New irrigation systems in arid regions benefit farmers but can increase the local malaria risk for more than a decade — which is longer than previously believed — despite intensive and costly use of insecticides, a new University of Michigan-led study in northwest India concludes.

The study's findings demonstrate the need to include a strong, binding commitment to finance and implement long-term public health and safety programs when building large-scale irrigation projects, according to the researchers.

"In these dry, fragile ecosystems, where increase in water availability from rainfall is the limiting factor for malaria transmission, irrigation infrastructure can drastically alter mosquito population abundance to levels above the threshold needed to maintain malaria transmission," said lead author and U-M graduate student Andres Baeza, who works in the laboratory of Mercedes Pascual in the Department of Ecology and Evolutionary Biology. In addition to Baeza and Pascual, Edward B. Baskerville, a U-M EEB graduate student in the Pascual lab, is one of the coauthors.

"Our results highlight the need for considering health impacts in the long-term planning, assessment and mitigation of projects related to water resources," Baeza said.

The findings were published online Aug. 12, 2013 in the Proceedings of the National Academy of Sciences.

The press release, which was translated to Hindi, is receiving widespread media coverage in India, including with the Asian News International (ANI), South Asia's leading multimedia news agency, and in many other media outlets.

Andres Baeza, Mercedes Pascual, Ed Baskerville.

U-M News Service press release.