The Coupled Human Health and Environmental Dynamics of Schistosomiasis

Ecological damage caused by human activity can directly influence infectious diseases and human health, but public health campaigns rarely turn to ecological solutions to mitigate infectious disease risk, instead favoring traditional approaches, such as vaccine development or drug treatment. This research project will conduct an experimental investigation of a novel disease-control strategy that incorporates the reintroduction of native prawns to determine whether they might help reduce the prevalence of the snails that host the parasitic worms for that spread schistosomiasis, which is one of the most prevalent parasitic diseases in the world. The project will test the idea that reintroduction of the native prawns as predators will repair the aquatic food web that has been disrupted by dam construction and significantly reduce transmission of schistosomiasis by reducing the prevalence of the parasites. The project will investigate whether and how prawn restoration can be sustainable as well as add an important protein food source and market resource for the people living along the rivers. The project will provide new understanding regarding the complex interaction of human and natural forces to alter patterns of disease transmission. It will enhance knowledge across a range of fields, including trophic ecology, epidemiology, aquaculture, economics, and other social sciences as well as mathematical modeling. The project therefore will provide new insights regarding how biodiversity may be enhanced, how human health may improve, and how native prawn aquaculture may provide benefits to the rural market economy. The transmission of schistosomiasis by parasites from infected snails when people use open water systems for bathing, washing clothes and equipment, tending livestock, farming, or playing has led to the infection of about 220 million people, with an estimated 200,000 deaths per year from schistosomiasis around the world. More than 95 percent of the infections are occur in Africa, and this project will be based in the Senegal River ecosystem of western Africa, but the project will provide both basic and applied insights regarding the dynamics of coupled natural and human systems related to the transmission of diseases in rivers and other water bodies in other locales, including many in the U.S. The project also will provide special education and training opportunities for post-doctoral researchers as well as graduate and undergraduate students.

The project will be conducted by researchers constituting a team drawn from many different disciplines. They will conduct experiments where prawns will be enclosed at water-use sites and disease transmission will be compared with control sites to determine the effect of prawns on snail abundance and on human infection rates. Reintroduction of the prawns will be combined with drug treatments and will be analyzed with economic models, consideration of human behavior, and monitoring of snail and human infections. The information from these components of the project will be synthesized with mathematical models. This project will contribute to the technology of cultivation of the prawns as part of the ecosystem recovery and augmentation of natural snail predators, and prawn-stocking and harvest strategies will be modeled to seek the best approach to maximize public health while also offering a nutritional and market incentive to sustain prawn populations.

Lead Investigator: 
Senegal river system, East Africa