The first local infestation of New World screwworm in the U.S. in more than 30 years has been confirmed in Florida.
The Texas Animal Health Commission (TAHC) was notified of the infestation on Oct. 3 by the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA APHIS). New World screwworm was confirmed in Key deer at the National Key Deer Refuge in Big Pine Key, Fla.
TAHC says if this pest became established in the U.S. again, it could have a devastating impact on the country’s livestock industry and for wildlife.
New World screwworms are fly larvae (maggots) that can infest livestock and other warm-blooded animals, including people. They most often enter an animal through an open wound and feed on the animal’s living flesh. Infested animals that are not treated in seven to 14 days may die.
While they can fly much farther under ideal conditions, adult flies generally do not travel more than a couple of miles if there are suitable host animals in the area. New World screwworm is more likely to spread long distances when infested animals move to new areas and carry the pest there.
Livestock and wildlife owners are advised to immediately contact their TAHC regional office or local veterinarian if they suspect an animal may be infested with screwworm larvae.
In response to this infestation, Florida Commissioner of Agriculture Adam H. Putnam declared an agricultural state of emergency in Monroe County, Fla. Additional deer from the same refuge and a few pets in the local area exhibited potentially similar infestations over the past two months, though no larvae were collected and tested in those cases.
All of the potentially affected animals are from the same Key. There have been no human or livestock cases.
In the 1950s, USDA developed a new method to help eradicate screwworm, using a form of biological control, called the sterile insect technique, which releases infertile male flies in infested areas. When they mate with local females, no offspring result. With fewer fertile mates available in each succeeding generation, the fly, in essence, breeds itself out of existence. USDA used this technique to eradicate screwworm from the U.S. and worked with other countries in Central America and the Caribbean to also eradicate it there.
USDA’s announcement on the New World screwworm can be found at http://www.tahc.texas.gov/news/2016-10-03_USDAScrewworm.pdf.