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Hideous, live-flesh-eating maggots, eradicated from the US since 1983, have made an appearance in the Florida keys.

October 13, 2016

2 Min Read


The United States Department of Agriculture's (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the presence of New World screwworm in deer from a wildlife refuge in Big Pine Key, Florida.

USDA's National Veterinary Services Laboratories in Ames, Iowa, confirmed this is a local infestation of New World screwworm, which has been eradicated in the United States for more than 30 years.

Florida Commissioner of Agriculture Adam H. Putnam declared an agricultural state of emergency in Monroe County, Florida.


“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,” Putnam said.

Beef Producer covered the history of the screwworm in a 2011 historical article.

In addition to the samples from three Key deer that were confirmed positive for screwworm, officials said other deer from the same refuge and a few pets in the local area exhibited signs of screwworm over the past two months, although no larvae were collected and tested in those cases. All of the potentially affected animals are from the same area of Big Pine Key and No Name Key. There have been no human or livestock cases. Human cases of screwworm are rare, but have occurred

Animal health and wildlife officials say the initial goal will be to keep the infestation from spreading to new areas, while eradicating the screwworm flies from the affected Keys.

screwworms are fly larvae (maggots) that can infest livestock and other warm-blooded animals, including people. They typically enter an animal through an open wound and feed on living flesh.

Adult flies generally do not travel more than a couple of miles if there are suitable host animals in the area, although they can fly much farther under ideal conditions. The screwworm is more likely to spread long distances when infested animals move to new areas and carry the pest there.

USDA's technique to eradicate screwworms from the US via release of sterile male flies has pushed the screwworm south of a "sterile fly barrier" at the Darien Gap between Panama and Colombia with the hopes of preventing the establishment of any screwworm flies that enter from South America. You can read the history of the screwworm eradication here.

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