EPA Approves Release of Disease-Fighting Mosquitoes

Mosquito-borne illnesses have plagued humans for millennia, but now, these pests may become the pesticide.

This month, the EPA announced its approval of a common insect-infecting bacteria to reduce mosquito populations in 20 states and the District of Columbia for five years. A biotech startup, MosquitoMate, raises male mosquitoes in the lab that are infected with the bacteria Wolbachia pipientis. Once they’re mature, the mosquitoes can be released into the wild.

The product, called ZAP males, wouldn’t affect all mosquitoes in your yard—they target the species Aedes albopictus, commonly called Asian tiger mosquitoes, which are active during the day and can carry diseases like dengue and chikungunya. Other species of mosquito wouldn’t be affected.

The Asian tiger mosquito

Here’s Emily Waltz, reporting for Nature:

The company says that over time, as more of the Wolbachia-infected males are released and breed with the wild partners, the pest population of A. albopictus mosquitoes dwindles. Other insects, including other species of mosquito, are not harmed by the practice, says Stephen Dobson, an entomologist at the University of Kentucky in Lexington and founder of MosquitoMate.

Unlike females, male mosquitoes don’t bite and thus can’t transmit disease, so they pose no risk to humans. To have an effect, all male ZAP mosquitoes have to do is mate with wild female mosquitoes. Eggs fertilized by ZAP males don’t develop properly because the Wolbachia infection puts paternal chromosomes out-of-sync with the rest of the fertilized egg when it starts to divide. This condition, called cytoplasmic incompatibility, can result in cells that lack a full set of DNA, which is fatal to the developing mosquito.

For a price, MosquitoMate can release ZAP mosquitoes in a person’s yard on a weekly basis throughout mosquito season. Since Asian Tiger mosquitoes tend to live within a few hundred yards of the place that they hatched, MosquitoMate says they can work with more specificity than sprayed pesticides. And Waltz points out, their bacteria-based solution seems less controversial than mosquitoes that have been genetically engineered to resist disease, like those created by the company Oxitec, which was blocked from conducting field trials in the Florida Keys.

Here’s Waltz again:

MosquitoMate plans to begin selling its mosquitoes locally, in Lexington, and will expand from there to nearby cities such as Louisville, Kentucky, and Cincinnati, Ohio. The company will work with homeowners, golf courses, hotels and other customers to deploy its insects, according to Dobson. “Now the work starts,” he says.

The company will have to start small. Suppressing the mosquito population of an entire city is likely to require the weekly production of millions of these mosquitoes.

Currently, the EPA has only approved ZAP males that target Asian Tiger mosquitoes, but MosquitoMate is working to fight other disease-carrying species as well. The company has done field tests in Florida to decrease populations of Aedes aegypti mosquitoes, which can carry Zika virus and malaria.

The solution to mosquitoes might just be more mosquitoes.