Raw pet food and human illness

My buddy Scott Weese, whom I haven’t played hockey with for about 15 years (but we won the faculty tournament in 2005, so I figured that was a good time to retire and move to Kansas; I’m the goalie, he’s third from left, back row) writes on his WormsAndGermsBlog that human health risks from raw pet food (either from exposure to pathogens in the food or in the feces of pets eating the food) are known to exist but they’re not well characterized. We know that dogs fed raw meat-based diets clearly have increased risk of shedding various pathogens, particularly Salmonella and multidrug resistant E. coli. We know this results in some degree of disease risk in animals and in humans, but the scope of the problem is poorly understood. A recent report from Public Health England provides some more information about the risks associated with feeding raw pet food.

The report is about four people who were infected with E coli O157, a particularly nasty strain of E. coli that can cause serious disease in people.

One person developed hemolytic uremic syndrome (HUS), a particularly severe consequence of infection, and died.

The four cases involved the same strain of E. coli O157. Three individuals had been exposed to dogs fed a raw meat diet. Tripe was the specific ingredient that was implicated.

Samples of raw pet food were collected for testing. All samples from one raw pet food producer were positive for STEC (shiga toxigenic E. coli, the group to which E. coli O157 belongs). A positive test was also obtained from the freezer of one of the affected individuals, and from one sample of raw tripe. It strain isolated from the tripe was a different from the outbreak strain but supported the notion that tripe might have been the cause. It’s not surprising that they couldn’t isolate the outbreak strain from the food, given the lag from the time of exposure of people to the time of sampling of pet food. Contamination is probably sporadic, with different strains contaminating different batches.

Feeding raw meat-based diets is popular, but associated with risks to pets and people (have we said that enough times yet?). My preference is for it not to be done, but I’m realistic enough to know that people are going to do it anyway. So, I focus on two things:

Who should definitely NOT feed raw meat to their pets?

Households where pets or people are at increased risk of severe disease, including those where young, old, pregnant or immunocompromised individuals (human or animal) are present.

If raw meat is to be fed, how can the risk be reduced?

We have a fact sheet on the Worms & Germs Resources – Pets page about how to reduce the risk. In response to this outbreak, Public Health England produced some similar recommendations on handling raw pet food and preventing infections.

Good on ya Scott.

Now, work on driving to the net.

Raw is risky: Kitten death and recall

I’d somehow dropped off the Worms & Germs Blog, hosted by my former hockey friend-buddy-guy Scott Weese at the University of Guelph, in the same way people lose barfblog.com.

We’re both still here (he’s in the back row, third from left, I’m the goalie in black, 13 years ago).


Scott writes about recent raw pet food outbreaks that, I haven’t written much lately about recalls of raw pet food because of Salmonella contamination. In large part that’s because it’s an expected event. There’s a reason we cook food…to kill things that can make us sick. We assume that raw meat intended for our consumption is contaminated with bacteria like Campylobacter and Salmonella (because it often is). Therefore, we similarly expect raw meat for pet consumption to be frequently contaminated. Various research studies have confirmed that.

A recent recall highlights the issues and risks. The recall involves Blue Ridge Beef of Eatontown, Georgia. They are recalling “Kitten grind” (an unfortunate name, in my opinion…but that’s a different story) after consumer complaints of deaths of two kittens. One death was confirmed to have been the result of Salmonella. Salmonella and Listeria were identified in the food (although it’s not clear to me whether it was the same strain and the same lot). Regardless, it’s not too surprising. Salmonella contamination of raw meat is common and while disease in animals is fortunately rare, it can happen, sometimes with fatal consequences.

This should be a reminder that handling and feeding raw meat is a risk for acquisition of pathogens such as Salmonella. My main recommendation is ‘don’t feed raw’. That’s particularly true in households where there are high-risk people (e.g. young kids, elderly individuals, pregnant women, immunocompromised individuals) or high-risk animals (same types as for people). If someone’s determined to feed raw, it’s important to reduce the risk as much as possible.

Hand hygiene at a petting zoo; room for improvement

OK hockey player and erstwhile blogger about all things zoonotic, Scott Weese, published a pretty cool paper about handwashing at a petting zoo on Friday.

Weese and doctoral candidate Maureen Anderson used a variation of our video observation system to watch and code the hand hygiene behaviors of visitors to a petting zoo at the University of Guelph’s annual open house, known as College Royal (that’s in Canada).

Video observation with discrete cameras has a couple of advantages: actions can be repeatedly viewed to make sure they are coded correctly, and video reduces the weirdness when people notice someone stalking watching whether they wash hands, in a bathroom, kitchen, or petting zoo.

As Weese writes in his Worms and Germs blog, “overall hand hygiene compliance was 58%. That means 58% of people that came into the petting zoo washed their hands or used a hand sanitizer on the way out. (It doesn’t mean they all did it well, but they at least did something). In some ways, that number’s good, when you compare to our earlier petting zoo observation study, (or even to results of hand hygiene rates of physicians in some hospitals). However, for such a short-term activity where there is easy access to facilities to wash hands or use a hand sanitizer, there’s much room for improvement.

“During the petting zoo, a few thing were changed at defined times to see if they could improve hand hygiene rates. Two things resulted in increased hand hygiene compliance; a combination of people offering hand sanitizer and improving signs, and having people at the exit reminder people to wash their hands. This suggests that people need a reminder to wash their hands. Whether they don’t think about it, or can’t be bothered unless someone points it out, is unclear, but having people encourage hand hygiene is a good think to consider. It’s practical for short-term events like petting zoos at fairs and similar exhibits, but not as practical for permanent exhibits.”

And not so practical for food service, hospitals and elsewhere. However a combination of rapid, relevant, reliable and repeated information, coupled with handwashing hall monitors, may increase rates of hand hygiene compliance. But more about that later. Some of the handwashing signs used in the Anderson and Weese experiment are shown, above right.

The abstract for the paper is below.

Video observation of hand hygiene practices at a petting zoo and the impact of hand hygiene interventions
Epidemiology and Infection
M. E. C. Anderson and J. S. Weese
Petting zoos are popular attractions, but can also be associated with zoonotic disease outbreaks. Hand hygiene is critical to reducing disease risks; however, compliance can be poor. Video observation of petting zoo visitors was used to assess animal and environmental contact and hand hygiene compliance. Compliance was also compared over five hand hygiene intervention periods. Descriptive statistics and multivariable logistic regression were used for analysis. Overall hand hygiene compliance was 58% (340/583). Two interventions had a significant positive association with hand hygiene compliance [improved signage with offering hand sanitizer, odds ratio (OR) 3·38, P<0·001; verbal hand hygiene reminders, OR 1·73, P=0·037]. There is clearly a need to improve hand hygiene compliance at this and other animal exhibits. This preliminary study was the first to demonstrate a positive impact of a hand hygiene intervention at a petting zoo. The findings suggest that active, rather than passive, interventions are more effective for increasing compliance.