Shawnee County K-State Extension

Kansas officials urge vigilance after New World screwworm detected in Texas calf

Kansas agriculture and animal health officials are urging livestock producers, veterinarians and pet owners to remain vigilant following confirmation of a New World screwworm infestation in a calf in Texas, marking the first detection of the pest in the United States in decades.

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service confirmed June 3 that a three-week-old calf in Zavala County, Texas, was infected with New World screwworm, a parasitic fly whose larvae feed on the living tissue of warm-blooded animals.

Kansas officials emphasized that while the case is a serious concern, the state remains at low risk and has spent months preparing for the possibility of the pest reaching U.S. soil.

Unlike many pests, screwworm larvae cannot create wounds. Instead, female flies lay eggs in existing wounds, where the larvae hatch and feed on living tissue.

Animals infested with screwworm larvae often experience significant pain and behavioral changes.

Because New World screwworm larvae can resemble other fly maggots, Olds said producers and pet owners should report any suspicious infestations in living animals to state veterinary authorities for proper identification.

Remember to inspect animals regularly, monitor wounds closely and treat injuries promptly.

** Read the entire news release online at https://www.k-state.edu/news/articles/2026/06/new-world-screwworm-cassandra-olds.html

For questions or concerns please reach out to our County Agriculture Agent: Dr. Terrie Casey at 785-232-0062

18 4-H youth attended the YQCA- Youth fir the Quality Care of Animals program on 5/28 at the Shawnee Co Extension Office. YQCA classes are required for all youth showing livestock at the county or state fairs. Youth are taught about humane treatment, veterinary requirements and biosecurity. A total of 32 youth have attended this training so far.

For more information about YQCA please reach out to Dr. Terrie Casey at 785-232-0062 or [email protected]

Our office is closed today, Thursday, June 11, for Professional Development. We'll open again Friday morning at 8am. Thank you for your understanding.