Irrigation in arid regions can increase malaria risk for a decade


By Jim Erickson
Dec 10, 2013 Bookmark and Share

An Anopheles stephensi mosquito, one of the species known to transmit malaria in northwest India. This mosquito is obtaining a blood meal from its human host through its proboscis. Image credit: CDC, Jim Gathany.

An Anopheles stephensi mosquito, one of the species known to transmit malaria in northwest India. This mosquito is obtaining a blood meal from its human host through its proboscis. Image credit: CDC, Jim Gathany.

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 recent U-M graduate Andres Baeza, who worked in the laboratory of Professor Mercedes Pascual. Baeza is beginning a postdoctoral fellow at the University of Maryland, Baltimore. In addition to Baeza and Pascual, Edward B. Baskerville, a recent graduate from the Pascual lab, is one of the coauthors. Baskerville is currently working on various research projects in the Pascual lab and with the lab of Sarah Cobey at the University of Chicago (Cobey is also a Pascual graduate).

"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 researchers studied changes in land use and malaria risk around a large irrigation project under construction in a semi-arid area in the northeast part of the Indian state of Gujarat. Water from the project is eventually expected to cover more than 47 million acres and will benefit about a million farmers.

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, received 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.

Michigan News press release