National Geographic: Somewhere beneath the mounds of snow covering Washington, D.C.'s Capitol Hill district, just steps from the Library of Congress, a cluster of tropical mosquitoes capable of carrying Zika and other viruses is holed up, waiting for spring.
Washington, D.C. is well beyond the comfort zone for these mosquitoes-this species can't survive winters north of Alabama and South Carolina. But this colony has somehow hung on for four years, genetic evidence shows, making it the northernmost permanent outpost...