Mosquitoes that carry Zika virus and Dengue fever are genetically distinct throughout the globe, a fact that may help public health officials assess risk to populations newly exposed to the species, a new Yale-led study shows.
Researchers described the genetic diversity of the Aedes aegypti mosquito — which also transmits yellow fever and chikungunya — in 30 countries and across six continents. In different locales, the mosquito species has different genetic signatures, the researchers report in the journal Molecular Ecology.
“This is important to know because these mosquitoes differ in their ability to transmit diseases,” said Andrea Gloria-Soria, associate research scientist in the Department of Ecology and Evolutionary Biology (EEB) and lead author of the study. Information on the mosquitoes’ origin can help officials to assess threat levels if the species shows up for the first time in a new location. For instance, if Aedes aegypti arrives in a southern U.S. state from areas of Brazil where levels of Zika infection are high, public health officials can launch aggressive prevention measures in those newly exposed areas.
And mosquito migration can be unpredictable, notes Jeffrey Powell, professor in EEB and senior author of the paper. For instance, when Aedes showed up in California in 2013, it was assumed that the mosquitoes had been imported from Mexico. Genetic testing showed that the insects had hitchhiked on planes, trains, or trucks from the New Orleans/Houston areas. In another case, Dutch officials were stunned to find subtropical mosquitoes in the Netherlands in 2010. Testing showed that the mosquitoes had arrived with cargoes of used tires shipped from Miami for disposal at centers in that country.