Robbie Ali

“HIV. SARS. West Nile. Mad Cow. More to come…”

So began a chilling presentation on environmental change and emerging infectious diseases by Pitt Professor Robbie Ali during an Oct. 22 panel discussion, “The Lab: Emerging Issues,” at the Society for Environmental Journalists conference in Pittsburgh.

Emerging infectious diseases are always an attention-getting topic, said Ali, director of Pitt’s Center for Healthy Environments and Communities and assistant professor in the Department of Behavioral and Community Health Sciences and the Department of Environmental and Occupational Health in Pitt’s Graduate School of Public Health (GSPH). Because of “the animals, the weird symptoms, and the fear factor,” he said, “yellow journalism is in its heyday here.”

A number of diseases have crossed over into humans from animals—HIV originally came from other primates, for example—and Ali predicted there will be many more. Despite the label “emerging diseases,” it’s often true that diseases exist prior to the arrival of humans. “We’re going to places where diseases have already been,” he said.

In some cases, a native population has long suffered from a disease before it gains widespread public attention. “Sometimes they say a disease is ‘emerging’ when a White person gets it,” he said pointedly.

Environmental change can contribute to a disease’s emergence. Ali cited a recent example: the Nipah virus. In 1999, Malaysia was experiencing a drought, which led to changes in the way the forests fruited. Fruit bats, which normally fed in the forests, started to invade pig farms—which were being built ever closer to the forests. As a result, the virus, which lived in the fruit bats, was transferred to pigs and then to their human owners, in whom it caused sudden death. One hundred people died, and Malaysia destroyed nearly a million pigs to keep the virus from spreading further.

But emerging diseases aren’t confined to exotic locales. Ali emphasized the fragility of human-built habitats. In our own urban, postindustrial ’Burgh, for example, it’s easy to forget what used to live here. “I grew up in Pittsburgh, and it took me a really long time to realize it was part of the eastern forest of the United States,” he said. “A squirrel used to be able to walk from the Atlantic to the Mississippi. We built a city on this pre-existing environment.”

In the United States, West Nile virus is on the rise as a result of environmental change. Disappearing wetlands have changed the migratory patterns of birds, which host the disease and are often used as indicators of its presence in a region. (Ali quoted Shakespeare: “There is a special providence in the fall of a sparrow.”) He pointed out that people can minimize the risk of West Nile by modifying their personal environments—for example, making sure that no standing water collects around their homes for virus-carrying mosquitoes to breed in.

A CNN reporter asked Ali if the United States had the medications to cope with emerging diseases. “Often, no,” he replied. “I think there’s a strong likelihood that there will be new diseases, a whole new range of problems. Some will be solvable, some not, and that’s the fear. I think what we can do is to be alert and try to respond quickly.” He compared emerging diseases to terrorism: “Typically, you have no idea where the attack is going to come from.

“That this is a science in its infancy is shown by the fact that it’s impossible to predict which outbreak will happen next,” he added.

Last month, GSPH hosted a workshop titled “Environmental Causes of Emerging and Re-emerging Infections” sponsored by the United Nations Environmental Program (UNEP) Scientific Committee on Problems of the Environment; Dean Bernard Goldstein was among its main participants. There, Ali and Douglas J. Perkins, Pitt assistant professor in the Department of Infectious Diseases and Microbiology, helped to write a report on environmental change and emerging infectious diseases. That document will be shared with environmental ministers at UNEP’s annual meeting in Nairobi.

Ali noted that China won a tough public health battle in the 1950s when it practically eliminated schistosomiasis, a liver and bladder disease caused by a parasite that spends part of its life cycle in aquatic snails and enters the human body through the skin. China accomplished this feat through huge public works projects, draining areas that served as snail breeding places. But Ali suggested that would be impractical in the United States. “When you have a Communist government, you can tell everybody what to do,” he noted.

So how ought the rest of the world deal with these diseases? Ali cited the recommendations of the UNEP workshop: more cooperation between different sectors—such as industry and public health—and different nations; considering the health and environmental impacts of projects; developing strategies for environmental control of infectious diseases; linking health and environmental surveillance systems; strengthening public health responses; and devoting more human resources and research to this problem. “We need more people working in this area, and we need more information,” he said.

Ali has been an emergency physician for 14 years and has worked in medicine and public health in Antarctica, Madagascar, and Rwanda, among many other places. He collaborates with the Nature Conservancy and the government of Indonesia on a health initiative for rainforest-dwelling peoples, part of an effort to protect endangered orangutans in Borneo.

Summing up the threat of diseases emerging from environmental change, Ali quoted Sierra Club founder John Muir: “When we try to pick out anything by itself, we find it hitched to everything else in the Universe.”

For more information on emerging infectious diseases, Ali suggested the following Web sites:

• Centers for Disease Control and Prevention: Emerging Infectious Diseases (cdc.gov/ncidod/diseases/eid) and

• World Health Organization: Communicable Disease Surveillance & Response (who.int/csr).