Verily Robot Will Raise 20 Million Sterile Mosquitoes for Release in California

Verily’s automated mosquito-rearing system at its factory in South San Francisco, California.

Alphabet’s life sciences arm, Verily, says it has built a robot that can raise a million mosquitoes a week and used it to produce infertile male insects. The company says it has started releasing the first batches of 20 million sterilized mosquitoes in Fresno County, California.

This field trial is expected to be the largest U.S. release to date of male mosquitoes treated with Wolbachia, a type of naturally occurring bacteria that infects many types of insects. Verily says it is using custom-built software algorithms and robots to ramp up the number of mosquitoes it’s able to grow and release. The company first announced last October that it planned to develop infertile mosquitoes designed to deplete populations, in an effort to fight diseases like Zika virus and dengue fever.

Verily’s effort represents a growing interest by industry and nonprofit organizations in using altered insects to stop the transmission of deadly diseases and protect crops from agricultural pests. The Bill and Melinda Gates Foundation is also exploring the idea of sterilized mosquitoes, and the U.K. company Oxitec is genetically engineering moths with a so-called self-limiting gene that makes the insects die off over time (see “Are Altered Mosquitoes a Public Health Project, or a Business?”). 

To help breed and release the mosquitoes, Verily has partnered with Kentucky-based Mosquito Mate and Fresno’s mosquito control agency, the Consolidated Mosquito Abatement District. When the treated males mate with females in the wild, the females’ eggs aren’t able to develop properly and don’t hatch. Male mosquitoes do not bite humans and cannot transmit disease to people, so Verily and its partners aim to release only males. The company has created an automated sex-sorting process to lower the risk that females will end up in the mix.

Mosquito Mate has previously run smaller field studies in Los Angeles and the Fresno area, among other locations, but Verily’s high-tech approach will allow for the release of one million mosquitoes a week, 25 times more than the Kentucky company was able to do before.

Linus Upson, a senior engineer at Verily, says the purpose of the study is to see if the approach succeeds at reducing the population of mosquitoes in the area where the bacteria-treated insects are released. He says Verily’s automated approach could help lower costs for communities wanting to control mosquitoes this way.

“If we really want to be able to help people globally, we need to be able to produce a lot of mosquitoes, distribute them to where they need to be, and measure the populations the populations at very, very low costs,” Upson says. He declined to give any cost estimates.

Mosquito Mate founder Steven Dobson originally created this line of mosquitoes, which belong to the species Aedes aegypti—the one that carries chikungunya, dengue, yellow fever, and Zika virus. Fifteen years ago, he began injecting newly laid mosquito eggs with Wolbachia using a tiny needle. The infection has been transmitted through female mosquitoes ever since, so there’s no need to inject each new generation. Wolbachia, which has been relatively well studied as a sterilizing technique, doesn’t infect humans and can’t be transmitted to humans through an insect bite.

The modified mosquitoes are regulated through the U.S. Environmental Protection Agency as “microbial pest control.” In an ecological risk assessment conducted in 2016, the agency said Mosquito Mate’s altered mosquitoes are not expected to cause any harmful effects to other organisms, including endangered species.

Upson says Verily also plans to conduct a field trial in Australia later this year. “We want to show this can work in different kinds of environments,” he says.