More than 101 million sterile screwworm flies have been released in the Keys

Antiparasitic medicine for endangered Key deer and an abundance of sterile New World screwworm flies continue to help fight the screwworm situation in South Florida.

More than 101 million sterile screwworm flies have been released by the U.S. Department of Agriculture in Marathon and the Lower Keys since October. In Homestead, where a stray dog was found with a screwworm infestation in December, nearly 2 million have been released.

They help to drive down the number of fertile flies by mating with wild flies to produce eggs that never hatch. Screwworms feed inside the open wounds of any warm-blooded living animal, which has resulted in the deaths of 135 endanger Key deer found only in Monroe County. Some have had to be euthanized and others have died from their screwworm-inflicted conditions.

The last time a Key deer was found with a screwworm infestation was Jan. 7, according to Ken Warren, spokesman for the U.S. Fish and Wildlife Service.

“That’s the longest we’ve gone yet without any cases,” he said, adding Florida could be declared screwworm-fly free as soon as June. “The trends are positive but there’s still work to be done.”

Warren said in order for the USDA to declare the state completely eradicated of screwworm, there has to be a three- to four-month span of no screwworm cases.

Refuge officers and volunteers continue administering doses of antiparasitic medicine doramectin to Key deer. Warren said a total 13,003 doses have been administered.

There have not been any other screwworm cases reported in the Homestead area, according to Jenn Meale, communications director for the state Department of Agriculture and Consumer Services.

A roadside checkpoint in Key Largo is still open for pet owners traveling out of the Keys where federal officials examine their pets for New World screwworm. So far, no cases have been found in the 12,925 inspected animals leaving the Keys since the 24-hour northbound checkpoint opened in early October.

This story was originally published February 4, 2017 at 1:06 PM with the headline "More than 101 million sterile screwworm flies have been released in the Keys."