Aëdes aegypti mosquitoes, known for spreading yellow fever, also transmit dengue, Zika and other viral infections. With warming temperatures their reach has been spreading steadily into more temperate northern regions from South America and Africa.
A recent study measured the rate at which available habitat for A. aegypti has been growing, and found that by 2050, with changing climate conditions, that rate could be two to three times faster. At that pace, its range would spread through North America and China along a frontier moving forward at pace of 2 kilometers to 6 kilometers a year.
This mosquito breed causes an estimated 390 million dengue infections and 51,000 to 380,000 yellow fever infections a year, with case numbers growing annually. Dengue was present in nine countries in the 1970s, but now can be found in 128 countries.