Will unleashing 20 million mosquitoes in Fresno reduce their numbers?

Releasing sterile mosquitoes
Releasing sterile mosquitoes 04:23

Just after sunrise in Fresno, California, a van circling a residential neighborhood is making a rather unusual delivery.

It's hard to see with the naked eye, but flying out of a tube are thousands of mosquitoes – new additions to the community, reports CBS News' Mireya Villarreal.

It's part of a new experiment in which 20 million mosquitoes will be released into a California neighborhood in the name of science.

"Are the mosquitoes going to bother us, are they going to bite us? But so far it hasn't been much of a problem," said homeowner Bonnie Smith.

It's not a problem for Smith because, despite putting more bugs in the air, the experiment in this van could actually decrease the mosquitoes in her backyard.

"The only ones we release are male mosquitoes, which don't bite, only the females bite, and the males we're releasing are sterile, so when they mate with the wild female, she'll still produce and lay eggs, but they'll never hatch," said Linus Upson.

Upson is running an experiment for Verily, the life sciences corporate cousin of tech powerhouse Google. In total, they're releasing a million mosquitoes a week for 20 weeks this summer.

Mosquitos are released from a van through tubes.  CBS News

"Once people understand that male mosquitoes don't bite, and that, if we're successful, we're going to reduce the population of mosquitoes that do bite them, people are usually thrilled," Upson said.

The wild mosquitoes do more than bite. The breed Verily is targeting, aedes aegypti, also spreads some of the world's most dangerous diseases, including dengue fever and Zika.

"If we release enough of them for a long enough period of time, we hope we can eliminate the population of aedes aegypti mosquitoes near where people live," Upson said.

To do that, Verily has spent millions of dollars building a lab that breeds, sterilizes and rears millions of bugs, then sorts them by sex, to ensure only the males are released.

"Producing a million male mosquitoes a week, it's quite a feat," said Jodi Holeman, who works for a local government-run mosquito control program. They tried a smaller-scale version of this last summer, but only released 800,000 pests.  Now partnered on this project with the deep pockets of Google, they're able to multiply that by a factor of 25.

"We really needed to have the ability to rear the number of males that would be needed to affect control," Holeman said.

But partnering with the Google family of companies comes with its own complications.

The Virely lab CBS News

"I always have a concern when Google says it's going to do anything," said John Simpson of the non-profit, Consumer Watchdog.

Simpson has kept a close eye on Google and its subsidiaries for years.  He sees nothing wrong with the science and safety of the Fresno experiment. It's what comes next that concerns him.

"In the future, if they've got all the proprietary information you have to meet their terms and if because of their powerful position, they can essentially dictate those terms, you then end up being at Verily's mercy," Simpson said.

"We don't know exactly how we're going to go to market with this as a business. Right now, we're just focused on showing that it can work," Upson said.

If it works, the project could serve as a model for other communities around the world. And even though dengue fever and Zika aren't threatening Fresno, people here don't seem to mind acting as test subjects for technology that could save millions of lives in the future.

"In a way, it's sort of neat to be a part of it in one small way," Smith said.

Researchers in Fresno are monitoring traps set throughout these neighborhoods and are hoping to see a drop in mosquito populations by the end of this summer