Schistosomiasis is an infestation of parasitic flatworms that can cause liver failure, bladder cancer and lasting cognitive impairment. The disease is spread by contact with fresh water contaminated with the parasites. These parasites are released from infected freshwater snails.
The disease is common to parts of the developing world, most commonly in regions in Africa. Prevention of infection includes improving access to clean water and by reducing the number of snails. The main treatment is via a drug called praziquantel (which also acts as a preventative medication.) The drug is not always effective and distribution of the drug to all ‘at risk’ people is costly and poses administrative problems. In addition the drug, like many medications, carries side effects.
As an alternative, researchers have been looking at the use of parasitic prawns. The idea is that the prawns could be added to the water where the infected snails are present and then let nature run its course, where the prawns will eat the snails.
Studies have been undertaken to look into the feasibility of using prawns at Stanford University’s Hopkins Marine Station. The lead researcher, Susanne Sokolow, explains in a research note: “We have to examine the drivers of infection and address transmission and reinfection cycles from both the human and environmental angles if we want to make a long-term impact.”
She also added: “For schistosomiasis control, that means addressing the snails that carry the parasite.”
The test study was carried out in Senegal. This indicated that the reintroduction of native prawns in pens located at strategic river access points resulted in fewer snails and this consequently reduced transmission of schistosome parasites to people.
With the success it is acknowledged that the use of prawns represents an additional measure, but it is not in itself a total solution for combating the parasitic disease. Still, it makes of an interesting headline, as scientist Gibran Mancus (@gibranmancus) tweeted: “Prawns vs Snails in fight against #schistosomiasis”, drawing an allusion to a sci-fir B-movie.
The new research is published in the journal PLOS Neglected Tropical Diseases. The research paper is titled “Global Assessment of Schistosomiasis Control Over the Past Century Shows Targeting the Snail Intermediate Host Works Best.”