University of California, Berkeley: Pesticides accelerate the spread of deadly waterborne pathogens

Kara Manke

Widespread use of pesticides and other pesticides accelerates the transmission of debilitating schistosomiasis while disrupting the ecological balance of the aquatic environment that prevents infection, led by UC Berkeley researchers Discovered in a new study.

Schistosomiasis, also known as snail fever, is caused by parasites that grow and multiply inside freshwater snails and are transmitted by contact with contaminated water. Infectious diseases, which can cause lifelong liver and kidney damage, affect hundreds of millions of people each year and are second only to malaria in parasitic diseases in terms of their global impact on human health. Second place.

Research published in the July edition of the journal Lancet planetary healthFound that pesticides can increase myriad schistosome worm infections innumerably: directly affect the survival of the water-borne parasite itself, destroy aquatic predators that eat snails carrying parasites, underwater Changing the composition of algae provides a primary food source for snails.

“We know that dam construction and irrigation expansion increase the transmission of schistosomiasis in low-income environments by disrupting freshwater ecosystems,” said UC, a PhD student in environmental health science and lead author of the study. Said Christopher Hoover of Berkeley. “I was shocked by the strong evidence that pesticide contamination was linked to the amplification of schistosomiasis infections.”

The discovery occurs when the relationship between environment and infectious disease is revealed by the COVID-19 pandemic. It is caused by an emerging pathogen believed to be associated with wildlife.

“Environmental pollutants can increase our exposure and susceptibility to infectious diseases,” said Justin Remais, chair of the Environmental Health Sciences Division at the University of California, Berkeley School of Public Health and lead author of the study. It was “From dioxins, which reduce resistance to influenza viruses, to air pollutants, which increase COVID-19 mortality, to arsenic, which affects lower respiratory and intestinal infections, reducing pollution protects the population from infectious diseases.” Studies have shown it to be an important method.”

After exploring about 1,000 studies collected in a systematic literature review, the research team identified 144 experiments that provided data relating pesticide concentrations to schistosoma life cycle components. We then incorporated these data into a mathematical model that captures parasite transmission dynamics. The model simulates the concentration of common pesticides following agricultural applications and estimates the impact on infections in the neighboring population.

Researchers have found that even low concentrations of common pesticides such as atrazine, glyphosate, and chlorpyrifos can increase infection rates and prevent efforts to control schistosomiasis. Amplification of parasitic infections by pesticides was not important. In the research community of the Senegal River basin in West Africa, the overburden of disease due to pesticide contamination was comparable to that caused by lead exposure, high sodium diet, and low physical activity.

“We need to develop policies that protect public health by limiting the spread of schistosomiasis infections due to pesticide contamination,” Hoover said. “More than 90% of cases of schistosomiasis occur in sub-Saharan Africa areas where the use of pesticides is widespread. Limiting their overuse in areas where schistosomiasis is widespread However, if we could devise ways to sustain the agricultural benefits of these chemicals, they would have an additional harm to public health in communities already experiencing an unacceptably high burden of illness.”

The research team included Samantha L Ramshrug and Jason R. Ruhr from the University of Notre Dame. Luke Struger from the University of California, Berkeley. Aratiarakara at the Royal Melbourne Institute of Technology. Former Manoj Gambhir of Monash University in Melbourne, Australia. Giulio A. De Leo and Susanne H. Sokolow of Stanford University.

This work was supported by a grant from the National Institute of Allergy and Infectious Diseases, the National Science Foundation, and the Fogerty International Center for the National Institutes of Health.

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This press release University of California, Berkeley.. The views expressed here are those of the author himself.