Engineered Mosquitoes Approved for Disease Control

Aedes aegypti mosquito biting a human (U.S. Dept of Agriculture)

21 Aug. 2020. In an apparent end to a long-running dispute, authorities in the Florida Keys approved a field trial of engineered mosquitoes to control tropical diseases. Oxitec Ltd., based in Oxford, U.K., received approval this week for a demonstration project of its Aedes aegypti mosquitoes, known carriers of viral diseases including Zika, dengue, chikungunya, and yellow fever.

Oxitec developed its genetically-engineered Aedes aegypti mosquito to head off outbreaks of these viral diseases. Oxitec uses genetic engineering techniques to insert a gene in males of the species that when released into the wild mate with females, produce non-biting offspring that die before becoming adults, and thus are prevented from having further offspring. As a result, the Aedes aegypti mosquito population in the area of the release is sharply reduced or eliminated.

As reported by Science & Enterprise in November 2016, Oxitec first proposed a field trial of its engineered mosquitoes in the Florida Keys, the string of islands stretching from the mainland into the Caribbean, but faced resistance from some residents. A referendum in Monroe Country, Florida that includes the Keys, found a majority of the country’s residents supported the trial, but the town of Key Haven, where the trial was set to take place, voted no. Later in the month, the Florida Keys Mosquito Control District board, the governing authority in the matter, approved the trial.

In September 2019, however, researchers in the U.S. and Brazil tested the company’s mosquitoes released in Brazil, and published data showing some engineered male insects survive into adulthood and pass on parts of their genome to future generations. The findings, reported in the journal Scientific Reports, were challenged by Oxitec that claimed the authors made speculative statements and ignored years of independent data supporting the company’s mosquitoes. In March of 2020, the journal issued an Editorial Express of Concern indicating some conclusions in the paper were not supported by the data, leading to several authors withdrawing their names from the paper.

Since the first Florida trial, Oxitec developed a new variety of engineered mosquito that the company submitted to federal agencies for review. Genes in the new variety of Aedes aegypti mosquito express an additional protein further limiting the viability of offspring. Earlier this year, the company received approval to conduct its demonstration project from the U.S. Environmental Protection Agency, Centers for Disease Control and Protection, and seven state agencies in Florida that the company says found no risk to humans, animals or the environment, including endangered species.

The Florida Keys Mosquito Control District approval finalizes the experimental use permit to proceed with the demonstration project. Oxitec says the control district authority will continue to monitor the project, which will be independently evaluated by CDC and University of Florida’s Medical Entomology Laboratory.

More from Science & Enterprise:

• Phone-Based Infectious Disease Diagnostics Being Developed
• Antibiotics Synthesized from Scorpion Venom
• Engineered Moth to Control Soybean Pest
• Crispr Deployed to Stop Disease, Pest Insects
• Trial Testing DNA Antibody Vaccine for Zika

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