May 1, 2021 - Science

Oxitec releases first genetically modified mosquitoes in U.S.

Members of the Florida Keys mosquito control department inspecting a neighborhood in Key Largo in July 2020.
Members of the Florida Keys mosquito control department inspecting a neighborhood in Key Largo in July 2020. Photo: Joe Raedle/Getty Images

Oxitec, a British startup determined to prevent instances of mosquito-borne disease, released thousands of genetically modified mosquito eggs in the Florida Keys this week as part of a test approved by the Environmental Protection Agency and Florida's agriculture department.

Why it matters: It marks the first release of genetically modified mosquitoes in the U.S. and has some locals worried about how this will impact the broader ecosystem, according to CNN.

How it works: Oxitec expects to target Aedes aegypti, an invasive species of mosquito that carries several dangerous diseases like yellow fever, dengue and Zika virus.

  • The startup aims to control the species by releasing genetically modified male mosquitoes that, like natural male Aedes aegypti, feed on nectar rather than blood and do not transmit diseases to humans.
  • The modified males carry a "self-limiting" gene that will target and kill future female Aedes aegypti, which feed on humans and can transmit dangerous diseases.
  • The company hopes that by releasing the modified males, it will lower the number of biting females and reduce instances of disease transmission.

By the numbers: Oxitec said that Aedes aegypti makes up just 4% of the mosquito population in the Keys but is responsible for virtually all disease transmission there.

  • The company has released more than 1 billion bugs around the world, including in Brazil and the Cayman Islands, Axios' Dan Primack reports.

What they're saying: "The challenges posed by disease-spreading mosquitoes is growing, not shrinking, making this pilot project a major step forward in bringing Oxitec’s safe, self-limiting technology to the [U.S.]," Grey Frandsen, Oxitec’s CEO, said in a statement.

  • “Our primary mission is to protect residents in the Florida Keys from all mosquitoes including the disease-transmitting Aedes aegypti," said Andrea Leal, executive director of the Florida Keys Mosquito Control District, which collaborated with Oxitec on the release project.

The big picture: If successful, the release of genetically modified males could become an alternative to controlling mosquito populations.

  • Currently, the primary way to control the populations is by spraying insecticides that can persist in the environment and unintentionally harm insects like bees and butterflies.
  • Yes, but: Some Florida Key residents have strongly opposed the release of genetically modified mosquitoes since the project was announced, according to CNN.
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