New World Screwworm Cases Climb to 31 in Texas as Parasite Spreads to Crockett County

The flesh-eating New World screwworm has now infected 31 animals across Texas and New Mexico, federal agriculture officials confirmed Thursday, marking another escalation in an outbreak that threatens the region's multi-billion dollar livestock industry.

The U.S. Department of Agriculture's latest tally includes 30 confirmed cases in Texas and one in New Mexico. The most recent detections—two infestations in sheep—were confirmed June 30 in Crockett County, a West Texas ranching community roughly 300 miles southwest of Dallas.

What Ranchers Need to Know Now

Unlike common maggots that feed on dead tissue, screwworm larvae attack living flesh. Adult female flies lay eggs in open wounds or natural body openings, and within hours the hatched larvae begin burrowing into tissue. Left untreated, infestations are fatal.

Texas A&M AgriLife livestock entomologist Sonja Swiger emphasizes that early detection remains the most effective defense. "Wounds that continue to worsen instead of healing, bloody or foul-smelling drainage, and visible larvae moving inside a wound—these are the warning signs," she explained in a recent interview with Texas Public Radio.

Animals at risk include cattle, horses, sheep, goats, pigs, deer, and domestic pets. While human infections remain rare, anyone with untreated wounds in affected areas faces potential exposure.

The Economic Stakes

Texas leads the nation in cattle production, with more than 13 million head spread across 130 million acres of ranchland. The state's white-tailed deer population—another vulnerable species—supports a hunting industry worth billions annually.

A widespread screwworm establishment could trigger devastating economic ripple effects: increased veterinary costs, livestock trade restrictions, wildlife population declines, and heightened demand for animal health services.

The Texas Animal Health Commission and USDA have responded by expanding surveillance networks, tightening animal movement monitoring, and promoting rapid reporting of suspected cases.

Eradication History and Current Response

The United States eliminated screwworm decades ago through the sterile insect technique—releasing millions of sterilized male flies to collapse wild populations. That success, one of pest control's greatest achievements, created a biological barrier protecting North American livestock.

But the parasite persists in Central and South America, and the current outbreak demonstrates how quickly reintroduction can occur. Federal and state agencies are now deploying the same sterile fly strategy along the Texas-Mexico border while conducting ground surveillance across affected counties.

What Texans Should Do

For most residents, daily routines need not change. The primary risk targets livestock, wildlife, and pets.

Animal owners should inspect wounds regularly, contact veterinarians immediately if wounds worsen or contain larvae, and avoid transporting animals with suspicious injuries until examination. Hunters must check harvested game for unusual wounds and report suspected cases to wildlife officials.

Anyone suspecting an infestation should contact a veterinarian before moving the animal. The Texas Animal Health Commission maintains a dedicated hotline and online resources for reporting and guidance.

The outbreak's trajectory remains uncertain, but the response infrastructure built during the original eradication campaign gives officials tools that didn't exist during previous screwworm eras. Whether those tools prove sufficient depends on detection speed, containment effectiveness, and the cooperation of ranchers across affected regions.