The construction of dams may lead to an increase in the prevalence of

The construction of dams may lead to an increase in the prevalence of malaria, bilharziasis, and onchocerciasis. When a dam is built, it creates an artificial body of water which provides a breeding ground for mosquitoes that transmit malaria. The stagnant water created by the dam may also increase the prevalence of bilharziasis and onchocerciasis, which are caused by parasitic worms that live in freshwater snails and black flies respectively. The increased prevalence of these diseases can be attributed to the increased exposure of people to the parasites, as well as the creation of suitable habitats for their respective vectors.