Debug Fresno just wrapped up a 20-week field study that resulted in a 68 percent decrease in harmful mosquitoes. Photo via Verily Life Sciences

A project spearheaded by a Google sister company to introduce 20 million mosquitoes into the Fresno-Clovis area has actually paid off in fewer potentially harmful mosquitoes.

That’s the word from Debug Fresno, which is winding down the project it started in July to fight mosquito-borne diseases, including Zika. Verily Life Sciences, which is owned by Alphabet, Inc. — Google’s parent company — led the initiative along with Kentucky-based mosquito control service MosquitoMate and the Consolidated Mosquito Abatement District in Fresno.

Targeting the Aedes aegypti mosquito — a vector for diseases include Zika, dengue and chikungunya — Debug Fresno introduced 20 million sterile male mosquitoes in a Clovis neighborhood treated with Wolbachia, a naturally occurring bacterium. When the male mosquitoes mated with wild females, the resulting eggs would not hatch.

The result of the 20-week field study was a 68 percent reduction in biting, female Aedes aegypti mosquitoes in the release area compared to other control areas in Fresno County.

“These are promising results for our first field study, and we are looking forward to expanding to additional sites over more than one season to see what can be achieved,” according to a Verily blog post.

The team called the project a “pressure test” for its first round of mosquito-fighting technology and practices. The next field study will begin later this month in the town of Innisfail in Queensland, Australia.

“As the mosquito season in Fresno County draws to a close, we want to thank the many people involved in this study, including our collaborators at Consolidated Mosquito Abatement District and MosquitoMate as well as the residents of Fresno County that have engaged with us in the Debug Fresno study,” according to the blog. “As our technology and research program continues to grow and improve, we hope to continue to partner with communities to learn how to reduce the threat of mosquito-borne diseases around the globe.”