Verily Life Sciences has released the first batch of up to 20 million bacteria-infected mosquitoes in California as part of a project that aims to fight mosquito-borne Zika, dengue and chikungunya viruses.
For the Debug Fresno field study, researchers started to release sterile male mosquitoes treated with the bacterium Wolbachia into the wild. When these sterile males mate with the female mosquitoes, the resulting eggs will not likely hatch and thus potentially help in controlling the population of the disease-carrying insects.
Verily used modified Aedes aegypti mosquitoes, which are responsible for transmitting dengue, chikungunya, yellow fever, and Zika viruses. Scientists have already found earlier that when the Wolbachia bacterium infects the Aedes aegypti mosquito, it helps stop the transmission of mosquito-borne viruses.
Wolbachia appears to block mosquito-borne viruses such as dengue from replicating in the tissues of mosquitoes. Since the virus cannot replicate, the insects do not transmit these pathogens to human victims, which can help curb the spread of disease.
"We hope to demonstrate success with Debug Fresno that will benefit the local communities working with us on this study and later other communities globally where Zika, dengue, and chikungunya are endemic," Verily said.
Does Wolbachia Pose Safety Risk To Humans?
The idea of releasing millions of bacteria-infected mosquitoes may raise safety concerns but experts said that the particular technique used by Verily has been fairly well studied and is considered relatively safe.
Researchers of a study that investigated how infecting mosquitoes with Wolbachia can help control the transmission of the Zika virus said the bacterium is not known to be dangerous to humans. The bacterium is also not capable of passing through the saliva of a mosquito, which means it can't be transmitted to humans through insect bites.
Kentucky-based Mosquito Mate has already tested the technique in other places, and the trials did not generate public outcry.
The U.S. Environmental Protection Agency also regulates the modified mosquitoes as microbial pest control. Based on the results of an ecological risk assessment made in 2016, EPA said the altered mosquitoes do not cause harmful effects on other organisms including endangered species.
"Wolbachia is largely benign for mosquitoes and the environment, although it may reduce the insects' egg production. But the potential benefits for humans are clear: if mosquitoes infected with Wolbachia become predominant in the wild, we expect dengue infection rates among people to drop," Scott O'Neill, of the Eliminate Dengue Program, wrote on the potentials of using the Wolbachia bacteria to fight dengue.