LONDON (Thomson Reuters Foundation) - The number of Africans at risk of malaria who live near dams will nearly double to 25 million by 2080 as areas where the disease is not currently present will become transmission zones due to climate change, researchers said on Monday.

Workers look for abnormal holes in mosquito netting at the A to Z Textile Mills factory producing insecticide-treated bednets in Arusha, Tanzania, May 10, 2016. REUTERS/Katy Migiro

Without prevention measures, the number of malaria cases associated with dams could triple to nearly 3 million a year over the same period, they said in a study published in Malaria Journal.

“While dams clearly bring many benefits ... the role of climate change on malaria around dams will fundamentally alter the current impact,” said Solomon Kibret of the University of California and the paper’s lead author.

“Accurately predicting the impacts of such changes is critical to planning effective disease control,” he said in a statement.

Malaria is transmitted by mosquitoes, which breed in stagnant water such as shallow puddles along dam shorelines.

The disease kills around 400,000 people a year, the vast majority of them children and babies in sub-Saharan Africa. World Health Organization (WHO) data show there are around 200 million malaria cases a year.

More than half of dams that are located in malaria-free areas that will turn into transmission zones as temperatures rise due to climate change are mainly found in the east African highlands and southern Africa, the study said.

In those regions the impact of dams may be especially harsh because of lower immunity among people who have not had to deal with the disease before, it said.

Africa is experiencing a surge in dam construction so as to generate electricity, irrigate crops and store water for fast-growing populations.

Dams should be designed and managed to minimize the breeding of mosquitoes, such as periodically drying out shoreline areas or introducing fish that eat mosquito larva in reservoirs, said the study.