How mosquitoes evolved to be attracted to humans, and what that means for the future

A wild female Aedes aegypti mosquito rests in a bucket in Thies, Senegal. The mosquitoes' evolution to bite humans is a by-product of their dependency on breeding in areas close to human water storage containers.

(CNN)Not all mosquitoes are created equal, even if it feels that way when they bite you.

There are about 3,500 species of mosquitoes around the world, but only a few are responsible for spreading infectious diseases to humans.
Among those mosquitoes that are thirsty for human blood is the Aedes aegypti, which is the primary spreader of yellow fever, Zika virus, dengue and Chikungunya virus.