The U.S. Department of Agriculture is mobilizing resources to contain the New World screwworm following the confirmed detection of the parasite in Texas. As of June 2026, the USDA has identified four cases of the screwworm, a parasitic fly whose larvae infest the flesh of warm-blooded animals. Secretary of Agriculture Brooke L. Rollins announced an $8.5 million investment in a sterile fly dispersal facility based in South Texas to combat the northward spread of the pest.
How the USDA is responding to the parasite
The USDA is utilizing a strategy centered on the release of sterile insects to suppress the screwworm population, a method previously employed during the program that eradicated the pest from the United States in 1966. According to the USDA, the department is currently distributing approximately 10 million sterile flies per week across affected areas via aerial and ground-based dispersal.
Secretary Brooke L. Rollins stated that the department is taking necessary actions to protect American livestock and prevent the parasite from spreading from southern Mexico. The federal response includes the appointment of a senior advisor for New World screwworm preparedness to oversee safety and distribution efforts.
What are the risks to livestock and the food supply?
The New World screwworm is a parasitic fly that lays eggs in the wounds of warm-blooded animals. Once hatched, the larvae burrow into the flesh, creating painful, potentially life-threatening wounds. While the parasite poses a significant risk to livestock, wildlife, and pets, the USDA reports that the screwworm does not infest meat, fruits, vegetables, or other food products.
The current cases include:
- Texas: Two confirmed cases, including one in a calf in La Salle County.
- New Mexico: One case involving a dog that lives in New Mexico, though the diagnosis was reported by a veterinarian in Texas.
Why the current situation is under scrutiny
The return of the screwworm marks the first time the parasite has been detected in the U.S. since the 1960s. This development has triggered a debate regarding border-related agricultural monitoring. Texas Agriculture Commissioner Sid Miller has publicly criticized the federal response, alleging that the USDA failed to act quickly enough to prevent the parasite from crossing the border. In response to these criticisms, Secretary Rollins emphasized that the department is moving at a rapid pace to address the threat and maintain the integrity of U.S. agricultural production.
Key Takeaways
- Status: Four cases of the New World screwworm have been confirmed as of June 2026.
- Containment: The USDA has launched an $8.5 million dispersal facility in South Texas and is releasing 10 million sterile flies weekly.
- Impact: The parasite affects warm-blooded animals but does not pose a direct threat to the safety of the food supply, such as meat or produce.
- History: This incident is the first recurrence of the screwworm in the United States since its eradication in 1966.