Authorities have approved plans for genetically modified mosquitoes to be released across the Florida Keys from next year.
British-based firm Oxitec has designed the project to test whether the altered mosquitoes are a viable alternative to pesticides to control and prevent the spread of diseases, including Zika and dengue.
In 2021, they will also be released in Harris County, Texas.
The male mosquito, called OX5034, is designed to produce female offspring which die when reaching the larval stage.
A protein is passed on which kills them before they hatch and are big enough to spread disease and bite. Male mosquitoes do not need to bite for blood as they feed on nectar.
This will be the first time genetically engineered mosquitoes will be released anywhere in the US, raising questions over the safety of the plan.
Dana Perls, a programme manager at Friends of the Earth, said: “The release of genetically engineered mosquitoes will needlessly put Floridians, the environment and endangered species at risk in the midst of a pandemic.”
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However, in a trial in Brazil where the engineered mosquito was released, Oxitec said they did not cause harm to other insects.
A decline in the population of disease-carrying mosquitoes was also seen in this trial.
Oxitec chief executive Mark Carnegie-Brown said: “We’re looking forward to working hand-in-hand with the Keys community to demonstrate the effectiveness of our safe, sustainable technology in light of the growing challenges controlling this disease-spreading mosquito.”
According to The World Health Organisation (WHO), approximately half of the world’s population are at risk of dengue with 390 million infections happening a year.
In 2016, Zika was declared an international emergency. It was later downgraded but the WHO said it was still a “significant public health challenge requiring intense action”.