Surveillance Urged of Animals for NWS

REDFIELD, Iowa (DTN) -- As the New World screwworm (NWS) cases continue to spread, mostly across several Texas counties, more animals have now been affected, with the first case in sheep reported.

As of the evening of June 13, 12 cases have been reported according to the NWS Confirmed Detections dashboard on USDA Animal and Plant Health Inspection Service website. These cases span over six Texas counties and one New Mexico county, and include cattle, goats, sheep and a dog. Up-to-date cases can be seen at: https://www.aphis.usda.gov/…

According to the Texas Animal Health Commission (TAHC), NWS are larvae or maggots of the NWS fly, that cause the painful condition NWS myiasis. Eggs are laid in open wounds or orifices of live tissue and can only survive on live tissue of warm-blooded animals. The eggs hatch into dangerous larvae which burrow or "screw" into the flesh with sharp mouth hooks.

"TAHC has been actively preparing for a resurgence of NWS for over two years," said TAHC Executive Director Bud Dinges in a news release. "We are putting these preparations into action, and we encourage all animal owners and caretakers to continue to remain vigilant for the presence of larvae in animal wounds and immediately report any suspicions."

USDA also urges everyone in the area to check animals for draining or enlarging wounds, maggots or egg masses, signs of discomfort, and lesions in body openings including the nose, ears, genitalia, and umbilical area.

If anyone suspects a screwworm infestation, they should immediately contact their veterinarian, state animal health official, or the USDA.

The distribution of sterile NWS flies is still the leading way to combat the spread. Since the NWS fly only mates once, the sterile flies mate with wild flies, preventing viable offspring. TAHC said when a case is identified and confirmed, sterile fly distribution is quickly evaluated, and dispersal may be shifted in the affected areas. Just this month, more than 19.5 million flies have been released through aerial, ground and vehicular dispersal.

The Texas A&M AgriLife Learn center has free NWS inspector training available for all Texans. The course covers NWS biology, inspection protocols, reporting and more. Those who qualify can apply to become a certified NWS inspector through TAHC. To learn more about the course go to www.tx.ag/NWSTraining.

For more DTN coverage of the New World screwworm threat and the response by the government and livestock industry, visit DTN's Spotlight on New World Screwworm page at https://www.dtnpf.com/….

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

Follow her on social platform X @JennCattleGal

(c) Copyright 2026 DTN, LLC. All rights reserved.