Aedes aegypti mosquito

This 2006 photo provided by the Centers for Disease Control and Prevention shows a female Aedes aegypti mosquito in the process of acquiring a blood meal from a human host. On Friday, Jan. 15, 2016, U.S. health officials are telling pregnant women to avoid travel to Latin America and Caribbean countries with outbreaks of a tropical illness linked to birth defects. The Zika virus is spread through mosquito bites from Aedes aegypti and causes only a mild illness in most people. But there’s been mounting evidence linking the virus to a surge of a rare birth defect in Brazil. (James Gathany/Centers for Disease Control and Prevention via AP)