In a follow-up on the first screwworm infestation in the United States in decades, and the first in Florida in half a century, the number of endangered Key deer that needed to be euthanized because of the deteriorated condition caused by the screwworm is in the dozens since September (Florida Department of Agriculture and Consumer Services reported more than 50 on Oct. 9).

putnamAccording to the Florida Department of Agriculture, The Key deer, a subspecies of the white-tailed deer, are federally endangered and live solely on islands in the lower Florida Keys from Little Pine Key to Sugarloaf Key and a few surrounding small islands. This is the only place in the world where Key deer are found, and in the 1950s, only 25-50 of these deer were in existence. Since the National Key Deer Refuge was established in 1957 and the Key deer became one of the first species protected under the Endangered Species Act, their population has climbed back up to approximately 1,000 individuals with the core population on Big Pine Key and No Name Key.

Earlier this month, Commissioner of Agriculture Adam Putnam declared an agricultural state of emergency in Monroe County.

The U.S. Department of Agriculture and the Florida Department of Agriculture and Consumer Services, as well as partnering agencies, are implementing an aggressive eradication effort in order not only to protect the Key deer, but also to protect human health, Florida’s livestock industry, and other animals including pets should the pest spread.

Some local pets and other deer have showed signs of infestation.

“While it sounds like a Halloween joke, it poses a grave threat to the last population of the subspecies of Key Deer,” Putnam said. “And if it gets beyond the Keys, it represents an enormous threat to the US livestock industry, because of potential quarantines and trade barriers that could occur if it gets into the livestock population.”

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 or, in the case of newborns, the navel. They feed on the animal’s living flesh and, if not treated, infestations can be fatal. While New World screwworm (Cochliomyia hominivorax) has not been widely present in the United States since the 1960s, it is still found in most of South America and in five Caribbean countries.

In the 1950s, USDA’s Agricultural Research Service developed a new method to eradicate the pest using a form of biological control called the sterile insect technique. Infertile male flies are released in infested areas. When they mate with local females, no offspring result. With fewer fertile mates available in each succeeding generation, the fly breeds itself out of existence.

USDA began using this technique in Florida in 1957 and eradicated the flies from the entire southeastern United States by 1959. The technique was next applied to the more extensively infested Southwest in 1962. By 1966, self-sustaining screwworm populations were eliminated from the United States.