Stanford researchers in Senegal have found a natural alternative way to combat freshwater parasite schistosomiasis. Their recent study suggests that by maintaining a steady population of prawns in the major river access points, the population of the parasite that reaches humans is safely reduced, without the need for access to high-cost treatments.

Worldwide, about 230 million people are infected with and 800 million people are at risk of being infected by schistosomiasis. The parasite, hosted in both humans and snails, is known to cause anemia, growth stunts, infertility, liver failure, bladder failure and lasting cognitive impairment. Although drug treatment for schistosomiasis is available, high treatment cost, lack of supply, and potential re-infection does not make the drug effective.

According to their study, which was published in the Proceedings of the National Academy of Science, freshwater prawns feed on the snails that host the parasites but cannot carry the disease themselves. Essentially, the prawns could “synergize with local efforts in the developing world to fight parasitic disease and to foster new aquaculture-based industries,” said Susanne Sokolow, a Woods-affiliated research associate at Stanford’s Hopkins Marine station.

The researchers found that over the course of 18 months when the river access point near a village was stocked with prawns the infected snail population decreased by 80 percent. Additionally there was 50 percent decrease in parasitic eggs found in the urine of the village where the prawns were released. Researchers suggested that stocking rivers with prawns and drug treatments should be used together for extremely effective disease control in high transmission areas. Along with stocking the river with prawns, researchers suggest that making dam-bypassing systems could promote the reproduction of prawns in the rivers so there can be a steady population of prawns for both food and disease control.

Contact Citlalli Contreras at 17ccontreras ‘at’ castilleja.org.