Sign up for TPR Today, Texas Public Radio's newsletter that brings our top stories to your inbox each morning.
Every Friday morning, cattle are prodded into the auction ring at the Beeville Livestock Commission. An auctioneer’s rapid-fire sales pitch rises above the bawling of cattle as buyers place their bids.
As the buyers talk among themselves, they trade stories and concerns about the latest threat to their herds — the New World screwworm.
Nearby, a brand-new U.S. Department of Agriculture poster hangs on the auction house’s bulletin board. It warns ranchers about the screwworm, a parasitic fly whose larvae burrow into wounds and feed on the living tissue of livestock, pets and wildlife.
The United States eradicated screwworm in the 1960s and eventually pushed it as far south as the Panama-Colombia border. It was kept contained across the Darién Gap. But the parasite has returned.
As of Thursday morning, there are 19 confirmed cases in Texas and another found in a dog in New Mexico. New cases are confirmed almost every day, and the spread has been moving from county to county in Texas.
“It’s here, and we’re going to have to deal with it,” said Donald Huser, who operates Coastal Bend Feed, a ranch-supply store in Beeville, about 100 miles southeast of San Antonio.
Huser said the federal government should have prepared more aggressively after screwworm began advancing through Mexico two years ago. He said the antiparasitic drug Dectomax, which can be used to treat screwworm infestations, has been difficult to obtain since the first U.S. cases were announced.
“They watched it progress through Mexico,” Huser said. “They could have got with these big pharma or whatever and started mass producing, like, Dectomax and had a bunch prepared for us.”
Huser also worries that some ranchers may treat suspected infestations themselves rather than alert authorities because they fear their animals will be quarantined.
“What are they going to do?” he asked. “Are they going to come in and quarantine your herd? How long are they going to quarantine it for?”
Texas Agriculture Commissioner Sid Miller said ranchers have expressed similar concerns to him.
“I had ranchers tell me, ‘I’m not reporting it. I don’t want to be locked down. I’m just going to treat it and shut up,’” Miller said.
The USDA has since clarified that the discovery of an infected animal will not automatically result in an entire ranch being locked down. Miller said that clarification should make livestock owners more willing to report suspected cases.
Under Texas’ emergency response rules, suspected screwworm infestations must be reported to the Texas Animal Health Commission within 24 hours.
The federal government is also releasing sterile male screwworm flies. When the sterile males mate with wild females, the females produce no viable offspring, gradually reducing the fly population.
Agriculture Secretary Brooke Rollins has acknowledged that the current supply of sterile flies is insufficient. The USDA is building a production facility in South Texas that is expected to produce hundreds of millions more. It's not expected to be operational until May 2027.
“Our goal is to have enough sterile flies deployed and out into Texas, and wherever else this happens to be, before the next summer season pops up,” Rollins said.
Huser said inspecting and treating livestock will not be enough to halt the parasite because wild animals can also serve as hosts.
“Yes, you can check all of your cattle and everything else, but you’re not going to catch all your deer,” he said. “Those are going to be our hosts in this fight.”
Texas has more than 5 million wild deer, according to the Texas Parks and Wildlife Department. Before screwworm was eradicated, the state’s deer population was significantly smaller, and historical estimates indicate the parasite killed 80% of newborn fawns.
Dr. Gaylon Wilmeth-Burleson, a South Texas veterinarian, said controlling screwworm in wildlife is particularly difficult.
“Unfortunately, with wildlife, there is no proven treatment,” she said.
Wilmeth-Burleson said older generations remember when screwworm infestations helped keep South Texas deer populations low.
“My dad can tell me stories about when he was a kid,” she said. “We didn’t have a lot of deer down here because of screwworm infestations.”
A major decline in the deer population could also damage the South Texas economy. The region is internationally known for producing large white-tailed bucks, and hunting generates substantial income for landowners, outfitters and rural businesses.
State officials are asking hunters to inspect harvested deer for signs of screwworm and report suspicious wounds. But the general deer season does not begin until November.
Until then, livestock producers, veterinarians and wildlife officials face a difficult task: finding and containing a parasite that can move through both managed herds and millions of wild animals.
