Full Breakdown
New World Screwworm Returns to Texas Amid Illegal Cattle Trafficking
6/11/2026, 10:08:32 PM
Reappearance in Texas
In June 2026 the U.S. Department of Agriculture (USDA) confirmed the first U.S. cases of New World screwworm ( *Cochliomyia hominivorax* ) in decades. A three-week-old calf in La Pryor (Zavala County) was the initial detection, followed by a second calf in La Salle County, a goat in Gillespie County, and a dog in Lea County, New Mexico (originally reported as Texas). State and federal officials have established 12-mile quarantine zones around the infestations and barred animal movement without inspection.
From Eradication to Resurgence
The screwworm was eradicated from the United States in 1966 after a multiyear sterile-male release program. The parasite re-emerged in Panama in 2023, spread through Costa Rica, Nicaragua, and Mexico, and accelerated in 2024-25. Researchers link the northward surge to organized-crime cattle smuggling across Central America, which bypasses health screenings and moves animals through protected areas such as Guatemala’s Maya Biosphere Reserve.
Timeline of Confirmed Cases
- Nov 2024 – First Mexican case reported.
- Jul 2025 – USDA closes southern border ports to livestock from Mexico.
- Feb 2025 – USDA begins sterile-fly releases in South Texas.
- June 3 2026 – Calf in La Pryor (Zavala County) tests positive.
- June 5 2026 – Second calf in Zavala County confirmed.
- June 8 2026 – Goat in Gillespie County and dog in Lea County identified.
- June 10 2026 – USDA reports five Texas cases; later updates cite six total including New Mexico.
Economic and Health Stakes
The U.S. cattle industry is valued at $113 billion, with Texas accounting for $17 billion. Modeling by USDA officials estimates up to $1.8 billion in damages if the pest spreads statewide. CDC data show more than 171,700 animal infections and 2,070 human cases across Central America and Mexico, with ten human deaths.
Government Response
USDA Secretary Brooke Rollins emphasized that the pest does not threaten the food supply, stating, “This does not affect the food supply system.” Undersecretary Scott Hutchins rejected the use of the Screwworm Adult Suppression System (SWASS), citing carcinogenic chemicals and interference with sterile-fly releases. Mexican President Claudia Sheinbaum’s office declined comment on the U.S. response but affirmed Mexico’s efforts to combat trafficking. The USDA has deployed millions of sterile flies from Moore Air Base, accelerated ground-release chambers, and announced a $750 million fly-factory slated for operation in South Texas next fall.
Rancher and Expert Criticism
Texas Agriculture Commissioner Sid Miller has pressed for SWASS deployment, arguing USDA inaction endangers the cattle sector. Ranchers such as Susan Storey and Stephen Diebel warn that current surveillance may be insufficient and have proposed privately funded sterile-fly plants. John Paul Schuster, a Kinney County judge, criticized the slow construction of sterile-fly facilities, suggesting a $4 million startup could accelerate control.
On-the-Ground Observations
Ranchers report rapid larval development in newborn calves, with one farmer in Chiapas noting losses of over $1,000 per infected cow. In Texas, rancher Christian Biedenharn highlighted the need for rapid sterile-fly deployment, while others stress vigilant wound inspection and preventive treatments.
Conflicting Reports & Gaps
Initial USDA releases listed the dog case as Texas-based; subsequent investigation reclassified it to Lea County, New Mexico, creating a discrepancy in case counts. Mexican officials dispute the effectiveness of the U.S. border-closure policy, while USDA maintains it delayed the pest’s arrival by a year.
Verbatim Quotes
- “Every cow that is being moved illegally has the potential to carry a screwworm and other diseases,” — Jeremy Radachowsky, Wildlife Conservation Society.
- “We're fighting for this so our grandchildren can keep what we have,” — Susan Storey, Texas rancher.
- “The idea that this department has not been transparent is absurd and does not match what ranchers are telling the department and our partners directly.” — USDA spokesperson.
- “What the hell is a good fly?” — Sid Miller, Texas Agriculture Commissioner.
- “We need those quarantine zones, and we actually have a methodology to treat them in terms of sterilization of those flies,” — Christian Biedenharn, Texas rancher.
Future Actions
The USDA plans to begin operations at a new sterile-fly production plant in southern Mexico within weeks and to bring the Texas factory online by fall 2026. Ongoing quarantine enforcement, expanded surveillance, and outreach webinars—such as those hosted by the Colorado Department of Agriculture—aim to contain the outbreak while authorities monitor for additional cases.
