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A parasite that hasn't been seen in the United States since the 1960s officially made a return on Wednesday.
Nebraska Cattlemen President Craig Uden previously warned Nebraska producers about the New World Screwworm threat, but now that it's here, his tone has shifted.
The U.S. Department of agriculture confirmed a New World Screwworm detection in a three-week-old calf in Zavala County, Texas, about 60 miles from the U.S.-Mexico border.
Uden, who in March warned that response efforts might not be ready before the parasite's inevitable arrival, said coordination between state and federal agencies has improved significantly since then.
"It's been very well prepared for, it has arrived," Uden said. "The U.S. beef supply is safe. This is an infestation, not a disease. So, it can be treated and not have any bearing on the product. We'll still produce very wholesome, safe, high-quality product."
Uden said that outside the established zone in Texas, it's largely business as usual, still putting emphasis on the added vigilance of cattle movement. For Nebraska producers specifically, he said the risk remains low.
"Nebraska producers just need to know where their cattle are coming from and make sure that, if they're bringing cattle in out of a different region, that they look over those cattle really well," Uden said. "There's not a real big concern up there at this time."
He added that Nebraska's cooler weather works in the state's favor.
"When the weather cools down, the cold weather will eliminate the flies," he said. "It's more of a summertime issue if it was going to be."
Dr. Matt Hille, an assistant professor and diagnostic pathologist at the University of Nebraska-Lincoln's Nebraska Veterinary Diagnostic Center, largely agreed with Uden's reassuring message, but he still questioned production of the United States' main defense to the pest.
Sterile flies, when released into the wild, mate with normal flies but produce no offspring — gradually collapsing the population. A Texas facility currently under construction will produce sterile flies at scale, but it is not yet operational. Hille says with no fully functioning facility in the United States, the best the country can do right now is buy producers some time.
"The issue we have right now is our capacity to produce enough sterile flies," Hille said. "The unfortunate thing is it just simply takes time to get these extra facilities up and running. We need to bide our time until we get enough of those flies."
He said that shortage helps explain why the parasite has been able to push northward at all.
"The reason it's continued to go northward is we haven't had enough flies to even stop it where it was, let alone slow the progression," Hille said. "There is going to be a little bit of a gap — and all the more reason for folks to just be diligent."
Hille said it's critical that producers in Nebraska know what to look for. The biggest red flag, he says, is maggots or larvae on a living animal. He stressed that maggots on a dead carcass are common and not cause for concern — it is only when they appear on a live animal that producers should be alarmed.
"If you see that and you're seeing physically maggots or larva on a live animal, that would be the biggest red flag in terms of screwworm," he said.
Hille said common ranching practices can create potential entry points for the fly.
"Any sort of wound or opening, laceration, any sort of break in the skin — castration is a very big one," Hille said. "And then the umbilical exposure in neonates are very common."
He added that most of Nebraska's spring calving is wrapping up, which reduces a potential risk window, for now.
Despite the current gap in sterile fly production, Hille said he is confident in the long-term response, pointing to the same sterile fly technique used to eradicate screwworm in the 1960s.
"We did it before, and we have the blueprint to do it," Hille said. "It was extremely successful back then. I see no reason that we wouldn't be as successful, or potentially even more efficient in doing that once we get enough flies.”
Hille said the veterinary profession has used the past two years of escalating threat to prepare for a pest most practicing vets had never encountered.
"A lot of veterinarians probably weren't near as up to date on their screwworm knowledge," he said. "But seeing the threat become more and more real has given us time, as a profession, to become collectively more educated and prepared."
New World Screwworm is a reportable disease. Hille said any producer who suspects an infestation should contact their local veterinarian or the Nebraska Department of Agriculture immediately and not move any animals.
Nebraska Cattlemen will hold an in-depth discussion on the screwworm threat at their summer meeting in Kearney on Thursday.