New World screwworm flies have now caused the euthanization of nearly 10 percent of the endangered Key deer population — and things could get worse before they get better now that the flies have been found on more than just Big Pine and No Name keys.
Entomologists with the U.S. Department of Agriculture said Tuesday they observed a screwworm-infested Key deer on Summerland Key, and screwworm flies have been found on Big Torch, Middle Torch, Little Torch, Cudjoe and Ramrod keys. That’s the first time agriculture officials confirmed the flies have gone beyond Big Pine and No Name.
As of Tuesday, the parasitic larvae had caused the euthanization of 97 Key deer — 67 in the past two weeks — among the 1,000-member herd of Key deer, found only in the Florida Keys.
Kate Watts, lead biologist at the National Key Deer Refuge, said the USDA observed the screwworm-infested Key deer on Summerland Key, but that she and other officers at the refuge had not been able to verify infected deer anywhere other than Big Pine and No Name.
Screwworm flies lay their eggs in open wounds where larvae hatch and feed, basically eating the deer alive. Many of the deer wounds are believed to come from rutting — males battling each other for mates.
USDA entomologists have been trapping and identifying flies in other areas while the release of millions of sterile screwworm flies on Big Pine and No Name to mate with female flies began last week. Female screwworm flies mate only once in their lifetime, storing male sperm to fertilize eggs in the future, so if it mates with a sterile male the life cycle is broken. The process could take six months.
Key deer inhabit 20 to 25 islands in the Lower Keys, ranging from No Name and Big Pine Key westward to the Sugarloaf Keys, according to the refuge website. The presence of the parasitic larvae for the first time in 50 years in Key deer, which grow to only about 3 feet tall, prompted the USDA to declare an agricultural emergency on Oct. 3.
Watts urged pet owners to continue checking their animals for any wounds they may have, as Proactive pet owners had their cats and dogs inspected for New World screwworm on Sunday at Winn-Dixie on Big Pine Key and none of the 75 pets showed signs of the parasitic larvae, officials said.
A pet inspection checkpoint at mile marker 106 in Key Largo remains open. Federal and state officials are inspecting pets for signs of the screwworm. As of Tuesday, 883 pets had been inspected and none were found to have screwworm.