Texas Launches Free Screwworm Training as Outbreak Mystifies Experts

The New World screwworm (NWS), a parasitic fly larva that feeds on living tissue of warm-blooded animals, has been detected in Texas for the first time in roughly five decades, with over 30 cases reported since the initial discovery in a calf in Zavala County. The outbreak has prompted both a free training program for livestock inspectors and a political debate over how the pest entered the U.S.

The Outbreak

• The first case in U.S. livestock in about 50 years was confirmed in early February 2025. Source: larepublicaco
• Cases have since risen to over 30, and experts remain uncertain about the origin and spread. Source: larepublicaco
• The screwworm is not contagious between animals and does not affect food safety, but it can be deadly if untreated. Source: clarin

Training Initiative

• Governor Greg Abbott announced a free online training course, developed by Texas A&M AgriLife Extension and USDA-APHIS, to certify more NWS inspectors. Source: clarin
• The course covers biology, surveillance, inspection protocols, and treatment; those who pass can issue official movement documents for livestock from infested areas. Source: clarin
• Eligibility initially includes veterinarians, vet techs, extension agents, and animal control officers, with the course open to all Texans for educational purposes. Source: clarin

Disagreement on Origin

• Secretary of Agriculture Brooke Rollins blamed "failed immigration policies" and the "open border" under the Biden administration for the pest's spread. Source: larepublicaco
• Rep. Teresa Leger Fernández countered that such claims are false and that "we should not spread misinformation." Source: larepublicaco
• Some experts note that screwworm flies can only travel short distances, suggesting infected livestock or human transport likely brought them across, but natural migration from Mexico cannot be ruled out. Source: larepublicaco