Swarms of genetically modified mosquitoes could be unleashed in California to wipe out an invasive species capable of spreading deadly diseases.
Under a project already tested in Florida, two million male mosquitoes could eventually be introduced that carry a “kill switch” built into their DNA, meaning that their offspring die before maturity. Their mission is to mate with the invasive females, leading to population collapse.
The target is Aedes aegypti, which was first detected in Los Angeles about a decade ago and has since spread to 20 counties in California.
Supporters of the plan argue that the invader, which originates from west Africa, increases the risk of transmission of dengue, Zika, yellow fever and other diseases. Unlike their native counterparts, which emerge at dusk, the black-and-white striped intruder hunts during the day and is an aggressive bloodsucker with a taste for humans.
The GM mosquitoes were created by Oxitec, a British company. Because all are male and modified Aedes aegypti, they do not bite or spread disease and will mate only with the invasive females of their own species.
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The Environmental Protection Agency has approved a pilot programme in Tulare county, northern California, and Oxitec must now wait for state regulators to allow the project to proceed.
Oxitec declared a 2021 pilot scheme in Florida a success and Grey Frandsen, the company’s chief executive, said that the project would combat “the growing health threat this mosquito poses across the US”.
In a trial in Brazil, Oxitec mosquitoes were sold in the state of São Paulo for about $10 to $30 a month through a subscription service. Customers were given a box to put in a garden or balcony and egg refill packs were delivered by post, with males hatching over a fortnight.
Not everyone is in favour of the plan. “We’re lab rats,” Angel Garcia, of Californians for Pesticide Reform, told San Jose’s Mercury News. “The community was not included in the process. If they really want to protect public health, we need to be at the table. There seems to be no transparency, no independent review and no public participation.”
Critics have also said that there have not been any cases of the mosquitoes spreading the dangerous diseases given as a reason for wiping them out.
