How the CDC Uses a One Health Approach to Investigate Outbreaks

Whenever the CDC is investigating an outbreak that involves animals, or contact with animals, the agency takes a One Health approach, says Megin Nichols, DVM, MPH, DACVPM, enteric zoonoses activity lead at the CDC.

“Anytime that we investigate a disease outbreak at CDC that involves animals or contact with animals, one of the things we want to do is think about it in terms of a One Health approach. What is One Health? For us, it means the health of humans is impacted by the health of animals and the environment. So, when we go and do an outbreak investigation and look at all of the factors that might have caused people to get sick, we really want to think not only about the human health, but also is there a component of animal health that has been impacted, and what can we do to modify or look at the environment to hopefully prevent and control future outbreaks of disease. This is especially true when it comes to antibiotic or antimicrobial resistance.

We are seeing an increase in the number of outbreaks that we're investigating—of Salmonella in particular—that result from animal contact and have bugs that are resistant to antibiotics. There was a Salmonella Heidelberg outbreak that occurred in people, and it was linked to contact with young dairy calves. And what we started to see was that this bug was antibiotic resistant, meaning it was not treatable with many of the first line antibiotics we use in humans. Another thing we figured out, through looking at it with the One Health approach, is that this particular bug was also impacting the health of the calves. Some producers saw up to about 50% mortality in the calves. So this is an economic impact and, when you looked at the antibiotics that were available to treat the cattle in this instance, there really weren't any that were allowed by regulation, because the bug was so drug resistant.

So, that can be a very scary public health issue that's impacting people and animal health, and these bugs can live in the environment. So, when we investigated the outbreak we had to really look at this from a holistic One Health approach in order to help prevent illnesses in people and in the animals.”