Local Vector Control Agency Monitors Plans to Release Genetically Engineered Mosquitoes in Central California

As summer approaches and conditions in Pasadena become more favorable for the spawning of potentially dangerous mosquitoes, a British company is experimenting with a genetic solution to mosquito control in Central California that is being closely watched by local mosquito authorities.

Millions of genetically modified Aedes aegypti mosquitoes could be released in 48 different locations in Tulare County to help suppress their populations, which could spread diseases.

Levy Sun, Director of Communications at San Gabriel Valley Mosquito & Vector Control District (SGVMVCD) said the agency is aware of the planned release of millions of genetically modified Aedes aegypti mosquitoes in the Northern California county.

The District believes that the new technology, spearheaded by British biotech company Oxitec, is promising as it releases only males, which do not bite and spread disease.

Oxitec’s safe, non-biting male mosquitoes are “designed to suppress local wild populations of disease-spreading mosquitoes,” Oxitec’s website states.

According to the company, the genetically modified mosquitoes have a “self-limiting gene,” which ensures that when the “friendly mosquito males mate with wild females,” their female offspring will die, ultimately reducing the overall mosquito population.

The U.S. Environmental Protection Agency announced in March that it granted Oxitec a permit to release their genetically modified insects on 29,400 acres in the counties of San Bernardino, Fresno, Stanislaus and Tulare, according to the LA Times.

But this experiment is yet to be approved by the state of California’s Department of Pesticide Regulation.

Sun said some local residents who are wary of the disease threats posed by Aedes mosquitoes have already contacted SGVMVCD to consider funding or implementing sterile insect techniques (SIT).

“Genetically modified mosquitoes, or self-limiting mosquitoes, is one of three main sterile insect techniques (SIT) that is used worldwide. Sterile insect technique has been used against specific species of pests such as medflies in California and screwworms in the US,” Sun said.

Despite saying that SGVMVCD is generally supportive of the evaluation and research of SIT, Sun cannot say as of now whether or not the SGVMVCD will use the technology to control the mosquito population in San Gabriel Valley, saying further studies are still needed.

“We are still watching the development and research of sterile insect techniques in mosquito control. In addition to gene modification, we are also monitoring the use of irradiation and Wolbachia as possible techniques,” Sun said.

Irradiation of male mosquitoes is done in a lab using radiation found in X-Rays. The resulting sterile male mosquitoes, which don’t bite, are released to mate with wild females, and the resulting eggs do not hatch. This technique reduces the number of mosquitoes over time, according to the Mosquito and Vector Control Association of California.

Wolbachia bacteria can also be used to control mosquito populations where male Aedes mosquitoes are grown in a lab with a specific type of Wolbachia. When these male mosquitoes mate with wild females with a different type of Wolbachia or none at all, their eggs do not hatch.

With unseasonable high temperatures, San Gabriel Valley has experienced an increase in the number of mosquitoes.

“Mosquito trap data from the San Gabriel Valley Mosquito & Vector Control District shows the average mosquito activity this week is 517.83% higher compared to the same week as last year,” the SGVMVCD said in a statement on February 10.