salmonella Java associated with pet turtles. Between May 2007 and January 2008, 107 infections were identified. The median age (the age in the middle of the range of affected people) was seven years old. Sixty percent of infected people reported exposure to turtles during the week before they got sick; 87% were small (<4 inch) turtles, and 34% were purchased at a retail store (despite the fact that the sale of turtles less than 4 inches long is banned in the US). Five infected people, all less than 10 years of age, reported kissing the turtle or putting it in their mouths.
When they compared people with Salmonella Java infection to people without the infection, 72% of people with Salmonella reported contact with turtles versus only 4% of controls.
Salmonella is far from rare but it's nothing to ignore. Thirty-three percent of infected people were hospitalized. Fortunately, no one died.
The link between turtles and Salmonella has been known for a long time. Healthy turtles can carry the Salmonella bacterium and be a source of infection, particularly for children. The sale of small turtles is banned in the US to reduce the likelihood of close contact between turtles and kids, but this law is widely flouted. An understanding of the link between turtles and Salmonella is surprisingly uncommon - only 32% of Salmonella patients in this study (and 28% of controls) reporting knowledge of this link. Clearly, there are a lot of areas which could be improved.
- If banning the sale of small turtles is truly an effective measure, then it should be enforced. "Black market' turtles are far too easy to find.
- More public education is needed, among the general population and particularly people buying turtles. You shouldn't be able to take a turtle home from a store without an information sheet about the risk of Salmonella and how to avoid it.
- People with turtles (or any reptile) need to recognize the risk and act appropriately. Good general infection control and hygiene measures are needed to reduce the risk of Salmonella exposure.
- Households with children under five years of age, or with immunocompromised individuals should not have pet turtles.
- Antibiotics are not the solution. Attempts to create Salmonella-free turtles with drugs have just led to the production of turtles carrying antibiotic-resistant Salmonella.
- Common sense needs to be a little more common. The picture above (from http://www.familylovezone.com/js_DeepAndWide.htm) was proudly posted by a parent.
More information about infectious disease risks associated with turtles can be found on the Worms & Germs Resources page.
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.
Tuttle Animal Medical Center in Florida has reported six dogs with severe bloody diarrhea, vomiting and fever, over the past month. The affected dogs were from the same general area in Sarasota County, and all but one died within 24 hours. However, care must be taken when interpreting information such as this. Apparently, most dogs were owned by people with limited finances, so it's hard to say whether they would have died if aggressive (and expensive) treatment could have been provided. A disease like parvovirus is highly fatal without treatment, but survival rates are excellent if proper treatment is provided.
Initial testing of these dogs to identify the causative agent has been unsuccessful, including a rapid in-clinic test for parvovirus. Because of limited finances, complete diagnostic testing has not been performed, and it's likely that only a very limited range of possible causes have been investigated. That's a problem with a user-pay system such as this. There's no incentive for owners of dead pets to pay for further testing that could help understand the problem and/or help other peoples' pets.
Various experts have been consulted, but it sounds like there is minimal material (e.g. saved fecal samples) to use for further testing. Trying to make a diagnosis based on clinical signs and basic laboratory data collected by the clinic during standard work-up and treatment is essentially impossible. Veterinary infectious disease expert Dr. Cynda Crawford told VIN News Service by e-mail last Wednesday "There is very little case material to work with, so am struggling with meaningful diagnostic approaches,...Everything is basically speculation at this point."
Florida's Division of Animal Industry is apparently "monitoring the situation." At this point, there's nothing that can really be done, but hopefully assistance with testing will be provided should further cases be identified. One official from this agency speculated that E. coli O157 could be the cause. That seems pretty unlikely. This bacterium can cause disease in dogs but it's quite rare. Six apparently unrelated cases due to such a rare cause seems pretty unlikely, although it shouldn't be dismissed.
A general tenet of medicine is "common things occur commonly." Situations like this are most often unusual presentations of a common disease (e.g. parvovirus) rather than a new disease. More aggressive diagnostic testing for known causes of disease, along with additional testing to try to identify new pathogens is needed if further cases are identified. Sometimes apparent outbreaks like this go away on their own without any intervention or diagnosis. Only time will tell whether this is a small local event or the "tip of the iceberg."
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.
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.
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?
A large outbreak of rabies continues to have devastating effects in Angola, Africa. While rabies outbreaks are not uncommon in some parts of the world, the number of people affected in this outbreak is remarkable. A hospital in Luanda, the nation's capital, has diagnosed rabies in at least 93 children in the past 3 months. All have died. The main source of the disease in this case is Angola's large stray dog population. Stray dogs can transmit rabies to other dogs and people through bites. The poor socioeconomic status of the country increases the risk of outbreaks like this because:
- Vaccines are not readily available (for dogs or people)
- It is difficult to organize and fund vaccination programs for stray dogs
- It is difficult to educate the general population about how to avoid and manage rabies exposure
- The healthcare system is relatively limited
These problems, all related to a poor economy, create a "perfect storm" for a rabies outbreak. The shortage of human rabies vaccine and the high cost of post-exposure prophylaxis (PEP) makes it much more likely that people will actually develop signs of rabies after being exposed. The cost of PEP is more than the average Luanda family makes in a month.
Fortunately, the outbreak seems to be waning. However, without improvements in stray dog management (including vaccination) and access to adequate PEP, future outbreaks and problems are inevitable. It was reported that "adequate" supplies of canine rabies vaccine are now available. Hopefully, a concerted effort to vaccinate as many dogs as possible will reduce the rabies load in the canine population, thereby helping to decrease the risk to the people living in the area as well.