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Schistosomiasis And Pesticides
by University of California - Berkeley
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| A man waters his crops near Lampsar, a community about 12 miles from the city of Saint Louis in the lower Senegal River Basin in West Africa. A new study led by researchers at the University of California, Berkeley finds that use of some agricultural pesticides can speed the transmission of the debilitating disease schistosomiasis, while also upsetting the ecological balances in aquatic environments that prevent infections. |
Widespread use of pesticides and other agrochemicals can
speed the transmission of the debilitating disease schistosomiasis, while also
upsetting the ecological balances in aquatic environments that prevent
infections, finds a new study led by researchers at the University of
California, Berkeley.
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.
The study, published in the journal Lancet
Planetary Health, found that agrochemicals can increase the transmission of
the schistosome worm in myriad ways: by directly affecting the survival of the
waterborne parasite itself, 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.
"We were shocked by the strength of evidence we found
also linking agrochemical pollution to the amplification of schistosomiasis
transmission."
The findings come as the connections between environment
and infectious disease have been laid bare by the COVID-19 pandemic, which is
caused by an emerging pathogen thought to be linked to wildlife.
"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 senior author of the study.
"From dioxins decreasing resistance to influenza virus, to
air pollutants increasing COVID-19 mortality, to arsenic impacting lower
respiratory tract and enteric infections — research has shown that
reducing pollution is an important way to protect populations from infectious diseases."
After combing through nearly 1,000 studies gathered in a
systematic literature review, the research team identified 144 experiments that
provided data connecting agrochemical concentrations to components of the
schistosome life cycle.
They then incorporated these data into a mathematical model that
captures the transmission dynamics of the parasite.
The model simulates concentrations of common agrochemicals
following their application to agricultural fields and
estimates the resulting impacts on infections in the nearby human population.
The researchers found that even low concentrations of
common pesticides — including atrazine, glyphosate and chlorpyrifos — can
increase rates of transmission and interfere with efforts to control
schistosomiasis.
In the study communities in the Senegal River Basin in West
Africa, the excess burden of disease attributable to agrochemical pollution was
on par with disease caused by lead exposure, high sodium diets and low physical
activity.
"We need to develop policies that protect public
health by limiting the amplification of schistosomiasis transmission by
agrochemical pollution," Hoover said.
"More than 90% of schistosomiasis cases occur in areas
of sub-Saharan Africa, where agrochemical use is expanding. 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."
The University of California at Berkeley (UC-Berkeley) is the
flagship of the University of California system. Berkeley was established in
1868 as the first of the public universities of the eventual 10 campuses. UC
Berkeley has an acclaimed physics department. It is the manager of the Los
Alamos National Laboratory, the Lawrence Livermore National Laboratory. Nearly
25,000 undergraduate and graduate students undertake UC Berkeley's 200 programs
and individual post graduate degree programs. UC Berkeley has a solid $2
billion endowment with the ability to attract grants from the National Science
Foundation and other foundations. UC Berkeley has numerous Nobel Laureates with
ties to its university and Medal of Science recipients.world.https://medicalxpress.com/news/2020-07-pesticides-deadly-waterborne-pathogens.html
