"The veterinarian cracked the case, and no one was interested in talking with her because she was a veterinarian," says Laura H. Kahn, a physician and biodefense researcher at Princeton. They should have listened: McNamara identified the first outbreak of West Nile virus in North America.
The West Nile story is important. It is also the story of avian flu, rabies, MERS, HIV, SARS, anthrax, and Ebola. The common thread: These are all illnesses that can be passed from animals to humans. "Often, infectious diseases circulate in animals for a long time before they cause outbreaks in humans," says Wondwossen Gebreyes, the director of Global Health Programs and a professor of molecular epidemiology at Ohio State University. "To prevent disease in humans, we should be able to address what's happening in the animal world and what is happening in the environment," Gebreyes says. Human and animal health are irrevocably linked. As a veterinarian, he says, "I've always been interested in saving human lives."
Seventy-five percent of newly emerging diseases are zoonotic, meaning they can be spread between animals and humans. And they wreak havoc: People fall ill having no natural defenses, and there is often no medicine to fill the gap. It's estimated that between 1997 and 2009, the cost of these diseases amounted to $80 billion worldwide. Every year, there are 2.5 billion cases of zoonotic illnesses in humans, resulting in 2.7 million deaths.
This concept—connecting human medical and veterinary science—is called One Health. And in this framework veterinarians are the sentinels, monitoring the animal kingdom for potential threats to humans. "Once outbreaks originate, like we are seeing with Ebola, often it is too late," Gebreyes says. Prevention of the spread from animals to humans in the first place is key.
Africa has the most to gain from a united medical front. Much of the continent is a hot spot for zoonotic disease—urbanization into biodiverse areas increases the chances for viral spillover. Combine that with poor health systems, unregulated bush meat economies, and poor veterinary systems, and the emergence of new diseases on the continent is not that surprising.
In the case of rabies, a zoonotic disease with an almost 100 percent fatality rate, a One Health approach means working with the local government to mass-vaccinate dogs. If you vaccinate the dogs, you save the people. It means educating the population about what a rabid dog looks like. It means identifying and tracking down the bats that give the rabies to the dogs. It means educating government officials. It also means setting up a health care system to treat humans with the disease. But the overall goal is to establish a system that is able to stop disease before it touches its first human.
If that framework is in place, medical disasters can be averted. "In the future, if they face—God forbid, Ebola or MERS or another major disease—they have a working system to be able to control it," Gebreyes says.