The New World screwworm, which can kill livestock within two weeks, was found on animals in Big Pine Key and No Name Key in Florida earlier this month, according to the U.S. Department of Agriculture.
There have been no human or livestock cases, the Florida Department of Agriculture and Consumer Services said.
"The screwworm is a potentially devastating animal disease that sends shivers down every rancher's spine. It's been more than five decades since the screwworm last infested Florida, and I've grown up hearing the horror stories from the last occurrence," said Adam Putnam, Florida Commissioner of Agriculture.
Using sterile flies to breed the insect out of existence has worked in the past. The USDA used the technique in Florida in 1957. By 1959 the flies were gone. It was used more extensively throughout the south and southwest to completely rid the area of the insect by 1982.
While not considered an infestation, the screwworm has been found in the U.S. since then. A dog that entered the country from Trinidad and Tobago in 2007 was found with screwworm larvae. Another dog was found with screwworm larvae in 2010 when it came to the country from Venezuela.
"This foreign animal disease poses a grave threat to wildlife, livestock and domestic pets in Florida," Putnam said. "Though rare, it can even infect humans. We've eradicated this from Florida before, and we'll do it again."