Shrimpocalypse: How reintroducing prawns could save humans from deadly disease

It's a familiar ecology story: human dam-building activities in the 1980s wiped out a species of prawn in the Senegal River by blocking its migration routes. But this one takes an unexpected turn into human health. A pilot study suggests that reintroducing the prawns to the river wouldn’t be good just for biodiversity—it could also help to control a parasite that causes disease in humans.

The research, published today in PNAS, found that when river prawns were reintroduced to a village’s water supply, the number of parasite-carrying water snails dropped substantially compared to a village with no prawns. The drop had a significant impact on the disease levels of the villagers.

No-one wants spiny eggs in their bladder

The construction of the Diama Dam in 1986 was followed by a massive epidemic of a nasty disease called schistosomiasis, occurring in the villages along the river. Schistosomiasis, also known as bilharzia, is a waterborne disease with a life cycle straight out of a horror movie: after the larvae penetrate human skin, they go on to mature in the intestine or bladder. The sharp, spiny eggs laid by the females—between 350 and 2,200 per day—are able to penetrate tissues, allowing them to travel through the body.