First Response

By Kathy Svitil, Illustrations by Josh Cochran

Published Jan 1, 2008 8:00 AM

The Bug Hunters

One of the hottest young foot soldiers in the war on disease is Nathan Wolfe, a professor of epidemiology in the School of Public Health and a new arrival from Johns Hopkins University. This is no ivory-towered academic. This is the very model of the scientist as action hero.

The adventurous epidemiologist worked with hunters in Cameroon, out in the jungle gathering scientific evidence, talking with tribal elders and trading like a native — one of his academic mentors called Wolfe a "ferocious bargainer" in an April 2007 profile in The Scientist. And the curly-haired scientist's Web site homepage opens with a huge headline declaring, "The HIV pandemic could have been averted. Our work may prevent the next one."

In May 2007, Wolfe, who received his doctorate in 1998 from Harvard University, teamed with UCLA Professor of Medicine and Infectious Diseases Claire Panosian Dunavan and iconic UCLA Geography Professor Jared Diamond — the Pulitzer Prize-winning author of Guns, Germs, and Steel, among other notable books — to report the first systematic analysis of the origins for all major human diseases. Their report, which also described the five-step process by which viruses jump from animals to humans and then become established, showed that the majority of infectious diseases for which origins could be identified had animal origins.

"The only real choices are either it comes from animals or it comes from your ancestors," says Wolfe. "You would really expect some of these diseases to be ancient diseases. Some of them are quite old, but all of them at some point crossed over from an animal to humans or our ancestors."

The finding is helpful in telling us about how to actually forecast disease-related threats before they appear, an early-warning approach that so far usually is reserved for physical or climatic phenomena (think of tornado warnings or all the global warming predictions). Wolfe wants to establish the first global surveillance network for the transmission of new viruses. Two years ago, he was awarded a Director's Pioneer Award from the National Institutes of Health to do just that.

Researchers have dubbed this "viral forecasting," in which the patterns associated with the previous emergence of viral diseases — say, HIV or influenza — are used to predict the emergence of future diseases. And, most importantly, to prevent them.

"Let's say that there are going to be 50 new diseases over the next 50 years," Wolfe explains. "If you hit [just] one or two of those, it will justify [the effort] because of the benefits you get from prevention ... and it's not just individual medicine. It's also population-level medicine."

Nathan Wolfe

Wolfe's surveillance network, for example, is coordinating with researchers in a number of other countries that are known to be hot spots for emerging disease. His first site is in Cameroon, where he and his collaborators are studying retroviruses such as HIV, pox viruses such as smallpox, and filoviruses like Ebola, along with plasmodium (the single-celled parasites that cause malaria), bacteria and a number of other disease-causing organisms. The network also includes China, home to countless wild animal markets where the close proximity of animal hosts and humans increases the chance of diseases jumping species, and Malaysian Borneo, where Wolfe did his doctoral research.

Once samples of disease-causing organisms are obtained in the field in these countries and at sites in places like Madagascar, Laos and New Guinea, the data is collected in a kind of viral museum in Wolfe's lab and analyzed to reveal underlying patterns about the nature of the organisms.

Wolfe isn't the only Bruin out in the field, or the jungle, helping to keep the home front safe. In the Democratic Republic of Congo, the disease surveillance program led by epidemiologist Anne Rimoin M.P.H. '96, an assistant professor in the School of Public Health, is investigating cases of monkeypox and other zoonotic agents (agents that can be transmitted from animals to humans).

Rimoin's undergraduate degree was in African history, which she admits had a lot to do with her scientific journey to search for and defend against emerging diseases in Africa. The scientist also worked in Africa while in the Peace Corps and for the World Health Organization. Among her accomplishments — training Peace Corps volunteers to do disease surveillance in the field. She describes the Democratic Republic of Congo as the "cradle of emerging disease."

"Monkeypox is the perfect example of a viral zoonotic emerging infection," Rimoin explains. "It is clinically indistinguishable from smallpox, so no one really knows when it first appeared." Once smallpox was officially eradicated in 1979, however, and blanket immunization for the disease ceased, the previously rare monkeypox — which also can be prevented with the smallpox vaccination — began causing larger, more severe outbreaks.

The disease is becoming increasingly prevalent for a number of reasons: the absence of smallpox vaccinations among individuals under age 30; high rates of HIV infection and its accompanying immune system suppression; an increasing dependence on bush meat (monkey meat); and urbanization. "That's why a disease like monkeypox is not only interesting, but important in many ways. It's a harbinger of what happens when you have a whole population that is susceptible to a disease-causing organism," Rimoin says.