Project Lead(s): Nicolas Jouanard
Schistosomiasis is a leading neglected tropical disease, with 1.9 million people infected in Senegal and another 4.2 million at high risk – 46% of the population.
An epidemic broke out in 1989 after the opening of a multinational dam system on the Senegal River, which dramatically increased the habitat for the vectors of schistosomiasis (aquatic snails) and decimated the entire population of the Macrobrachium vollenhovenii, a migratory river prawn that is the natural predator of the aquatic snails.
The project team assessed whether the restoration of indigenous river prawns to village water points in the Senegal River Basin could reduce the transmission of schistosomiasis to humans.
Simultaneously, a prawn hatchery was built and managed in partnership with the Senegalese government, and will produce post-larvae prawns that will serve to reintroduce the prawns, and to serve as a supply for prawn aquaculture and polyculture farms throughout Northern Senegal.
Phase I of the project resulted in the development of a successful reproductive protocol for breeding prawns in captivity.
The team completed a larval reproduction cycle in 54 days, with an output of 60 post-larvae per litre of water, with a survival rate of 44% in the first generation of prawns.
In terms of schistosomiasis control, the total number of aquatic snails at test sites was, on average, 40% less than at control sites.
One year after the Phase I trial, the speed of re-infection in the test population was half of that of the control group.
After 18 months, there was a clear drop in schistosomiasis prevalence, with prawn-protected sites having 40% lower prevalence than the control group and 38% lower prevalence than baseline.
The project received scale-up funding, which will be run as a partnership between Grand Challenges Canada, the Bill & Melinda Gates Foundation and the Government of Senegal.
The funds will be used for human infection control tests, the prawn production business and to develop a hatchery.