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?