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The first genetically modified mosquitoes released in the United States

A man walks on a road in Florida, holding a tray and wearing a shirt with the words

Biotechnology company Oxitec is working closely with the Florida Keys Mosquito Control Area to monitor the field testing of its genetically modified mosquitoes.Credit: Oxitec 2021

After a decade of struggle for regulatory approval and public acceptance, a biotech company has released genetically engineered mosquitoes for the first time in the United States. The experiment, launched this week in Florida Keys – against the objections of some local critics – is testing a method of suppressing wildlife populations. Aedes aegypti mosquitoes that can transmit diseases such as zika, dengue, chikungunya and yellow fever.

The company Oxitec, based in Abingdon, UK, which developed the mosquitoes, previously tested the insects in the field in Brazil, Panama, the Cayman Islands and Malaysia.

But so far, thanks to a series of regulatory decisions and repulsion by Florida residents (see The Long Road), no genetically engineered mosquitoes have been tested in the United States – although the country has previously allowed genetically modified diamond tests. moth (Plutella xylostella) in New York and designed a pink worm (Pectinophora gosipiela) in Arizona, both developed by Oxitec. “When something new and revolutionary comes along, the immediate reaction of many people is to say, ‘Wait,'” said Anthony James, a molecular biologist focused on bioengineered mosquitoes at the University of California, Irvine. “So the fact that [Oxitec] Being able to start the process on the spot in the US is a big deal. “

The experiment has started

Aedes aegypti makes up about 4% of the Keys mosquito population, a chain of tropical islands off the southern tip of Florida. But he is responsible for virtually all mosquito-borne diseases transmitted to humans in the region, according to the Florida Mosquito Control District (FKMCD), which works closely with Oxitec on the project. Researchers and technicians working on the project will release bioengineered men Aedes aegypti mosquitoes that do not bite to mate with the wild female population responsible for prey bites and disease transmission. Genetically engineered males carry a gene that is passed on to their offspring and kills female offspring in the early stages of the larvae. Male offspring will not die, but instead will carry the gene and pass it on to future generations. As more women die, Aedes aegypti the population must decrease.

FKMCD turned to Oxitec in 2010 to test its approach at Keys, as Florida is – and still is – experiencing an increase in mosquito-borne disease. In 2009, the state began seeing cases of locally transmitted dengue, and a few years later, locally transmitted Zika.

At the end of April this year, researchers at the project placed boxes containing Oxitec mosquito eggs in six locations in three key zones. The first males are expected to appear in the first two weeks of May. About 12,000 men will come out of the boxes every week for the next 12 weeks. In a second phase later this year, designed to gather even more data, nearly 20 million mosquitoes will appear in about 16 weeks, according to Oxitec.

Genetically engineered mosquitoes are an alternative to insecticides that are used extensively in the United States to control insect populations. This has led to the evolution of mosquitoes that are resistant to insecticides.

A box labeled Oxitec is placed near a plant

Oxitec has placed boxes of mosquito eggs in undiscovered locations in Florida Keys to prevent vandalism.Credit: Oxitec 2021

“Unfortunately, we are seeing our toolbox shrink due to resistance,” said Andrea Leel, CEO of FKMCD, at a press conference last week. “That’s one of the reasons we’re really looking at these new innovative tools and new ways to control this mosquito.”

To monitor the progress of the test, researchers will use capture devices to catch mosquitoes for research. They will measure how far male mosquitoes travel from the boxes, how long they live, how effectively they suppress the wild female mosquito population, and whether all females with the gene actually die. Oxitec mosquitoes carry a gene for a fluorescent marker that makes them glow when exposed to a certain color of light, which makes identification easier.

The biotech company plans to present the results to the US Environmental Protection Agency (EPA), which gave the green light for the test. The data will help the EPA determine whether Oxitec can release mosquitoes more widely in the United States. The company is still testing them in Brazil and other countries.

Housing repulsion

Opposition to the field experience in Florida has been fierce by some Keys residents. Worried about mosquito bites or insects that would disrupt Florida’s ecosystem – and generally unhappy that they were chosen as a testing site – some are threatening to thwart experiments by spraying insecticides near release points. “As you can imagine, emotions intensify and there are people who really feel strongly for or against,” said molecular biologist Natalie Kofler, who lectures at Harvard Medical School in Cambridge, Massachusetts and is the founder of Nature Editing. “, An organization that advocates for the responsible development and oversight of gene editing technologies. “And I see how, if you don’t agree to that, it can be really disturbing to let mosquitoes in your neighborhood.”

Many of the concerns stem from the uncertainty of the new technology, said Kofler, who has been following the project for years. Oxitec is working with the Florida Keys community to provide answers to inquiries. They explained, for example, the very low probability that female mosquitoes with the deadly gene could reproduce. But many people don’t trust what they hear because it comes from a company, Kofler said.

Kofler hopes that enough data has been collected to assess the impact of mosquitoes, including on other species in keys and local ecosystems, and that this is being done “in a way that is transparent and in a way that can make some members of the community to feel better about the whole situation. “

Oxitec employees took precautions against vandalism by placing their mosquito boxes on private, fenced properties and did not disclose their exact location to the public.

A long way

Over the past decade, Oxitec has faced regulatory assessments from three different U.S. federal agencies and opposition from Florida residents, while seeking approval for the first time to launch its experimental mosquitoes in the United States.

March 2010: Oxitec has applied to the US Department of Agriculture (USDA) for a field test with its genetically modified mosquitoes.

October 2011: The USDA says it has no regulatory jurisdiction over Oxitec mosquitoes.

November 2011: The US Food and Drug Administration (FDA) is claiming jurisdiction to regulate mosquitoes, so Oxitec is applying to the process agency in Key Haven, Florida.

August 2016: The FDA approves the test. The start date depends on the approval of the Florida Keys Mosquito Control Board (FKMCD) at mosquito sites.

November 2016: Residents of Key Haven voted against the referendum process, but elsewhere in Monroe Country, Florida, enough residents voted in favor of it to keep the project afloat.

October 2017: The FDA has transferred Oxitec’s mosquito jurisdiction to the United States Environmental Protection Agency (EPA).

March 2019: Oxitec is moving to second-generation mosquitoes due to advances in technology and is seeking EPA experimental permission to conduct field trials in Monroe County.

April 2020: EPA highlights the project.

August 2020: The FKMCD Council voted to continue the process.

April 2021: The test begins when boxes of genetically modified mosquitoes are placed in the Cudjoe, Ramrod Key and Vaca Key of Monroe County.

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