These bacteria-infected mosquitoes are killers. Letting millions loose will save lives, scientists say

They say to keep your friends close, and your enemies closer.

When that enemy in a mosquito, though, scientists are starting to advise something a little more unconventional: Infect your enemy’s friends with a sterilizing bacteria, researchers say. Then set millions and millions of those bacteria-infected enemies loose, and watch as they decimate the population of their pesky, disease-carrying compatriots.

Scientists say this novel solution to defeating mosquitoes just might work — and it could be coming to a state near you.

Earlier this week, Kentucky-based biotechnology startup MosquitoMate got the go-ahead from the U.S. Environmental Protection Agency to release hordes of lab-grown mosquitos that have been infected with the bacterium Wolbachia pipientis, Nature reports. The bugs will be set loose in 20 states and the District of Columbia, starting with Kentucky.

And once they’re released, those infected mosquitoes will act like assassins, CNET reports, spreading the bacteria to mosquitoes that carry viruses that harm and even kill humans — think Zika virus, dengue and yellow fever — and preventing them from reproducing.

“It’s a non-chemical way of dealing with mosquitoes, so from that perspective, you’d think it would have a lot of appeal,” David O’Brochta, an entomologist at the University of Maryland in Rockville, told Nature. “I’m glad to see it pushed forward, as I think it could be potentially really important.”

And it could help rein in Zika, dengue and other mosquito-borne viruses. Dengue alone killed nearly 1,200 in the Americas in 2015, according to the World Health Organization, while Zika can cause severe birth defects in the children of infected mothers.

So how does it work?

The company breeds and raises mosquitoes infected with the bacteria in their lab. Then they sort out the males — which unlike female mosquitoes, do not bite, according to MosquitoMate. Those male mosquitoes, infected with a bacteria that makes them sterile, are released into the wild, where they mate with female mosquitoes.

But the Wolbachia-infected chromosomes the lab-raised male mosquitoes provide mean that the hatchlings never hatch, according to Nature — cutting the number of potentially Zika- or dengue-carrying mosquitoes in the area. Or at least that’s the hope.

Getting the strategy to work is no small feat, Nature reports: It requires millions of released mosquitoes each week to keep down the mosquito population in just one city.

In Fresno, Calif., MosquitoMate has already seen results, the Fresno Bee reports.

By releasing sterile, bacteria-infected male Aedes aegypti mosquitoes to mate with females, MosquitoMate and its local partners were able to cut the number female bugs — the ones that bite you — by about 68 percent at the peak of the 2017 mosquito season.

“It’s one of the largest reductions that people have seen in these type of studies,” Jacob Crawford, lead scientist for the so-called Debug Fresno project, told the Bee.

Still, local experts say, it’s just one tool among many.

“It’s important that we try to use every method that we can get to get control of this mosquito,” said Steve Mulligan, manager of Freno’s Consolidated Mosquito Abatement District, told the Bee.

But not everyone is on board with MosquitoMate’s approach.

Some think it’s better to replace existing mosquito populations with bugs that don’t carry viruses that impact humans, rather than trying to surpress the mosquitoes that do.

That’s the approach championed by the Eliminate Dengue Program, a non-profit led by Monash University in Australia. The program releases both male and female bacteria-infected mosquitoes that can’t carry viruses like dengue that impact humans. As those populations replace disease-infected mosquitoes, it helps keep those diseases from spreading to humans, the Miami Herald reported last year during Florida’s Zika virus outbreak.

“It’s ecologically sounder,” Phil Lounibos, a professor at the Florida Medical Entomology Laboratory at the University of Florida, told the Herald last year. “It’s unrealistic to think that you can just eliminate a mosquito species as simply as one of these sterile-male control programs wants to do.”

Quartz reports that the 20 states that have been approved for MosquitoMate to release the bacteria in are California, Connecticut, Delaware, Illinois, Indiana, Kentucky, Massachusetts, Maine, Maryland, Missouri, New Hampshire, New Jersey, Nevada, New York, Ohio, Pennsylvania, Rhode Island, Tennessee, Vermont and West Virginia.

This story was originally published November 8, 2017 at 5:14 PM with the headline "These bacteria-infected mosquitoes are killers. Letting millions loose will save lives, scientists say."