Food supply threatened by 'flying piranha' putting 'fist-sized holes' in animals: report

Once thought to be eradicated, the screwworm could be screwing up our food supply as soon as this summer, according to a Bloomberg report.

The screwworm affected live stock ranchers from the 1930s through he 1980s.

The insect is essentially a “flying piranha” that eats its host from the inside out and has the ability to kill a full-grown steer in 10 days.

Eggs are laid in a wound, eye, or even the nose, or the udders of any animal. The eggs then hatch into larvae, which burrow or “screw” deep into the host’s flesh.

“The larvae eat around and down until there is a hole inside the animal the size of your fist,” Rick Tate, a lifelong rancher from Marfa, Texas, told Bloomberg.

After three to five days, the larvae turn into a fly and begin to reproduce.

Experts warn it could be back by this summer as nearly 1,000 cases have been reported in Mexico this year.

It isn’t exclusive to farm animals; it also impacts wildlife, including deer, squirrels, raccoons, and birds.

It’s also been found in horses, dogs, “and at least one goat,” according to the USDA.

The worm has also infected humans: In 2024, screwworms were found in the leg of a Canadian man after a trip to Costa Rica.

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While the screwworm was detected in the 1930s, it wasn’t until after WWII that the USDA could fight it.

They used airplanes to drop hundreds of millions of sterilized flies over infected areas. This caused the sterile flies to mate and overwhelm the reproduction of native flies, essentially rendering the population infertile.

Some called the program “wasteful federal spending,” but by 1982, it pushed the screwworms out of the United States to the Darien Gap in Panama.

The Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG) was keeping the fly at bay until the pandemic, when a “perfect storm” happened.

The number of inspectors looking for the screwworm border decreased. Sterile fly production also slowed because of supply-chain issues. At the same time, the illegal transport of cattle across borders increased as millions of people began moving north through the Darien Gap.

Now the screwworm is making a comeback, and ranchers are attempting to stop it once more before it impacts our wildlife and food supply, the report states.