People don’t live in bubbles; people live on a planet teeming with animals and pathogens, a frothing soup that simmers or boils depending on how the environment fires the pot.
That’s an oversimplified – and overwrought – analogy, but the fact remains, people face infectious-disease risks from the living world around them. That’s the essence of the One Health concept, which is a way of thinking about how new human infections arise and spread.
One Health means that physicians "can’t just focus on people anymore" to understand human infections, Dr. Timothy Brewer told me when I spoke with him at the International Meeting on Emerging Diseases and Surveillance in Vienna.
"If my goal is to prevent infections in people, I have to think about other issues, and recognize the role of diseases in animals as a source of human disease. We all accept this concept today, but I don’t know whether people realize how novel this was 10 years ago," said Dr. Brewer, an infectious disease specialist and vice provost for interdisciplinary and cross-campus affairs at the University of California, Los Angeles.
For example, the Centers for Disease Control and Prevention (CDC), and many state and local health departments, track West Nile virus cases in birds and horses. "That would not have happened 10 years ago," Dr. Brewer said. "Instead of waiting for human outbreaks, today we look at birds and other animals and think that maybe we can intervene before human cases occur. That’s a big shift."
He traces the concept of One Health to the 2003 outbreak of severe acute respiratory syndrome (SARS) that infected more than 8,000 people in 29 countries, with a 10% mortality rate during a roughly 1-year period. "SARS was a "wake-up call to public health agencies that we need to be aware of infections that can spread from animals to people," he said. The SARS pathogen turned out to be a bat-borne virus that first infected people via civet cats.
Another landmark was the creation of the One Health Initiative (www.onehealthinitiative.com) in 2008, after "One Health" was defined by a panel organized by the American Veterinary Medical Association and the CDC.
I also spoke at the meeting with Dr. Anne Schuchat, acting director of the CDC’s Center for Global Health, who recalled how West Nile virus was identified in 1999. "Someone at the Bronx Zoo noticed that many birds were dying," said Dr. Schuchat. The experience proved that "there are lots of ways to think about everyone being part of the same community."
Globalism is another facet of One Health. "We not only have to think about the environment and animals but also [about] public health in other countries," said Dr. Brewer. "The CDC’s job is to protect U.S. health, but to do that you need to deal with public health issues in other countries." He noted that the CDC now has about 300 employees staffed in some 60 countries to get a jump on new, suspicious infections regardless of where they first appear.
The growth of One Health has led to a heightened study of animals for the potential human pathogens they might carry, and surveillance of animals by groups like the CDC for the appearance of known pathogens, such as West Nile virus. Dr. Brewer predicted a future of heightened collaboration between physicians and veterinarians as they explore links between animal and human disease.
–By Mitchel L. Zoler
On Twitter @mitchelzoler