Mosquitoes like this one can carry the virus that causes dengue fever, which may become a bigger problem in some regions as biodiversity is lost. James Gathany/CDC Public Health Image Library hide caption

itoggle caption James Gathany/CDC Public Health Image Library

The Lone Star tick, common to the southeastern U.S., is responsible for inducing meat allergies in some people, scientists say. CDC Public Health Image Library hide caption

itoggle caption CDC Public Health Image Library

Last year, Tom Mather caught 15,000 deer ticks in the woods of southern Rhode Island. "People really need to become tick literate," the University of Rhode Island researcher says. Brian Mullen for NPR hide caption

itoggle caption Brian Mullen for NPR

Lyme disease is spread by deer ticks like this one. A study finds that some people can be reinfected many times with the bacteria that cause the disease. Lauree Feldman/Getty Creative Images hide caption

itoggle caption Lauree Feldman/Getty Creative Images