New World Screw Worm Returns to US Livestock in Texas and New Mexico

After a 60‑year hiatus, the parasitic fly Cochliomyia hominivorax, known as the New World Screw Worm, has been confirmed in U.S. livestock. Laboratory testing verified infections in three calves in Texas and a pet goat in Lea County, New Mexico. The U.S. Department of Agriculture has placed federal and state animal‑health agencies on high alert, deploying veterinarians and epidemiologists to conduct extensive surveys and decontamination efforts around the affected sites. Authorities warned producers to keep wounds clean and report any suspicious cases promptly.

The parasite’s larvae feed on living tissue, causing rapid damage and secondary infections. The last recorded outbreak on American soil occurred in 1966. Scientists say the recent sightings near the Texas‑Mexico border could signal a resurgence that threatens the cattle and sheep industries if not contained swiftly.