Missouri Activates Response Plan Following New World Screwworm Detection

Livestock producers and animal owners are encouraged to stay alert following the recent confirmation of New World screwworm (NWS) in the United States. While the pest has not been detected in Missouri, state officials have activated a response plan to protect livestock and limit the risk of spread.

On June 3, 2026, the U.S. Department of Agriculture confirmed NWS in a 3-week-old calf in Texas. The pest had been eradicated from the United States in 1966 but has been moving north through Central America and Mexico in recent years.

New World screwworm larvae feed on the living tissue of warm-blooded animals, including cattle, sheep, goats, horses, swine, pets and wildlife. Infestations can cause severe tissue damage and may be fatal if not treated quickly.

Missouri has assembled a multi-agency response effort involving the Missouri Department of Agriculture, University of Missouri Extension and other partners to monitor and respond if needed.

“Right now, this isn’t something to panic over, but it is something to pay attention to,” said Brenda Schreck, University of Missouri Extension livestock field specialist.“Good animal husbandry—watching animals closely, keeping wounds treated and managing flies—goes a long way. If something doesn’t look right, don’t wait.”