The Food and Drug Administration on Friday tentatively approved a British company’s request to release its genetically modified mosquitoes in the Florida Keys, a trial aimed at slashing the number of insects that carry Zika virus.
Officials said the company, Oxitec, cannot perform its field test until the FDA digests public input and makes a final ruling. But for now, the agency said the proposal did not appear to pose a significant risk to humans and the local environment.
“The consequences of escape, survival, and establishment of [the modified mosquitoes] in the environment have been extensively studied: data and information from those studies indicate that there are unlikely to be any adverse effects on non-target species, including humans,” the FDA said in a statement of preliminary findings.
The effort is part of broader attempts to eradicate the pesky Aedes aegypti mosquito that carries Zika, which is blanketing Latin America and spreading locally in Puerto Rico.
Though many people do not show symptoms, the virus has been linked to serious birth defects and a syndrome that can cause paralysis.
“The more we learn about Zika in pregnancy, the more concerned we are,” Dr. Tom Frieden, the director of the Centers for Disease Control and Prevention, told reporters Thursday.
The World Health Organization recently called for additional field trials of genetically modified mosquitoes, as it prods Zika-affected nations to explore both old and new methods of mosquito control.
Oxitec reported in January that its modified male aegypti, which mate with wild females to produce offspring that do not survive into adulthood, were able to reduce wild mosquito larvae by 82 percent during trials in Piracicaba, Brazil, in 2015.
According to the FDA, the company would produce eggs of the modified mosquitoes in Oxford, England, and ship them to Marathon, Florida, for rearing in the lab before they are released down in Key Haven, Florida.
“We look forward to this proposed trial and the potential to protect people from Aedes aegypti and the diseases it spreads,” Oxitec CEO Hadyn Parry said.
Scientists say female mosquitoes do not seek new male partners after they’ve mated once in their short lifespans, so techniques that leave them with unviable offspring trim down the overall population.
On its website, Oxitec acknowledges that there “of course remains a small possibility, as with any new technology,” of unforeseen consequences.
But the company insists that its upside far outweighs any potential risks, and that it is targeting aegypti mosquitoes that are invasive to this part of the world, anyway.
The modified mosquitoes would die off within a few days, and wild-type aegypti would be expected to return to normal levels after the trial.
Also, the FDA found that “it is highly unlikely that release of [modified] male mosquitoes would contribute to the increase in transmission of dengue or other diseases transmitted by mosquitoes,” as the males do not bite people or other animals.
In the meantime, officials have been urging people in affected areas to wear insect repellant and long-sleeved clothing, and to wipe out areas of standing water where the mosquitoes breed.
The CDC also advised pregnant women to avoid travel to Zika-affected countries if they can. Studies have shown a dramatic surge in the number of babies born with abnormally small heads — a condition known as microcephaly — to women who’ve been infected.
“Puerto Rico remains a great place to visit, as long as you’re not pregnant,” said Dr. Frieden, who recently visited the island to get a firsthand look at its Zika response.
He said the island is on the “front line” of the battle against the virus, and risks seeing hundreds of thousands of Zika infections before the year is over.
Fearing the situation could get much worse, President Obama requested $1.9 billion in emergency funding from Congress to address the Zika outbreak at home and abroad, though House Republicans have told the administration to use leftover Ebola funds first, causing scientists to complain their agencies are being stretched thin.
“Funding from Congress is urgently needed,” Dr. Frieden said.
Though Zika is not transmitting locally in the states, there have been nearly 200 cases among travelers returning from affected areas, plus cases of sexual transmission to partners.
The outbreak is also affecting the U.S. military.
Navy Adm. Kurt W. Tidd, commander of U.S. Southern Command, told reporters this week that two servicemen — in Brazil and Colombia — were diagnosed with Zika. They’ve both gotten over the virus and returned to duty.
Also, a pregnant female service member in the region took advantage of a military policy that allowed her to return to the U.S. earlier than planned — a precaution to avoid Zika.
“This was just a very slight acceleration to an already scheduled departure,” Adm. Tidd said.
• Tom Howell Jr. can be reached at thowell@washingtontimes.com.
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