Zika virus is another flavirus that originated from Africa.  Although the same mosquitoes can transmit dengue and chikungunya are known to transmit Zika, there are differences in the symptoms of the virus.  Although one in four individuals infected with Zika will experience symptoms, the negative effects are much greater than those of dengue and chikungunya.  Zika has been linked to microcephaly and other birth defects in babies and neurological impacts such as Guillain-Barré syndrome, but it can also be transmitted through sexual contact.

Zika was the cause of an outbreak of disease in the Yap Islands of Micronesia in 2007, followed by an extensive epidemic throughout the South Pacific islands. Cases were first noted in Brazil during May 2015, and by January of 2016 an estimated 1.5 million Brazilian cases had occurred. At the same time at least 22 countries in the Americas had reported Zika cases in their residents, but Zika transmission by mosquitoes had not been detected within the USA.  By the end of 2016, more than 1,100 Florida residents had aquired Zika infections while traveling outside mainland USA, 292 of the cases were pregnant females.  At the same time, 285 additional Zika cases were not imported but belived to be the result of exposure to infected mosquitoes in Miami.  This constituted the first US example of a local transmission cycle arising from frequent imported infections