How ocean temperatures can predict a malaria epidemic half a world away

An Anopheles stephensi mosquito, which can carry the malaria parasite.

CDC

When you think of monsoons, floods (like those in Pakistan in 2010) might be the first thing to come to mind. But in some areas, malaria epidemics can follow the monsoon rains. Malaria is caused by the Plasmodium protozoa carried by mosquitoes. These mosquitoes hatch from standing water. In some of the drier parts of India, the conditions necessary for malaria are only present during the monsoon season—the wetter the year, the greater the risk.

Being able to forecast a likely malaria epidemic far enough ahead of time to mobilize help for those regions could save a lot of lives. The best we can do at present is watch the rainfall totals. Recognizing particularly wet weather gives about a month’s notice before the malaria cases will start to climb. A new paper in Nature Climate Change seeks to increase that lead time by using sea surface temperatures in the South Atlantic to predict the rainfall before it happens.

The researchers looked for correlations between malaria in India and sea surface temperatures around the globe, which affect atmospheric circulation and weather patterns. The tightest correlation was between malaria in the drier regions of northwest India and temperatures in the South Atlantic.