Disease-Carrying Mosquitoes Will Thrive as the Climate Warms
Climate change is expected to devastate wildlife around the world, but it will be a boon for one particular pest—and that’s bad news for people.
In a new study, researchers at Montana State University in Bozeman, Montana, have found that Aedes aegypti, the mosquito species that carries viruses that cause dengue fever, chikungunya, and yellow fever, will become resistant to Permethrin, a widely used pesticide, as temperatures rise.
“Climate change will bring higher temperatures, and a one- to two-degree increase is enough to reduce the control on mosquitoes,” said Robert Peterson, coauthor of the study and an entomologist at Montana State University.
There are more than 3,000 species of mosquitoes that transmit diseases ranging from West Nile virus to dengue fever. Mosquitoes can be carried hundreds of miles by the wind, and Peterson thinks the insects' ranges will expand with hotter temperatures.
“Disease-carrying mosquitoes could go up in number as climate warms up and pesticides' effectiveness decreases,” he said. “Warming climate also speeds up insect development, so combined with reduced effectiveness of some pesticides, this could increase their population.”
Permethrin is a synthetic chemical called a pyrethroid that is used in spray, aerosol, liquid, and powder forms on crops, lawns, livestock, and buildings to control Aedes aegypti.
Dengue fever has popped up in Hawaii, the Florida Keys, and south Texas, and chikungunya is now in Florida. Peterson points out that the cases are homegrown and not brought back by returning overseas travelers.
Public health departments across the country use different pesticides to keep mosquitoes under control, and Peterson suggests that they pick products that will be effective in the hotter years ahead. There are other types of insecticides, including different types of pyrethroids, that do work in hot weather.
“We need to get more sophisticated in tackling pests in a warming planet as climate changes,” he said. “We need to recognize there may be limitations to effective control in higher temperatures.”