Polluted water interferes with drug that combats parasitic scourge

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.