Oxitec rep explains ‘14.3 million mosquitoes’ in FDA report

As time passes, more questions buzz around about the potential release of genetically modified mosquitoes in the local fight against Zika virus.

A lengthy environmental assessment released by the U.S. Food and Drug Administration last month holds the answers to those questions about British biotech company Oxitec’s possible release of the mosquitoes in the Lower Keys neighborhood of Key Haven.

But some of the information in the 138-page document requires clarification, such as a paragraph that states more than 14 million Aedes aegypti mosquitoes would be released — almost five times more than previously reported — over a two-year period. Aedes aegypti carry the Zika virus, which can cause birth defects in the newborns of women. For others, it causes flu-like symptoms.

An estimated one female per 500 of male genetically modified mosquitoes released is also in the document, which breaks down to 28,704 biting females among 14.3 million, or 62 female mosquitoes per person in the 460-resident testing area.

Derric Nimmo, product development manager at Oxitec, explained the numbers on Thursday.

“That’s an absolute maximum amount of time,” he said of the two-year trial, and as with any environmental assessment, Oxitec was required to provide the timeline as a protocol. “This trial is very likely to take about nine months and about 3 million males. It’s not like we’d release 14 million all at once.”

About the females that wind up mixed in with the males, Nimmo said Oxitec has improved its sorting ability.

“Only about one in every 10,000 males is a female. The FDA report does say more than that, but that’s because the Panama trial was done in 2014,” and those numbers were included in this year’s report for Key Haven, Nimmo said.

Oxitec has performed three trials in Brazil, one in Grand Cayman and another in Panama. Those locations are no longer in trial stages, Nimmo said, and genetically modified mosquitoes will soon be released over more populated areas.

“We don’t want to release females. In fact, if we could get rid of all the females, we would, but there’s no technical harm in releasing them,” he said. “The females still carry the gene.” That gene makes them die within about five days of release. Genetically modified males die off within two or three days.

Oxitec says the offspring of its GM mosquitoes die almost immediately, resulting in a smaller population of Aedes aegypti. In two nonbinding referendums on Nov. 8, Keys residents will vote for or against the release of the mosquitoes in Key Haven. One vote is for Key Haven residents, the other for voters countywide.

Katie Atkins: 305-440-3219