The Zika virus currently spreading throughout the Americas is the latest of several dangerous pathogens communicated from person to person by a mosquito called Aedes aegypti. Other species from the genus Aedes might be competent vectors (i.e. transmitters or carriers) as well, but so far the evidence fingers aegypti as the main culprit.
Before 1492, Aedes aegypti did not live in the Americas. It came from West Africa as part of the Columbian Exchange, probably in the context of the transatlantic slave trade. It gradually colonized those parts of the Americas that suited its feeding and breeding requirements, and for centuries served as the primary vector for yellow fever and dengue, viruses that are cousins of Zika.
Read the rest of Prof. McNeill's article at AHA Today.
John McNeill is the author of, most recently, Mosquito Empires: Ecology and War in the Greater Caribbean, 1620-1914 (2010).