Kevin Flores, 11, remains under a mosquito net while being treated for dengue fever at La Mascota hospital in Managua, Nicaragua, last fall. Inti Ocon/AFP/Getty Images hide caption

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A health official takes a blood sample from a child's finger for a malaria test at a clinic in Bong Ti Lang village on the Thai-Myanmar border. Narong Sangnak/EPA /LANDOV hide caption

itoggle caption Narong Sangnak/EPA /LANDOV

Scientists have discovered four new DEET-like mosquito repellents. Three of them are safe to eat. Courtesy of Pinky Kai/University of California, Riverside hide caption

itoggle caption Courtesy of Pinky Kai/University of California, Riverside

The mosquitoes that feed on people are attracted to over 300 gases and other compounds emitted by human skin. CDC Public Health Image Library hide caption

itoggle caption CDC Public Health Image Library

Many criteria — from blood type to body temperature — can play a role in affecting who attracts mosquitoes. abadonian/iStockphoto.com hide caption

itoggle caption abadonian/iStockphoto.com