Five months after the New World screwworm was detected in the United States for the first time in more than 30 years, the pest, a maggot that kills animals by eating their flesh, has been eradicated, said USDA’s Animal and Plant Health Inspection Service. No new cases have been reported since Jan. 10 in Florida.
USDA chief veterinarian Jack Shere said close to 150 million sterile flies were released during the eradication effort, which began last October. The sterile flies disrupt reproduction of the screwworm flies and steadily cut into the population. Eradication is achieved three life cycles after the last detection of the screwworm; a life cycle is 21 days.
The eradication drive was triggered by the discovery of New World screwworm in Key deer in a federal refuge on Big Pine Key last Oct. 3. Infestations were found in Key deer on a dozen other of the keys off the Florida peninsula. The USDA says adult screwworms usually do not travel more than a couple of miles when suitable hosts — animals with open wounds — are available, so the most likely pathway for the screwworm to reach the Keys was transport of larvae by a human or an animal.