Skip to main content

Natural Awakenings Jacksonville-St. Augustine

Genetically Modified Mosquitoes Released in Florida Keys

May 28, 2021 09:31AM ● By Erin Lehn
The British company Oxitec, a Bill Gates-backed biotech firm, has recently released the first batch of 750 million genetically modified mosquitos in the United States in an effort to control the mosquito population in the Florida Keys.

Local Florida officials state that this trial attempt is necessary as pesticides have become increasingly ineffective against the overwhelming mosquito population. While the Aedes aegypti only accounts for approximately 4 percent of the total mosquito population in the Keys, the species was responsible for 70 cases of dengue fever in 2020. They can also carry diseases such as the Zika virus, chikungunya and yellow fever.

“At the end of the day, our hope is to be able to control this mosquito more efficiently and keep our population below any sort of disease transmission threshold,” says Andrea Leal, executive director of the Florida Keys Mosquito District, in an article featured in USA Today. “Our toolbox for Aedes aegypti control is shrinking, unfortunately, and that’s making us think outside of the box.”

Over the course of 12 weeks, approximately 144,000 genetically modified mosquitoes will be released each week, for a total of more than 1.7 million, with more anticipated if the experiment is successful. Once the non-biting Aedes aegypti males are released, they’re expected to mate with the biting females, thereby genetically modifying their offspring. The projected outcome is that future generations of female offspring will die before reaching maturity, thus reducing the mosquito population, and controlling disease transmission in humans and animals.

However, opponents argue that releasing genetically modified mosquitoes into the environment could cause unintended long-term consequences. “When you disrupt an ecological system whether it’s a small disruption or a big disruption, you’re going to have an impact,” says Dana Perls, program manager at Friends of the Earth, in that same USA Today article. “History has taught us time and time again that we need serious precaution with new genetic engineering experiments and technologies. Once you release this genetic material into the wild, you can’t recall it.”

Friends of the Earth is one of many environmental organizations concerned about the outcomes of the research. “People here in Florida do not consent to the GE mosquitoes or to being human experiments. We are demanding sound science, not marketing hype. It is critical to prioritize the less risky, more environmentally sustainable, lower cost and natural alternatives,” says Barry Wray, executive director of the Florida Keys Environmental Coalition, in an article posted on the Friends of the Earth website.

An article by Dharna Noor posted on cites a 2019 Yale University study warning that the plan could backfire. “Those scientists found that while most female offspring from the GMO bugs die off, between 3 and 4 percent of them generally survive into adulthood, and it’s not clear if they’re infertile,” writes Noor. “That means by mating with the disease-spreading mosquitoes, the Oxitec mosquitoes could create hybrid babies that could actually be more resistant to insecticides than wild mosquitoes and worsen the spread of disease.”

The article also states concerns about how the mosquitoes will interact with the local ecosystems. “One field study on the mosquitoes from Brazil found that the bugs’ engineered genes spread into wild mosquito populations,” shares Noor. “It’s not clear what ecological effects that could have in the Florida Keys, which is worrisome because the region is home to such rich and sensitive habitats. Last month, a panel of independent experts testified at the Florida Keys Mosquito Board, raising these issues.”

For more information, visit Friends of the Earth at or the Florida Keys Environmental Coalition at