NPR 20 Jun 09;
The swine flu outbreak caused a minor panic all over the world, but swine flu's got nothing on the great Rift Valley fever epidemic of 2006. Don't remember that epidemic? That's because it never actually happened. Scientists at NASA and the Department of Agriculture used some high-flying technology to help stop the outbreak.
Scientists can use weather satellites to track things like sea surface temperature and cloud cover, which are good indicators of heavy rainfall. But what does that have to do with Rift Valley fever?
It turns out that rainfall is the key to the disease. Dr. Ken Linthicum, director of the USDA's Center for Medical, Agricultural and Veterinary Entomology, once did fieldwork in east Africa, where the disease is common, and noticed that outbreaks seemed to follow heavy rains.
"We eventually figured out that when it rains to a very large extent … and areas start to flood, that eggs of a certain kind of mosquito start to hatch — and those eggs actually contain the virus," he says.
Dr. Assaf Anyamba tracks climate data at NASA's Goddard Earth Sciences Technology Center. In September 2006, his group predicted heavy rainfall over east Africa. The first human case of fever followed in mid-December, Anyamba says, "so there were four months during which response measures could be taken, including vaccination, mosquito control, public education."
So predicting rainfall helps predict Rift Valley fever outbreaks — and that makes weather satellites a powerful tool in curbing the spread of disease.
