Incidence of malaria jumps when Amazon forests are cut

Terry Devitt in the University of Wisconsin-Madison News: Establishing a firm link between environmental change and human disease has always been an iffy proposition. Now, however, a team of scientists from the UW–Madison, writing in the current (June 16, 2010) online issue of the CDC journal Emerging Infectious Diseases, presents the most enumerated case to date linking increased incidence of malaria to land-use practices in the Amazon.

The new UW study shows that a 4 percent increase in deforestation can spark a 48 percent jump in the incidence of malaria by creating favored habitat for the mosquito that is the primary carrier of the disease in the region.

The report, which combines detailed information on the incidence of malaria in 54 Brazilian health districts and high-resolution satellite imagery of the extent of logging in the Amazon forest, shows that clearing tropical forest landscapes boosts the incidence of malaria by nearly 50 percent.

“It appears that deforestation is one of the initial ecological factors that can trigger a malaria epidemic,” says Sarah Olson, the lead author of the new report and a postdoctoral fellow at the Nelson Institute, Center for Sustainability and the Global Environment.

The clearing of tropical forests, say Olson and senior author Jonathan Patz of the University of Wisconsin School of Medicine and Public Health, creates conditions that favor malaria’s primary carrier in the Amazon, the mosquito Anopheles darlingi, which transmits the malaria parasite if it draws its blood meals from infected humans….

Map by Barry Carlsen, and the University of Wisconsin-Madison website