Missouri Activates Screwworm Response Plan After Texas Case

By Blake Jackson

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) has confirmed a case of New World Screwworm (NWS) in the United States after the pest was identified in a three-week-old calf in Zavala County, Texas, on June 3, 2026.

The detection has prompted Missouri officials to activate their New World Screwworm Response Plan to help protect livestock and wildlife across the state.

New World Screwworm larvae feed on the living tissue of animals, posing a major threat to livestock, pets, wildlife, and, in rare cases, people and birds. The parasite can cause severe injuries and significant economic losses for producers.

Missouri’s response plan was developed by a joint working group led by State Veterinarian Steve Strubberg and includes representatives from USDA, the Missouri Department of Agriculture, University of Missouri Extension, the Missouri Department of Conservation, and the Missouri Department of Health and Senior Services.

Animal movement requirements into Missouri include:

• Animals from an infested state but outside an infested zone must have a Certificate of Veterinary Inspection (CVI) confirming they did not originate from or travel through an infested area. 
• Animals originating from an infested zone must meet state movement requirements, obtain a Missouri permit, and have a CVI stating they were individually inspected and found free of wounds. 

Producers are encouraged to protect their animals by:

• Maintaining strong fly and tick control programs.
• Cleaning and covering open wounds promptly.
• Delaying procedures such as castration, dehorning, or branding when possible.
• Registering farms for a premises identification number.
• Regularly inspecting animals for wounds, maggots, unusual drainage, foul odors, fever, reduced appetite, or other signs of infestation.

Anyone who suspects an infestation should immediately contact a veterinarian, the Missouri Department of Agriculture Animal Health Division at (573) 751-3377, or the Missouri Department of Conservation for wildlife cases at (573) 522-0142.

Photo Credit: gettyimages-ahavelaar