CDC Opens Emergency Operations Center as Screwworm Infestations Spread Across Texas and New Mexico

Federal health and agriculture officials escalated their response to New World screwworm on June 11, 2026, when the Centers for Disease Control and Prevention activated its Emergency Operations Center at Level 3 — the agency’s initial activation tier — to support containment of an insect parasite not confirmed in U.S. animals since a landmark eradication campaign concluded in 1966.

The organism in question, Cochliomyia hominivorax, is a fly whose larvae burrow into the living tissue of warm-blooded animals, consuming healthy flesh from the inside. Untreated infestations are fatal to livestock. The parasite had been absent from the continental United States for six decades, eliminated through a campaign that became a model for pest control worldwide.

Six Confirmed Animal Cases; No Locally Acquired Human Cases

As of June 9, 2026, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service had confirmed six animal infestations in two states: four cattle and one goat in Texas, and one dog in New Mexico. Texas confirmations span Zavala, La Salle, Gillespie, and Edwards counties; New Mexico’s single confirmed case involves a dog in Lea County. USDA has designated an Infested Zone covering ten Texas counties — Edwards, Gillespie, Kerr, Kimble, La Salle, Sutton, Uvalde, Val Verde, Webb, and Zavala — with quarantine and movement controls in place.

No locally acquired human infestations have been confirmed in the United States. One travel-associated human case was confirmed in 2025 in a Maryland resident who had returned from El Salvador, and human cases continue in Mexico and Central America, where a northward-moving outbreak has been active since 2023. Those cases are distinct from the current U.S. animal detections.

Sterile Fly Program Reactivated

USDA began releasing sterile screwworm flies on June 4, the day after the first confirmed detection in a three-week-old calf in Zavala County, Texas. The program deploys approximately 2 million sterile flies twice weekly by air and an additional 4 million per week through 24 ground release chambers within and around the detection zone. The sterile insect technique — which works because female screwworms mate only once, ensuring offspring from a sterile male cannot survive — was the same approach that achieved eradication in 1966, a program developed by USDA scientists Edward Knipling and Raymond Bushland.

The CDC’s Level 3 EOC activation formalizes coordination with USDA and the Texas Department of State Health Services and positions the agency to scale surveillance should human health risks change. While C. hominivorax can infest humans — particularly targeting open wounds or mucous membranes — human cases in the United States have historically been rare and confined to travel-associated exposures. Clinicians are advised to consider screwworm myiasis in patients presenting with wound infestations and a history of travel to affected regions.