(Radio Iowa) – The first human case of a dangerous, flesh-eating parasite has been confirmed in the United States, in someone who recently traveled to El Salvador, and U.S. Agriculture Secretary Brooke Rollins warns the “New World Screwworm” could devastate cattle herds if it reaches the U.S. “The New World Screwworm is a real threat to America…The last time it really hit our shores was in the ’50s and ’60s. It took 30 years for our cattle industry to recover,” Rollins said at a press conference during the Iowa State Fair. The U.S. Department of Agriculture is building a facility in Texas, near the southern border, to produce and release hundreds of millions of sterile flies in hopes of eradicating the pest in Mexico before it reaches the U.S. “The last case of the screwworm that was an isolated case, but nevertheless a case, was found about 370 miles south of the Texas border,” Rollins said.

U.S. Agriculture Secretary Brooke Rollins spoke at a news conference before participating in the Governor’s Charity Steer Show at the 2025 Iowa State Fair. (RI photo)

In July, the Mexican government announced it was building a $51 million facility that will also produce and release sterile flies in hopes of pushing the screwworm population further south to the border between Panama and Colombia. Rollins said teams of USDA employees will be dispatched to Mexico, too. “We are staffing up in the hundreds to get down into Mexico so we can trust, but verify the data they’re giving us,” Rollins said. “That’s part of the problem. We’re relying on Mexico which has some significant cartel issues, significant funding issues, so we’re really grateful for their partnership, but we’re going to trust, but verify with our own teams down there.”

The U.S. government has stopped imports of live cattle from Mexico and the USDA is training dogs that will be able to detect screwworm infestations in animals at U.S. border crossings.