Dams contribute to 1 mn malaria cases in Africa

Over one million people in sub-Saharan Africa contract malaria every year because they live near a large dam, a new study warns.

Construction of an expected 78 major new dams in sub-Saharan Africa over the next few years will lead to an additional 56,000 malaria cases annually, the study predicted.

Encouraged by the increased volume of international aid for water resource development, sub-Saharan Africa has, in recent years, experienced a new era of large dam construction.

"Dams are at the center of much development planning in Africa. While dams clearly bring many benefits--contributing to economic growth, poverty alleviation and food security--adverse malaria impacts need to be addressed or they will undermine the sustainability of Africa's drive for development," said lead study author Solomon Kibret from University of New England in Australia.

The study looked at 1,268 dams in sub-Saharan Africa and compared detailed maps of malaria incidence with the dam sites.

The researchers found that a total of 15 million people live within five kilometres of dam reservoirs and are at risk, and at least 1.1 million malaria cases annually are linked to the presence of the dams.

"Our study showed that the population at risk of malaria around dams is at least four times greater than previously estimated," Kibret said, noting that the authors were conservative in all their analyses.

Malaria is transmitted by the Anopheles mosquito, which needs slow-moving or stagnant water in which to breed.

Dam reservoirs, particularly shallow puddles that often form along shorelines, provide a perfect environment for the insects to multiply.

Thus dam construction can intensify transmission and shift patterns of malaria infection.

The study was published in the Malaria Journal.