Screwworm found in Crockett County

Ozona — State animal health officials have imposed livestock movement restrictions across portions of West Texas after a sheep in Crockett County tested positive for New World screwworm larvae.

The Texas Animal Health Commission designated the affected area as Infested Zone 07 following the June 20 detection and issued an emergency quarantine covering parts of eastern Crockett County as well as portions of Schleicher and Sutton counties.

The quarantine took effect immediately and will remain in place until lifted by the commission.

Threat to livestock industry

New World screwworm is a parasitic fly whose larvae feed on the living tissue of warm-blooded animals. The pest can cause severe injury and death if left untreated. 

The parasite has historically caused hundreds of millions of dollars in economic damages in Texas. The fly, and its parasitic larva, have been effectively extinct north of the United States-Mexico border after eradication efforts eliminated it from the United States in 1982. 

Screwworm flies lay eggs in wounds or other vulnerable areas on animals. The larvae burrow into living tissue, causing extensive damage and an increased risk of infection.

Movement restrictions enacted 

Following confirmation of the case, Lewis R. Dinges, the Texas Animal Health Commission’s executive director, issued an order restricting the movement of livestock in a designated area spanning parts of the eastern portions of Crockett County along with Schleicher and Sutton counties, enacting a quarantine on the region.

“Warm-blooded animals located within Infested Zone 07 may not be moved outside of the zone without prior authorization from the commission,” the order states. 

Animals approved for movement must first be inspected, treated if necessary and issued a permit or movement certificate by a commission representative.

The restrictions also apply to animal products capable of harboring the parasite.

“Hides, carcasses, and parts of any animal capable of serving as a host for NWS must be inspected and undergo any treatment deemed necessary by a Commission representative prior to removal from the Infested Zone 07,” the order states.

Unauthorized movement of livestock or other regulated materials could result in administrative penalties or criminal prosecution.

The quarantine will remain indefinitely until lifted by the commission.

The Crockett County case is one of 16 New World screwworm detections in Texas since June 3. Additional cases have been confirmed in nearby Terrell, Sutton, Edwards and Tom Green counties.  

According to the most recent U.S. Census of Agriculture, Crockett County ranks number one in sheep and goat: wool, mohair and milk production. Local producers generate approximately $13.5 million in sales from these activities. The census counted 51,197 sheep and lambs in the county.  

Martin Childress, a rancher and owner of the historic Childress Ranch, expects the quarantine to have an economic impact on one of his ranches located in Crockett County. The ranch is home to about 1,500 sheep and goats. 

“[It will take] more labor and [means] not getting our product to market in time,” Childress said. “It’ll be more of a pain in the ass.” 

Childress said his ranches have not improved their prevention and detection efforts, though he is concerned about the impact NWS could have on the area. The top priority, he said, should be the release of sterile flies into affected areas. Childress places blame on the outbreak on the illegal smuggling of livestock. 

“They had an outbreak in the 70s, real similar and they already had the irradiated flies ready to go, and they got it knocked down pretty quick,” he said. “This all goes back to the cartel. They're the ones that brought them across the Panama border. So, that needs to be addressed too.”