The New World screwworm Texas threat reached a new level of urgency on April 10, 2026, when Texas Agriculture Commissioner Sid Miller confirmed that the parasite had been detected in the Mexican state of Nuevo León, only 90 miles from the U.S.-Mexico border. Miller described the situation as a direct and imminent threat to Texas ranchers, the livestock industry, and the food supply, saying the state was moving aggressively to stay ahead of it. He urged all producers to inspect their animals daily, check every open wound, and report anything unusual immediately, directing them to the federal information resource at screwworm.gov.
The Nuevo León detection is the northernmost New World screwworm case confirmed to date in this outbreak. Miller said openly that despite steps taken by the USDA, the spread of the parasite has not been successfully contained, and that this failure underscores why Texas must be proactive rather than waiting for federal containment to succeed. He called it a high-stakes situation with zero margin for delay, saying that early detection is the difference between containment and a full-blown crisis.
New World screwworm Texas alarm follows months of escalating detections
The April 10 warning from Commissioner Miller did not come out of nowhere. The outbreak has been building since late 2025, moving steadily northward through Mexico. In early January 2026, USDA’s Animal and Plant Health Inspection Service confirmed an active case in González, Tamaulipas, just 215 miles from the Texas border — the third active case in that state. By January 15, the total confirmed cases in Tamaulipas since December 30, 2025, had reached eleven. By early February, Texas Governor Greg Abbott had issued a statewide disaster declaration, directing the Texas Parks and Wildlife Department and the Texas Animal Health Commission to establish a joint Texas New World Screwworm Response Team.
The response has included a significant federal commitment. Texas officials partnered with USDA Secretary Brooke Rollins to fund a new $750 million domestic sterile fly production facility in Edinburg, Texas. The sterile insect technique works by releasing mass-produced male flies that have been sterilized with gamma radiation, which mate with wild females that only mate once in their lifetime, causing the population to collapse over successive generations. However, Miller warned that the Edinburg facility will take three years to become fully operational, and that the current strategy of releasing 100 million sterile flies per week in affected Mexican regions has not retreated the outbreak. For more on how the federal response has been taking shape, Agroinformacion has been tracking the FDA’s expanding drug response to the New World screwworm threat.
The threat extends well beyond cattle to wildlife, pets, and people
Miller has been consistent in emphasizing that the New World screwworm Texas threat is not limited to cattle operations. Texas has approximately 200 mammal species, all of which are susceptible to screwworm infestation. The parasite is a flesh-eating fly whose larvae infest any open wound on a warm-blooded animal, feeding on living tissue and causing severe damage or death if untreated. In Mexico, the current outbreak has already resulted in 18 confirmed human cases and two deaths.
An unusually mild winter across northern Mexico and southern Texas has added to the concern. Miller noted in February that screwworm flies were active 187 miles south of the Rio Grande during what should have been the dormant winter season. The combination of a mild winter, a failing sterile-fly containment effort, and a rapidly advancing detection zone means the threat to Texas livestock could intensify significantly when warm-weather fly activity peaks in late spring and early summer. Ranchers, deer hunters, and pet owners have all been urged to prepare now.
What Texas producers should do right now?
Miller’s guidance for Texas producers is specific and immediate. Ranchers should inspect every animal daily, paying particular attention to any open wounds, fresh cuts, ear tags, dehorning sites, or navel areas on newborns. The screwworm larva is distinctive — cream-colored maggots in a wound that deepen rather than heal. Any suspicious wound should be reported immediately through official channels rather than treated and monitored privately. Modern antiparasitic medications are available and effective for protecting livestock and pets, and Miller urged producers to consult their veterinarians for proper protocols before a detection event forces emergency action.
The full warning from Texas Agriculture Commissioner Sid Miller and additional producer guidance are available at screwworm.gov. The original warning and detection report were published by KRGV on April 10, 2026.