While a mosquito bite is often no more than a temporary bother, in many parts of the world it can be scary. One mosquito species, Aedes aegypti, spreads the viruses that cause over 100,000,000 cases of dengue, yellow fever, Zika, and other diseases every year. Another, Anopheles gambiae, spreads the parasite that causes malaria. The World Health Organization estimates that malaria alone causes more than 400,000 deaths every year. Indeed, their capacity to transmit disease has earned mosquitoes the title of deadliest animal.