November 26, 2020

Plan to stop dengue fever in US

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This 2006 photo made available by the Centers for Disease Control and Prevention shows a female Aedes aegypti mosquito acquiring a blood meal from a human host at the Centers for Disease Control in Atlanta. Scientists have made a promising advance for controlling dengue fever, a tropical disease spread by mosquito bites. They've rapidly replaced mosquitoes in the wild with skeeters that don't spread the dengue virus. The report is to be released in the Thursday, Aug. 25, 2011 issue of the journal Nature. (AP Photo/Centers for Disease Control and Prevention, James Gathany)

A plan to introduce genetically modified mosquitoes in the Florida Keys to try to stop the spread of dengue fever is waiting for state and federal approval.

The Florida Keys Mosquito Control District is working with England-based Oxitec on the project, which would release the mosquitoes sometime in 2012.

The district’s executive director, Michael Doyle, tells The Key West Citizen that officials are waiting for federal and state approval to test the program’s technology. It would be the first such project in the U.S.

Keys officials want to reduce populations of the Aedes aegypti mosquito, a common urban mosquito known to transmit dengue fever, a flulike virus that is also known as breakbone fever because of the intense joint pain it causes in extreme cases.

The illness once disappeared from the United States, but cases were reported in the Keys in 2009 and 2010. There were no documented cases in 2011, according to the Monroe County Health Department.

The genetically modified mosquitoes would be bred in a lab and then the males, which don’t bite, would be released into the wild. Their offspring would die early in their life cycles, theoretically suppressing the mosquito population.

Between 5,000 and 10,000 of the mosquitoes would be released over a two-week period into an undisclosed 36-square-acre block near the Key West Cemetery, where the first case of dengue fever was reported. The initial trial is expected to last about two months, and the mosquitoes would be dusted with a fluorescent powder for identification purposes and then trapped to see how far they are flying.

Trials in the Cayman Islands in 2009 and 2010 were successful in wiping out 80 percent of the mosquitoes in one test area, said Oxitec Chief Executive Officer Hadyn Parry.

Meanwhile, the environmental group Friends of the Earth has published a report questioning the program’s costs and long-term impact on the Keys environment.

“While attempts to limit the spread of disease are laudable, there are many regulatory, environmental and ethical challenges facing the release of GE (genetically engineered) mosquitoes in the United States and there are even more unanswered questions,” the group wrote. “The behaviour of these mosquitoes and the risks they pose to human health and the environment are hard to predict, leaving the public with more questions than answers.”

The program could cost between $200,000 and $400,000 a year, Doyle said.

Doyle said concerns about the program’s environmental impacts, including the potential for other disease-carrying invasive species to fill the mosquitoes’ niche, would be addressed over the next several months in the permitting process.

“Do keep in mind that none of this will happen unless the agencies approve it,” Doyle said. “Regardless, we have plenty of time to look at these issues in depth, and if everyone is convinced it’s worth doing, we’ll open it up for public discussion long before starting any field experiments.”

The federal government is still working out which agency would permit the test, Doyle said.

The genetic modification program is an alternative to pesticides and would allow officials to target specific species, Doyle said.

Removing the Aedes aegypti mosquito would likely have little impact on the Keys ecosystem because it is a non-native species that came from Africa, Parry said.

“It is promising enough to try it,” Doyle said.

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