Biosecurity

While Brazil Was Eradicating Zika Mosquitoes, America Made Them Into Weapons

The exact moment when one of the world’s most dangerous mosquitoes arrived in the Americas is unknown. It's clear that they came from Africa, and they may have crossed the Atlantic as early as 1495, on some of the first European ships to reach Hispanola. By 1648, when yellow fever broke out on the Yucatan peninsula, Aedes aegypti had definitely arrived.

Their behavior upon arrival, though, was unusual. Most of the world's 3,500-plus mosquito species are innocent of lust for human blood but on these long journeys across the sea, the mosquitoes that survived were the ones willing to bite humans. Female mosquitos females need blood to lay eggs. En route to America, A. aegyptilearned to love ours.

Now, A. aegypti is one of our boon companions, an unwanted, constant domestic creature that house-broke itself. By the 1930s, this species was found in every country in South and Central America, throughout the Caribbean and across the American southeast.