Zika is a flavivirus related to dengue virus at the sequence level. It is enveloped with a 10.7-kb, positivesense RNA genome. The virus was isolated from a febrile rhesus macaque in 1947 during yellow fever surveillance studies in the canopy of the Zika forest in Uganda. It is path pathogenic and neurotropic in animal models. Zika was subsequently recovered from Aeds africanus mosquitoes.