The U.S. Centers for Disease Control and Prevention (CDC) was able to connect contaminated dog food to a Salmonella outbreak spread across nine states on Thursday thanks to a combination of routine state-level testing and a national online infection database operated by the CDC itself.


Several brands of Diamond Pet Foods dry dog food manufactured at a single South Carolina facility have tested positive for Salmonella Infantis, a rare strain that has infected at least 14 people and hospitalized at least five. The individuals contracted the illnesses either through handling the tainted kibble or having contact with a dog that had eaten it.

“This is a great case study on how animal feed safety and human health are connected,” said Jennifer Holton, spokeswoman for the Michigan Department of Agriculture & Rural Development (MDARD).

The connection between the dog food and the human Salmonella Infantis illnesses first arose after the rare Salmonella strain was discovered in an unopened bag of Diamond Pet Foods kibble during routine retail sampling by the MDARD on April 2.

Knowing the genetic fingerprint of the Salmonella, the CDC consulted PulseNet, its online network that connects public health and regulatory personnel around the country to share information on disease infections. They found that a handful of human Salmonella infections around the country matched up with the bacteria in the dog food. 

When public health officials followed up with those individuals, most of them reported an association with Diamond Pets dog food. Bingo — a link was made.

“PulseNet is critical to our food safety system,” said Dr. Casey Barton Behravesh, who leads the Outbreak Response Team at the CDC. “It’s a very important way for us to detect these big, multi-state outbreaks. There may be only one or two cases per state, but if you can look across the country and add them up, the need for an investigation becomes much more apparent.”

No dogs ill?

In recent press releases announcing recalls of certain kibble brands, Diamond Pet Food’s has claimed that no dog illnesses have been reported in association with the outbreak. While that may be true, the claim may be leaving some pet owners with a false sense of security.

According to both the CDC and the MDARD, no pet illnesses have been reported because state and federal agencies don’t track pet illnesses. The fact that no dog illnesses have been reported does not mean that no dog illnesses have occurred: There is simply no system in place to confirm dog illnesses.

“Dogs may get sick and may or may not get taken to a veterinarian,” said Behravesh, who is a veterinarian. “Very uncommonly are they tested for Salmonella or germs that could give them a gastrointestinal illness.”

In fact, a spokeswoman for the Michigan Department of Community Health anecdotally told Food Safety News that she had heard of a dog in Michigan becoming sick related to the outbreak, but could not confirm any more information. The outbreak includes one human illness in Michigan.

The remainder of the illnesses are spread across the following eight states: Alabama (1 illness), Connecticut (1), Michigan (1), Missouri (3), North Carolina (3), New Jersey (1), Ohio (2), Pennsylvania (1) and Virginia (1).

As the CDC’s investigation continues, Behravesh said the outbreak highlights a crucial reminder for pet owners:

“It’s important for people to be aware that dog food can be contaminated with Salmonella. After handling it, they need to wash their hands before eating or feeding infants.”