SAN FRANCISCO, July 18 (Xinhua) — Widespread use of pesticides and other agrochemicals can speed the transmission of schistosomiasis and upset the ecological balance in aquatic environments, according to a study released by the University of California, Berkeley (UC Berkeley) on Friday.
The study, published in the July edition of the journal Lancet Planetary Health, found that agrochemicals can increase the transmission of the schistosome worm by directly affecting the survival of the waterborne parasite itself. It does this by decimating aquatic predators that feed on the snails that carry the parasite and by altering the composition of algae in the water, which provides a major food source for snails.
After combing through nearly 1,000 studies, the research team identified 144 experiments that provided data connecting agrochemical concentrations to components of the schistosome life cycle.
They then incorporated this data into a mathematical model that captures the transmission dynamics of the parasite.
The researchers found that even low concentrations of common pesticides can increase rates of transmission and interfere with efforts to control schistosomiasis.
“We were shocked by the strength of evidence we found also linking agrochemical pollution to the amplification of schistosomiasis transmission,” said UC Berkeley’s Christopher Hoover, a doctoral student in environmental health sciences and lead author of the study.
“If we can devise ways to maintain the agricultural benefits of these chemicals while limiting their overuse in schistosomiasis-endemic areas, we could prevent additional harm to public health within communities that already experience a high and unacceptable burden of disease,” he added.
“Environmental pollutants can increase our exposure and susceptibility to infectious diseases,” said Justin Remais, chair of the Division of Environmental Health Sciences at the UC Berkeley School of Public Health and co-author of the study.
“Research has shown that reducing pollution is an important way to protect populations from infectious diseases,” Remais said.
Schistosomiasis, also known as snail fever, is caused by parasitic worms that develop and multiply inside freshwater snails and is transmitted through contact with contaminated water.
The infection, which can trigger lifelong liver and kidney damage, affects hundreds of millions of people every year and is second only to malaria among parasitic diseases in terms of its global impact on human health, according to the study. Enditem