For over a year, a top concern for Texas agriculture experts has been the New World Screwworm flies, creeping closer to the U.S. from the south, laying eggs that feed on the living tissue of warm-blooded animals, but for many Texas ranchers, watching out for parasites like this has long been a part of doing the job.
In the 1950s, screwworm infestations devastated herds across the U.S., and were once considered eradicated with efforts from the then newly developed science of releasing sterilized flies to prevent the bugs from reproducing, but cases continued to appear in the decades after.
Dace Duke is a cattle rancher south of Coleman, in the very heart of Texas. He remembers working for a livestock company as a teenager when screwworms would come through on the cattle.
“We were getting in like, 1,000-2,000 head a day, and we'd get some in that had it,” Duke said. “It's just like they get into a sore and then you have to clean it out and stuff, put iodine on it.”
So far, most Texas cases that have developed have appeared in southern counties, but the pest is moving north quickly and is not restricted to cattle. One case identified in Andrews County in west Texas was linked to a dog from Lea County, New Mexico.
“People down south, I don't know what they're dealing with, really, you know,” Duke said. “I've experienced it, but it's been a long time ago, and you definitely know when you have it, because it's god-awful smells, dead animals smell, because it's rotten flesh.”
With new developments in the sterilized fly technique, state officials are cautiously optimistic, but they are putting pressure on the construction of a federal facility to respond to the threat.
U.S. Department of Agriculture Secretary Brooke Rollins joined Gov. Greg Abbott in a briefing on Monday at the Knipling-Bushland U.S. Livestock Insects Research Laboratory, discussing the state and federal response to the latest screwworm cases.
“Our amazing Kerrville scientists, a few standing behind me, are the teams that developed a novel strain for the sterile new world screwworm that doubles production output that we will soon be deploying,” Rollins said.
Rollins said this is a situation the department has been monitoring for over a year, but critics like Texas Ag Commissioner Sid Miller have argued the federal response has not been fast enough. When ground broke in April for a USDA facility in Edinburg to release the new sterilized flies, the goal was to produce 100 million flies per week with operational capability by November 2027, but Texas officials are saying it must be sooner if it’s going to slow a wide-scale effect on the livestock industry. In that time, they’re relying on the awareness of Texans.
Experts say the new world screwworm can often be easily treated in animals if it can be identified quickly.
Alongside the Texas Animal Health Commission, Texas Parks & Wildlife has also joined in the fight, as wild animals are expected to be a particularly tough place for targeting infestations.
Phillip Kaufman is a professor of entomology at Texas A&M University and chair of the Agrilife Task Force on New World Screwworm. He spoke to Texas lawmakers in May about the latest screwworm concern.
“We have other issues now that we didn't have 50-60 years ago,” Kaufman said. “We have a thriving wildlife population, particularly in South Texas. The white-tailed deer population in the 60s was probably at about 1.5 million or so across the state. We're over 6 million white-tailed deer now. We have huge numbers of feral hogs. We have all these exotics, all of those are hosts that will only amplify the number of flies in the environment, and all of those animals are next to impossible to capture and treat, and so they are going to be a source of fly populations that the livestock producers are going to be dealing with the impacts of.”
Those livestock producers have already been dealing with issues like rising input costs from fuel and materials, drought, and a consolidating cattle industry leading to the smallest U.S. cattle herd in 75 years. As this new fly settles in open wounds, like the navel areas of newborn calves, there’s a concern that the herd could continue shrinking. Kaufman said it could have a $1.8 billion impact on the Texas cattle industry, but he’s confident in Texas producers doing their part in an emergency.
“What we talk to producers constantly about, and AgriLife is in the education business, is to be proactive rather than reactive,” Kaufman said. “Ranchers have management plans for hurricanes if you live in the coastal bend. If you're in the panhandle, you have wildfire emergency plans. Develop a screwworm emergency plan. What are you going to do if and when it shows up?”
Texas A&M AgriLife Extension, in coordination with the Texas Animal Health Commission, is expected to publish a New World Screwworm Training Module, so ranchers can be certified to inspect their animals.
On the ranch, Dace Duke is still going about his business, but he’s also recommending a closer eye for cattle raisers.
“You just have to really watch them. If you've got a bunch of cattle and a bunch of brush, it's very difficult,” Duke said. “You've got to get on horseback and get in there and check them all.”
Duke said he’ll still be going to the sale barns and taking care of his cattle, even if the work just got a bit tougher, and he gave a very simple reason for it:
“Everybody tells me, 'Why don't you quit?’ You know, you know, relax a little bit. I said, yeah, but I enjoy it, so I'm just gonna keep on going,” Duke said.
Suspected cases can be reported to the Texas Animal Health Commission 24-hour veterinarian call line at 1-800-550-8242.
People who observe deer, feral hogs, or other wildlife showing signs of infestation or unusual wounds are asked to report it immediately to the Texas Parks and Wildlife Department biologists at 512-389-4505.