I would have thought this would fall under the realm of common sense, but as the saying goes: Common sense is like deodorant, the people that need it the most don’t use it.
A recent report out of Scotland is warning people not to kiss their pet reptiles, in response to four people who were hospitalized with salmonellosis after kissing bearded dragons, and other reptiles.
Reptile-associated salmonellosis is a major concern, and while there are ways to make reptile ownership very safe for most people, some risk will always remain. Certain behaviours will increase that risk. A large percentage of healthy reptiles have Salmonella in their intestinal tracts, and anything that’s in the intestinal tract ends up in the animal’s habitat and on its skin. Kissing reptiles is an obvious way to be exposed to this bacterium, which can cause serious disease in some situations.
Among the report's recommendations are:
- Families that own a bearded dragon or similar reptiles are advised to consult their doctor if they become ill with symptoms of fever, vomiting, abdominal pain and/or diarrhoea.
- They should also inform their GP that they keep a reptile. Children are particularly at risk because they like to stroke and handle pets.
- NHS Forth Valley have also issued a guide for pet owners to reduce the risk of catching Salmonella from lizards, which includes supervising children to make sure they do not put the animal, or objects it has been in contact with, near their mouths.
- It also recommended washing hands with soap and water immediately after handling a reptile, its cage or any other equipment, keeping a reptile out of rooms where food it prepared or eaten, and disposing of droppings and waste water down a toilet, rather than in a sink or bath.
Just common sense.
More information about reptiles and Salmonella can be found on the Worms & Germs Resources - Pets page.
Sometimes, people send me links to articles because they think I’d be interested in them. Sometimes, they do it to see what kind of response they can evoke. I’m not sure which one this was:
I was directed by a couple of people to a recent post of PLOS’s blog about snakes in classrooms. (I don’t really know why a scientific journal organization has a blog to which people who aren’t experts in a given field can submit posts. I would have thought a PLOS blog would relate to PLOS papers, but what do I know.)
I’m sure many people would agree with the sentiments in this blog, but (surprise, surprise), I don’t. It’s not that I’m anti-reptile, anti-pet-in-classroom, or think that the writer is clueless. Rather, he seems to be a passionate and well-meaning educator who just doesn’t see the issues with reptiles in classrooms. I’ve seen the issues and have my take on some of his points (in italics) below.
In this post I hope to give other educators a good foundation for keeping snakes in their classroom. A classroom pet is always a good way to teach responsibility. Administrators love any outside-the-box methods of teaching. Let them know students will be using this animal not just to learn science, but to learn important life skills like responsibility and compassion.
- True, but it has to be logical and safe. It also has to be educational. Animals can be used in classrooms for educational purposes, but they can also be distracting. The practice can be questionable from an animal welfare standpoint (especially for nocturnal species). They can be associated with disease. Reptiles are the leaders in that class, and reptile-associated salmonellosis has occurred from classroom snakes and other reptiles. Widespread Salmonella contamination of feeder rodents adds an extra level of concern.
- I also doubt administrators like outside-the-box ideas that pose a health risk to students (and therefore liability).
Your administrator may bring up questions about health risks. Salmonella is often associated with pet reptiles. This can be a bit misleading. Most animals, including pets like hamsters and guinea pigs can carry salmonella, but because turtles are wild caught, and often live in terrariums there is a better chance of salmonella living on their shell.
- No…(multiple no’s actually). While most animals can carry Salmonella, the prevalence of Salmonella shedding by pet mammals is very low. The rate of Salmonella shedding by captive reptiles is, in contrast, very high. Studies looking at snakes over time have shown that virtually all captive snakes are shedding Salmonella.
- It’s not just wild caught turtles that are the issue. Captive turtles are also a big concern (the bigger concern, actually).
Most snakes are kept in the same cage setup as hamsters and have little risk of ever having salmonella on their skin.
- Not a chance. Most do. As mentioned above, studies have shown high (to ubiquitous) carriage of Salmonella by snakes.
I have been handling snakes for 25 years and admittedly have poor hand washing skills and have never had an issue.
- That’s similar to saying “Gee officer, I drive drunk all the time and I’ve never killed anyone, so you have to let me go.” Yeah, that’s an extreme analogy but you hopefully get the point. Reptile contact causes thousands of cases of salmonellosis in people every year. There might be no infections in this classroom over the next ten years - or a child could die next week. It’s more likely that the former will happen, the the latter is possible.
I do keep multiple bottles of hand sanitizer in the classroom and make sure the students properly sanitize after handling and/or cleaning.
- That’s great. It’s an important risk reduction tool, but it’s not perfect and doesn’t compensate for the risk.
I would wager students are more likely to salmonella in the lunch line than they are from snakes in a classroom.
- I doubt it. Even if it was true, eating is a required event. Having a snake in the classroom is not.
Once bitten, the students lose most of their fear and wear it as a badge of honor.
- Multiple issues with this one...
Some issues are often overlooked:
- Do teachers always know if they have any high-risk (immunocompromised) kids in the class?
- Do teachers always know if there will be any high-risk kids visiting the class?
- What if a student is very afraid of snakes? How is that managed? (Is it managed? Might a child be afraid to say anything and instead work in a very stressful situation in silence?)
- Are students eating in the same area as the snake (a high risk activity to be sure)?
Here's my standard disclaimer: I actually like reptiles. Now that our kids are beyond the high-risk ages, Heather would be the main barrier to a request from them for a reptile, not me. However, while I like reptiles, I don’t like them in all situations. When the Salmonella risk can’t be contained and assurances can’t be made that only low-risk people will be exposed, reptiles shouldn’t be kept around. A classroom is a perfect example of just such a situation.
More information about Salmonella and safe management of different pets can be found on the Worms & Germs Resources - Pets page.
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.
As fall fair season starts, concerns about petting zoo outbreaks rise. While deficiencies are still common, petting zoos seem to be getting better with their infection control measures. People too are starting to get better at doing what their asked to do - namely washing their hands after visiting these exhibits. However, as we’ve shown through a few different studies, compliance with handwashing after being in a petting zoo is far from perfect. People also often fail to recognize the need to wash hands after being in a petting zoo even if they don’t touch an animal. It’s not uncommon to see a family come out of a petting zoo and the parents direct the kids to wash their hands, while the parents themselves just stand back and watch. Yes, if you touch the animals you’re more likely to have contaminated your hands. However, it’s been shown in a few studies and outbreaks that just being in the petting zoo area is a potential risk, and that disease-causing bacteria can be spread to a variety of hand contact surfaces. In short, the bugs aren't just on the animals.
A recent study in Zoonoses and Public Health (Pabilonia et al 2013) provides more evidence. Researchers visited poultry exhibits at agricultural fairs in Colorado and collected samples from areas like cages, feed, floors and tables, i.e. areas where there was direct contact with birds and areas that visitors might touch. They were able to grow Salmonella from 10 of 11 fairs that they visited. Overall, greater than 50% of surfaces that they tested were contaminated with Salmonella. It wasn’t surprising that finding Salmonella was fairly easy, but that number is pretty high.
Does this mean that poultry exhibits should be banned? No. But it indicates that there is some risk, presumably with any poultry exhibit anywhere.
How can you reduce the risk?
- Don’t eat or drink in poultry exhibit areas.
- Wash your hands after leaving (even if you don’t touch anything).
- Don’t take in items that might go into a child's (or anyone's) mouth (e.g. sippy cups, pacifiers).
Particular care must be taken with kids less than five years of age, elderly individuals and people with compromised immune systems. That could mean staying out of the exhibit altogether, or just being extra diligent about the basic measures listed above - it really depends on the scenario, the ability to follow these practices, and the level of risk aversion.
What should fairs do?
- Take measures to reduce environmental contamination, such as housing birds in such a way that bedding doesn’t get spread everywhere.
- Regularly clean environmental hand contact surfaces (e.g. railings, arms on seating/benches).
- Provide signs to make sure that people know what to do (e.g. wash their hands, don't eat and drink).
- Supervise exhibits.
- Provide good hand hygiene facilities.
These measures aren’t too hard to implement and they’re much better than dealing with an outbreak.
I grew up with cats, and they were all indoor/outdoor. I never really thought about it since that was just the way things were done. Yet, as much as he’d like to convince us otherwise, our current cat Finnegan is an indoor cat. There are a lot of reasons for this.
One reason for keeping Finnegan in the house is zoonotic disease prevention. I was recently giving a talk about "Pets and immunocompromised owners" at the American College of Veterinary Internal Medicine forum, and a recurring theme for reducing the risks associated with cats was keeping them inside. (Want to reduce the risk of the cat being exposed to Toxoplasma? Keep it inside. Want to reduce the risk of Salmonella exposure? Keep the cat inside...).
Another important reason is the animal's own health:
- Cat vs car rarely ends well for the cat, and untold thousands of cats meet their ends on roads every year.
- Cat vs cat isn’t as bad but can lead to cat bite abscesses and transmission of a few different pathogens such as feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV).
- When outside, cats can also be exposed to various insect borne pathogens that can be of concern. This kind of risk varies between regions, with areas such as those where there are ticks carrying Cytauxzoon felis (a parasite normally carried by bobcats) perhaps being the biggest concern.
Wildlife is another concern, in two ways. Just like with cars, cat vs larger critter such as a coyote rarely ends well for the cat. From an ecological standpoint though, greater problems occur from cats killing smaller wildlife. It’s been estimated that free-roaming domestic cats kill billions (yes, Billions) of birds and small mammals every year. I won’t go into all the details here, but there’s a good article on the Canadian Cooperative Wildlife Health Centre’s website healthywildlife.ca about the impact such avid feline predators can have on local ecology.
Some people would argue that cats are better off going outside. Looking back at the cats with which I grew up, a lot died early because they were allowed to go outside. It’s hard for me to justify the risk to the cat, wildlife and public health for some anthropomorphic “he’d really enjoy being outside” argument.
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.
I have three kids that are all now (thankfully) past the diaper stage. I have no idea how many diapers I changed, but I don't have a huge desire to start doing it again, especially for chickens.
I understand the whole urban chicken concept. I don't actually have many issues with it if it's done right - but that's a big IF, unfortunately. Keep your chickens on your property, don't do it if you have young kids or other high risk individuals in the household, use good basic hygiene practices, feed them right, don't get roosters, and don't run screaming to the newspapers or local politicians if some get eaten by carnivorous urban wildlife. The nuisance and risk of backyard poultry can be limited.
Live chickens inside the house... that's another story.
Chickens aren't house pets in my world. I'm not sure if the chickens benefit at all from living in a house with people, and it's probably actually detrimental in many ways. I'm not sure what the benefit is to people either. Although I haven't seen any studies on this specific topic, it stands to reason that keeping a chicken indoors would be associated with a fairly high risk of widespread contamination of the household with bacteria like Salmonella and Campylobacter, two bugs that cause millions of infections in humans every year.
I'm all for risk mitigation, including using creative (and sometimes off-the-wall) measures - but diapers for chickens? Not so much.
Yet, Pampered Poultry makes diapers for your indoor chickens, and not just run-of-the-mill diapers: they're (allegedly) both functional and fashionable. This isn't the only company that sells chicken diapers either, much to my surprise.
One website states "Our chicken diapers are not just for the fashion obsessed hen. They offer your and your home protection against the inevitable! Our diapers fit comfortably and allow you to enjoy your birds in the house or car [car?] without worry."
Does using chicken diapers make sense?
I have a hard time believing these diapers are very useful. They probably do reduce the burden of pathogens that are deposited in the environment, but they are presumably far from 100% effective at containing all of a bird's droppings. It's also likely that chickens are contaminated with these bacteria on other parts of their bodies. Thinking you've eliminated the risk of household contamination from your pet poultry by using diapers isn't logical. The diapers also need to be changed (risk of more contamination) and disposed (don't we have enough waste already?) or washed (risk of cross-contaminating other items).
If you want fashionable chickens, go ahead and dress them up in diapers. Nothing says haute couture like a chicken walking around the living room in pink floral undies. Just don't convince yourself that you're reducing the infectious disease risk for other animals and people in the house. Better yet, let the chickens be chickens and keep them in a proper coop outside. I've seen too many indoor goats, pigs, miniature horses and other species with profound health problems from owners thinking they're just like people.
Apart from diapers, the store also sells "saddles" for the chickens. I'm not even going to start on that one.
Allegedly, spring is here. The foot of snow on the ground and minus double-digit temperatures don’t really convince me, but the calendar can't lie, I guess.
Anyway, spring brings with it many things, one of which is hatching chicks. I saw signs for them at a local farm supply store a couple of days ago, and perhaps not coincidentally, this week’s edition of CDC’s Morbidity and Mortality Weekly Reports provides an update on the 2012 human Salmonella outbreak that was linked to contact with chicks and ducklings from a single supplier.
This outbreak has been talked about before, but this report gives some final numbers.
- Ultimately, 195 people infected with the outbreak strain of Salmonella Infantis were identified. (That’s probably a major underestimation too, since in outbreaks like this lots of people get sick but don’t have fecal cultures for Salmonella performed.)
- 33% of affected individuals were children 10 years of age or less.
- 79% of people who got sick reported contact with poultry in the week before illness started.
- Birds were obtained from various feed stores or directly from hatcheries, and 87% of people that provided information about chick or duckling sources reported getting them from a single mail-order hatchery in Ohio.
Chicks and Salmonella go hand-in-hard. Chicks are high-risk for shedding the bacterium, and people can get infected by handling chicks or having contact with their environment. Children are at high risk for infection since they tend to have closer contact with chicks and because they are more susceptible to Salmonella. That’s why it’s recommended that kids less than 5 years of age not have contact with young poultry. Day cares and kindergartens planning on their annual hatching chick programs… please take note.
The article includes some more recommendations.
- Feed stores should use physical barriers (e.g., a wall or fence) between customers and poultry displays to prevent direct contact with poultry.
- Educational materials warning customers of and advising them on how to reduce the risk for Salmonella infection from live poultry should be distributed with all live poultry purchases
Part of the last point is keeping young kids away from chicks and stressing good hand hygiene practices. Like most things in infection control, a little common sense goes a long way.
I write a lot about reptiles, and while it's usually in the context of their biohazardous nature, I actually like them. I've owned some before and it's not outside of the realm of possibility that we'll get more in the future (I might be safe with that statement since Heather doesn't read this blog. However, her co-workers that do will likely rat me out).
Reptiles can be good pets in some situations. The key is understanding and accepting the risk. That involves understanding the risks associated with reptiles, understanding the types of households where the risk is high, and knowing what to do to reduce the risk.
Denial isn't an effective infection control measure.
- Uh...no. Reptiles are clearly higher risk when it comes to Salmonella. Reptile contact has been clearly and repeatedly shown to be a risk factor for human salmonellosis. Dogs and cats (and various other animals) are potential sources of salmonellosis, but while many more people have contact with dogs and cats, reptile contact is much more likely to result in Salmonella transmission. It only makes sense. Reptiles are at very high risk for shedding the bacterium. Dogs and cats rarely do (especially when they're not fed raw meat).
"She’s never seen a case in the 30-plus years she’s been working with reptiles."
- Ok. So, since I've never actually seen influenza virus, I'll never get the flu?
- I know a lot of infectious disease physicians who have had a very different experience. In fact, it's rare for me to talk to an infectious diseases physician without him/her providing details of various reptile-associated salmonellosis cases.
Talking about the risk of Salmonella shouldn't be taken as insulting or a threat to reptile enthusiasts. People should accept that the risk is present and try to minimize it. The article actually has some useful information along those line. "Just use common sense - wash hands thoroughly after handling the animal or its cage. A good rule of thumb is to keep hand sanitizer nearby. While children under age 5 should avoid any contact with reptiles, Hart doesn’t advise snakes for children under age 7 or 8 for fear they could unwittingly harm the creature."
Reducing the risk is common sense. Keep reptiles out of high risk environments and use basic hygiene and infection control practices.
However, any semblance of common sense goes out the door when a rescue like this offers programs where you can pay them to bring reptiles to daycares, pre-schools and grade schools. So much for young kids avoiding contact with reptiles.
Reptiles aren't bad, they're just bad in certain situations. Common sense needs to be more common.
I tend not to write about recalls but the recent, large and expanding pet treat recall has lead to a lot of questions that are worth discussing. At last report, treats manufactured by Kasel Associates Industries Inc from April 20-Sept 19, 2012 were potentially contaminated with Salmonella and recalled. Not surprisingly, most of the recalled treats are things like pig ears, bully sticks and jerky strips made from raw animal products. The impact on pets isn't clear beyond a vague statement about "a small number of complaints of illness in dogs who were exposed to the treats." Anyway, here are some common questions I've been hearing:
My dog ate a recalled treat, will it get sick? Maybe, but probably not. It's not clear how many treats were really contaminated, so it's quite possible that most products weren't contaminated. Furthermore, the dose of Salmonella that a dog ingests is important. Low-level contamination is less of a concern, particularly in otherwise healthy dogs. The strain of Salmonella itself also plays a role since some strains seem to cause more serious disease or cause disease at lower doses than others. I haven't seen much information about the strain (or strains) involved here.
If my dog gets sick, what will happen? That's highly variable. Salmonella can cause disease ranging from vague (e.g. a little depressed and decreased appetite) to classical intestinal disease (e.g. diarrhea +/- vomiting) to rare but severe systemic disease (e.g. sudden death, bloodstream infection with subsequent overwhelming body-wide infection or focal infection of different body sites like joints).
Should my dog be tested for Salmonella? Not if it's healthy. The main question is what would be done with the result. If positive, it wouldn't mean that anything needs to be done or even that disease is likely to occur. A negative isn't very helpful either since a single sample is far from 100% sensitive. The key point is that we treat disease, not culture results. If the dog looks healthy, it's not going to be treated, regardless of the culture result. You'd also need to have the isolate tested to see if it's the same as the strain in the recalled treats if you wanted to determine whether treats were the source, and that testing is not readily available.
Should my dog be treated with antibiotics? As you can guess from the paragraph above - no. There's no evidence that antibiotic treatment of an exposed dog or a healthy carrier reduces the risk of disease or shortens the shedding time. In fact, it might even make things worse by disrupting the normal protective intestinal bacterial population, which might make disease more likely or make it harder for the body to eliminate Salmonella. Treatment might also encourage development of antibiotic resistance, something we don't need any more of with Salmonella.
What can I do to reduce the risk of disease? Not much. If a dog has eaten a Salmonella-contaminated treat, there's not really anything that can be done after the fact beyond watching for signs of disease.
So... what should I do? Relax and watch. The odds of a problem are low. If a problem develops, odds are it will be mild. That's not to say that severe disease can't or won't happen, it's just that it's unlikely and there's nothing that you can do after exposure anyway. Identifying signs consistent with early disease (e.g. lethargy, decreased appetite, diarrhea) and getting prompt veterinary care should help reduce the risk of complications or serious disease.
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.
1) Do you know what a bully stick actually is?
2) Do you know what's in it?
A recent study headed up by Dr. Lisa Freeman, published in this month's Canadian Veterinary Journal (Freeman et al., CVJ 2013;54:50-54), looked into this by asking people what they thought bully sticks were made of, and testing the treats for calorie count and bacterial contamination.
The answer to question 1 is: bully sticks are raw, dried bull penis (which explains the need for a cuter name).
- Only 44% of people surveyed knew that.
Also, bull penis is considered a by-product, yet 71% of people that fed bully sticks to their dogs said they avoid by-products in food.
- This just shows a lack of understanding about what by-products are and their nutritional value. Many people classified things that are prohibited from by-products as being by-products, such as hooves, horns, road kill and euthanized pets. By-products aren't always bad and can, in fact, have good nutritional value. Also, they can be environmentally friendly and ethical since they are often made from nutritionally valuable parts of the animal that might otherwise be thrown out, thereby providing food for pets without taking anything out of the human food supply chain.
"What's in it?" was approached from 2 standpoints:
Firstly, caloric content was assessed.
- Treats often get ignored when thinking about a pet's caloric intake, but calorie-dense treats can certainly contribute to obesity. Fifty percent of people surveyed underestimated the calorie counts of bully sticks. The average caloric density was 3 calories/gram, and given the variation in size of bully sticks, total calorie counts for a single stick ranged from 45-133 calories (9-22 calories/inch). So, yes, size matters.
Secondly (my bit part in this study), we looked at contamination by a select group of bacteria.
- Salmonella wasn't found, which was encouraging since high Salmonella contamination rates have previously been found in some treats (mainly pig ears), and contact with pet treats has been implicated in some outbreaks of salmonellosis in people. We found Clostridium difficile in 1 treat (4% overall). That doesn't worry me too much since it's increasingly clear that we encounter this bacterium regularly. With common sense and handwashing, it's probably of little risk, but in some people (e.g. elderly, people on antibiotics, people with compromised immune systems) it might be more of a concern. We also found methicillin-resistant Staphylococcus aureus (MRSA) in one sample. This was a "livestock-associated" MRSA strain that can cause infections in people, but the risk is unclear. Theoretically, it's a potential source of exposure. If someone got MRSA on their hands from the treat then touched their nose (where MRSA likes to live) or a skin lesion (where it can cause an infection), then it could potentially cause a problem. Overall, the risk is probably quite low, but it's another reason to wash your hands after handling treats.
None of this means dog owners need to avoid bully sticks. It does mean that you should pay attention to what you feed your pet, think about treats when considering your pet's caloric intake (especially if your dog is overweight), keep treats away from high risk people (e.g. don't use a bully stick as a teething toy) and wash your hands after handling dog treats (of any kind).
Photo: A variety of bully sticks (also known as pizzle treats) often fed to dogs as chew treats (photo credit: Gergely Vaas 2006 (click for source))
The fact that Salmonella and reptiles go together is old news. I often get questions about testing reptiles to see if they are Salmonella carriers and I tell people not to bother since even with a negative result, I'd consider the animal to be positive. A recent study in the Journal of Zoo and Wildlife Medicine (Goupil et al 2012) provides more evidence for this.
This study involved testing 12 snakes used in a public educational program, by sampling them weekly for 10 weeks. Here are the highlights:
- 11/12 snakes were positive at least once.
- 58% of snakes were positive on 5 or more weeks.
- On a weekly basis, between 25-66% of snakes were positive.
- Fifteen (!) different types of Salmonella were identified. Nine snakes shed 2 or more different Salmonella types over the study period.
- Two samples from feeder rodents were also positive.
This shows nicely how a single negative sample doesn't guarantee that a snake is truly negative. It also shows how common Salmonella is in snakes. The positive cultures from the feeder mice aren't surprising either, but shows that even if a snake was truly Salmonella negative, it could be exposed at any time through its food, and that there is potential public health risk from contact with feeder mice (something that large international outbreaks of human infection from infected feeder mice have shown).
This study just reinforces some key concepts:
- Assume all snakes are Salmonella carriers.
- Use good hygiene practices around snakes and feeder rodents.
- Keep snakes away from high risk individuals (e.g. the very young, elderly, pregnant, immunocompromised).
- Don't waste your money testing your snake for Salmonella. Focus your efforts on smart and practical management practices.
More information about reptiles and Salmonella can be found on the Worms & Germs Resources - Pets page.
The 15 cm of snow that fell last night is as good of an indicator as any that agricultural fair season is over in this region. But, planning ahead is important (and often not done well with fair petting zoos), so it's never to early to make a plan for next season. Petting zoos can be fun and educational, but are also associated with infectious disease risk. There's always some inherent risk with any kind of animal contact, since all animals (and people) carry a multitude of infectious agents. However, understanding pathogen shedding patterns is useful to help determine the best control measures.
A recent study in Comparative Immunology, Microbiology and Infectious Diseases (Roug et al 2012) looked at shedding of selected pathogens by cattle, sheep, goats, pigs, poultry, rabbits and horses at a California county fair. Here are some of the highlights:
- E. coli O157 was found in one animal. This is the main outbreak concern when it comes to petting zoos, because very low numbers of bacteria are required to cause disease and human infections can be very severe. Surprisingly, the positive animal was a pig, not a ruminant, as would be typical.
- Salmonella was isolated from feces of 3 animals: 2 pigs and 1 chicken.
- Campylobacter jejuni, another potential cause of diarrhea in people, was found in 3 animals: 2 cattle and 1 sheep. The 2 positive cattle were adult dairy cattle and they represented 17% of all tested cattle. That's a surprisingly high rate for adult dairy cattle, in my experience.
- Other Campylobacter species were found in 2 cattle, 3 goats (30% of all goats tested) and 1 chicken.
- Antibiotic-resistant E. coli were common, particularly in pigs.
- The parasites Cryptosporidium and Giardia, and the bacterium Vibrio, were not found.
The study didn't look at other aspects of the petting zoo, such as the types of contacts that were allowed, but based on the pictures that were included with the paper, they weren't optimal. Given the results, the picture of two children in the pen with the pigs (including one child who was sitting on the ground leaning against a pig) should raise some concern.
Does this study change anything? Not really, but more information can't hurt. We know that petting zoo animals can carry pathogens, and we have to assume that every animal in a petting zoo is carrying something that could cause an infection given the "right" circumstances. That's why there's a focus on good general hygiene and infection control practices (especially hand hygiene), along with excluding animals that are at particularly high risk. As the authors say "The study findings should not be interpreted as a deterrent to visit agricultural fairs, but as a reminder that good hygiene and sanitation are critical in these settings."
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 received an email from a relative the other day with a pet question. I get lots of these, but the surprising part is this relative doesn't have any pets (and I think is generally of the opinion that pets are okay, as long as they're not hers). She was asking about turtles. As a responsible prospective pet owner should, she was looking into the issues pertaining to the pet before getting the pet. I think she was more focused on general aspects of care and management, but zoonotic disease risks play into the equation too. This one was a no-brainer, since they have a young child in the house and reptiles shouldn't be present in households with children less than five years of age. So, problem averted, and the need to make a decision later about removing an inappropriate pet from a household was also avoided (along with the awkward "oh, you got a turtle?" Christmas dinner conversation).
But, what happens when people aren't so proactive? Turtles are often passed from house to house as people get bored with them, as they outgrow small aquariums or as parents of young or otherwise high-risk children tune into the Salmonella risks or owning such a pet. If you don't have a friend willing to take your turtle, what do you do?
Petco, a pet products company in the US, has launched a "turtle relinquishment program," whereby they take in "wayward" or unwanted turtles. As of a few weeks ago, 111 people from 10 US states had surrendered their turtles to Petco. The turtles are sent to a turtle farm in Louisiana.
So, this is an option for individuals (at least in the US) with no local way to rehome their turtle. The fact that the turtles are going somewhere to make more turtles (and more Salmonella) is a bit of a concern, but I can see the greater good. Staff at the farm say that turtles are treated for any signs of Salmonella when they arrive. This is a bit strange, since turtles don't typically develop disease from this bacterium - they simply shed it with no signs. Hopefully that doesn't mean the farm is just treating all the animals. It's basically impossible to eradicate Salmonella from turtles, so if they are routinely treating, they're probably breeding drug-resistant Salmonella along with baby turtles.
I know the typical round of emails is going to follow, from reptile advocates who have pretty much done everything except burn me in effigy (or in real life, fortunately). As I've said before, reptiles can make great pets, just not in all households. I've owned various reptiles myself, but reptiles and small kids don't go together. Too many kids get sick every year from pets like turtles. A small number die. That's just unacceptable.
More information about turtles and Salmonella can be found on the Worms & Germs Resources - Pets page.
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.
While I'm certain I'll face more wrath from the keep-reptiles-in-schools group that is currently bashing me on the internet (there's even a Facebook page... at least I'm making an impact!), this brings up a few serious issues. One is the whole idea of putting a python around the neck of a young child. I won't go there, and in reality the risk of injury is very low. The main issue is, obviously, Salmonella exposure, because of the high rate of Salmonella shedding in reptiles and the high susceptibility of young kids to salmonellosis. A recent paper in Zoonoses and Public Health (Hydeskov et al. 2012) provides more evidence that the concerns about Salmonella exposure in such situations are valid.
- This study involved the reptile collection at the Copenhagen Zoo. There, the reptile collection consists of two groups: the main group is comprised of animals in the breeding centre, quarantine station and the primary zoo exhibit; the other group is a smaller collection that's used for education and hands-on teaching. The latter group has direct contact with many people, including kids.
- Salmonella was isolated from 35% of reptiles overall, with the highest prevalence in snakes (62%).
- Reptiles from the education group had a significantly higher prevalence than the other reptiles; 64% vs 23%.
- While these numbers are high, they are presumably an underestimation, since other studies have shown that you will miss a reasonable percentage of positive animals if you only test a single sample from each individual. So, it's fair to say that at least 62% of snakes and at least 64% of education-group reptiles were Salmonella positive.
Has the zoo ever been the source of Salmonella in a person? Nothing's been confirmed; however it's important to note that in Denmark, official investigation of salmonellosis cases only occurs as part of an outbreak. Since reptile-associated salmonellosis would most likely occur as sporadic cases, not an outbreak, cases might not be identified and reported.
It's also possible that the zoo hasn't been a source, because of the short-term nature of contact with the reptiles, contact only by older children and their hygiene practices.
At the Copenhagen Zoo, all reptile contact by kids is supervised, and students are required to wash their hands after touching a reptile. That's a great approach (as long as compliance is good), and the risks should be low for a short-term supervised activity such as this. High-risk kids, from an age standpoint, aren't involved since only 7-18 yr old students participate. So, the main group that would be of concern is immunocompromised children, who comprise a small but important subset of participants, and one that may slip by the established control measures since not all immunocompromised kids are readily identifiable. Unless schools know about all high-risk kids (and I'm far from convinced they do) and know that there are things these kids shouldn't do (e.g. have contact with reptiles), there are still some concerns. Those can be lessened further by ensuring that there is good communication between parents and the school, such that schools are really aware of any high-risk kids. That requires adequate knowledge on the part of the parents and the school, good communication in both directions and trust (since private health information is being disclosed). We have a long way to go to get there, and few people seem interested in starting those discussions.
Back to the Guelph paper photo. This wouldn't happen at the Copenhagen Zoo, since they apparently don't let 3-year-olds have contact with reptiles. I wasn't there so I don't know what was done in terms of hygiene, but even if this girl washed her hands after, there would still be a good chance that Salmonella was present on her skin or clothing based on how she handled the animal. This nature centre does some excellent work but I worry about the shows they offer for birthday parties. Their advertisement for this, with the "bring your cake and touch a snake" approach, and the picture of another young child with a snake draped around her raises concerns.
Reptile contact isn't inherently bad. There are just situations when it's high-risk and should be avoided. Beyond that, if it's going to be done, it must be done right. Unfortunately, more often than not, that's not the case.
I get a lot of emails about this blog. Some are complementary, some... well... not so much.
When it comes to the latter group, the most common (and often the most grammatically-challenged) group is raw meat feeders. They're a constant source of interesting comments about my intelligence and other aspects of my life. Some actually provide well-written explanations of why they do what they do and I've had some good discussions with a few. Others just like to call me stupid and move on. The guy who provides treatment recommendations for dogs based on fish antibiotics (and his buddies) was another interesting one. The dodgy equine protozoal myelitis clinical trial person (and her friends) was another (she also wrote to my Dean... that's another story). The list goes on.
The latest group has been people upset that I have concerns about reptiles in schools. It seems that a post I wrote a while ago about a school reptile club ended up on a reptile website, whose members are now inundating me with emails. While I appreciate the fact that they are reptile enthusiasts and like their pets, they're missing the big picture.
Yes, reptiles can be good pets, in certain situations. I actually like reptiles. I used to own a few, and the first patient I treated in practice was a reptile.
I've also spoken with people whose children have acquired Salmonella from a reptile. I've read numerous papers about kids that died from Salmonella from a reptile, and I think I've yet to meet an infectious diseases physician who doesn't almost immediately launch into reptile-Salmonella stories when they hear what I do.
The fact is, reptile exposure accounts for a very disproportionate number of Salmonella infections in people, and kids bear the brunt of this. That's why the CDC and various other groups say that reptiles shouldn't be in households with young kids (or the elderly, pregnant women or people with compromised immune systems). The same applies for schools and day cares, where young kids are present, parental knowledge of the exposure is often non-existent, and basic infection control practices are spotty, at best.
No one is saying people shouldn't keep reptiles as pets. However, to me, the evidence is clear that certain people shouldn't have reptiles as pets or be in contact with them. Adults can decide to do things that compromise their health. Adults shouldn't make decisions that compromise the health of their kids or kids for whom they are responsible. Ensuring high-risk children stay away from high-risk animals like reptiles is part of that.
In response to Salmonella outbreaks linked to these critters, their popularity as pets for young kids, and efforts to ban them in some areas, we've developed an info sheet regarding African Dwarf Frogs. As with our other info sheets, it discusses the good and bad points of owning these little guys, things to consider when deciding whether to get one, and measures to reduce the risk of infection.
This info sheet, along with many others, can be found on the Worms & Germs Resources - Pets page in the Information Sheets for Pet Owners section.
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)
Let me say it again... yes, dogs can get salmonellosis.
...and in French, oui, les chiens peuvent devenir malades de salmonellose (hope that's close)
...and in Swahili, ndiyo, mbwa anaweza kuwa na wagonjwa salmonellosis (thank Google Translate for that one).
What prompted my recurrent 'yes dogs can get Salmonella rant'? Another fluff piece on feeding dogs raw meat diets, this time in the Globe and Mail (a national paper in Canada).
The "dogs can get Salmonella" rant doesn't actually stem from the newspaper, since the article didn't even bother to get into potential infectious disease or nutritional deficiency concerns with these diets (in-depth reporting it was not). Rather, the rant is in response to comments on the paper's website that include the typical garbage that dogs are not susceptible to Salmonella because of their short and acidic intestinal tract. It's a fallacy that's widely distributed on the internet on raw pet food sites, and it's wrong (although ironically enough, many of these same sites also talk about how dogs get sick from Salmonella from commercial foods).
To set the record straight:
- Dogs can get Salmonella.
- Most often they don't get very sick, but sometimes they die.
- Ingesting Salmonella from food or other environmental exposures is the source.
- The more Salmonella a dog eats, the greater the risk of disease.
- Raw meat is often contaminated with Salmonella.
Now that I've gotten that off my chest, I'll get back to the article. It's written by someone who feeds her dog raw meat. I have no major problems with that for the average dog and average person. It increases the risk of salmonellosis in the dog and in the family (and potentially anyone or anything in contact with the dog or its poop), but the risk of infection for your average, healthy dog and person is relatively low. It's a bigger issue when there are high risk people or animals in the house, and human and pet infections from feeding raw meat certainly do occur.
I'd rather people not feed raw (or at least make sure they feed high pressure pasteurized raw meat) but I'm a realist and I realize some people are going to do it anyway. I therefore focus on trying to educate people about situations when they really shouldn't feed raw meat (e.g. high risk dog or person in the household, young growing animals) and what to do to decrease the risk of transmission of Salmonella. More information of this kind is available on the info sheet that can be found on the Worms & Germs Resources - Pets page).
Anyway, back to the article (I really mean it this time). The article includes some interesting information, particularly the very high cost of feeding a raw diet compared to commercial dry or canned foods. However, it also contains some of the same drivel that's found in most of these articles. For example:
"'Dogs don’t have microwaves or grocery stores in the wild,' she says with a laugh, adding that she believes a dog that eats raw will lead a longer, healthier life than one fed traditional dog food."
- They also don't necessarily live long, happy and healthy lives in the wild. Today's domestic dog is long removed from the mystical wild dog. My dog Meg wouldn't make it very far in the wild, unless there are dog food trees somewhere that I don't know about.
"'On a kibble diet, her dogs were 'overweight, with no energy - scratching all the time from all the allergies,' she says. 'These were our fat, miserable, lethargic dogs.'"
- Less food, more exercise and good veterinary care could probably have taken care of that too.
As I said above, people are free to make their own choices, but they should get informed, and they need to go beyond raw food company websites and support groups. They need to think about potential benefits, potential risks, cost, hassle and other factors to determine if it's right for them and their dog. Getting real information and critically assessing the information that's out there are critical steps.
Markham, Ontario's city council has passed a bylaw prohibiting the keeping of African Dwarf frogs. While in reality more of a ban on the sale of frogs in the city (since I doubt there will be any effort to search for contraband frogs in households), and perhaps of somewhat limited impact because of the availability of the potentially Salmonella-laden critters in neighbouring areas, not to mention the common practice of pet retailers flouting laws like this, it's nonetheless a step that will hopefully reduce the number of these animals in households.
Why the fuss about African Dwarf frogs?
- Mainly, it's because of the risk of transmission of Salmonella from these frogs to people. Large numbers of Salmonella infections have been linked to these frogs internationally, and the risks are amplified with pets like this that are marketed toward young kids (especially as pets to keep in their bedrooms) and for schools and childcare facilities, because children are one of the highest risk groups for developing salmonellosis.
- The other important issue is animal welfare, since these frogs are often sold in unsuitable habitats and have a fairly limited lifespan in captivity.
Not surprisingly, the owner of the US company that is one of the main distributors of these animals is unhappy with the decision. It's hard to be sympathetic given the fact that they essentially ignore the risks these animals pose to people, at least in the materials they present to the public. Despite the fact that they are marketing what is considered a high-risk animal as a pet, there's little effort put into providing information about that risk or risk mitigation. Looking at their promotional materials, I can find lots of information about how to care for the aquarium. Yet, none of it mentions Salmonella. There's no statement about keeping young kids away from frogs. There's no mention of washing hands after contact with frogs or their environment, or that aquarium water shouldn't be dumped down bathroom or kitchen sinks... or any other basic, relevant infection control practices. They do have some CDC information on their website if you look around, which is better than nothing, but it needs to be more prominent. Everyone that purchases one of these frogs should get a clear information sheet that explains the risk of Salmonella transmission and how to avoid getting sick. Yes, it puts a bit of a damper on the new pet, but a lot less than being hospitalized.
Back in Markham, it's hard to say whether the ban will have an impact on frog ownership because of the ability to buy frogs a few minutes away in neighbouring municipalities, and the likely lack of any real enforcement effort. However, it's a start and if nothing else, and publicity associated with the ban may help educate people. African Dwarf frogs that are already in households are exempt and can live out their natural (albeit often short) lifespans, but people can't replace them when they are gone.
More information about Salmonella can be found on the Worms & Germs Resources - Pets page. We don't have a dwarf frog info sheet (it's coming) but most of the information on the Reptiles info sheet equally apply to frogs.
Today's Toronto Star has an article about a reptile club in a Toronto Elementary School. Teacher Jim Karkavitsas runs a session every day that teaches students about a range of reptiles. His menagerie has expanded from one snake five years ago to more than 40 different species in his classroom. Some are loaned out to other classroom's on request and two lizards now make their home in the school's main office.
- Learning about, and interacting with, animals can be very important for kids, especially those who don't get exposure to animals at home and outside of school. It can teach responsibility and empathy, and be the springboard for a range of educational discussions.
- The animals are kept in a room adjoining the classroom, so they are relatively contained and all students aren't forced to be around them (since some kids might be afraid of them). Housing the reptiles in a different room also means students presumably aren't eating in the same room in which the reptiles are housed.
- Kids use hand sanitizer before and after contact with reptiles. This is a very important preventive measure for the problems outlined below, but it's not 100% protective (or usually performed all the time or done properly).
- Mr. Karkavitsas takes the animals home during the summer. A problem with some classroom pets is people don't assume ownership for them to take care of them properly when school's not in session. Similarly, the school's parent council provides $5000 to cover the cost of keeping the reptiles. Hopefully, that also means that veterinary care would be provided if something happens, which can be a problem in many cases when classroom pets need care but no one has a mandate to arrange or pay for it.
The bad and the ugly
- Salmonella. That's the big one. Reptiles are classic sources of Salmonella. You can almost guarantee that more than one of these reptiles are shedding the bacterium. If a reptile is shedding Salmonella in its feces, it will also likely have the bacterium on its skin, in its cage and in any areas where it roams. It also means that anyone touching it (or its environment, or contaminated areas) can pick up Salmonella on their hands, with subsequent transfer into the mouth. This is a high-risk situation since reptiles are a major source of salmonellosis, especially in kids. Reptile-associated salmonellosis does occur in classroooms.
- Mr. Karkavitsas buys frozen rats to feed the snakes. Frozen rats can also be contaminated with Salmonella, and frozen rats have caused salmonellosis in kids in a school (which was also brought home and spread other family members). There's also been a large (and likely ongoing) international salmonellosis outbreak associated with frozen rodents.
- Standard recommendations are that children less than five years of age (along with pregnant women, elderly individuals and people with compromised immune systems) not have contact with reptiles. This is a grade 5-6 classroom, so the students would be older than this, but I wouldn't be surprised if younger kids in the school also have contact with the reptiles. Additionally, the immunocompromised group is an issue, since many people have compromised immune systems due to various diseases or treatments. Teachers may not know about all of these and parents may not realize that their high-risk child is having contact with high-risk animals in school. When you can't be sure that high-risk people won't have direct or indirect contact, that's a problem.
The sentiment is great and I applaud the teacher's efforts to engage kids and teach them about animals, However, it's a cost/benefit situation and the potential costs (which may be extreme) outweigh the benefits (significant as they may be). While reptiles can be great pets in certain situations, they're not meant for schools where there are lots of kids, challenges with supervision, difficulty implementing good infection control practices and potentially individuals at high risk for infection.
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.
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.
The large recall and salmonellosis outbreak associated with a variety of foods produced by Diamond Pet Foods continues to expand, in terms of species involved, the number of cases, the number of recalled products and geographic scope. The only thing that's not expanding in information from the company.
Reports (of varying strength) of Salmonella cases in dogs have been cropping up, but it's not just a US problem or a problem only involving people and dogs anymore. Two cats from a Montreal animal shelter have apparently died. At least two people in Canada have also been infected, one each from Quebec and Nova Scotia.
As with many outbreaks, the depth of information is variable when it comes to potential cases and it's hard to say if everything that's reported in the press is real. Just because an animal has been eating recalled food and gets sick, that doesn't mean that the food caused the disease. Testing is required to make the diagnosis of salmonellosis and confirm the involvement of the outbreak strain. However, enough reports are coming in to be fairly convincing that this is a very large, wide reaching outbreak involving people, dogs and cats, and multiple countries.
Communication is critical when managing an outbreak. It can let companies show they are doing everything that's necessary (and more), demonstrate their commitment to correcting the problem, show how they are helping people with affected animals, and provide confidence that once the problem was identified, it was (or will be) rectified and the product can be considered safe. Some companies shine during outbreaks. Some don't.
Here, communications don't seem to be ideal.
- Another product was added to the recall list, without too much publicity.
- We know recalled food is in the US, Canada and Puerto Rico (with sick people and animals in at least Canada and the US), but has contaminated food gone any further? Importantly, has information about the potential risk gone anywhere the food might have gone, since the FDA's mandate ends at the US border. eFoodAlert reports some concerning information in that regard. The Taste of the Wild website lists over 50 countries where the food is available and a correspondent for the site apparently bought a recalled product in Ireland. What is actually being done to correct problems that lead to the outbreak is also unclear.
- I also haven't seen any press releases from the company addressing the numerous FDA violations that were identified in the outbreak investigation.
Outbreaks happen. Sometimes they're not preventable. Sometimes mistakes happen. That's an unfortunate aspect of life. However, how a company deals with those issues, both in terms of correcting the problem and restoring consumer confidence, is critical, and seems to be lacking here.
A good adage when it comes to outbreak communications is "never announce a problem without announcing a solution." That doesn't mean hide outbreak information (something that is done too often). Rather, it means don't just say that you have a problem. Be clear about your problem and at the same time be clear about what you are doing to fix it. Hopefully, Diamond Pet Foods has an aggressive ongoing response to correct these problems, and that's what consumers need to know about. In the absence of any clear information, we're left wondering whether they are doing anything at all.
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.
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.
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.
.A five-month-old Britich baby was hospitalized with salmonellosis that was presumably acquired from a family pet. The baby developed severe diarrhea and was rushed to hospital. Fortunately, the child has recovered, something that's far from assured in such cases, since salmonellosis can be life-threatening in infants.
As expected, an investigation followed the diagnosis of salmonellosis. Typically, these investigations focus on food and animal contact, and since this family had a bearded dragon (see picture) and tortoises, the investigation honed in on the reptiles. Reptiles are high risk for Salmonella shedding and are commonly implicated in human infections. Further, the type of Salmonella that infected the infant, S. Pomona, is commonly associated with reptiles. It doesn't sound like they've confirmed that the same strain of Salmonella was present in the reptiles, but I assume that testing is underway.
Reptiles should not be present in households with infants. It doesn't matter if the animal never leaves its enclosure, because while the critter may not leave the enclosure, Salmonella will.
In low risk households (households without kids less than five years of age, elderly persons, pregnant women or immunocompromised individuals), good management practices can be used to minimize the risk of transmission of Salmonella, but given the potentially fatal nature of salmonellosis in infants and other high-risk individuals, these precautions are not adequate in high-risk households. While reptiles can be great pets, they're just not worth the risk in some situations.
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.
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.
Yet another outbreak of salmonellosis traced back to pet turtles has been investigated by CDC and Pennsylvania's State Health Department. Pet turtles are notorious Salmonella vectors, for several reasons, including the fact that small aquatic turtles very commonly carry the bacterium, they are marketed towards young kids (who are increased risk of infection), and people tend to use poor (or no) hygiene practices when handling turtles or having contact with their environments. Efforts to restrict the sale of small (less than 4-inch long) turtles have greatly reduced Salmonella infection rates in people in the US, but have come under continual pressure from the turtle breeding industry, and the regulation is often flaunted by pet stores and road-side turtle sellers.
From August 5 to September 26, 2011, 132 cases of Salmonella Paratyphi B infection were identified in 18 US states.
- The median age of infected individuals was 6 years, and 2/3 were less than 10 years of age. This is consistent with a pet-associated outbreak.
- 56 patients (and their families, presumably) were interviewed, and 64% of them reported turtle exposure. That's a lot higher than one would expect if a random sample of the general US population was surveyed, and suggests that turtles were an important source.
- Of the 15 people who could provide details about the turtle, 14 of them described turtles that would have been too small to be legally sold in the US. This isn't surprising, and shows both the risk associated with these small turtles and the fact that this law is being widely ignored.
- The same strain of Salmonella was isolated from turtle tank water in five homes (it's not clear if only five were tested or if there were some negative tanks too). That's further evidence implicating the turtles.
This is yet another reminder of the risks posed by small turtles, particularly to young kids. Small turtles have high Salmonella shedding rates, are easy to handle and are even small enough for kids to put in their mouths (yuck!). That's a bad combination.
In 2007, Louisiana turtle breeders sued to reverse the FDA's small turtle ban. Fortunately they weren't successful, however it's clear that the turtle ban needs to be enforced, but that's hard to do. Perhaps more important, then, is increasing public awareness of the risks. If people are better informed of the issues, they can make better decisions about acquiring pets and how to properly manage them. One such resource for the public is the Turtles fact sheet that we have freely available on the Worms & Germs Resources page.
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.
CTV has a consumer reports segment and a recent topic involved feeding pets "natural" diets (although no one ever defined what that really means). In the report on the CTV Consumer Alert website (it's currently about the third story into the video if you just press play, or you can shortcut to it using the link below the main video window), a 26 year old cat is held up as a poster child for the health benefits of raw food. Making it to 26 is a noteworthy accomplishment for a cat, but it's far from rare, and you can't know whether the cat survived because of its diet or despite its diet. At the end of the clip, they mention he cat has kidney disease, not an uncommon problem in older cats but one that is often blamed by raw proponents on commercial foods. It's also not a condition that I'd want to see someone try to manage with a raw diet.
Anyway, the story has the typical statements (including one from a veterinarian) about how raw and "natural" diets produce a healthier animal, stronger immune system and shinier haircoat, but without citing any proof (because there is none) and with no discussion whatsoever about the potential animal and public health impacts of raw meat feeding.
Good investigations are good. Quick reports put together with little thought or consideration of the issues are just time filler. The host, Pat Foran, said in his conclusion that "natural" pet foods have less filler so there's less to come out the back end of the dog. Well, news reports comprised of filler produce the same kind of by-product.
If you are going to feed raw, at least take the time to research how to do it safely, both for your pet and your household. Raw feeding can be done in a nutritionally sound manner, but it takes time, effort and money. Some people are willing and able to do that, but if you're not, don't feed raw. Raw feeding also carries some risk of gastrointestinal disease like salmonellosis in the animal as well as exposure of people in the household to those same bugs. Certain households, particularly those with high risk individuals (e.g. elderly, infants, pregnant women, immunocompromised persons) should avoid raw feeding or only use products that have been high pressure pasteurized. There are a few commercial raw diets that are treated in this manner and these are preferable as the process should kill most relevant bacteria, reducing or eliminating the infectious disease risks to pets and people.
Like many other things in life, the key is being informed so you understand the risks and benefits, and whether recommendations made by people have any substance behind them. Too often, people make a major change like feeding raw based on a comment on a website or from another dog owner, with no clue about the issues and no effort to figure out how to do it right. That's just asking for problems.
More information about raw diets can be found on the Worms & Germs Resources page.
NDM-1 (New Delhi metalloproteinase 1) is a little bacterial gene that's attracted a lot of attention (and controversy, due to its name). NDM-1 can be picked up by certain types of bacteria, making them resistant to a whole lot of antibiotics. Some bacteria that carry NDM-1 are resistant to virtually every available antibiotic, which raises the spectre of the "untreatable infection."
Since it's discovery, NDM-1 has been found in multiple countries, often in people that were in India as tourists (or "medical tourists" who traveled to India for medical procedures they couldn't have done in their own countries), and in a few different types of bacteria. Recently, NDM-1 was found in an American upon his return from India, this time in Salmonella (Savard et al. 2011, Antimicrobial Agents and Chemotherapy).
The 61-year-old man was hospitalized in India in late December 2010 following a severe bleed in his brain. He was transferred back to the US on January 25, 2011. Upon arrival, he developed a fever and a multidrug-resistant bacterium, Klebsiella pneumoniae, was isolated from his breathing tube. This was concerning by itself, but later, Salmonella Senftenberg was isolated from the man's rectum. The strain was highly atimicrobial-resistant and was determined to carry the NDM-1 gene.
There have been complaints from people in India about the stigma associated with the "New Delhi" component of the name. In hindsight, many people wish it had been named differently because of this, but at least at the moment, it's undeniable that India is a (or the) hotbed of NDM-1. It's been found in various bacteria from water and seepage samples in New Delhi, but this is the first report in Salmonella. It's concerning because of the difficulty that would be encountered treating highly resistant Salmonella in infected people. Usually, antibiotics aren't needed when someone has salmonellosis, but when they are needed, it's important that they work. Highly drug resistant strains increase the chance of a bad outcome if ineffective antibiotics are used initially (before it's determined that the strain is resistant).
NDM-1 has not been reported in animals... yet. I assume it's inevitable that it will occur, since this gene appears quite able to move between bacterial species. If it increases in humans and in human-feces-contaminated sources like water, exposure of animals will certainly occur. If NDM-1 containing bacteria establish themselves in the intestinal tracts of healthy animals, it's going to be much harder to control.
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 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).
Easter is one of those holidays when there are concerns about dumb pet purchases. Spur-of-the-moment purchases of inappropriate pets can lead to animal suffering and death, and risk of human infection. Easter's problems: baby chicks and rabbits.
Rabbits can make great pets. They're a long-term commitment, but they’re relatively low maintenance, a lot is known about how to raise them and they are generally low risk for transmission of infections to people. Chicks are a different story. Chicks are notorious Salmonella vectors and have been linked to numerous outbreaks. They are easily injured and often improperly raised. They also grow up (well, some of them do, at least) to be full sized poultry, something that most people don't really want.
A story from Vidalia, Georgia highlights some of the issues with Easter pets. In it, Tracy Gunn describes his need to buy a chick for his daughter - and not just any old chick, but a dyed chick, something that’s illegal in 36 US states, but not Georgia. Gunn states "I don't know what she's going to do with it." Sounds like a recipe for a few minutes of novelty, followed by a relatively short life for the chick. At least his daughter’s 17, and not in the high risk group for salmonellosis.
Alongside the cage full of multicoloured chicks was a collection of rabbits.
“The bunnies sell real good for Easter. We've been selling a lot of them about the last month. Can't keep enough of them.” said a store employee.
He followed that up with “They buy (rabbits) for their kids for Easter, then they take Easter pictures and stuff like that with them, I'm not sure about what happens to them afterward.”
That’s the problem. Kids get a few minutes of novelty enjoyment, but then a lot of those animals end up dead, released into the wild (not a good thing) or dropped off at an animal shelter, because people don't think about the "afterward" part before they buy.
Pet purchases need to be made with thought and foresight:
- Do I really want this pet?
- Am I committed to taking care of it for its entire life?
- Can I take care of it properly with my current living situation?
- Can I afford to take care of it properly?
- How do I take care of it?
- Are there any disease risks that I need to be concerned about?
- Are there any people in the household who are at high risk for disease caused by this type of animal?
If you can't answer these questions, don't buy or adopt an animal - of any kind.
A month or two ago, there was a lot of press about the risks of pets sleeping in beds. It was in response to an article in the journal Emerging Infectious Diseases that didn't put forth any new information, but summarized a few diseases that could potentially be transmitted by pets. Unfortunately, the relative risk of those diseases wasn't really explored, and some media reports latched onto diseases like the plague, transmission of which can occur between pets and humans but the likelihood of this in most areas is essentially nil.
Anyway, an article at Scienceline.org has taken a more balanced approach towards the subject. One sentence perhaps say it best: "Many of those scare headlines, however, missed the main point of Chomel’s work: For most people, the risks are minimal, and there are easy ways to go about preventing pet-to-owner disease sharing."
I won't go into details here, since you can read the article yourself, but a key component is that pet ownership is never no-risk, but is usually low-risk. Basic hygiene practices and common sense can reduce the risks further. The cost-benefit needs to be considered, and while we can never completely eliminate the "cost" aspect, the benefits of pet ownership certainly outweigh the costs in the vast majority of households.
The US CDC is investigating a large, long-lasting and widely dispersed outbreak of salmonellosis that has been linked to contact with pet frogs, such as African dwarf frogs (see image). Between April 1, 2009 and April 5, 2011, 217 infections were identified in people in 41 states. A strain of Salmonella Typhimurium has been implicated.
Of the 217 infected people, 34% were hospitalized, which is quite a large proportion, but is probably due (at least in part) to the fact that stool samples aren't often cultured from people with milder disease (who don't go to the hospital). If you have severe diarrhea and are in hospital, you're more likely to be tested. As with most outbreaks, the 217 diagnosed cases presumably represent only the tip of the iceberg.
Of the people who got sick, 64% reported contact with frogs in the week before their illness began. Of these, 84% had contact with African dwarf frogs. This type of widespread outbreak with a single strain and a fairly clear link to a specific type of animal raises questions about whether there's a major breeder or supplier that is the source of the problem. Not surprisingly, the investigation identified a single water frog breeder in California as the source of frogs associated with this outbreak. Salmonella was identified from environmental samples at the breeder's facility. Testing is still apparently underway to confirm whether it's the outbreak strain, but it's pretty likely.
As with any other reptiles or amphibians, there are standard recommendations to avoid infections from aquatic (water) frogs:
- They should not be in households with high-risk people: children less than five years of age, the elderly, pregnant women and immunocompromised individuals.
- Care should be taken to prevent contamination of the house from aquarium/terrarium water.
- To avoid contamination, aquarium water should not be dumped down kitchen or bathroom sinks.
- Hands should be washed thoroughly after contact with aquarium water or the frogs themselves.
Photo: An African dwarf frog (Hymenochirus boettgeri) (photo credit: James Gathany).
A sure sign of spring is the proliferation of classrooms hatching out chicken or duck eggs. While chicks may be cute and entertaining, they are also high-risk sources of Salmonella and some other infectious microorganisms. Numerous Salmonella outbreaks have been linked to contact with hatchling chicks, and care must be taken if teachers are considering having chicks in classrooms.
Things to consider:
- Who will be in contact with the chicks? Children under 5 years of age, pregnant women and people with compromised immune systems should not have contact with young chicks. This rules out having chicks in preschool and some kindergarten classes, however not everyone follows those standard recommendations. It's also very hard to know whether there may be immunocompromised kids in the classroom. Unless a teacher/school is sure that there are no high-risk children present, they shouldn't have high risk animals.
- Where will the chicks be hatched and raised? Is it in a contained area?
- Is the chick area easily and always supervised to ensure that rules are followed? This is important for both children and chicks, since chicks can easily be injured or killed through improper handling.
- Are protocols in place regarding safe handling and hygiene?
- Are the chicks going to be in an area where students eat?
- Are parents going to be notified in advance?
- Are there plans for sending the birds to an appropriate home when they're done in the classroom?
- Are the chicks there for a true educational purpose, or just as a novelty?
Hatching chicks can be done relatively safely in appropriate classrooms, with older children, no high-risk individuals, easy access to hand hygiene stations, appropriate protocols and proper supervision. The problem is, these aren't always (or even often) present, and inadequate thought often goes into bringing chicks into classrooms.
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.
Jones Natural Chews Company has recalled 2705 boxes of pig ear treats because of a "potential" for contamination with Salmonella. The recall was the result of a routine sampling program by the Washington State Department of Agriculture which revealed that the finished products contained the bacteria.
This shouldn't come as a surprise. Salmonella contamination of raw animal-based pet treats is nothing new, and contaminated treats have been implicated in outbreaks of human salmonellosis. There is a risk to pets as well, since Salmonella can cause disease ranging from mild to fatal. Typically, dogs that eat a little Salmonella don't get sick, but they may under the right circumstances, and even dogs that appear healthy can potentially infect people they are around. Handling the treats is also a risk to people, especially the very young, very old, pregnant women and people with compromised immune systems. Households with any individuals from these groups should avoid having any raw animal-based treats around (unless irradiated). Anyone having contact with treats (whether they're in a high-risk group or not) should wash their hands afterwards.
When a particular animal species or breed gets a lot of attention, such as through a popular movie or TV show, there's sometimes a major increase in people wanting one as a pet. The proliferation of Dalmatians after 101 Dalmatians, and people buying Jack Russell terriers in response to Eddie from Frasier are only two examples. Sometimes the trend is fine, but it can result in problems when people get breeds or species that really aren't right for them (this was a big problem with the Dalmatians), and with puppy mills pumping out large numbers of poor quality animals to meet the demand. The problems can be even worse when an exotic species is involved.
Concern has been expressed about the potential for this to occur following the success of the animated movie Rango. The movie features a chameleon, a fascinating reptile but also one that is not that easy to properly maintain in captivity and, like all reptiles, carries a risk of Salmonella transmission to household members.
PETA and some other groups have expressed concern about a PetSmart promotion whereby people can get a $10 discount on reptiles if they bring in a Rango movie ticket stubs.
Any increase in demand for chameleons resulting from this promotion will be trouble, because:
- Odds are most of the animals will not do well if purchased on a whim by someone who isn't adequately prepared to take care of them.
- Smuggling or legal importation of wild-caught chameleons will probably increase, with the associated very high death rates during the collection and shipping process.
- Chameleons may end up in households where reptiles are not appropriate, such as those with kids under five years of age, elderly individuals, pregnant women or people with compromised immune systems.
Hopefully the concerns are unfounded, but anyone considering purchasing a chameleon needs to carefully research the care requirements, be aware of the risk of disease transmission in the household, and should look for ethically sourced (i.e. captive bred and properly raised) animals.
An Irish study has reported a high rate of Salmonella contamination in pig ear treats. Various earlier studies have identified Salmonella in pig ear treats, and human infections have been associated with contact with such treats. Recommendations for processing and handling of pig ear treats have been made and have hopefully reduced the likelihood of contamination, but there's no information about adherence to these recommendations.
In the most recent study, published in Food Research International (Adley et al. 2011), researchers purchased 102 pig ears from 4 pet shops in Limerick City, Ireland. Salmonella was detected in 28% of samples. A variety of different Salmonella types were found, including antibiotic resistant strains and types that are common causes of disease in people.
Interestingly, all of the contaminated treats were from 2 of the 4 stores. The two negative stores only sold treats sourced from within the European Union, and one of them only sold pre-packaged treats. The other two stores sold treats sourced from the EU and Brazil, and sold some in bulk bins. All positive treats were from the same distributor, and all were from bulk bins.
The high prevalence of Salmonella in these treats is concerning, particularly in light of standard guidelines for processing such treats and and EU regulation that if treats are not Salmonella-free, they must have less than 1 Salmonella bacterium per 25 g of product.
Contamination of bulk bin treats isn't surprising, as I mentioned in a post just the other day. Bulk bins allow for cross contamination, and a single positive treat (or a single contaminated hand going into the bin) can result in contamination of many other treats. Also, picking treats out of a bulk bin can potentially contaminate consumers' hands, and there's an additional concern that bulk bins are often kept at a level where young children (a high risk group) can access them.
Contact with Salmonella in pig ear treats is a risk, and people should wash their hands after any contact with a pet treat. Avoiding bulk bin treats is a good idea. Purchasing irradiated and individually packaged treats should also help reduce the risk. Unfortunately, stores do a lousy job of notifying people about the risk. As the paper states "We recommend public awareness advertising in pet shops to alert pet owners of the risks associated with pig ear pet treats and hygiene practices that should be followed."
Merrick Pet Care has recalled Junior Texas Taffy pet treats because of the potential for contamination with Salmonella. No illnesses have been reported but contamination of treats could pose a risk to both pets and owners.
Contamination of pet treats is not uncommonly reported, but the overall scope of the problem isn't well understood. Outbreaks of salmonellosis in people have been reported in association with handling contaminated treats. The impact on animal health is unclear. Most recalls are not associated with reports of animal illness, however it's possible that small numbers of sporadic cases of disease would not be identified or reported.
Recalls like this highlight the potential risk from any pet treat or pet food. You can never absolutely eliminate risk but you can do things that will probably reduce the risk and identify situations where there are greater concerns.
- Packaged treats may be lower risk than treats from bulk-bins, because a single contaminated item can lead to cross contamination of many others in these large bins.
- Individually packaged irradiated treats are presumably of little to no risk.
- "Human-grade," "premium" or other catchy descriptions have absolutely no meaning with regard to food safety.
- People should wash their hands or use a hand sanitizer after handling treats.
- Care should be taken when handling any animal-based pet treats, particularly in households that include people with compromised immune systems, infants, elderly individuals or pregnant women. In these households, particular attention needs to be paid to handwashing after contact with treats, or - better yet - avoiding treats (or at least non-irradiated treats) altogether.
Tegus are large South American lizards that are sometimes kept as pets. As with other reptiles, Salmonella is a concern, as highlighted by a recent study in the journal Zoonoses and Public Health (Maciel et al. 2010). In that study, the authors tested feces of 30 captive-born tegus. From the first round of samples, they isolated various types of Salmonella from 87% of the animals. They collected a second fecal sample from the 4 tegus that were initially negative, and found Salmonella in feces of all of them.
It's not particularly surprising to find Salmonella in tegus, just like in other reptiles. The fact that it wasn't too hard for the authors to find this important bacterium in all of the reptiles highlights the public health concerns regarding reptiles and Salmonella. Further, they showed (as has been shown with other reptiles like snakes) that Salmonella can be shed intermittently, so a negative culture doesn't mean the animal is truly Salmonella-free.
Reptiles can make good pets, but they are accompanied by an increased degree of risk with regard to infectious diseases. They are not recommended for households with children less than five years of age, elderly persons, pregnant women or people with compromised immune systems. In low-risk households (i.e. households without people in these categories), the risk can be reduced (though not eliminated) by basic common sense practices, particularly close attention to handwashing after touching the animal or its environment, and preventing the animal from roaming around the house.
Image from http://ns3.powerblogs.com/my_pet_tegu/
Here's a comment from a well-meaning but ultimately misinformed reader. I'm commenting on it because these misconceptions are not uncommon.
"This blog post appears to be based on inadequate knowledge of iguanas. I am an iguana keeper and have been for several years. Unlike many reptiles, iguanas do not carry salmonella on their skin and are not a high salmonella risk. Furthermore, as long as the bath tub is disinfected afterward, there is generally no problem with iguanas bathing or even defecating in bath tubs shared with humans (although I do understand concerns of those with babies or immunocompromised people)."
Iguanas can and do carry Salmonella on their skin. It mainly resides in their intestinal tract but can easily contaminate their skin. For example, a 10-week study of 12 green iguanas reported that they all shed Salmonella at least once during the course of the study (Burnham et al, J Am Vet Med Assoc 1998). You have to assume that every iguana is carrying Salmonella.
People can and do get Salmonella from iguanas. There are numerous reports of salmonellosis from pet iguanas, including fatal infections. In a study of salmonellosis in people associated with exotic pets, iguanas were the most common source, accounting for over 50% of infections (Woodward et al, J Clin Microbiol 1997) Babies and immunocompromised people are at greatest risk, but infections occur in people outside of these high-risk groups as well.
Disinfection is far from foolproof. Yes, disinfection will kill Salmonella IF (and that's a big if) it's done properly. That includes properly disinfecting all tub surfaces, along with any other areas that were potentially contaminated (e.g. by splashes). This is far from guaranteed to happen in most cases, since people rarely understand what is required for proper disinfection and how to do it.
I'm not saying people should never have iguanas. Some people shouldn't: households with children under five years of age, elderly individuals, pregnant women or immunocompromised individuals. In other households, the risk is lower, but it's still there. An important part of managing the risk is knowing that the risk does exist. Pretending there is no risk doesn't do anyone any good.
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.
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 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.
Salmonella vs salmonellosis
- Salmonella is the bacterium.
- Salmonellosis is disease caused by infection with the Salmonella bacterium.
When an animal is exposed to the Salmonella bacterium from food or feces, a variety of states can develop.
- No Salmonella, no disease: In these cases, Salmonella does not survive passage through the intestinal tract and nothing happens. The animal doesn't get sick and Salmonella is not detectable.
- Colonization (also called "carriage"): This is when Salmonella survives passage through the stomach and grows, at least for a while, in the intestinal tract, but does not cause disease. Colonized animals may shed Salmonella, meaning they pass the Salmonella bacterium in their feces, and may therefore be a source of infection for people or other animals. Colonized animals will most often eliminate Salmonella on their own in a short period of time (days to a couple of weeks) and usually don't get sick. It is possible, however, that a colonized animal could develop salmonellosis from Salmonella living in its intestinal tract. This is most likely to occur if something allows the bacterium to overgrow in the intestinal tract or reach the bloodstream, which is most likely in young, old or sick animals.
- Transient passage: This occurs when live Salmonella that have been ingested survive passage all the way through the intestinal tract, but without the bacterium becoming established in the body and without disease. Salmonella can be detected in feces. It's hard to distinguish transient passage from short-term colonization, and it's not clear whether transient passage really occurs.
- Enteric salmonellosis: This is the most common form of disease, characterized by diarrhea and potentially varying degrees of depression, weakness, lethargy, decreased appetite and vomiting.
- Systemic salmonellosis: This uncommon and severe form of disease occurs when Salmonella enters the bloodstream (by invading through the intestinal wall) and causes a bloodstream infection and/or infection of other body sites/organs. This form is often fatal. It is most common in young and old animals, or animals with other diseases that affect their ability to fight infections.
- Contamination: It is also possible for animals to spread Salmonella that has only contaminated the outside of their bodies. For example, a dog eating contaminated food might get Salmonella on its face. The bacterium doesn't make in to the intestinal tract and can't cause colonization or disease in the dog, but the dog's face could be a source of infection for other individuals for a short period of time, until the bacteria die or are physically removed.
Image: Salmonella sp. on an XLD agar culture plate 24 hours after innoculation. (Source: CDC Public Health Image Library #6619)
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.
The recent run of Salmonella recalls in dry foods, raw foods and supplements has resulted in a lot of questions about when animals should be tested for Salmonella. In general, testing is only indicated in animals that have disease suggestive of salmonellosis. Diarrhea is the main issue, but other problems such as fever, decreased appetite and bloodstream infections can also occur. Clearly, any animal with signs such as these needs to be tested for Salmonella. However, there is no indication to test healthy dogs and cats that have been exposed to recalled products.
Why is that? An important concept in medicine is that you should always have a plan about what to do with the results of diagnostic tests - the result should have an impact on what you do. When you think about what would happen with a negative versus a positive test for Salmonella in a healthy pet, it shows why testing is not useful.
What would I tell you about a negative result?
- I'd say it means the animal is probably negative, but it could be a false negative because of intermittent shedding of Salmonella in stool or a false negative test result.
- I'd also say that even if there was no Salmonella, every animal is shedding multiple potentially harmful pathogens in its stool.
- So, I'd emphasize that if the animal became sick, Salmonella still needs to be considered and that good hygiene measures should be used around the animal (particularly its stool).
What would I say about a positive result?
- I'd say that means the animal was shedding Salmonella at the time the sample was collected, but that doesn't tell us if the animal is still shedding or how long it will do so.
- There's no indication to treat the animal. There is no evidence that treatment of dogs and cats that are shedding Salmonella is needed. There's also no evidence that it's effective. In fact, there are concerns that giving antibiotics could prolong shedding of Salmonella and that it could increase antibiotic resistance.
- Salmonella is certainly a public health concern, but there's not much specific to be done.
- So, I'd emphasize that if the animal became sick, that Salmonella still needs to be considered and that good hygiene measures should be used around the animal (particularly its stool).
Since my recommendations for a positive result and a negative result from a healthy animal would be the same, why test?
Recent Salmonella recalls have led to some questions about the best way to diagnose salmonellosis in dogs and cats.
The first issue is when to test. In general, there is no indication to test healthy animals. Testing should be reserved for animals with diarrhea or other signs of salmonellosis (e.g. fever).
When testing is indicated, a few things should be considered:
- A fresh sample is best. It should be submitted for testing as soon as possible, but it can be kept cool (i.e. refrigeration temperature) for a day or more if it can't be submitted right away. (Do NOT keep a fecal sample in your fridge at home! Take it to your local vet clinic and they will keep it in a designated specimen fridge.)
- More is better. A reasonable volume of stool (e.g. a tablespoon or two) is preferred to something like a rectal swab. Testing can be performed on rectal swabs but they are lower yield because they contain a lot less stool. See image right: standard-size 30 mL fecal sample containers (click for source).
There are two tests used to detect Salmonella in feces: culture and PCR.
Culture is used to grow and isolate the Salmonella bacterium. Usually, enrichment culture is used, whereby the sample is first cultured in a selective broth culture medium, then put on culture plates. This increases the recovery rate but takes more time.
Advantages of culture are:
- A positive is definitive - the bacterium is definitely there and alive.
- An isolate is available for subsequent testing such as determining the susceptibility to antibiotics and typing it to see what strain is involved.
Disadvantages of culture:
- Salmonella can be hard to grow for labs that don't have a lot of experience and good protocols.
- A few days are required to obtain results, particularly if proper enrichment methods are used.
PCR (polymerase chain reaction) is a molecular diagnostic test that looks for DNA from a particular organism (in this case, Salmonella).
Advantages of PCR:
- Speed. Results may be available within 24 hours.
Disadvantages of PCR:
- Tests validated for dogs and cats are not usually available.
- The test detects both live and dead bacteria, so a positive result could theoretically be from ingestion of dead (and therefore irrelevant) bacteria.
- False negative results can occur from low levels of Salmonella or substances in the stool sample that inhibit the test.
- Lab quality control is critical but not always good.
Current recommendations are to base diagnosis on culture. PCR can be used as a faster presumptive test, but culture should be performed to confirm the diagnosis and get a bacterial isolate that can be further tested for antibiotic sensitivity and typed to see what strain is involved.
Recently, Kings of Leon canceled an outdoor concert after a pigeon (with very good aim, apparently) in the rafters above the stage managed to poop on band members, including one shot that hit the face of the band's bassist.
Besides, the "ick-factor," what are the concerns?
Various studies have found potentially nasty microorganisms in pigeon poop, including:
- E. coli
- Various microsporidia
- Various Cryptococcus species
- Multidrug resistant Staphylococcus spp
- Chlamydophila psittaci
- Mycobacterium avium complex
The risk of disease is pretty low for most people, and we are potentially exposed to many of those bugs on a daily basis. The risks increase with higher ingested doses (so direct-deposit of poop is a much greater concern that inadvertent contamination of your hands) and in people with compromised immune systems. It's unlikely but not impossible that someone would get sick from exposure to pigeon feces, and don't eat poop is a good general philosophy for life.
Following on the heels of a limited recall of feline dry renal diets because of potential contamination with Salmonella, Proctor and Gamble has now recalled all Iams Veterinary Dry Products, as well as Eukanuba Naturally Wild, Eukanuba Pure and Eukanuba Custom Care Sensitive Skin. These products are sold across the US and Canada, and all products with best-before dates between July 1, 2010 and Dec 1, 2010 (so, presumably everything that is on the market at the moment) are included. The broad scope of the recall is apparently a proactive measure based on the premise that since Salmonella was found in some products made at a particular production facility, there is the potential for contamination of everything made there. More data about what they have found and how widespread the contamination is would be nice (but is not forthcoming at the moment).
No illnesses have been reported. If your pet is being fed one of the recalled diets and develops diarrhea, vomiting or other signs of illness (e.g. weakness, fever, decreased appetite), it is important to consider the possibility of Salmonella. Similarly, if any people in the house develop these types of symptoms, they should make sure their physician knows they may have been exposed to Salmonella. Presumably, the level of contamination was low and the risks to the general public (human and canine/feline) are relatively low, with higher risks to people and animals with compromised immune systems or other diseases that limit their ability to fight off a bug like Salmonella.
Proctor and Gamble has announced a recall of two lots of Iams' Veterinary Formulas Feline Renal, a prescription dry cat food. The lot numbers are 01384174B4 and 01384174B2. Anyone that has this food should stop using it immediately. Since these are prescription diets that should only be available through a veterinarian, affected customers should presumably contact their veterinarian for information about a replacement or refund. If a cat that has eaten this food develops diarrhea, Salmonella should be considered as a possible cause and a stool sample should be tested.
As with most of these recalls, no illnesses have been reported, although lack of reported cases doesn't necessarily mean lack of cases. While Salmonella contamination of dry pet food diets is quite uncommon, it can happen. It's a good reason for people to make sure they wash their hands after having contact with any pet food or the pet's food bowl, and to make sure that pet food is kept separate from food meant for human consumption.
A couple of more Salmonella recalls have occurred recently. Feline's Pride Natural Chicken Formula, a raw chicken diet, has been recalled, as has Natural Balance Sweet Potato and Chicken, a kibble diet.
Finding Salmonella in commercial raw diets is expected and I'm surprised about the recalls that have happened. If you buy raw meat, you need to assume that it's contaminated with Salmonella and various other potential pathogens. Salmonella in kibble diets is more surprising, and is a concern because people do not tend to handle kibble as potentially contaminated.
These recalls highlight a few points to me:
- Always assume you have Salmonella and other nasties in raw meat. Careful attention to handling of raw meat and personal hygiene (e.g. handwashing) is critical.
- While lower risk, kibble is not innocuous, so wash your hands and prevent cross-contamination of kibble with human foods.
- "Natural," along with "organic," "super premium" and other marketing catch-words tell you nothing about the quality and safety of a product. There's no evidence that any products marketed as organic, natural, or anything else along that line are at all superior to diets produced by reputable companies, particularly diets that have undergone proper development and testing, including AAFCO feeding trials.
All lots of "Pro-Pet Adult Daily Vitamins" have been recalled by United Pet Group, Inc. because of Salmonella contamination. At least one lot has tested positive for Salmonella, although there is no mention about whether the bacterium was detected during routine testing or in response to a problem. Regardless, Salmonella contamination of these products is a concern because of the potential for disease in dogs fed the vitamins. Further, people could become infected from contact with dogs that become infected from the vitamins, or from handling the vitamins directly. If you have these vitamins, stop using them immediately. If your pet has been receiving these vitamins and develops fever, diarrhea, anorexia or any other signs of illness, take your pet to your veterinarian and make sure he/she knows there has been a chance of Salmonella exposure.
I use frozen raw food. Doesn't freezing kill harmful microorganisms?
- No. Freezing is an effective way to eliminate most parasites (with an adequately low temperature and adequate time, which varies between parasites). Campylobacter also does not survive freezing well. However, other bacteria, including Salmonella, tolerate freezing quite well. Studies of previously frozen raw diets have found high rates of bacteria like Salmonella.
My dog doesn't defecate in the hospital, so why are we paying attention to intestinal bacteria?
- Inadvertent exposure to fecal bacteria is common. Most gastrointestinal infections in people are from ingestion of bacteria and viruses from feces (e.g. Salmonella, Clostridium difficile, norovirus). We don't knowingly ingest feces, but we get exposed to these organisms nonetheless. Fecal bacteria can end up on pets' haircoats, people's hands and many surfaces in the general environment, and then wind up in the intestinal tract of a susceptible person.
Is there any way to eliminate Salmonella and other harmful bugs from raw meat?
- Yes. Besides the obvious (cooking), there are a couple options. One is irradition, which is a safe and highly effective way to eliminate bacteria. The main problems are cost and consumer fears of irradiation (which is actually harmless). Another approach is high pressure pasteurization. This process uses high pressure (with a slight increase in temperature) to kill harmful organisms. The effectiveness of this for raw meat hasn't been clearly determined, but it's an option, and one company is now doing this for all of their diets.
Why don't you just go into hospitals, ask nurses whether animals visit and compare infection rates, so you can see if there is a true health risk?
- It would be nice if it was that easy. Firstly, asking nursing staff doesn't give enough information. You need to know if animals visit, but also if they visited particular patients, and whether they visited before those patients developed infection. Just comparing infection rates between hospitals or wards that allow dogs to visit, and knowing the dietary status of the dogs, is useless. A proper study would require clear documentation of which animals visited which patients (something that is rarely recorded) and whether patients subsequently developed any infections that were not present before visitation (which is not easy to document), while concurrently investigating other possible sources of infection (similarly challenging). Ideally, bacteria causing human infections would be compared to those found in animals to provide stronger evidence of a link. Because the incidence of infections is relatively low, a large number of people would need to be enrolled. There are significant logistical issues, research ethics board issues, problems with the quality and availability of medical records and other things that make this very, very difficult. It needs to be done but it's not as simple as many people think. If it was easy, it would have been done by now.
Dogs have a short and acidic intestinal tract and are not susceptible to Salmonella.
- This statement appears thousands of times on the internet and there's absolutely no evidence supporting it. Dogs can and do get salmonellosis. For every email I've had talking about how a raw diet has made a big difference in someone's dog's health, I get at least one email from an owner or vet whose dog got salmonellosis while eating raw meat (and sometimes people in the house also got sick). A dog that eats Salmonella can shed it in its feces. The bacterium can clearly survive passage through the intestinal tract. Most dogs that ingest Salmonella do not get sick. Some do. Sometimes their owners do as well.
Wild dogs eat raw meat. That's what they've evolved to do.
- Wild dogs also have a much, much shorter lifespan than domestic dogs. It's obviously not all related to diet, but I don't want my dog to have the lifespan of a "natural" dog, I want her to have the longer and healthier lifespan of a modern pet dog. Take a look at older cemeteries and see the number of headstones of very young children. Raw milk played a big role in many of those.
- Regardless, the question isn't about the health of dogs fed raw meat. That's a completely separate issue. The issue is the risk that raw-fed dogs might pose to the highly compromised people that are found in healthcare facilities. People need to think about the health of those susceptible individuals when they get involved in this debate.
Since my post about Delta Society and raw diets, I've had multiple questions or comments about the research behind it.
Here's one question:
"Please site the research that "clearly show..." that raw-fed animals shed bacteria at a higher rate."
Here's the answer:
- Study following therapy dogs over the course of a year. Diet history was recorded. Raw-fed dogs were 17 times as likely to be shedding multidrug-resistant E. coli compared to non-raw-fed dogs, and more likely to be shedding Salmonella.
- Study of healthy dogs in households. Dogs fed a commercial or homemade raw diet were greater than 5 times as likely to be shedding Salmonella than other dogs.
- Study investigating therapy dogs in Ontario and Alberta. Raw-fed dogs were 23 times as likely to be shedding Salmonella and 17 times as likely to be shedding multidrug resistant E. coli.
- Campylobacter jejuni was found in the feces on 2.6% of raw-fed dogs and Salmonella was found in 14% of raw-fed dogs. Neither was found in any dogs not fed raw meat.
That's pretty clear to me.
Delta Society has recently announced a policy prohibiting animals fed raw meat or raw animal products from participating in their Pet Partners program. This policy was established because of research indicating dogs fed raw meat are much more likely to be shedding harmful bacteria like Salmonella and drug resistant E. coli in their feces compared to dogs fed commercial or home cooked diets, and the fact that these dogs come into close and frequent contact with people that are more susceptible to infections and at increased risk having severe infections.
Not surprisingly, internet chat sites are abuzz, and there's much condemnation and consternation from some. Some of the more vocal minority are stating that they'll just lie and say that they're not feeding raw. I guess such dishonest actions would be based on a combination of ignorance and arrogance - feeding raw is your own decision, but blatantly flouting a policy that was put in place to reduce risks to those most susceptible is stupid and irresponsible.
One of the problems with peoples' reactions is the fact that they are confusing two separate issues. One debate is whether raw feeding is more healthy or more harmful to the pet. That's a controversial area, but this policy has nothing to do with that. This policy deals with the increased likelihood that raw-fed pets are shedding harmful bacteria. That's been very well proven in scientific studies. Do raw-fed pets cause disease in people in hospitals? We don't know. However, we have enough evidence to indicate there is the potential for increased risk to patients, and that added risk can be eliminated by not feeding raw meat products.
Hopefully, people will realize that this policy has been put in place for a good reason, and that it's focused on protection of people at high risk of serious illness. It's not a broad condemnation of raw diets, it's just a statement that it is not considered appropriate for dogs that will have contact with high risk populations - a recommendation that's far from new.
Disclosure: I'm a member of Delta Society's Medical Advisory Board. However, the opinions expressed here are mine and do not necessarily reflect the views of Delta Society.
Among the various things I've been called in response to blog posts is "anti-reptile." Actually, I like reptiles. I've owned and treated them, and think many of them are quite fascinating species. They can be reasonable pets in certain situations. The main problem is that they have high rates of Salmonella carriage and are the cause of a large number of infections in people. That's why the CDC, among other groups, recommends that people under the age of 5, the elderly, pregnant women and people with compromised immune systems avoid them.
Why do I bring this up (again)? I read an article today about the Fall River, Massachusetts, library and their resident tortoise, Franklin. Why am I concerned?
- Who goes to a library? Lots of people. Kids and elderly individuals probably go more than average. Those are the high risk groups.
- You could try to make the argument that having a tortoise in a library wouldn't necessarily pose much of a risk if it was kept in a cage or terrarium. That's probably reasonable, as long as good management and hygiene practices were used, but it's not a guarantee. Infections have been reported in households where the reptile never leaves its enclosure and in people who never have direct contact with it.
- Regardless, Franklin doesn't spend his days in a cage of any kind. He gets out and cruises around the library, especially in the carpeted Children's Room. That's a bigger problem. This tortoise is certainly not house trained (my tortoises' repertoire was pretty much limited to eat, poop, wander around, repeat... I don't think there was an extra neuron for something like litterbox training). Tortoises can also easily contaminate their feet and shell with feces. So, we have a potentially poop-contaminated tortoise who may also leave a fecal present at any time wandering around a carpeted (almost impossible to disinfect) surface on which young kids play. Not a good combination.
- See the picture above. The person is described as a "library senior aide" and is presumably in the high-risk group based on age. The tortoise has its leg (which presumably walked over some tortoise poop sometime in the recent past) practically in her mouth. That's not good either.
What should the library do?
1) Ideally find a good home for Franklin. One with no high-risk people.
2) If that's not an option, a protocol should be in place for how to manage Franklin and reduce the risk of Salmonella transmission. This would involve:
- Keeping him in a proper enclosure. Not letting him roam around public areas. Visits outside to walk around on the grass (during the appropriate seasons) are fine, but there should be no walking around general library areas (especially not the Children's Room).
- Not letting the general public handle him. Reptiles are "look but don't touch" pets.
- Emphasizing hand hygiene for anyone that has contact with Franklin or his environment, and facilitating hand hygiene by having convenient access to a properly equipped sink or alcohol-based hand sanitizers.
- Excluding high-risk groups from contact, if people are allowed to have direct contact with Franklin at all. Any public contact should be supervised and there must be immediate washing of hands or use of a hand sanitizer afterwards. Since this is unlikely to be done properly, avoiding all public contact makes the most sense.
- Using Franklin to help teach. Perhaps he could be brought out in a small glass terrarium and people could watch him as part of stories or other events. He (and the way he's handled) could also be used to explain things about infectious diseases and infection control.
Image source: www.wickedlocal.com
It's encouraging to see the number of press reports warning people not to bring home baby chicks or ducklings as Easter presents for kids. The warnings are because of the potential risk of salmonellosis associated with contact with poultry and fowl, particularly among children. Young kids (less than five years of age) are at high risk for this type of infection, and are at higher risk of developing more serious illness and complications. They also tend to be at higher risk for exposure because of the close nature of contact that they may have with pets, or in this case Easter chicks. Add close contact and increased susceptibility to the generally low level of hygiene associated with household animal contact, and you have a perfect recipe for sick kids.
Salmonella carriage is an ever-present concern with chicks and duckings. It doesn't matter how they were raised or from where they came - you can never know by looking it it whether a baby bird is shedding Salmonella, and you should assume that they all are to be on the safe side.
The CDC has some basic advice on the topic. The key points are:
- Never buy chicks or ducklings on a whim. If in doubt, buy a stuffed animal.
- Never buy chicks or ducklings for kids under five years of age or people with compromised immune systems. These individuals should not have any contact with chicks or ducklings.
- Don't let these animals roam freely around the house. They're not house trained and can contaminate the household environment.
- Always wash your hands thoroughly after contact with chicks or ducklings.
- Don't eat around chicks and ducklings, since it increases the chance of inadvertently ingesting Salmonella.
Baby chicks and ducklings don't make good pets because of the Salmonella risk. They also grow up, and become larger, messier, and noisier birds for which many people are not prepared to care. Don't buy a baby bird unless you have a low risk household, can properly implement measures to reduce the risk of exposure to Salmonella, and have a plan to properly take care of the bird when it gets older.
Nature's Variety has expanded their recall based on more concerns about Salmonella contamination of their products. In a lot of ways, this makes no sense to me since you have to assume that raw meat is contaminated with Salmonella, E. coli, Campylobacter and various other pathogens. That's been clearly shown in studies of raw meat for humans and animals, and that's why we cook meat intended for human consumption and emphasize good food handling practices. It's also why there are concerns about feeding raw meat to pets, and the explanation for various studies showing pets fed raw meat have much higher rates of shedding potentially harmful bacteria like Salmonella. You have to assume that a reasonable percentage of Nature's Variety's food has been contaminated with Salmonella, not that this is an uncommon and preventable event.
Because of the problem or consumer concerns, Nature's Variety has announced that they will be treating all of their diets using high pressure pasteurization. Basically, this process uses very high pressures (with only a slight increase in temperature) to reduce bacterial levels. I can't find any scientific literature about the effectiveness of this method on Salmonella contamination of raw meat (it's mainly used with milk and cheese) but it should be able to greatly reduce bacterial levels in meat. That's a good thing, as long as it works. What's important to know, however, is whether it is really highly effective in this situation and whether all potentially harmful bacterial will be eliminated every time.
I'm concerned that if people think this food is "sterile" and it's not, they might not take the necessary food handling precautions. If this method usually, but not always, kills all of the bad bacteria, or if it reduces levels greatly but not completely, then there could still be the risk of infection of people and pets. This information is critical. In the absence of clear scientific data, I think we need to assume that some level of contamination could still be present (although probably much less often and at a much lower level), and make sure that proper food handling practices are used.
It's good to see this company taking measures to reduce the risks associated with raw meat feeding. Let's hope that some objective research is made available to indicate what risks might remain.
Image source: www.defendingfoodsafety.com
A study by Erin Leonard of the University of Guelph and others, that has just been published in the journal Zoonoses and Public Health, once again points to the increased risk of Salmonella shedding associated with feeding raw diets to dogs. The study looked at 138 dogs from 84 households in Ontario. One-quarter of households (21/84, 25%) had at least one dog (32/138, 23.2%) that was shedding Salmonella at one time, which is considerably higher than the 1-4% of pet dogs that are typically expected to be shedding this zoonotic pathogen. Only 4 of the 32 positive dogs had any history of diarrhea in the last month, so the vast majority of these dogs had no signs that they were shedding Salmonella. Here were the study's main findings:
1. Consuming a commercial or homemade raw diet, a homemade cooked diet, or raw meat and eggs, increases a pet dog’s risk of carrying Salmonella.
Raw is raw, and by now we're hoping that people are getting the message that raw is contaminated, whether we're talking about a commercial or homemade raw diet, or feeding any raw animal products (e.g. meat, eggs). The fact that homemade cooked diets also made the list could be explained by the fact that in order to make such a diet, owners still need to start with the raw ingredients. Handling and cooking raw meat and animal products for your pet should be done with the same precautions as handling and cooking raw meat for yourself or your family. If these homemade diets were not cooked as thoroughly as they should have been, or if there was contamination of the dog's dishes with raw product, that could explain the association with Salmonella shedding. Although traditional commercial diets can also be contaminated with pathogens (usually after processing), the risk with these is much lower.
2. Testing multiple consecutive whole fecal samples greatly improves Salmonella recovery in dogs.
This is no great surprise either. Dogs (and many other species) shed Salmonella intermittently, so not every fecal sample from a Salmonella-positive dog is going to yield Salmonella on culture. The authors tested five daily fecal samples from each dog. Based on this study, the sensitivity of testing a single fecal sample in a dog (i.e. the likelihood that a Salmonella-positive dog will test positive on one fecal sample) was only 35.5%. That means almost two-thirds of positive dogs will be missed if they're only tested once. The take-home message on this point is that in order to find Salmonella in a healthy pet dog, multiple samples should be tested.
3. Having multiple dogs in a household, using probiotics and contact with livestock are important potential risk factors that need to be investigated further.
These were factors that were flagged by the authors for future investigation, because at first they seemed to be associated with Salmonella shedding in the dogs, but when the feeding of raw diets was taken into account the associations were no longer significant. A larger study, or one using a different design, will be needed to help tease apart the potential effects of these factors from feeding practices.
The bottom line: Feeding raw is risky business. Some people swear by the benefits of raw diets, but the objective evidence is lacking. There is clear evidence of the risks. In my mind, the potential up-side simply cannot outweigh the well-established down-side of feeding raw diets to pets.
Nature's Variety has recalled chicken-based raw meat products because of Salmonella contamination. After a customer complaint about "digestive problems," they tested the food and found Salmonella, prompting the recall. (For more details about the recall, click here.) In some ways, this doesn't make a lot of sense to me. If you think Salmonella contamination should be an uncommon event and a problem, you should test routinely, not wait until animals get sick. If you think that Salmonella contamination of raw meat is expected (which it is), then why test or recall? Just assume that every raw meat sample is positive for Salmonella (and Campylobacter, and E. coli). Recalling raw meat for Salmonella isn't logical. Presumably, a large percentage of the raw meat that they have sold and which they will sell in the future is contaminated, based on various studies of commercial raw meat. Handling and feeding raw meat carries an inherent risk of human and animal infections with Salmonella, Campylobacter, E. coli and other bacteria. People that feed raw meat need to understand that risk, and consider whether it's a reasonable risk for their pets and the people in the household. I don't think feeding raw meat is a good idea, but in some situations it's a particularly bad idea (e.g. when there are infants, elderly persons or immunocompromised people in the household, when the pet is very old or very young, when the pet visits high risk people).
More information about raw meat feeding can be found on the Worms & Germs Resources page.
The Hollywood effect is quite real when it comes to various trends, including pets (remember the glut of Dalmatians after 101 Dalmatians?). I can understand how seeing a cute puppy of some breed might lead to people wanting to get one. However, when Disney's The Princess and the Frog was released, I didn't really think a lot of people who watched this movie were going to start running around kissing frogs. I assumed that some degree of common sense would apply. Apparently, I was wrong.
Various news outlets are reporting that at least 50 children (mainly kids under the age of 10) have become sick in the US after copying the movie's Princess Tiana by kissing frogs. There's not a lot of information regarding what they contracted, whether the illnesses were all clearly linked to frogs, or whether these were truly associated with the movie, but there are certainly disease risks associated with kissing a frog. While we pay more attention to reptiles as a source of Salmonella, the risk is also present with frogs, and the best thing is to do is assume that all frogs are carrying this potentially harmful bacterium. Accordingly, high-risk people (e.g. kids less than 5 years of age, the elderly, people with compromised immune systems) should have no contact with frogs - they shouldn't even be in the same house. Hands should always be washed after touching a frog, and no one should ever kiss a frog. The chances of living happily ever after with a prince are much lower than the chances of a nasty bout of diarrhea (or worse)!
A recent report in the Journal of Pediatrics (Tabarani et al 2010) describes a case of infection around the brain, at the site of a previous subdural hematoma, in a five-month-old child. Four reptiles (all bearded dragons) were present in the child's foster household, but the foster parent reported that the baby did not have any contact with them. Salmonella Houtenae was identified as the cause of the infection. The reptiles were an obvious potential source given what we know about Salmonella and reptiles, the unusual Salmonella strain that was isolated from the baby, and the lack of any other obvious risk factor. All previous human infections caused by this type of Salmonella have been associated with reptiles, and all occurred in young children. Unfortunately, the reptiles in this case were euthanized before they could be tested.
This report highlights a few important points.
- Direct contact with reptiles is not needed to cause an infection. There are many reports of people (especially infants) being infected by Salmonella from a pet reptile despite them having no direct contact with the animal. The common statement that 'there's no risk to my child because my child is never allowed to touch the animal' is completely false.
- Reptiles should not be in households with children less than five years of age. In this report, the child was in a foster home. In some jurisdictions, reptiles are banned from foster homes for this very reason.
- The majority of reptiles carry Salmonella. This is expected and impossible to prevent. That's why people at high risk of serious infection (e.g. young children) should not be around them. It's also why euthanasia of the reptiles in this case was highly questionable. Why kill the lizards for carrying a bug that we assume they (and most other reptiles) normally carry? Finding them a new home that doesn't have high risk people would be more appropriate.
Image: Central Bearded Dragon (Pogona vitticeps) (photo credit: Eigene Arbeit, 2007)
Gurnee's Serpent Safari is being sued by the family of a two-year-old boy who allege the child contracted salmonellosis from a snake at the zoo. The child became ill and was hospitalized three days after visiting the zoo and petting a snake. The boy's mother got sick shortly thereafter. It's unclear if the same Salmonella strain was found in the snake or what degree of proof is present that the zoo was the source, but contact with reptiles is a huge risk factor for salmonellosis.
Exposure to zoonotic infections like Salmonella is an inherent risk of animal contact. We accept some degree of risk in everything that we do. The question is "Did the zoo take reasonable precautions to reduce the risk of disease transmission?" Based on the information in the Chicago Tribune news report, the answer is pretty clearly no.
There are standard guidelines for animal contact events that should be followed. These include:
- Children less than five years of age should not have contact with reptiles.
- There should be good, convenient access to hand hygiene (handwashing stations or alcohol hand sanitizers).
- Signs should be present to encourage people to wash their hands after animal contact and discourage high risk people (e.g. two-year-olds) from having contact with high risk animals (e.g. snakes)
The family alleges that the zoo is negligent because it:
- Did not have notices regarding handwashing after contact with reptiles.
- Did not provide hand sanitizers for patrons.
- Did not provide warnings regarding the risk of Salmonella for high risk groups.
- Allowed and encouraged the child to touch the snake.
We live in a pretty litigious society, but people need to assume responsibility for their (and their childrens') health and safety. However, exhibits that allow people to have contact with animals have a moral and legal responsibility to provide as safe of an environment as reasonably possible. Risk will never be zero and people can get sick from the best run events, but there is no excuse for failing to implement basic measures to reduce the risks.
As we approach the holidays, a lot of people are going to eat and/or drink too much, and suffer the consequences. The same can happen with dogs, and sometimes both the dog and their owner pay the price. Dogs get into things they shouldn't all the time... too much food, garbage, dead critters and various other "dietary indiscretions" can easily lead to diarrhea (and sometimes more serious problems). During the holidays, there's often a greater opportunity for dogs to steal food or to be fed too many treats or leftovers. Sometimes it's dramatic - like a 60 pound Lab eating a 15 pound turkey - but often the first sign of a problem is the pile of diarrhea on the floor (usually at 3 AM, in the case of my dog).
So, after yelling at the dog, blaming someone else for leaving food out, and perhaps cleaning off your foot (depending on where you stepped), how do you clean up this mess without getting sick yourself?
The good news is diarrhea from dietary indiscretions is not usually associated with zoonotic microorganisms like Salmonella or Campylobacter. However, those and other potentially harmful bacteria can be found in any dog feces, and you have to assume that diarrhea is infectious. The risk of infection of people is probably low, but you don't want to take unnecessary chances (especially over the holidays).
First things first: Clean up as much of the diarrhea as possible. Ideally wear gloves, and clean up the diarrhea using paper towels or something else disposable. Don't wander around the house with the diarrhea-soaked items - bring a garbage bag with you to the scene of the "accident".
After the bulk of the mess has been removed, your next step depends on a few things, including the surface, what you have available, and whether any high risk people are in the house (i.e. infants, elderly, people with compromised immune systems).
- Smooth, sealed surfaces (e.g. tile, laminate, sealed wood) are easy to clean and disinfect. A general cleaner can be used to remove traces of diarrhea. If you want to disinfect the area, use a general household disinfectant or dilute bleach solution (1 part bleach to 50 parts water). While general household disinfectants may not kill everything, I'm not sure aggressive disinfection is needed in most households. Thorough cleaning does a very good job, and we aren't trying to make the house sterile. I'd be more concerned about disinfection in a household with high-risk people (particularly infants who may crawl over that part of the floor). If you are concerned about bleach damaging the surface, use something else or test it on an out-of-the-way area.
- Carpet is problematic because it's pretty much impossible to disinfect. After removing as much diarrhea as possible, use of a carpet cleaning spray might be helpful (but it's more effective for removing stains, not pathogens). A few disinfectants can be used on carpets safely. Bleach isn't a good idea unless the carpet is already (or was originally) white. Even with a good disinfectant, you're very unlikely to kill all of the bacteria present, because of the ability of microbes to hide in fabric. Steam cleaning is another option.
Once that's done, don't forget the most important step: wash your hands thoroughly. (The second-most important step might be to cordon the dog off in a more easily cleanable area for the rest of the night in case further accidents occur).
Overall, the risk of getting sick from overindulgence-associated dog diarrhea is pretty low. I focus on cleaning up the mess and don't worry about thorough disinfection. That's probably reasonable in a low risk household, but I'd be more wary around high-risk individuals.
My daughter's kindergarten class is having a gingerbread cookie decorating event tomorrow. They're supposed to bring a guest (in Amy's case, me) and some items (e.g. candy sprinkles, gummies) to put on the cookies. I was surprised (but impressed) to see a statement asking people to avoid bringing items from bulk bins because of the potential for cross contamination. The concern is that bulk bin items could be contaminated with items such as nuts, which are banned from schools because of allergies.
Cross contamination can also involve bacteria, and can extend into the realm of pet treats. Salmonella contamination of rawhide treats is a problem, and rawhides and other raw pet treats have been the cause of multiple outbreaks of salmonellosis in people. Salmonella (and E. coli, and other bacteria) contamination is a concern with any raw animal-origin product, and while there have been improvements in some areas in manufacturing practices, some risk will always be present. That's why rawhides, pigs' ears and similar treats shouldn't be present in households with young children, elderly individuals or people with compromised immune systems, and why good attention to hand hygiene is needed when these products are handled. Buying individually-packaged rawhides (instead of bulk bin items) is also recommended. Bulk bins may offer some cost savings, but you are at the mercy of cross-contamination and potential accumulation of Salmonella and other bacteria. If one rawhide is contaminated, it can cross-contaminate all the other rawhides in the bin. If bins are just topped up as they get low, this can lead to contamination of a large number of rawhides. There's also the risk of exposure when you reach into the bin and grab one (and it's unlikely that you'd wash your hands afterwards).
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.
My oldest daughter's latest favourite TV show is Cake Boss, a TLC show about life in a bakery (don't ask why... I guess it's better than John and Kate Plus 8). On a recent episode, they were making a cake for a circus sideshow and one of the performers appeared in the bakery's kitchen with a large albino snake. It makes for good entertainment but it's a break with common sense and presumably health codes.
Reptiles should never be allowed in a kitchen, let alone a commercial kitchen (especially one that presumably prepares items often eaten by children). Contact with reptiles is a significant risk factor for salmonellosis, and cross contamination is a concern in kitchens. All pets should be kept out of food preparation areas, but particular care should be taken around high risk species like reptiles, and every reptile should be assumed to be carrying Salmonella.
I heard this on the radio yesterday morning, I kid you not: Butterball has a "Turkey Talk" toll-free helpline, which naturally gets busy around turkey holidays like Thanksgiving and Christmas. Like many helplines, they get stories of every kind, and this year apparently one person called in and asked if it was alright that she thawed her frozen turkey in the bathtub - while her kids were in it taking a bath!
Anyone who has read anything about food safety hopefully knows that raw meat can potentially be (and usually is) contaminated with many different pathogens - that's the biggest reason why observing proper cooking times and temperatures is so important. Raw poultry in particular should basically be treated like it's contaminated with Salmonella and/or Campylobacter until proven otherwise. You can just imagine the field day that these bacteria could have in a nice warm, wet bathtub - it's just the way they like it, and it's exactly what we try to avoid in the kitchen, where food is ideally kept either nice and cold or nice and hot in order to prevent (or at least minimize) bacterial growth. Then of all things to put young children in this veritable cesspool of bacteria - turkey and all - it's just a gastrointestinal disaster waiting to happen. You also needs to consider what the turkey could become contaminated with sitting in bathwater. Even children who don't have diarrhea can be shedding intestinal pathogens - human pathogens which are obviously transmissible to other people. If you really cooked that bird well (maybe deep-fried it) I suppose that should ultimatley eliminate any surface contamination anyway, but I don't think I'd be able to get past the "ick" factor. Don't throw the baby out with the bathwater, but of there's a turkey in there (as far as I'm concerned) that can go.
I realize this is primarily a food safety issue, but it made me think about what else this person (or others) may put in a bathtub. In previous posts in which we've talked about reptiles kept as pets (all of which should be treated as Salmonella carriers), we've mentioned that ideally (if they need a bath) they should be bathed in their own designated container (like a big rubbermaid) and not in the bathtub. If there is no other option and the bathtub must be used, it should be thoroughly cleaned and properly disinfected (keeping contact-time with the disinfectant in mind) before it is used again by a person (especially children).
Ideally the same precautions should be taken if you bathe a dog in the bathtub, but the risks are not as high as with reptiles (unless the dog is very dirty, has skin lesions, or has (or recently had) diarrhea). We've talked about the limited risks of allowing dogs in backyard swimming pools (but of course there is even less chlorine in bath water). I hope no one ever bathes their dog with their kids - we could debate the risks, which likely aren't high anyway, but in the end the risk is simply unnecessary. The pool is one thing, but there's no reason for a dog to be in the tub at the same time as the kids (and really, how clean are the kids going to get with a dirty dog in the tub?). If you're trying to save water you can always throw the dog in after the kids are out.
If you're attempting to bathe a cat in the tub... well, based on most feline behaviour I'd say your primary risks are bites and scratches more than enteric bacteria and parasites. Proceed at your own risk!
A happy (and hopefully healthy) American Thanksgiving to all of our US readers!
Three Louisville, Kentucky children and their father recently contracted Salmonella from two lizards (green anoles) that the kids brought home from school. Two weeks after the lizards were brought home, the youngest child got sick. Then the other kids and the father got sick.
This outbreak highlights numerous problems:
Schools are not pet stores: Why is an exotic (and difficult to care for) pet that is a known Salmonella vector being sent home with students? Apparently, the school sent home a standard letter they use when students take home pets. (I assume sending animals home must be a very common event if the school has a standard form for it.) The letter provides "caretaking tips" but apparently mentions nothing about Salmonella and reptiles. The school has now modified the letter to include a "reminder to parents that good hygiene is imperative when dealing with any kind of living organism as a pet, so they need to make sure their kids wash their hands well after handling them or cleaning them out." That's better, but if they are sending home reptiles, they need a clear statement about the risk of Salmonella exposure. They need to be direct and highlight the greater risk associated with reptiles.
Lack of education before getting a pet: Too many pets die and too many people get sick because people don't take the responsible step of finding out about the animal before they adopt it as a pet. This is particularly true with exotic pets, and death of the pet is a common outcome. It doesn't take a lot of effort to find out basic information about reptile care, and information about the risk of salmonellosis should be easy to find.
Poor knowledge (or a poor attempt at damage control) by the school: The teacher "noted that other common pets, such as dogs, can also carry salmonella. Like lizards, they're perfectly safe as long as you practice proper handwashing when you handle them." Except for the fact that 0-1% of healthy dogs carry Salmonella while very high percentages of reptiles do, that tens of thousands of cases of reptile-associated salmonellosis occur every year, that contact with reptiles is a major risk factor for salmonellosis, and that the CDC (among other groups) recommends that children less than five years of age and other high-risk groups not have contact with reptiles. This type of statement is misleading. It's unfortunately either an indication of ignorance of the issues or an attempt to cover their butts and not take their share of the responsibility for what happened. Certain reptiles can be good pets in certain situations, but are clearly inappropriate in others.
The "it's never happened before so it must be safe" fallacy: The school's disappointing response was that they've been using lizards in classrooms for years and no one has gotten sick. Well, their luck just ran out. Just because I could drive around without a seatbelt and not get hurt doesn't mean not using a seatbelt is a perfectly safe plan. Risky behaviours tend to catch up with you eventually.
The "it didn't happen here so it's not our fault" excuse: School officials said teachers are well-trained on the proper way to prevent students from getting Salmonella, but that's pretty debatable since three kids got sick because of their actions (i.e. sending the reptiles to the children's home). The infections may not have originated in the school but the school was still the source of the problem.
Poor hygiene associated with reptile contact: The father admitted that they didn't wash their hands regularly after handling the lizards.
There's little excuse for sending reptiles home with kids. Reptiles require specialized care and commitment, and many (many!) die each year from inappropriate care. The last thing we need is to make it easier for people to obtain them without much forethought. Reptile-associated salmonellosis is a serious problem, especially in kids. Serious, including fatal, infections can occur. Schools need to realize the liability they might assume by sending these animals into households, especially with inadequate scrutiny and education. Reptiles should not be kept in households with kids less than five years of age, pregnant women, elderly individuals or immunocompromised individuals. I doubt they asked whether any such people lived in the household before sending the reptiles home.
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.
The last time I visited the Aberfoyle (Ontario) Fall Fair, the petting zoo was so bad that I ended up writing to the fair organizers and the Wellington-Dufferin-Guelph Public Health Unit. (Neither group replied). It was pretty bad. Young poultry are inappropriate petting zoo animals because of the risk of transmission of bacteria like Salmonella, yet baby chicks were being passed around to young children. One chick was injured by rough handling and the petting zoo supervisor just threw it (still alive) in the garbage. There was a diarrheic calf, poor hand hygiene facilities, and other problems.
We went back to the fair yesterday and I was quite pleasantly surprised: no chicks, no calves, all appropriate and healthy-looking animals, a clean facility and good hand hygiene stations. There were still a couple of suboptimal things, like not having hand sanitizers by one exit, and having a "supervisor" who was staring off into the wilderness and smoking inside the tent filled with kids and straw, but it was night-vs-day compared to the last time. I doubt my letter had much to do with it, but you never know. I think it's important that people not accept inadequacies that put the public (particularly children) at risk. People need to raise a stink when they see a problem. I wrote earlier today about a child who had her finger bitten off by a petting zoo zebra that had bitten other people. The previous bites may not have been reported because they were minor, but we need to report apparently minor problems so they don't escalate into major injuries, disease outbreaks or other bad scenarios.
Anyway, it was great to see an improvement, and people in the petting zoo appeared to be having a good time. Now if they'd just work on "Big Ned's" food concession, where the only sink seems to be a storage area with no soap or paper towels, and which appeared to be in need of a serious cleaning, or on the little midway, where they were hand cranking the questionable kiddie ferris wheel to get kids off when all the rides stopped working. Baby steps, I guess.
The Centers for Disease Control and Prevention (CDC) has released updated Guidelines for the Prevention and Treatment of Opportunistic Infections Among HIV-exposed and HIV-infected Children. A small but still important part of this document involves recommendations for contact with animals. It's a nice, balanced document that acknowledges the risk but doesn't make unnecessarily restrictive recommendations.
Among the important recommendations regarding animals:
- When getting a new pet, avoid dogs and cats less than 6 months of age or strays: These animals are at higher risk for shedding various infectious diseases and are more likely to have problems with biting and scratching.
- Avoid contact with animals that have diarrhea.
- Wash hands after handling pets.
- Avoid contact with pet feces.
- Avoid contact with reptiles, chicks and ducklings: These are very high risk for Salmonella.
- Avoid contact with calves or lambs at farms or petting zoos: These animals are high risk for various infectious diseases such as Cryptosporidium and Salmonella.
These recommendations also largely apply to other high-risk groups, including people (of all ages) with compromised immune systems and young children (especially less than 5 years of age). A key point is normal contact with common household pest using basic hygiene practices is considered a low risk. Infection control isn't rocket science. It involves basic and practical measures that can reduce risks associated with animal contact.
It seems like whenever a hit TV show or movie features an animal, there's concern about the "101 Dalmatians effect," whereby there's a mad rush to get the animal for a pet. When 101 Dalmatians was a hit movie, there was a huge spike in sales of this rather unusual breed - a breed which is certainly not for everyone. This results in unqualified breeders and puppy mills churning out marginal or poor quality pets and people getting a pet that really doesn't suit them. The end result can be a lot of disappointment, heartache and abandoned pets. This pattern has been repeated with various other breeds and animal species, and there is concern that the same will happen with guinea pigs as a result of the new Disney movie G-Force.
In terms of human health, guinea pigs are relatively benign. Bites and scratches are probably the biggest concern, and are often the result of improper handling. Bites can become infected from bacteria in the guinea pig's mouth or from bacteria on the person's skin. Allergies are also a potential problem. The number of diseases that are known to be transmitted by them is relatively small, and the risk of disease transmission is rather low.
Lymphocytic choriomeningitis virus (LCMV) is a concern with all rodents. It typically only causes disease in people with compromised immune systems, but can result in fatal infection. The risk of a guinea pig carrying this virus is likely greatest in animals from large rodent breeding facilties and when there is contact with wild rodents.
Ringworm is perhaps the most common infection that people get from guinea pigs (apart from infections following bites). Even healthy guinea pigs can carry the fungus that causes this disease.
Guinea pigs can carry Salmonella, but they are quite susceptible to infection and usually get quite sick. The risk of a healthy guinea pig shedding Salmonella, especially for a prolonged period, is pretty low. The risk is presumably greatest shortly after purchase.
Rabies is always a potential problem in mammals but the risk is very low with small rodents such as guinea pigs. (Very low isn't zero though, since hamsters have been sources of potential rabies exposure).
There are other potential problems too, but they are all quite rare.
The keys to reducing the risk of infection are:
- Purchase a guinea pig that looks healthy, is eating well, has no skin lesions or diarrhea, and is active and alert. Ideally, purchase an animal from a local breeder as opposed to a store that might have obtained the animal from a large breeder, via an animal warehouse, hundreds or thousands of miles away.
- Learn how to properly handle a guinea pig to reduce the risk of bites and scratches, as well as injury to the animal.
- Keep pet guinea pigs away from wild rodents.
- Use good general hygiene. Wash your hands after handling the guinea pig and after contact with bedding.
- Thoroughly wash any bites or scratches.
- Take particular care in the period shortly after purchase.
- Even though the cost of the guinea pig is less than the cost of a vet visit, a veterinary examination is important when the animal is sick. Apart from our ethical responsibility to take care of our pets, it's important to make sure that illness isn't caused by a disease that can be transmitted to people.
More information about the diseases mentioned above is available on the Worms & Germs Resources page. While we don't have a specific guinea pig info sheet yet, much of the information on the hamster information sheet also applies to guinea pigs.
A recent case report in the Journal of Clinical Microbiology (Cooke et al. 2009) described isolation of Salmonella Apapa from the feces of a 67-year-old woman with abdominal pain. The patient had a history of various medical disorders but no clear evidence of a compromised immune system. She was hospitalized, and Salmonella Apapa was identified from a stool sample collected the day after admission. Fortunately, her abdominal disease resolved (whether it was caused by Salmonella or whether Salmonella was an incidental finding can't be stated definitively), and she was ultimately discharged from the hospital.
Salmonella diagnoses usually lead quickly to questions about food and reptiles. In this case, the woman's son had recently moved in with her, along with his two bearded dragons. The lizards were kept in a tank, and the woman reported having no direct contact with them. Samples from the lizards' feces and the tank environment were collected, and the same Salmonella strain was isolated. While getting Salmonella from a reptile is certainly nothing new, this case report highlights some important points.
- The person that was infected did not report any contact with the reptiles or their tank. Therefore, some type of indirect exposure must have occurred. This is why reptiles should not be kept in high-risk households even if the high-risk people don't have direct contact with them. High-risk households include households with young children (less than 5 years of age), elderly individuals, pregnant women and immunocompromised individuals.
- It's not just high-risk people that get sick. This person was perhaps on the crux of being considered high-risk based on her age and previous medical problems, but she was certainly not a clear example of the people we assume are at higher risk. A huge number of reptile-asociated cases of salmonellosis are reported every year. While high-risk people are more likely to get sick (and more likely to develop severe illness), healthy individuals can be infected as well.
Reptiles can make good pets. I used to have a pair of Red-Footed tortoises, so I'm certainly not anti-reptile (despite what the emails I typically get after posts like this say). People who have or who are comtemplating getting a reptile for a pet need to be aware of the associated risks, as they are certainly real and should be taken seriously.
In response to recent posts about Salmonella and turtles, a reader posed these questions:
Okay, so turtles and tortoises can carry salmonella. Does that mean that all do?
- Not all, but a lot of them do. Aquatic turtles are probably a greater risk than tortoises.
If a vet analyzes a poop sample from my Russian Tortoise and there is no Salmonella, does that mean we can quit worrying about it?
- Unfortunately no. We can never be confident in declaring a reptile "Salmonella-free." Salmonella can be shed intermittently, so a single negative sample doesn't mean the reptile is truly negative. We don't know what the optimal testing protocol is in terms of what to sample, how often to do it and how many samples are needed. I'd never tell anyone a turtle or tortoise is Salmonella-free. To err on the side of caution, we have to assume that all reptiles are carrying Salmonella.
Conversely, if the poop does show Salmonella, is there any way to eliminate it from the tortoise and then quit worrying about it? Our tortoise is isolated from other pets and only eats what we consider clean, fresh produce - so I am hoping the chance of reinfection would be minimal.
- Unfortunately, no again. There's no proven way of eliminating Salmonella from a reptile. Getting rid of Salmonella in an animal that is a carrier is different than treating a typical bacterial infection. Salmonella is a commensal bacterium in reptiles, meaning it can be a normal component of the animal's bacterial microflora. It is very difficult to eliminate commensal bacteria since they have evolved to survive in (or on) their host. Unlike in clinical infections, which tend to be short term infections of a site where the bacterium does not normally live, using antibiotics to eliminate Salmonella carriage is unlikely to be successful. Giving antibiotics can also upset the normal intestinal bacterial population, which can actually make it more likely for bacteria like Salmonella to proliferate. Salmonella can also live inside intestinal cells, where most antibiotics can't reach them. Treatment, therefore, is unlikely to be ineffective, and might just result in increased antibiotic resistance (something we certainly want to avoid).
Check out the Worms & Germs Resources page for more information.
Following a report on black market turtle sales in Maryland, a letter to the Baltimore Sun by Maryland veterinarian Dr. Jeffery Rhody wanted to "set the record straight".
"All reptiles carry salmonella as part of the normal bacterial population in their body."
- Not really true, however Salmonella can commonly be found in healthy reptiles, so the overall sentiment is valid.
"The risk of getting infected with salmonella from a reptile can be greatly reduced with common sense hygiene practices."
- Absolutely. General infection control practices are critical to reduce (but they do not eliminate) the risk of Salmonella transmission.
"In fact, the incidence of reptile-borne salmonella infections is much less than salmonella infections obtained from improperly handled poultry products."
- Statistics can be manipulated to either support or refute this. The absolute number of Salmonella cases from food is certainly greater than those from turtles. However, I'm not so sure turtles end up looking good when you consider the number of cases compared to the number of people exposed to these factors - a lot more people eat food than own turtles. The number of cases of Salmonella associated with reptile contact every year is stunning, even though only a small percentage of people own reptiles. Fatal infections can occur, so it's not something to take lightly. Statements like the one above can get into some questionable logic, like saying that a machine gun can kill more people than a handgun, so handguns must be safe. Certainly, Salmonella is a risk with handling raw poultry, and efforts are taken to get people to reduce risky behaviours (like contaminating kitchen surfaces with raw meat). The same should apply to reducing risky behaviours with regard to pet contact.
"Of course, if you lick a turtle, the risk of salmonella infection is greatly increased."
- Yep. That's why the focus is on small turtles. But, people get Salmonella from larger turtles too.
"No one who owns a slider should be concerned about breaking the law."
- They should, however, be concerned about getting sick. Turtle owners should learn about risks and preventive measures from sources such as a the information sheet in our Resources page.
As someone who has owned turtles, I understand the appeal of these animals. As someone involved in zoonotic diseases, I understand the risks. People need to have enough information to understand the risks and benefits, to make logical, informed decisions. The risks to healthy adults who handle the animals properly is quite low. That's why the focus is on high risk households like those with young children, the elderly or immunocompromised individuals. There are good reasons for the ban on the sale of small turtles. Banning the sale of small turtles doesn't hurt anyone (except for people wanting to profit from selling them), and may prevent disease. Seems logical to me.
There is apparently a thriving black market for baby red-eared slider turtles in Baltimore. The sale (and possession) of small turtles is illegal in Maryland, like many other regions, largely because of public health concerns regarding Salmonella.
Over 100 hatchling turtles have been seized in the past 2 weeks. Baby turtles offer a good profit margin for black market vendors. They can be purchased from farms in the southern US for about $1 each and then resold for many times that amount. One person was caught selling turtles out of the back of a van. (Why anyone would buy anything from someone selling out of the back of a van is beyond me!)
People buy turtles thinking they make cute pets, not realizing what they need to do to keep them healthy as they grow. Turtles that are fortunate enough to be raised properly create another problem, since most people are not willing or able to take care of adult turtles that reach 10-12 inches in length. This can result in turtles being killed or abandoned.
Another major problem in the risk of Salmonella. Turtles very commonly carry this potentially harmful bacterium, and they are an important source of infection in people. The concerns are greatest with young children who may handle small turtles and put them in their mouths. People need to think before they buy. Before getting any pet, learn about the animal, including requirements for care and human health risks (and also if it's legal). A little common sense goes a long way.
More information about Salmonella and turtles can be found on the Worms & Germs Resources page.
As is common this time of year, outbreaks of Salmonella infection in wild birds have been widely reported in parts of the US. Salmonella circulates regularly at low levels in the wild bird population, and sporadic outbreaks involving large numbers of sick and dead birds are periodically encountered. These are often noticed in urban areas when dead birds are found around bird feeders.
Salmonella can infect a wide range of species other than birds, including cats (and people). Cats can be exposed to Salmonella during these outbreaks from catching and eating sick birds, or healthy birds that are carriers of the bacterium. In fact, one name for salmonellosis in cats is songbird fever, a testament to the role of birding in feline salmonellosis. An example of the potential effect of wild bird Salmonella outbreaks on cats is described in the The Daily Journal from International Falls, Minnesota. In this report, a local veterinarian explains that he has seen an increase in salmonellosis cases in pets at his practice, mainly in cats. In the past 2 weeks, he has diagnosed approximately 20 cases, which is a pretty impressive number. Most of the infected cats had known contact with wild birds or areas around bird feeders.
If your cat goes outside, it is at higher risk for Salmonella. If there is an outbreak of salmonellosis in wild birds in the area (or you're seeing dead birds around the feeder), then the risks are probably much higher. While Salmonella is usually associated with diarrhea, not all cats that are infected develop diarrhea. Some develop mild disease without diarrhea (e.g. fever, lethargy), some get serious systemic infections (septicemia), and some may show no signs of illness at all but still pass Salmonella in their stool. In any case, the bacterium can still be transmitted to and infect people.
Any outdoor cat that develops diarrhea should be considered a Salmonella suspect. Really, Salmonella should be considered in all outdoor cats with fever and signs of illness that are not specific for a particular disease. Stool culture can be used to diagnose Salmonella.
Avoiding wild-bird associated salmonellosis in cats is pretty easy - keep your cat indoors. A cat that can't catch birds or hang around contaminated areas surrounding bird feeders won't be exposed to Salmonella from wild birds. At a minimum, cats should be kept inside if there is an outbreak of Salmonella in wild birds in the area, or if dead birds are found around your bird feeder. Ideally, they should be kept inside all of the time, for many reasons.
More information about Salmonella in pets can be found on the Worms & Germs Resources page.
One more post about illogical and dangerous activities associated with animals and young children and I'll hopefully get off the subject for awhile. I came across this daycare's website today. Keep in mind (again) that the the Centers for Disease Control and Prevention (CDC) recommends that children less than 5 years of age not have contact with reptiles, and that the Compendium of Measures to Prevent Disease Associated with Animals in Public Settings published by the National Association of State Public Health Veterinarians states that wild or exotic animals may not be appropriate in school settings. The photo gallery from this particular daycare included some great pictures of things that you should NOT do with young children. Some of the more striking example are below:
1) Letting a large snake wrap its body around the neck of a young child.
2) Letting a young child kiss a snake.
3) Letting a child touch a turtle.
4) Letting a young child pet a pygmy hedgehog. (Like reptiles, hedgehogs very often carry infectious pathogens, including Salmonella.)
- whether anyone made sure these children immediately washed their hands after they touched the animals.
- how may kids but their hands in their mouths before they washed their hands. (Probably almost all of them, considering the "animal visit" probably went on for quite a while.)
- whether this activity took place in the same area where the children later ate lunch or a snack.
- whether the parents knew that this was going to happen.
I'm not against young children having contact with animals. I think pet contact can be very rewarding for young children. However, these individuals are at higher risk for infection and it is our responsibility to protect them. Putting them in high risk situations like these is inappropriate. Animal visitation in daycares is not necessarily a bad thing, if it involves animals that are a low risk species (e.g. dogs and cats), that are healthy, and that have been temperament tested (to show they are at low likelihood of biting). It is also important that parents provide consent for their children to participate, that good hygiene practices are used (and enforced), and that the people bringing in the animals know what they are doing.
Just last week I blogged about concerns regarding young children handling baby chicks in classrooms. Baby chicks are high-risk animals because of the potential for transmission of Salmonella. The Centers for Disease Control and Prevention (CDC) recommends that children less than 5 years of age not have contact with baby chicks for this reason. Unfortunately, few people seem to know this (or at least pay attention to it). If I have a problem with baby chicks in kindergarten classrooms, you can imagine the conniption I have about chicks in preschools. These pictures illustrate my concerns in phenomenal fashion.
If you look closely at this first picture (right), you can see the plop of "chick poop" on this child's sweater (which he seems all too happy about). The picture is from a blog written by the child's mother - she gives absolutely no recognition that this is an infectious disease concern.
The second picture (left) is from a news article about a preschool. The preschool obviously has no clue about infectious disease risks because they allowed this c to put the chick on his head and were apparently proud enough of it to have the reporter take a picture.
And last but certainly not least, we have a great picture (below) of a child either kissing a chick or eating very undercooked poultry. Either way, it's a bad idea. This picture is from another parent's blog, who apparently thought it was cute.
Baby chicks should not be in preschools - ever. The novelty factor of having chicks in the facility does not supercede the infectious disease risks and recommendations from public health agencies.
An annual "ritual" in some schools is hatching chicken eggs in the classroom. This can be a great educational experience for children as they learn about eggs and incubation, watch them hatch and see the baby chicks. It can also be a great source of infection for children if certain precautions are neglected. The picture on the right, from an article in the Ilkley Gazette, shows a good example of a bad idea. This four-year-old boy has a newly hatched chick on his shoulder. Why does this bother me?
- Chicks are a great source of potentially harmful bacteria, particularly Salmonella.
- You can't litter train a day-old chick. I wouldn't be surprised if it left a little biohazardous "present" on the child's shoulder.
- Outbreaks of salmonellosis in people associated with baby chicks have been reported.
- The Centers for Disease Control and Prevention (CDC) recommends children under five years of age should not have contact with chicks.
If there are going to be chicks in a classroom:
- They should only be in classrooms with older students.
- Contact with chicks should be restricted and always supervised.
- Careful attention must be paid to handwashing. Everyone who handles chicks or comes in contact with their environment (e.g. box, cage, incubator) should immediately and thoroughly wash their hands.
- Chicks should never be allowed to roam free in the classroom.
- Chicks should never be handled during lunch or snack time.
- Immunocompromised children should not be present in the class.
It's common sense, but it's amazing how uncommon "common sense" seems to be sometimes.
The latest edition of the Centers for Disease Control and Prevention (CDC)'s publication Morbidity and Mortality Weekly Reports consists of the revised Guidelines for Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents.
Among the highlights relevant to pets:
- HIV-infected patients should be advised to wash their hands after handling pets or other animals.
- They should avoid direct contact with diarrhea or any stool from pets, particularly stray pets or dogs and cats less then six months of age.
- Gloves should be worn when handling stool or cleaning areas that might have been contaminated with stool from pets.
- Contact with calves or lambs (e.g. on farms or at petting zoos) should be limited or avoided. Attention should be paid to hygiene and avoiding direct contact with animal manure when visiting such premises.
- Contact with reptiles, chicks and ducklings should be avoided because of the risk of Salmonella.
So, nothing earth-shattering or nothing we and others have not been saying all along. That's because basic measures, while not flashy, are the most useful tools. Use common sense, avoid contact with stool and high risk animals, and above all wash your hands.
As you undoubtedly know, a large Salmonella outbreak has occurred in the US, associated with contaminated peanuts. The scope of this outbreak continues to expand in unexpected areas, including pets. The latest development is a voluntary recall of bird seed. The recall affects 20-pound packages of Wild Birds Unlimited Wildlife Blend bird food (produced by Kentucky-based Burkmann Feeds) with the manufacturing date code 81132200 2916 08124.
The contaminated bird seed was linked to the deaths of several birds in North Carolina, and it was confirmed that the bird seed manufacturer received peanuts from the Georgia facility that was implicated in the Salmonella outbreak.
People that have used this bird seed should clear out their bird feeders, ideally while wearing gloves. The feeders should be thoroughly cleaned and then disinfected (although this may be easier said than done). Hands should be washed after handling the bird seed, potentially contaminated feeders or any other potentially contaminated items.
The risk to people is presumably quite low, but people handling the bird seed could potentially contaminate their hands with Salmonella and then inadvertently swallow some of the bacteria. Concerns are greatest in people with compromised immune systems, the very young, the elderly and people taking antibiotics, as they are more likely to get sick following exposure to small numbers of Salmonella.
More information about Salmonella can be found on the Worms & Germs Resources page.
I used the think the New York Times was a reputable newspaper and source of reasonable information. However, considering some of the articles I've seen, I no longer have a good opinion of this newspaper. One example from a few years ago came across my desk recently. The article is basically an infomercial for an unqualified person that sells pet health products. The person in question is an industrial designer by training - you'd think a reasonable news source would look for someone with training in veterinary medicine, nutrition or pharmacology when discussing pet health. (Given the level of expertise they require, I guess I'm qualified to comment in the New York Times about how to solve conflict in the Middle East or fix the economy). Among some of the gems in this article are:
- People "have to include raw and whole foods in their pets' diets..." and "[Pets] don't get E. coli or Salmonella." Tell that to the dogs and cats that get sick and die from Salmonella. I can't believe people that sell raw foods continue to falsely claim that pets can't get Salmonella. Outbreaks of salmonellosis associated with raw foods have been reported. Dogs have even been sickened in the recent peanut butter Salmonella outbreak.
- The big problem with the pet food industry is that people treat pets like televisions and get a new one if they're sick. Apart from the last part being ludicrous, what does that have to do with the pet food industry?
- The alley dogs this guy grew up with in the Bronx lived a long time. Now, a dog is considered old if it lives past 7 years. Show me any evidence that feral dogs live longer than household pets. Not a chance.
- Pets are dying younger because of low grade nutrition and pharmaceuticals. Again, show me evidence that pets are living shorter lives. I'm certain it's the exact opposite.
People need to make sure that they critically assess things that they read about pet health and diseases. Just because something is written in a high profile newspaper doesn't mean it's necessarily correct. In the internet era, volume overload and differentiating good sources from bad sources can be difficult. Here are some tips:
- Look for advice from qualified individuals. That's not a guarantee, but I'd rather have my car fixed by a mechanic than a gardener.
- Beware of advice from people that are in a conflict of interest, such as people selling a product. For most reputable companies, representatives can be sources of good information, but unfortunately it's not always true.
- Ask your veterinarian about questions relating to animal health and nutrition.
- Use common sense. If something seems too good to be true, it probably isn't. Something that claims to cure all that ails you probably cures nothing.
My oldest daughter is in Grade 2, and last year her class hatched chicken eggs in the classroom. As a parent, I was somewhat torn about the idea. My main concern was the risk of exposure to Salmonella. A recent article in Morbidity and Mortality Weekly Reports described outbreaks of salmonellosis associated with contact with live poultry. Most cases were associated with handling baby chicks obtained from agricultural stores or by mail order. Infections from classroom and petting zoo-associated contacts were also reported.
Salmonella contamination of eggs and carriage by baby chicks is very common. The CDC recommends that children less than five years old do not have any contact with baby chicks, and that older individuals pay close attention to hygiene in order to prevent transmission of Salmonella. Being six years old, my daughter was just over this age cutoff (although there's nothing magical about going from five to six years old, so I'd still consider her at somewhat higher risk). So, as long as good infection control practices were used (e.g. hand hygiene), the risk to the children was probably quite low. Were the benefits of hatching eggs in the classroom worth the risk? I don't know, but she enjoyed the experience and did learn a few things along the way. Concerns about infectious diseases are often dismissed, which is a problem, but sometimes excessive concern gets in the way of life. There's rarely a clear answer as to what is acceptable and what is too risky, given the potential benefits.
- Eggs and chicks should not be kept in classrooms where children under five years old will be present, or if there are immunocompromised children in the class. It's unclear whether all teachers would know if they had a high-risk child in the class. Parents of immunocompromised children should make sure teachers know about their child's increased risk.
- It is prudent for teachers to send home a note to inform parents if eggs/chicks will be in the classroom, or if similar activities involving animals are undertaken.
- Eggs and chicks should be kept in a complete enclosure, in an area that is always supervised when children are around.
- Chicks should always be kept in their enclosure. They should never be taken to areas (e.g. a student's desk) where food might be consumed.
- Direct contact with eggs and chicks (and their environment) should be kept to a minimum.
- Hands should be thoroughly washed or an alcohol hand sanitizer used immediately after contact with eggs, chicks or their environment.
- Appropriate thought should go into the use of eggs and chicks in classrooms. They should be there for more than the "novelty factor". There should be a clear teaching plan associated with them so they provide the maximum educational value possible.
- Testing eggs and chicks for Salmonella isn't practical. A negative result cannot guarantee that Salmonella is not there. As well, there are other infectious diseases that are of concern. Consider all eggs and chicks Salmonella-positive and handle them appropriately.
Maybe the only thing surprising about this is that it's taken this long, but there has now been a dog infection reported in association with the massive peanut butter recall due to Salmonella contamination. This outbreak has made hundreds of people sick, and caused a few deaths so far. Pets that eat contaminated "people food" or pet treats are also at risk. So, it's not too surprising that an infection in a pet has now been reported (and reported cases are usually just the tip of the iceberg).
The case reported involves a dog in Oregon that was diagnosed with salmonellosis after being fed Happy Tails dog biscuits. The Salmonella strain recovered from the dog, who had severe diarrhea, was from the same serogroup as the strain involved in the peanut product outbreak. The product (Happy Tails Multi-Flavor dog biscuits, UPC 41163 42403, 4 lb box, “best by” date Oct 31 09) was tested at IEH Laboratories & Consulting Group in Lake Forest Park, WA and Salmonella was identified. Other products from this and several other companies have been recalled, so pet owners should check the products against recall lists. If in doubt, do not feed your pet(s) any treats until their safety can be verified.
Salmonella can cause disease in dogs ranging from mild diarrhea to severe bloody diarrhea and bloodstream infection that can be fatal in some cases. Dogs with salmonellosis can also transmit the infection to people, because they can shed large numbers of Salmonella in their stool.
If pets have been fed potentially contaminated peanut butter or treats, they should be watched carefully for signs of diarrhea, lack of appetite or decreased activity, and taken to a veterinarian promptly if there are any concerns. There is no indication to test or treat healthy pets that have potentially been exposed. Even if stool samples were tested and Salmonella was found, treatment of healthy animals would not be recommended. As always, careful handling of stool and frequent handwashing are key factors for preventing transmission of disease to people.
A Las Vegas woman reportedly agreed to babysit a friend's pet python. She brought the 18-foot snake into her house, where her three-year-old son also lived. Bad move, for many reasons. At one point, the woman returned from the bathroom to find the snake wrapped around her son, who was turning blue. The mother stabbed the snake 17 times before it released the child.
Large snakes can be dangerous, particularly to young children. Without proper (escape proof) enclosures and people who know how to handle them (and some common sense), there is a real risk of injury or death, as was clearly demonstrated here. Also, reptiles of all kinds (including snakes) are prime sources of Salmonella infection. Allowing reptiles to roam the house and/or have direct or indirect contact with young children is an unnecessary risk. Various groups have stated that reptiles are not appropriate pets for children less than five years of age, nor for people with weakened immune systems, primarily because of the risks of Salmonella.
Hopefully the child in this terrifying case is alright, although he was also bitten, which can lead to complications of its own. The snake had to be euthanized because of the stab wounds. So, we have an injured child and a dead snake resulting from the stupidity of a couple of adults who didn't apparently see a problem with leaving a large predatory carnivore free in the same location as a prey-sized child. Authorities are still deciding whether to charge the mother with child endangerment.
I'm sure you've heard about the large outbreak of salmonellosis in people in the US associated (again!) with contaminated peanut butter. Based on the extent of the outbreak, it probably should not come as a surprise that pet treats are now caught up in the recall. The FDA has announced that the recall now includes some pet food products that contain peanut paste produced by the Peanut Corporation of America (PCA) at its Blakely, Georgia processing plant. The concerns here are two-fold: the risk of disease in pets fed the treats, and risk to people handling the treats. If you have peanut butter-containing pet treats, you should stop feeding them to your pet(s) until you can determine whether or not they are affected by the recall.
The recommendation in the recall notice really applies at all times: "It is important for people to wash their hands--and make sure children wash their hands--before and, especially, after feeding treats to pets."
More information on Salmonella and pets can be found on the Womrs&Germs Resources page.
BarfBlog is a food safety blog run by Dr. Doug Powell, who used to be at the University of Guelph, before moving to Kansas State. (I played hockey with him and can confidently state that he is one of the better hockey goalies working in food safety in Kansas). Doug and his group have put together numerous useful, and often entertaining, fact sheets about food safety issues, as well as some related infectious disease and infection control topics. One of those is about Salmonella in pet turtles, something we've discussed on Worms&Germs periodically. The info sheet, and associated commentary from Ben Chapman, can be found here.
A recent report in the Daily Gleaner discusses the book Iguanas for Dummies. In this book, the author recommends frequent bathing of iguanas because they normally soak in the wild. Bathing iguanas in the tub is also recommended on various websites. Letting iguanas soak in water is a good recommendation for their health, but there are good ways to do this and bad ways to do this. Soaking them in a bathtub (or sink) is a bad idea.
The Daily Gleaner article points out that bathing iguanas in bathtubs when there are children or immunocompromised people in the house is a bad idea, and that a separate bathtub should be used. I'm glad to see the risks of infectious disease to immunocompromised people are considered, however I'd take it a step further.
- Reptiles are high risk pets in terms of Salmonella infection. There is a disproportionate rate of Salmonella infections in people that have contact with reptiles, not just immunocompromised people. Fatal infections are rare, but do occur. People that own reptiles need to be aware of this and take practical measures to reduce these risks.
- Iguanas should never be bathed in the bathtub, regardless who lives in the house.
- Iguana cages should be of adequate size and design so that they can soak in their own enclosure. Otherwise, a container (e.g. a large plastic storage bin) that is only used for bathing the iguana should be used. Waste water should not be dumped in kitchen or bathroom sinks. The container should be disinfected regularly. Hands should be washed immediately after handling the iguana, the container or the waste water.
- Households with immunocompromised people or young children should probably not have iguanas.
More information that is applicable to iguanas can be found in the Turtle information sheets on the Womrs & Germs Resources page. There are also sheets with more information on Salmonella.
People are increasingly concerned about exposure to infectious agents, both for themselves and their pets. This has led to marketing of various products to reduce the risk of disease transmission. Some are good, some might be useful but are unproven, and some are just horrible. Many in this last category manipulate scientific data to try to convince people that their product is useful. I ran into one of those today while I was reading an article that recommended the use of electrolyzed water to protect pets from Salmonella.
Electrolyzed water is a weak electrolyte solution (such as tap water) that has had an electric current applied to it. The electric current acts on salt in the water and forms a weak acid and oxidizing agent (i.e. a weak disinfectant). It has been shown that electrolyzed water can be useful for disinfection of surfaces in food-handling areas, for reducing bacterial numbers when sprayed on carcasses in slaughterhouses, and possibly for treatment of contaminated food. The effect of spraying electrolyzed water on final food products, like pet food (raw or commercial) is unclear.
The science behind electrolyzed water has been used by some companies as an excuse to sell expensive electrolyzed water products for pets (and people) to drink. There is no evidence that drinking electrolyzed water helps reduce disease. Really, why would you want to drink a disinfectant, regardless of how "natural" it is? Bleach (at the right concentration) can kill Salmonella, but that certainly doesn't mean that drinking a weak form of bleach is good for you.
It's likely the biggest thing you have to lose with products like this is money, but make sure you don't use unproven (or illogical) products in place of basic, common sense measures to reduce the risks of disease. If you are considering buying products to promote the health of your pets or yourself, do some research and try to find as much objective, independent information as possible. Don't rely on company information and testimonials. Here's an example of one company's website that sells electrolyzed water. This page is about the human product but their pet version is the same. My general rule is that anything that purportedly cures all that ails you probably cures nothing.
P.S: This same company's site contained one of the funniest false quotes that I've seen in a while. The site states that "The New England Journal of Medicine reports that more than 80-90% of canine skin and other problems are caused by toxins in a dog's body." The New England Journal of Medicine is a world-renowned journal of human medicine, which certainly has better things to do than report false science about dogs (or anything about dogs for that matter!).
I frequently get e-mails from people who are proponents of feeding raw meat to pets. The e-mails often start by calling me an idiot, and they generally go downhill from there. Some, however, go into detail about why they think there are no health concerns for themselves or their pets associated with feeding raw meat. Recently, one argument I've heard repeatedly is that using only organic meat lowers the health risks. While there are certainly merits to the organic food movement, there is absolutely no evidence that organic meat is any less likely to be contaminated with bacteria than non-organic meat, nor is there any reason to even suspect that this would be the case. Bacterial contamination occurs during slaughter and processing, and organic raising of animals has no impact on that.
More discussion about the health concerns associated with raw meat diets can be found in our raw meat archives and elsewhere. I do not recommend that people feed raw meat, particularly in certain situations such as when there are young children or people with weakened immune systems in the house. If you are considering feeding a raw meat diet to your pet, learn as much about this practice as possible so you can make an informed decision. More information about raw meat feeding and things you can do to reduce the risks that come with it can be found on the Worms & Germs Resources page.
Remember: Using organic meat is NOT an infection control measure.
A report about the health risks in children associated with nontraditional pets was recently published in Pediatrics, the official journal of the American Academy of Pediatrics. The report also discusses diseases associated with animals in public settings such as petting zoos and pet stores. Although contact with pets and animals can be beneficial to growth and development in children, it is very important to be aware of the risks associated with certain kinds of animals. Physicians, veterinarians and public health personnel can help parents select appropriate pets in order to maximize the benefits while minimizing the risks to children.
One of the most important pathogens discussed in the report is Salmonella. Although Salmonella can be transmitted by many animal species, including traditional pets like dogs and cats, it is a particularly high risk with certain other kinds of pets, including reptiles, amphibians and baby poultry (chicks and ducklings). It has been estimated that direct or indirect contact with reptiles or amphibians is responsible for 6% of all sporadic Salmonella infections in the US, and 11% of cases among people younger than 21 years. There is also a relatively high risk of Salmonella transmission associated with animal-derived pet treats, such as pig ears, and raw meat.
The report makes several recommendations about how to reduce the risk of infection, injury and allergies from nontraditional pets, many of which you may have seen before on the Worms & Germs website. Just a few of these are:
- Always wash your hands after contact with animals, animal products or their environment, and after contact with animal-derived pet treats.
- Supervise hand washing for children less than five years old
Children less than five years of age and individuals with weakened immune systems should avoid contact with reptiles, amphibians, rodents, ferrets and baby poultry. These animals:
- Should not be kept as pets in households where children less than five years of age or individuals with a weakened immune system live.
- Should not be brought to childcare centres.
- Should not be allowed to roam freely in ANY house or living area.
- Should not be permitted in kitchens or anywhere food is prepared.
More information about Salmonella in pets and the risks associated with feeding raw meat and animal-derived treats to pets can now be found on the Worms & Germs Resources page.
Rawhide treats, as the name suggests, are raw treats that are literally made from the hide of typically cattle or pigs. The finding of Salmonella in rawhide treats is not particularly surprising, since Salmonella is commonly found in raw meat products, especially chicken. In this case it is not known exactly how the product may have become contaminated. High rates of contamination of raw pet treats have been reported, although a recent study reported improvement in products in Canada. This has likely occured because of action from the industry in response to outbreaks of disease in people that originated with treats. It's important to remember that any raw animal-based product that has not been treated (e.g. irradiated) to get rid of bacteria could contain harmful pathogens like Salmonella. They are best avoided, especially if high risk individuals (e.g. very young children, elderly persons or anyone with a weakened immune system) might come in contact with the treats or the pet to which the treats are fed. If you do decide to feed your pet raw animal-derived treats, care should be taken to reduce the risks of transmitting pathogens like Salmonella, as is recommended with raw meat diets. More information about raw meat feeding and Salmonella in pets can be found on the Worms & Germs Resources page.
You may notice a recurring theme in many of our posts and on virtually all of the information sheets on the Worms & Germs Resources page: an emphasis on handwashing. There is increasing emphasis on hand hygiene (i.e. hand washing and use of alcohol hand sanitizers) education in hospitals because the hands of healthcare workers are a major (if not the most important) means of disease transmission between patients. Despite hand hygiene being easy, cheap and effective, people rarely wash their hands as often as they should, and they often don't do it properly.
Most of the research about hand hygiene that has been published has focused on its use and impact in human hospitals, but this area is now also being studied more with regard to animals and veterinary medicine. A study published earlier this year in Veterinary Microbiology provided more evidence that hand hygiene is a critical infection control measure when dealing with animals. The study, coordinated by Dr. Maureen Anderson (of Worms&Germs fame) looked at MRSA carriage rate in veterinarians who work with horses. In addition to finding a high rate of MRSA carriage among these veterinarians (which was consistent with other reports indicating that equine vets are at higher than average risk for exposure to MRSA), the study looked at factors associated with MRSA carriage. Vets that reported routinely washing their hands between farms and those that reported washing their hands after contact with potentially infectious cases had a significantly lower rate of MRSA carriage. That should come as absolutely no surprise, but it's one more piece of evidence that we need to pay more attention to this routine infection control measure, in human hospitals, in veterinary environments and in households.
Remember, the 10 most important sources of infection are the fingers on your hands!
If you are looking for an interesting website to play around with, you should try HealthMap. This is a website created by the Harvard-MIT Division of Health Sciences and Technology that maps infectious disease reports from various sources. You can search by region and see what disease problems have been reported recently, or select specific diseases and find out where they've been reported. Some examples are shown below. The top image shows all disease reports worldwide (in the last 30 days), while the bottom image shows reports of Salmonella in North America during the same time period. The site relies on reports of diseases (many cases of various diseases occur but are never reported), so it focuses mainly on outbreaks or high profile cases , but it is still quite interesting.
Above: All reported disease outbreaks/cases worldwide in the last 30 days.
Below: Reported outbreaks/cases of Salmonella in North America in the last 30 days.
See the HealthMap site for more details.
Yet another reminder of the risks associated with handling turtles (and other reptiles) comes to us from a report published earlier this year regarding an outbreak of salmonellosis in people tied to contact with turtles. In this case, more than 100 people in 33 US states were affected. The report sparked additional public education efforts in Los Angeles county, CA, where eight of the cases occurred.
The report comes as no surprise - turtles are actually relatively commonly implicated in cases of salmonellosis in people (although still not nearly as commonly as foodborne transmission). It's particularly a concern in children, because kids may have close contact with pet turtles and may be more susceptible to serious infection.
In response to the cases in Los Angeles, the county Department of Public Health emphasized that parents must be wary of buying turtles for their children. Even though the sale of small turtles (less than 4 inches long) was banned in the US over 30 years ago, unfortunately these animals are still widely available in many pet stores, flea markets, and from other sources. Los Angeles Public Health personnel reported that children were getting sick because they were kissing their pet turtles - something that is very risky and should never be done by anyone, especially children. If people have pet turtles, they must be very diligent to practice good hygiene to reduce the risk of transmission of Salmonella.
More information about the risks associated with pet turtles, and measures that should be taken by people who own turtles, is available on the Worms & Germs Resources page.
The recent pet food recall for Salmonella has generated a lot of attention and, encouragingly, more resources containing information about reducing the risk of Salmonella from handling pet foods. One is a video from Drs. Doug Powell and Randy Phebus of Kansas State University, that can be seen by clicking on the image below. Another is an information sheet produced by the FDA. Many of the recommendations, as well as those we've made in previous posts, are basic and common sense, but are often overlooked because handling pet food is not perceived as a risk for infectious disease. While the overall risks of infection from handling commercial pet food are low, these easy, common sense measures should still be used.
Mars Petcare has recalled certain pet foods produced in a plant in Everson, Pennsylvania and sold in several US states. This is being done because two lots of pet food were found to be contaminated with Salmonella Schwarzengrund. This is the same Salmonella strain that was identified during a pet-food associated outbreak of salmonellosis in people in 2006-2007. Production of pet food at this facility was stopped in July because of a potential link between pet food produced there and infections in two people. More information about this recall is available from the FDA.
While commercial pet foods undergo rigourous quality control and are much less likely to contain potentially harmful bacteria such as Salmonella than, for example, raw meat diets, it is important to remember that situations such as this can happen. So it's still a good idea to wash your hands after handling pet food, of any kind.
In a recent post, I discussed a study about the health effects of feeding raw meat diets to pets. Because of the significantly higher rates of shedding of certain potentially harmful bacteria by dogs that are fed raw meat, I think raw meat diets are a bad choice - especially in households with young children, elderly individuals or people with compromised immune systems. However, if you are going to feed raw meat to your pet, you should take some basic precautions.
- Only use meat that is suitable for human consumption. Don't buy 'adulterated' meat or meat labeled unfit for human consumption.
- Keep raw meat frozen until you need it. Only thaw out the portion that is need for the next feeding, and thaw the meat in a sealed container on the bottom shelf of a refrigerator.
- Handle raw meat with care. Do not allow it to contaminate kitchen surfaces or items that may come in contact with other food. Clean and disinfect any items that come into contact with raw meat.
- Wash your hands thoroughly after handing raw meat or anything that has touched raw meat (e.g. your dog's food bowl).
- If your pet does not finish all the meat fed right away, discard any uneaten raw meat promptly. Do not allow raw meat to sit in a bowl at room temperature. Some dangerous bacteria can multiply rapidly under these conditions.
- Regularly clean and disinfect your pet's food bowl, but bear in mind that a recent study showed that it is very hard to eliminate Salmonella from raw meat in food bowls.
- Make sure your veterinarian knows that you feed raw meat. This is particularly important if your dog develops vomiting or diarrhea.
- It is very important to make sure that your pet's diet is well balanced, which can sometimes be difficult to do when feeding non-commercial or raw diets. Read about raw meat feeding, and try to find good sources of information (which is not always easy) to reduce the risk of problems caused by feeding an unbalanced diet.
- Never feed raw meat to sick dogs, puppies or pregnant dogs.
Feeding raw meat diets to dogs is a very controversial issue. Some proponents passionately advocate these diets (e.g. the BARF diet) based on vague and unproven recommendations. Opponents cite various studies showing that pets fed raw meat (not surprisingly) have high carriage rates of potentially harmful bacteria such as Salmonella, and reports of diarrhea or nutritional imbalances in these animals. However, there have been only a few good studies looking at the true health benefits and risks of feeding these diets to dogs.
A recent study in the journal Zoonoses and Public Health described the risks of therapy dogs shedding Salmonella and other potentially harmful bacteria. The authors tested 200 dogs over a 1 year period, 20% of which were fed raw meat as part of their normal diet. Dogs fed raw meat were 23 times more likely to shed Salmonella compared to other dogs. They were also 17 times as likely to be shedding extended spectrum beta-lactamase (ESBL) Escherichia coli (a highly drug-resistant form of E. coli).
The study concluded that, because of the risk of Salmonella shedding and the high-risk nature of the patients and other people that therapy dogs interact with, dogs that are involved with hospital/patient visitation programs should not be fed raw meat.
What does this tell us about feeding raw meat to pets?
Although this study doesn't answer all of the questions about the risks of raw meat diets, it reinforces the fact that pets fed raw meat have significantly higher rates of shedding of potentially harmful bacterial such as Salmonella and antibiotic-resistant E. coli. Eating pig ear treats has also been associated with Salmonella shedding. However, there was no association between a dog being fed raw meat and the animal itself developing diarrhea. In fact, raw-fed dogs had a lower incidence of extra-intestinal infections (combination of eye, ear, skin and urinary tract infections).
In general, raw meat diets should be avoided. While adverse health effects were not reported in this study, disease (including deaths) from Salmonella has been reported in dogs in other studies. While the overall risk may be low, feeding raw meat is an avoidable risk. However, it would be inappropriate to completely ignore the finding that raw-fed dogs had lower rates of certain infections. It is possible that there can be health benefits from feeding raw meat in certain dogs, but the potential benefits must be weighed against the potential risks to the animals and people with which the has contact. Raw meat diets should never be fed to pets that have contact with immunocompromised people (in the household or as part of visitation program), infants or the elderly.
If you are going to feed raw meat to your pet, make sure you take precautions to reduce the risk of infecting yourself or someone else. We'll post more on that aspect soon.
Many dog owners love to take their canine companions to the beach with them during the summer. Unfortunately, other people (particularly non-dog owners) sometimes take exception to having Bowser on the beach. These individuals often cite potential infectious disease risks as a reason to ban dogs from the beach.
While there are some potential infectious disease risks associated with having pet dogs at the beach, they are minimal. Also, some simple, common-sense steps can greatly reduce the risks that do exist. The infectious disease risks from feral (wild) dogs and wildlife defecating in the sand are much greater.
- The biggest health risk is actually probably from dog bites. Bites can be avoided through proper handling and training of dogs that are brought to public beaches.
- Many different bacteria (e.g. Salmonella, Campylobacter) can be passed in the stool of even healthy dogs. Some of these can be harmful to people, but only under certain circumstances, such as if they are swallowed or if they contaminate an open wound.
- Promptly picking up any stool passed by a dog greatly reduces the risk of significant contamination of the sand. Also, sunlight is an excellent “disinfectant” and will help kill any residual bacteria left behind.
- Dogs can also have different kinds of zoonotic parasites in their stool.
- Some of these parasites (e.g. roundworms, hookworms) are passed in a form that takes days to become infectious to people. So promptly removing dog stool from the beach minimizes the risk of transmission.
- Other parasites, such as Giardia, are immediately infectious when passed in the stool, but must be swallowed to cause infection. Prompt removal of dog stool, good hand hygiene with soap and water or an alcohol-based hand sanitizer before eating, and avoiding sand contamination of food and drink should largely eliminate this risk as well.
Overall, the risks of having dogs on beaches are very low if people behave responsibly, specifically properly restraining their dogs and promptly picking up stool.
More information about zoonotic diseases associated with contamination of sand and Sandboxes is available on the Worms & Germs Resources page.
An ongoing outbreak of listeriosis in people in Canada has been linked to prepared meat products from Ontario. At least six deaths have been reported, and others are under investigation. While it is unlikely that there has been widespread exposure of dogs and cats, it is certainly possible that some pets were fed the recalled (and potentially contaminated) meat.
Listeriosis is an infection caused by the bacterium, Listeria monocytogenes. It can affect many animal species, but it is rarely identified as a cause of disease in dogs and cats. When signs do occur, fever, diarrhea and vomiting are most commonly reported. Rare cases of neurological disease in dogs and cats, and one case of suspected miscarriage in a dog due to listeriosis have been reported. Listeria skin infection has also been reported in dogs.
Overall, the risk of listeriosis in pets associated with the tainted meat products is very low. Pets that ate any of the recalled food products do NOT need to be tested or treated if they are not ill. However, should a pet that ate recalled meat become ill, it is important to inform the animal's veterinarian about the potential exposure to Listeria.
Reptiles are common pets, and the risk of transmission of Salmonella from reptiles is fairly well known. Most of the attention regarding Salmonella in these cases involves direct contact with reptiles, especially turtles. However, both direct and indirect contact with other reptiles also carry risk, as can contact with other animals. A recent report about a 2005/2006 outbreak of salmonellosis in 4 people from Minnesota highlights this:
- Three affected people were from the same junior high classroom, which contained pet snakes.
- Two of the people reported contact with the snakes, and one other student from the school did not handle the snakes but was often in the classroom, while the fourth infected student had a sibling in the class.
- The same Salmonella Typhimurium strain was found in the classroom snakes, various classroom surfaces and vacuum-packed rodents that were purchased over the internet and fed to the snakes.
- Presumably, the snakes became infected from the rodents, and the students became infected from handling the snakes, or from touching contaminated surfaces in the classroom (they reportedly had no contact with the rodents).
A broader US investigation identified 7 other people infected with the same Salmonella strain from handling vacuum-packed rodents. The outbreak was eventually traced back to the (unlicensed) rodent supply facility.
Pets can be educational and entertaining in classrooms, however some pets are better than others. Educational value, ability to properly (and humanely) care for the pet, and classroom safety need to be considered when determining what pet might be appropriate. Careful consideration of measures to reduce the risk of disease transmission is required. The teacher in this case reported that he did not know snakes could carry Salmonella, that he did not wash his hands after cleaning the cage, and that he did not tell students to wash their hands after touching the snake, so it is clear that there was inadequate consideration to these issues.
This case report also highlights the potential risks of reptile ownership in households. Reptiles are high risk for Salmonella, and not appropriate for all households. Good hygiene should be used when handling reptiles, their environment and their food. More information about reptiles can be found in the Turtles information sheet on the Worms & Germs Resources page.
Image: Corn Snake (Pantherophis guttatus) by Mike Wesemann
Pet treats derived from raw animal products such as rawhides and pig ears (yes, pig ear treats are actually dried, raw pig ears) are widely available and commonly fed to pets, particularly dogs. Being a raw product, there is an inherent risk of contamination with potentially harmful bacteria such as Salmonella. In 1999, an outbreak of salmonellosis linked to contact with raw pet treats was identified in people in western Canada. A subsequent investigation found Salmonella in over 50% of pig ear treats and 38% of other animal-derived treats. Similar results were reported by a later study in the US, and other outbreaks of disease have been reported. In Canada, the pet treat industry and government groups met and made various recommendations to reduce the risk of contamination.
To evaluate the effect of these changes, a Canadian follow-up study was performed. Only 4% of treats were contaminated with Salmonella, which was a marked contrast to the earlier study. Even so, the fact that Salmonella was present in a detectable percentage of treats means that certain precautions are warranted.
- Always wash your hands thoroughly after handling pet treats such as rawhides and pig ears
- Avoid buying treats from 'bulk bins', as there may be an increased risk of cross-contamination between treats in the bin
- Buy packaged treats so that you don't have to touch them directly when buying them or bringing them home
- Never store treats in areas where other food is kept or prepared
- Ask whether the treats you are buying have been produced under the Guidelines for the Manufacturing of Natural Pet Treats for Pets. There guidelines were developed by the American Pet Products Manufacturers Association with input from the Food and Drug Administration (FDA)
- Avoid buying raw treats if you have young children or anyone with a weakened immune system living in the household, as these treats may pose a small but unnecessary risk of exposure to Salmonella
- Contaminated treats seem to be a bigger problem for people than pets, however Salmonella can also cause disease in pets. If your pet develops diarrhea after eating an animal-product treat, be sure you tell your veterinarian
Image: Pig ear dog treat from www.foodpoisonblog.com
Where do you think the goat's mouth just came from? The ground, along with manure from various animals.
What might the bottle have been contaminated with? E. coli O157, Salmonella, Campylobacter, Clostridium difficile...
Where do you think this bottle is going next? The baby's mouth.
What will probably happen to the child?: Nothing.
What might happen to the child?: Disease caused by one of the above-named microorganisms (or others), ranging from mild diarrhea to fatal infection.
While there is good information available about precautions that should be taken for petting zoos, such as from the National Association of State Public Health Veterinarians, not all petting zoos take adequate precautions. A recent study pointed out common deficiencies.
Some important points to consider:
- Petting zoos are safe for the vast majority of the population if common sense measures are used.
- Items that will end up in the mouth of a child should never go into a petting zoo.
- Children should be closely supervised in petting zoos.
- Uncontrolled animal contact should be prevent.
- Hands should be washed after contact with animals or the petting zoo environment.
- Try to prevent your pet from eating/touching dead birds.
- If your pet develops diarrhea after eating a dead bird, it is probably not a health concern for anyone else but Salmonella infection is possible, so consider taking your dog to the veterinarian. This is especially important if the dog appears sick (i.e. besides vomiting and diarrhea, the dog also is not acting like itself) or if there are people in the household that are at higher risk for getting sick from bugs like Salmonella (i.e. infants, people with weakened immune systems). All diarrhea should be considered potentially infectious to other animals and people. Extra care should be taken around affected pets and their stool, including extra attention to hand washing, and disinfecting the site of any "accidents" that occur in the house.
- In some areas where bird testing is performed for West Nile virus or avian influenza surveillance, public health personnel will collect dead birds. Contact your public health department if you are unsure what is done in your region.
- Do not touch dead birds with bare hands.
- Use heavy-duty, leak-proof gloves to place the bird in a leak-proof plastic bag. Alternatively, fold two bags over your hand and use the bag to cover your hand when picking up the bird (like people do when poop-scooping), or use a shovel to place the bird in a bag.
- Double bag the bird.
- If the bird is not being collected for testing, contact your local waste management agency regarding disposal instructions.
- Always wash your hands with soap and water as soon as you're done.
For approximately 20 years I have been involved in waste collection for the Parks Division. A considerable amount of the waste which I collect on a daily basis is dog excrement. This is usually, but not always contained in a plastic bag and thrown into a large garbage barrel which I man-handle and dump in a waste truck. Years ago I contacted the local Health Unit and asked if there was any special health risks associated with this job. They advised me at that time the main danger to health would be with E.coli contamination. I use neoprene gloves while carrying out my duties and of course try to ensure that I do not come in contact with any debris. This is not always possible.
There are 3 main risks with handling dog stool: exposure to bacteria that cause diarrhea, exposure to intestinal parasites and infection of wounds.
Various bacteria that can cause diarrhea can be present in dog stool. These include Salmonella and Campylobacter. E. coli is not a major concern because strains found in dogs are not typically those that cause disease in people. A few intestinal parasites are also of concern, including Giardia and roundworms. The risk of exposure to these is hard to say because you don't know anything about the health status of the dogs, but it's wise to treat all stool as infectious. However, for these to cause disease, they must go from the garbage and into your mouth. The risk of this should be minimal with basic common-sense precautions.
A large number of bacteria present in stool can cause infections of wounds like cuts and scratches, or other skin lesions such as eczema. Direct contact of these lesions with stool would be required to cause infection. The risks of this can also be greatly reduced with basic preventative measures.
Some basic precautions (many of which you are doing) include:
- Wear gloves when handling bags containing stool.
- Change your gloves if they become contaminated with stool.
- Have your gloves cleaned periodically, and whenever they become contaminated. Otherwise, use disposable gloves.
- Promptly wash or disinfect your hands if they become contaminated. Carrying an alcohol-based hand sanitizer in your truck would be useful.
- Wear coveralls or some other sort of outerwear that can be removed easily if contaminated. If your clothing becomes contaminated, change it (and wash your hands after).
- Wash your hands after removing your gloves (and especially before eating).
Overall, the risks to you should be very low.
Petting zoos and similar animal contact events carry an inherent risk of infectious disease transmission. Outbreaks of various infectious diseases have been reported, mainly associated with farm animals. Reptiles are a particular concern because they can have high rates of Salmonella carriage. Terrestrial reptiles like bearded dragons and pythons are lower risk than species like aquatic turtles, but these animals can still be the source of salmonellosis in humans.
Petting zoos can be entertaining and educational, and fairly safe if run properly. However, deficiencies are often present. At this facility, there were multiple hand hygiene stations, consisting of alcohol-based hand sanitizers, which are very effective. Food and drink were banned in the area and there were staff supervising all animal contacts. These are all good things, however the best measures are useless if they are not used or enforced. While I made sure that my family carefully cleaned their hands, we were definitely in the minority. The hand hygiene stations were not particularly easy to access and there was't one present at the exit, so if you weren't looking for it you would probably just leave. Further, despite the signs, staff allowed people to eat and drink in the area where they were handling reptiles. Allowing people to eat and drink, and not providing easy access to the hand sanitizers (two pretty basic measures) were major problems and greatly increase the risk of disease transmission.
I'm not suggesting we should avoid petting zoos. My kids enjoy them and we will surely attend a few this summer. The key with animal contact exhibits is common sense....avoid high risk animals, keep you hands out of your mouth and wash your hands thoroughly when leaving (even if you didn't touch an animal since you probably touched other surfaces). Some animal species are particularly high risk, including young poultry and young ruminants (e.g. calves, lambs, goats). Reptiles fit into this high risk group, which is why I had more concern about this event than a standard petting zoo. People with compromised immune systems should avoid animal contact, particularly with calves, chicks, lambs and reptiles.
And above all, WASH YOUR HANDS.
A good source of information about animal contact events and infectious diseases is available from the National Association of State Public Health Veterinarians.
The CDC has released the findings of an investigation of a prolonged multistate outbreak of salmonellosis that was linked to dry dog food in 2006-2007. This outbreak implicated two different dog food brands, both made by the same manufacturer in the same plant in Pennsylvania, as the source of a particular strain of Salmonella Schwarzengrund. The strain infected numerous people, and was also found in some dry dog food samples and stool samples of dogs that were fed the food, with which the affected people had had contact. No illness was reported in the pets. It is unclear whether people were infected from contact with the food or contact with the pets' stool.
This is the first report of salmonellosis associated with dry pet food. Previous outbreaks have been associated with contact with raw pet treats such as pig's ears. Overall, the risk from contact with dry pet food is quite low, although this outbreak clearly demonstrates that some risk exists. Handwashing after contact with pet food should greatly reduce the already low risk.
This report is certainly not a reason not to feed your dog or cat a commercial pet food. One concern that I have is that this report will (and already seems to) be used by proponents of raw meat diets as support for this feeding practice. Feeding of raw meat has been clearly shown to increase the rates of shedding of potentially dangerous bacteria such as Salmonella. Illness and death from these bacteria have been identified in dogs fed raw meat. The high rates of Salmonella shedding in raw-fed dogs are a significant public health concern, and these concerns have been previously reviewed. Outbreaks of human salmonellosis have not been reported in association with raw meat feeding. This could indicate minimal risk, but could equally be due to lack of identification of sporadic cases that would be more likely with raw food than large-batch commercial contamination or better hand hygiene practices associated with raw meat handling.
- The risk of Salmonella exposure is still much lower with good quality commercial pet food compared to raw meat.
- Wash your hands after handling pet food (of any variety), as well as food and water bowls.
- Care should be taken when handling animal stool to avoid any direct contact with it. Wash your hands after picking/cleaning up any type of stool, even if you use a plastic bag or a designated scoop to do so.
No...hedgehogs aren't sneaking out of their cages and attacking people as they sleep. Rather, they can carry a variety of microorganisms that can be transmitted to people. There have been a few reports describing infections associated with hedgehogs, particularly Salmonella and ringworm. An excellent report in the journal Emerging Infectious Diseases highlighted the diseases hedgehogs have been shown to, or could, transmit to people. Hedgehogs don't have to be sick to be a source of infection.
Hedgehogs have been available for years, but they may be a fad pet at the moment. One breeder is quoted as saying “They are going up these last two months we actually have a waiting list about twenty people,” said Sarah Roberts a breeder in Mansfield. “That's never happened in the year’s of breeding we've done.”
While any pet could transmit infections to people, certain pets are higher risk. Overall, species that are rare or 'fad' pets may be of greater concern because we simply don't know much about them (i.e. what diseases they can transmit, how to reduce risks...).
These small creatures can probably be safe pets in some households, but are they really better than other species? You probably should not have a hedgehog if you or someone else in the household has a compromised immune system or if you have small children. If you do have a hedgehog, don't let it roam freely in the house and wash you hands after handling it.
A report in the Centers for Disease Control and Prevention (CDC)'s journal MMWR described a multistate outbreak of human salmonellosis caused by contact with pet turtles. Officials investigated 103 cases of disease cause by a specific type of the Salmonella bacterium. Contact with turtles was identified as an important risk factor for disease. Sixty-three percent (63%) of people infected by this strain of Salmonella reported contact with turtles in the week before getting sick, compared to only 4% of others. Many people that became ill reported having touched a turtle. Some even reported kissing a turtle (don't ask me why... I'm not making this up). Salmonella was cultured from turtles or their aquariums in some households. No fatalities were reported but some people were seriously ill and required hospitalization.
The association between turtles and Salmonella is nothing new. Upwards of 90% of healthy turtles may carry Salmonella bacteria. Antibiotic treatment is not effective at eliminating Salmonella carriage and there is no way to declare a turtle 'Salmonella-free'. People can become infected through direct contact with turtles or their environment. Sale of turtles with a shell length of less than 4 inches was banned in the US over 30 years ago. This was because of the strong association between turtles and salmonellosis, particularly in children. Small turtles are more likely to be handled by children and put in their mouths.This measure has been estimated to have prevented 100 000 infections every year, however it is clear that (illegal) small turtles can still be readily purchased from pet stores or other sources. Turtles were less than 4 inches long in 86% of cases in this report where turtle size was reported.
While turtles can be fascinating, they are definitely a high-risk pet. I used to have turtles but wouldn't consider it now that I have young children. There are much better and safer pets for children. They should be avoided by households with children or people whose immune systems may be compromised. People who have pet turtles need to take precautions to reduce the risk of infection, but it cannot be completely eliminated.
More information about turtles can be found in our
Recently, a story about a man who brought a horse into a hospital to visit his father was widely reported. The horse apparently made it to the man’s room, which included a trip in an elevator. The son, who appeared intoxicated, was eventually asked to leave (and take the horse with him). Said a hospital spokesperson “We do have a pet visitation policy, but it does not include a horse”. Strangely, the horse that was brought to the hospital apparently wasn’t even the father’s horse (which supports suspicions of the son’s lack of sobriety).
There are guidelines about which animals are appropriate for hospital visits, although it shouldn’t take an expert to figure out that a horse is not an appropriate candidate. Kicks, bites, and trauma from being crushed or run over are among the most obvious concerns. Horses can also carry a variety of bacteria that are potentially dangerous, especially to people in hospitals. These include Salmonella and methicillin-resistant Staphylococcus aureus (MRSA). There also aren’t that many house-trained horses out there.
So, while I can easily see how someone in a hospital would like to see his or her horse, there’s no way this should even be considered.
Some closing thoughts
- Would you like to ride in an elevator with a horse?
- Would you like to be stuck in an elevator with a horse?
- Do you think the horse was house trained?
- Do you think any of the healthcare personnel washed their hands after touching the horse?
This isn't the first time a horse has been in hospital, and some even get invited. The picture is from a story in Veterinary Practice News that described a program where horses were brought into hospitals!
While it is certainly true that any healthy animal (and person) can carry infectious diseases, and that prudence is reasonable, there is simply no evidence supporting this recommendation for the average household. Any contact with pets carries a very slight risk of disease transmission, just like any contact between people. There is currently no evidence, however, that sleeping with a pet in the bed increases the risk of disease. For your average pet and average household, this is probably exceedingly low risk and the recommendation is very difficult to justify. It is a reasonable recommendation when the pet is known to be carrying something that is transmissible to people (such as MRSA or Salmonella) or when a person has a compromised immune system. Banning pets from the bedroom completely doesn’t make any sense.
Personally, my dog is not allowed in my bed. However, that’s not because of disease concerns, it’s because she’s a large dog that snores and certainly can be a bed-hog. I have no problems with my cat on the bed. Life is never completely free of risk. If you enjoy having your pet in the bed, and you’re both healthy, I don’t see a reason to stop.
INFORMATION SHEETS specifically for KIDS, for VETERINARIANS, for PHYSICIANS and for PUBLIC HEALTH PERSONNEL are also available on the Worms & Germs RESOURCES page!
Click on the highlighted topics below for information sheets. Topics that are not highlighted are in development and coming soon. Sheets for other animal species and diseases are also under development and will be added when they are available.
- Your veterinarian and physician are your ultimate resource for information about the health of your pets or your family.
- Information provided here is accurate to the best of our knowledge, but infectious diseases can be unpredictable and these sheets are for general information purposes only.
- There can be great variation in disease risks in different geographic areas. The information provided was developed for Ontario, Canada, but most of the information is relevant for other regions as well.
2012 International Clostridium difficile Symposium
2012 International Conference on Equine Infectious Diseases IX
2011 ASM-ESCMID Conference on Methicillin-resistant staphylococci in animals
- Miconazole susceptibility of MRSA and MRSP
- Livestock associated MRSA in community hospitals in Ontario
- Equine hospital MRSA surveillance
- Biofilm production by S. pseudintermedius
- Methicillin-resistant staphylococcal pyoderma in dogs, and impact of treatment on colonization rates
- Surgical site infections in a small animal hospital
2011 University of Guelph Centre for Public Health and Zoonoses Symposium
- Pet ownership, interactions and animal-associated disease risks in Canadian households
- Metagenomic investigation of the oral microflora in healthy dogs
2011 Canadian Animal Health Laboratorians Conference
2011 Canadian Association of Clinical Microbiology and Infectious Diseases
- 2011 American College of Veterinary Internal Medicine Forum, June
- 2011 ASM-ESCMID conference on methicillin-resistant staphylococci in animals, Sept