USDA Detects Possible New World Screwworm In South Texas, Sends Sample To Iowa Lab

The U.S. Department of Agriculture said a possible case of the New World screwworm was detected in South Texas, and the potentially-infected sample was sent to a USDA lab in Iowa for confirmatory testing.

“Federal officials are investigating what could become a significant development in the ongoing battle against New World Screwworm, announcing Tuesday that a potential case has been detected in South Texas and is undergoing confirmatory testing”

AGDAILY

The USDA said on social media, "We have already activated personnel on the ground and are working with local partners," and it added, "What you can expect from us is transparency, candor, and most important — action."

AGDAILY

Reuters reported that samples from two calves on a cattle ranch in La Pryor, Texas were taken on Tuesday and sent to a federal lab in Iowa, and Texas Animal Health Commission told Reuters there has been no confirmed case of New World screwworm in Texas.

The Texas Tribune said the USDA is testing the sample at the USDA’s National Veterinary Services Laboratories in Ames, Iowa, and it noted the suspected case would be the first in the U.S. if confirmed.

CBS News said the potential case was found in southern Texas and that a sample was sent to the USDA's National Veterinary Services Laboratories in Ames, Iowa for confirmation.

The announcement came after Texas state Rep. Don McLaughlin said the fly was just one mile away from the Texas-Mexico border, a claim USDA officials publicly pushed back on.

MySA reported that Agriculture Secretary Brooke Rollins told reporters during a press call on Tuesday, June 2, according to reporting by Beef Magazine, "This is not true — we have no confirmed case within one mile of the border."

Agrolatam

AGDAILY said USDA’s earlier response on social media stated, "This is not true. We have no confirmed case within 1 mile of the border," before federal officials said a suspected case was being investigated in South Texas.

CBS News said the screwworm detected in Mexico was found in a 5-year-old goat on May 28 in Mexico's Coahuila state, and it said the USDA tracked 32 cases of the parasitic fly throughout Coahuila, including 19 active cases.

USA Today reported that USDA data showed New World screwworm was detected about 25 miles from the southern border in Coahuila, and it quoted Dr. Michael Payne saying it "does significantly raise the urgency and perhaps may lead to an increase in resources" to accelerate prevention plans.

Texas officials and federal agencies have been preparing for the possibility that the parasite could cross into the state, with the Texas Tribune saying the USDA announced the suspected case in South Texas and that it would mark a significant development for Texas livestock producers and wildlife officials.

“A possible case of New World screwworm has been reported in South Texas”

Ars Technica

The Houston Chronicle said the USDA has taken steps to prevent the advancing epidemic from impacting U.S. herds, including closing the border to cattle and building a planned $8.5 million facility in South Texas to disperse sterile screwworm flies.

WATE 6 On Your Side reported that a screwworm outbreak could cost Texas around $1.8 billion annually, with cattle producers facing $735 million to $745 million in losses each year, and it said the state’s $9.6 billion hunting industry also faces risk as 80% of Texas white-tailed deer were wiped out during a 1960s outbreak.

The Texas Tribune said the USDA shut down the southern border to live animal imports in May 2025, preventing cattle from Mexico from entering the U.S., and it described efforts to eradicate the pest using the sterile fly method.

WATE 6 On Your Side quoted Andrew Mahaleris, a spokesman for Abbott, saying, "If the case is confirmed positive, the NWS Response Team will immediately establish an incident response post," and it said the response would include restricting animal movement to prevent further spread.