Polluted water interferes with drug that combats parasitic scourge

Arsenic contamination fuels resistance to treatment for leishmaniasis

Regular exposure to arsenic in drinking water could make one drug that kills the Leishmania parasite, shown here in a bone marrow cell, less effective.

CDC/Dr. L.L. Moore, Jr.

Water contaminated with arsenic may block the effectiveness of a drug doctors use to treat leishmaniasis, a deadly parasitic scourge spread by sand flies.

Alan Fairlamb of the University of Dundee in Scotland and colleagues noticed resistance to antimony-based treatments in regions of India where people lived near arsenic-laced water. In the lab, the scientists gave mice drinking water contaminated with arsenic and then infected the rodents with Leishmania parasites. The scientists then moved the parasites into a second group of mice also given water with arsenic. Some of those mice also got Pentostam, an antimony-based treatment. Parasites in the treated mice were resistant to the drug.

The results, which appear October 28 in the Proceedings of the National Academy of Sciences, suggest that arsenic contamination could contribute to ineffectiveness of one of only four drugs doctors currently have to treat leishmaniasis.

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.

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