So how do you find the next Ebola, the next rabies, the next West Nile, before it comes to infect humans? You actively look for it in the wild.
That's what the University of California, Davis, is doing by deploying teams of veterinarians into zoonotic hot spots around the world—in Africa, Asia, Central America, and South America—to detect outbreaks in animal populations before they get out of control. Through their Predict initiative, funded through USAID, they also empower local governments by giving them the tools to detect and diagnose strains without having to ship samples abroad.
"We're looking for viruses in viral families that have had a lot of zoonotic diseases, especially ones that have high pandemic potential—viruses like influenza, viruses like MERS, flaviviruses [e.g., encephalitis]," Christine Kreuder Johnson, a UC-Davis veterinarian and epidemiologist, says.
In 2012, the UC-Davis group encountered five dead howler monkeys in Boliva. The team immediately collected samples, ran diagnostics, and discovered a deadly strain of zoonotic yellow fever in the necropsies. That triggered a comprehensive response from the Bolivian government. "Before any human cases could develop, [the Bolivian government] implemented a vaccination campaign, public outreach to talk about the situation so that people knew to avoid mosquitos, and a mosquito-control effort," Johnson says. "There were zero human cases."
With greater surveillance of wildlife diseases, Johnson says, it's possible we find out that the spillover of animal viruses to humans is far more common than we currently realize. Viruses have been evolving without detection in animals for thousands of years. And humans are pushing farther and farther into natural habitats. "It's just a matter of chance that some of those viruses will be able to find the right pathway to emerge in people," she says.
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In 2000, what was then the U.S. General Accounting Office released a critical report on the West Nile outbreak response. "A consensus that the bird and human outbreaks were linked, which was a key to identifying the correct source, took time to develop and was initially dismissed by many involved in the investigation," it read. "Better communication is needed among public-health agencies." Regardless, when New York officials initially misdiagnosed the human outbreak as St. Louis encephalitis, they activated mosquito control and probably saved lives. But what if it wasn't a mosquito disease, and for three weeks CDC was fighting the wrong virus without any success?
Now, CDC has an office for One Health under the umbrella of its National Center for Emerging and Zoonotic Infectious Diseases. Casey Barton Behravesh, a veterinarian working on zoonosis at CDC, says that the agency maintains much greater collaboration and communication with the USDA, universities, and local wildlife agencies to better implement a One Health approach in the United States.