A parasitic disease known as bilharzia, or schistosomiasis, has infected more than 200 million people, but scientists in northern Senegal say they have made a breakthrough in treating it.
Bilharzia is carried by small snails that are invisible to the naked eye. It penetrates the skin slowly and destroys internal organs.
The Diama dam, built in 1986 to protect farmland from brackish water, changed the Senegal River's ecosystem, wiped out the snail's only predator, the prawn, and allowed bilharzia to multiply and infect hundreds of thousands of villagers.
Now scientists are reintroducing prawns into the ecosystem in enclosures and are seeing positive results.
Bilharzia is the second most common parasitic disease in the world after malaria.
Al Jazeera's Nicolas Haque reports from Lumpsar, northern Senegal.
Source: Al Jazeera