The first transmissions of the virus to vertebrate hosts were mainly in monkeys via mosquitoes, with only an occasional transmission to humans. In fact, before 2007, the Zika virus rarely caused infections in humans. Whereas other flaviviruses, such as the yellow fever, chikungunya, and dengue viruses had become established as human diseases spread by mosquito to human cycle. In 2015, reports detailed the rapid spread of the Zika virus in Latin America and the Caribbean, and as August, 2016, more than 50 countries have now experienced local transmission of the virus.
Typically, mosquitoes carrying the Zika virus will lay their eggs in and near standing water, such as buckets, bowls, flower pots, and vases. The mosquitoes prefer to live both indoors and outdoors near people where they can bite individuals, usually during the daytime. Mosquitoes usually become infected with the Zika virus when they feed on a person already infected with the virus, leading to the infected mosquito spreading to other people through their bites.
