Schistosomiasis is a parasitic disease that causes organ damage and death, affecting more than 250 million people worldwide in 2021, according to the World Health Organization.
The disease is transmitted by freshwater snails that harbor the worms that infect humans. The snails thrive in water with plants and algae that grow in areas of agricultural runoff containing fertilizer.
People become infected during routine activities in infested water, such as bathing, washing, fishing, and farming.
A recent study by researchers from the University of Notre Dame, published in Nature, found that removing invasive vegetation at water access points in and around several Senegalese villages reduced rates of schistosomiasis by almost a third.
Moreover, the removed vegetation can also be used for compost and livestock feed, creating a win-win solution for public health and agriculture.
How removing vegetation reduces schistosomiasis
LUIS ROBAYO/AFP via Getty Images
The researchers spent seven years on the project, with research conducted in 23 villages and clinical trials in 16, as per Phys.org.
They found that villages with substantial fertilizer use had more submerged vegetation. These villages had more snails and a higher prevalence of schistosomiasis infection in children.
The researchers hypothesized that removing vegetation could reduce infections by decreasing the habitat and food sources for the snails, as well as providing greater access to the open water that is crucial for daily activities and recreation.
So, they conducted a three-year randomized controlled trial in 16 communities, where children were treated for their infections and the researchers removed more than 400 metric tons of vegetation in water access points from half the villages.
These removals resulted in a decline in snail abundance as well as schistosomiasis infection rates being nearly a third lower than those observed in control villages.
The researchers also found that removing vegetation reduced the turbidity and improved the quality of the water.
The researchers also tried to profitably improve food production by partly closing the nutrient loop, returning nutrients captured in the removed plants back to agriculture, as per ScienceDaily.
They found that the removed vegetation could be used for compost and livestock feed, which could enhance soil fertility and crop yields, as well as provide income and food security for the villagers.
The researchers estimated that the value of the compost and livestock feed generated from the removed vegetation could exceed the cost of labor and equipment for the removals.
They also calculated that the removals could prevent about 1,500 disability-adjusted life years (DALYs) per year, which measures the burden of disease on human health. This translates to an economic benefit of about $3 million per year.
The researchers concluded that removing vegetation at water access points is a cost-effective and sustainable intervention that can reduce schistosomiasis transmission and improve agricultural productivity.
They suggested that this approach could be scaled up and integrated with other control measures, such as mass drug administration, snail control, sanitation improvement, and health education.
