ATLANTA — The world’s reliance on cutting-edge medical innovations may be replaced with new techniques involving one of the world’s oldest and most primitive life forms- the freshwater crayfish. Recent development efforts in West Africa’s Senegal River basin are lending credibility to the practice of using various species of African river prawn to prevent the spread of schistosomiasis, one of the world’s deadliest tropical diseases.
Schistosomiasis – also known as ‘snail fever’ – is a waterborne parasitic disease that infects over 240 million people worldwide, and kills over 280,000 individuals annually. It is transmitted to humans through contact with contaminated freshwater snails. The debilitating effects and chronic symptoms associated with the infection devastate impoverished populations in developing countries and obstruct development efforts.
Until recently, the snail vector population of West Africa had been controlled naturally by the presence of their natural predator, the African river prawn. The biological predatory cycle that kept the schistosomiasis epidemic at bay was interrupted in the 1980s by the construction of hydroelectric dams along the Senegal River basin. Now, in an effort to restore the biological balance and reduce rates of schistosomiasis, Project Crevette is working to reintroduce African crayfish into the ecosystem from which they originated, and cut back the number of snails who transmit the deadly disease.
Founded in 2011, Project Crevette has been wildly successful in their attempts to halt the spread of schistosomiasis. Their pilot project in Lampsar, Senegal succeeded in reducing infection rates by 80 percent only six months after restoring the prawn population of the local ecosystem, and today the section of river that borders Lampsar is confirmed to be completely free of any schistosomiasis-transmitting snails.
The crayfish also serve purposes beyond preventing disease. The creation of prawn hatcheries along the Senegal River basin provides affected communities with an incredibly valuable economic resource; African giant river prawns sell for five times the price of fish in the local marketplace and provide an invaluable addition of protein into the diets of nutritionally deprived rural communities.
Traditional methods of treating schistosomiasis prove problematic with respect to reducing the impact of the disease; while the drug praziquantel, the most commonly utilized schistosomiasis treatment, is both cheap and effective (it costs less than 50 cents to treat a patient for a full year), international funding for the distribution of the medication lacks the backing needed to consistently reach affected populations. Since there is no proven vaccine or treatment that prevents reinfection of schistosomiasis, nearly all individuals who receive praziquantel eventually experience a resurgence of symptoms.
The work of Project Crevette provides new hope in the fight against schistosomiasis. Combined with established control efforts – distribution of praziquantel, educational campaign promotion, and improved access to clean water and sanitation facilities – the reintroduction of African river prawns is proving to be a lifesaving intervention in the fight against one of the most destructive diseases in the world today.
– Brady Mott
Sources: Project Crevette, Imperial College London, BBC
Photo: 20 by 20