USDA races to contain New World screwworm fly in Texas

(NewsNation) — A parasitic fly whose larvae eat animals alive has reached U.S. soil, with agriculture officials racing to contain it before it spreads.

The U.S. Department of Agriculture (USDA) confirmed Wednesday the New World screwworm fly was found in a calf in La Pryor, Texas, about 50 miles from the Mexican border.

It’s the first confirmed case in Texas since 1966 and only the third time in decades that the pest has appeared in the United States at all. Agricultural inspectors in Florida stopped a case of the screwworm from entering the U.S. on an imported horse from Argentina in early February.

What makes screwworm flies so dangerous?

Female New World screwworm flies lay eggs in open wounds, noses, ears, eyes or mouths of any warm-blooded animal. The eggs hatch into larvae that burrow deeper into living flesh. If left untreated, infestations can be fatal.

The pest can affect livestock, wildlife, pets and, in rare cases, humans.

Texas has the largest cattle herd in the nation, and that herd is at its lowest level in 75 years. Tight beef supplies have already pushed prices to record highs for consumers. An unchecked screwworm outbreak could devastate ranchers. In today’s dollars, estimated losses for Texas alone could reach $1.8 billion, according to Reuters.

How did the screwworm get here?

The screwworm was eradicated from the U.S. in the 1960s through a program that released massive numbers of sterilized male flies to mate with wild females to produce eggs that would never hatch. It stayed contained in Panama until 2021. By 2024, it had reached Southern Mexico. The country has since confirmed more than 27,000 cases, with more than 2,000 currently active.

U.S. and Texas agriculture officials have warned about the fly for over a year. USDA efforts have included releasing 100 million sterile flies weekly along the border and deploying 8,000 fly traps.

What’s being done now

Secretary of Agriculture Brooke Rollins says response teams are already on the ground in South Texas. A 12-mile quarantine zone has been established around the detection site. Officials have expedited sterile fly releases in the area.

Rollins says the USDA is confident that there is “no threat of mass infestation” and stressed that the food supply is not at risk. That’s because the parasite doesn’t spread through meat, poultry or dairy.

Texas Agriculture Commissioner Sid Miller, however, says the federal response hasn’t been enough. He’s urging President Donald Trump to deploy an additional pest-suppression system that uses targeted insecticides alongside the sterile fly program.

A new sterile fly production facility is under construction in South Texas but isn’t expected to be operational until fall 2027.

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Mexico News Daily

USDA races to contain New World screwworm fly in Texas

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