Zika is a virus. It is spread by mosquitoes. It was first discovered in the Zika Forest of Uganda in 1947. For many decades, it was thought to be a rare cause of infection. It was found only in small areas of Africa, the Yap Islands in the Pacific, and Easter Island in Chile. But in April 2015, it was found in Brazil. It later spread to many countries in South America and Central America, the Caribbean, and Mexico.
A number of cases have also been found in the U.S. Most of these people got the virus while visiting other parts of the world where mosquitoes are spreading it. Rarely, the virus has been spread by mosquitoes in the U.S.