The disease, first reported in the U.S. in 1999, causes flu-like symptoms that can lead to fatal encephalitis in people with compromised immune systems, like the elderly.

Though not yet proven, scientists believe the West Nile Virus may be spread across the country by infected birds traveling along their migration routes. Mosquitoes that act as a vector carry the virus, and pass it on when feeding on hosts like birds, livestock, other animals and people.

The satellite maps show nation-wide temperatures, distributions of vegetation, bird migration routes and areas pinpointing reported cases. The combined data helps scientists predict disease outbreaks by showing where conditions are right for the insects to thrive and where the disease appears to be spreading.

"The images are derived from satellite data that capture a number of variables that are crucial for detecting whether a habitat is suitable for a vector, like a mosquito that carries West Nile Virus," said David Rogers, the lead author of the study. Rogers is Professor of Ecology at Oxford University in the United Kingdom and a member of the International Research Partnership for Infectious Diseases (INTREPID) group, based at NASA's Goddard Space Flight Center. This paper is the cover story in the most recent issue of Photogrammatic Engineering and Remote Sensing.

"It's not a single variable that tends to determine whether a disease will occur, but rather a combination of variables," Rogers said.

Satellite sensors, like the National Oceanic and Atmospheric Administration's Advanced Very High Resolution Radiometer (AVHRR), provide information on vegetation and peak and aver
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Contact: Cynthia M. O'Carroll
cynthia.m.ocarroll.1@gsfc.nasa.gov
301-614-5563
NASA/Goddard Space Flight Center
5-Feb-2002