Sea surface temperatures in the tropical South Atlantic Ocean can be used to accurately forecast, by up to four months, malaria epidemics thousands of miles away in northwestern India, a U-M theoretical ecologist and her colleagues have found.

Colder-than-normal July sea surface temperatures in the tropical South Atlantic are linked to both increased monsoon rainfall and malaria epidemics in the arid and semi-arid regions of northwest India, including the vast Thar desert, according to Professor Mercedes Pascual and her colleagues, who summarize their findings in a paper published online March 3, 2013 in the journal Nature Climate Change.

Previous efforts to forecast malaria outbreaks in northwest India have focused largely on monsoon-season rainfall totals as a predictor of the availability of breeding sites for the Anopheles mosquitoes that transmit the disease. That approach provides about a month of lead time before outbreaks occur.

The new forecasting tool should improve public health in the region by increasing warning time, thereby informing decisions about treatment preparedness and other disease-prevention strategies, said Pascual, the Rosemary Grant Collegiate Professor of Ecology and Evolutionary Biology and a Howard Hughes Medical Institute investigator. Planning for indoor insecticide spraying, one widely used control measure, could benefit from the additional lead time, for example.

"The climate link we have uncovered can be used as an indicator of malaria risk," Pascual said. "On the practical side, we hope these findings can be used as part of an early warning system."

Andres Baeza a U-M EEB graduate student was one of Pascual's co-authors on the Nature Climate Change paper.

The paper is being covered extensively in the media, including these articles: Livemint and The Wall Street Journal and The Times of India. Malaria and the Indian monsoon is the featured story on the nature climate change website.

U-M News Service press release

Captions: (top) A female Anopheles stephensi mosquito, which transmits malaria in western India. Credit: Kedar Bhide.(bottom) Mercedes Pascual, Andres Baeza.