The release of some 8 million genetically modified mosquitoes in West Bay has had a significant impact in reducing populations of the disease-spreading insects in the targeted area, researchers say.

Preliminary data from the Mosquito Research and Control Unit shows that the genetically modified males are successfully mating with females in the wild.

The MRCU statistics also show a significant reduction in Aedes aegypti eggs found in traps in the targeted zone compared with a non-treatment area.

Now officials are contemplating a national rollout of the project in the hope that it can vastly reduce or even eradicate the mosquitoes, which spread various potentially deadly diseases including Zika, chikungunya and dengue fever.

Bill Petrie, director of the MRCU, said, “These results certainly give us confidence that this can be successful island wide.”

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Roy McTaggart, councilor for health, said the progress of the project was encouraging.

“Government will await the final report and recommendations from the MRCU but we are fully behind the project and will look favorably at any recommendation for the expansion or rollout.”

British-based biotech company Oxitec, in partnership with the MRCU, started the GM mosquito project in West Bay over the summer, releasing about 300,000 male Aedes aegypti mosquitoes a week. The idea is that Oxitec’s males will mate with wild females, and the genetic modification means the next generation will not survive to adulthood.

Bill Petrie, head of the MRCU, said the unit was tracking the success of the project on a weekly basis, through a built-in biological fluorescent marker, which showed up in larvae from the GM mosquitoes.

In the most recent data, collected over the past two months, the fluorescent marker showed up in 94 percent of larvae collected in the targeted zone, demonstrating they had out-competed males in the wild for mates.

“What this shows us is that the first part of the technique is working. The GM mosquitoes are mating with the wild females with a high degree of success,” he said.

The MRCU is also tracking the number of Aedes aegypti eggs collected in traps in the targeted area, compared with a control area, where no GM mosquitoes have been released.

Last week’s figures showed there were 88 percent less eggs in the treatment area.

“What we are able to show now is that the Aedes aegypti population in the treatment area is significantly reduced compared with the non treatment area. The trend is very strong,” said Mr. Petrie.

Though the concept of releasing genetically modified mosquitoes has proved controversial in Cayman and elsewhere, including the Florida Keys, Mr. Petrie said the science was well established.

“We need to separate science fact from science fiction. We wouldn’t be doing this if we didn’t think it was safe, if we didn’t think it was of huge benefit. The House of Lords, the World Health Organization, various bodies around the world have looked at this and studied it over many years and deemed it not just to be safe, but potentially safer than any other method available.”

Officials say they are unconcerned by continued opposition from a vocal group of protesters, who brought a judicial review in an effort to stop the project. The group has called a press conference for next week as part of an ongoing campaign against any further expansion of the genetically modified mosquito program.

Jennifer Ahearn, chief officer in the Ministry of Health, said the time limit to appeal the judge’s decision had passed and there was no apparent scope for further court action.

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  1. What impact has there been on antibiotic resistant bacteria with the release of the tetracycline dependent GM mosquitoes?

    Remember, they require an antibiotic bath of tetracycline so that their young grow up. The tetracycline was meant to have nothing to do with bacteria or infection, but e company has yet to show any culture data on the to be released adult GM mosquitoes. Fleming warned in his Nobel Prize speech that we should beware those who use antibiotics in dangerous ways. The United Nations recognized the problem in September as a crisis killing 700,000 people a year. Why Oxitec has not given this specific piece of data is a strong reason why a large number of Key Haven, Florida physicians petitioned to have the cultures done. It was not done and key Haven voted the test down. Is anybody looking at tetracycline resistance rates in the release area? Does the hospital in that area see a change in tetracycline resistance on its antibiotogram since the release?

    • Oxitec principal scientist Derric Nimmo said any risk of antibiotic resistance is “negligible.”

      “The problem of antibiotic-resistant S. aureus is a significant challenge to health and one that we take very seriously. So does the Food and Drug Administration. The FDA-led review team, which also included experts from the Centers for Disease Control and Prevention and Environmental Protection Agency, looked specifically into this issue and concluded that ‘the likelihood of the adverse effects associated with development of anti-microbial resistance is extremely low and the risk is negligible,’” Nimmo said in a letter to Norris.