U.S. officials confirmed the first case of New World screwworm in a three-week-old calf [2] in La Pryor, Texas, on June 4, 2026 [3].
The emergence of the flesh-eating parasitic fly poses a significant threat to the national cattle industry. Because the parasite can devastate livestock populations, federal agencies have launched an emergency containment effort to prevent a wider outbreak.
Agriculture Secretary Brooke Rollins said the case was confirmed in the calf in La Pryor, which is located near the U.S.-Mexico border [1]. This marks the first time the parasite has been detected in the U.S. in approximately 60 years [1].
Local authorities and federal agents have established a livestock quarantine in the affected area. Reuters staff said the quiet cattle town has become ground zero in the fight against the parasite [4]. The quarantine aims to restrict the movement of animals to ensure the parasite does not spread to other regions of South Texas, or across state lines.
As of June 5, 2026, officials reported zero additional cases beyond the initial calf [3]. This suggests that the containment measures may be working, though officials remain on high alert.
To combat the spread, the U.S. may employ a biological control strategy. A Wired report said that releasing sterilized flies can crash a local population of flesh-eating screwworms [5]. This method prevents the flies from reproducing, effectively starving the local population of the parasite over time.
Texas ranchers remain on edge as they monitor their herds for signs of infestation. The USDA continues to coordinate with local veterinarians to identify any other potential cases in the region.
“The case of New World screwworm was confirmed in a 3-week-old calf in La Pryor, Texas.”
The re-emergence of the New World screwworm after six decades highlights the vulnerability of the U.S. agricultural supply chain to invasive species. While the current containment of a single case is a positive sign, the proximity of the outbreak to the U.S.-Mexico border suggests a potential breach in biological barriers, necessitating a sustained federal surveillance effort to protect the livestock economy.
