A total of 28 research dogs were enrolled in the study: 16 were fed a single Salmonella contaminated raw-food diet meal, and the remaining 12 dogs were fed a meal consisting of Salmonella-free raw food. Each fecal sample was tested for the presence of Salmonella, and all Salmonella isolates underwent serotyping and antimicrobial susceptibility testing.Of the 16 dogs given the Salmonella-contaminated diet, 7 (44%) shed Salmonella in their feces within 1 to 7 days of consuming the contaminated diet. Five of these dogs shed the same serotypes as identified in their food; the other 2 shed a serotype other than the one found in the food. Dogs fed Salmonella-free raw foods did not shed Salmonella. No clinical signs were noted in either group. It was concluded that Salmonella infections in dogs tend to be nonclinical. The authors suggest that owners be made aware that raw foods are often contaminated with Salmonella and that dogs that eat them have a high probability of shedding the organism. In particular, owners at a higher risk for acute salmonellosis should be warned about handling raw-food diets or their dogs' feces if a raw diet is fed.
COMMENTARY: Dogs have been recognized as a possible source of Salmonella infection for humans, and there are many potential sources of Salmonella for dogs. This article shows how raw pet food diets act as one of these sources.Given the variety of origins for the raw meat used in these diets, which does not undergo any sterilization processes, they may contain parasites and/or bacteria. It also seems that dogs do not show clinical signs, making it difficult to gauge the risk for owners. Interestingly, the most common serotype found in the diets in this study was Salmonella heidelberg, which is the most common cause of salmonellosis in humans in Canada, accounting for 26% of cases in 2003.Given this information, along with concerns about increasing emergence of antimicrobial resistance in bacteria, veterinarians may want to be extra vigilant in warning owners of the risks that come with feeding raw pet food diets.
The risk of salmonellae shedding by dogs fed Salmonella-contaminated commercial raw food diets. Finley R, Ribble C, Aramini J, et al. CAN VET J 48:69-75, 2007.