New Screwworm Cases in U.S. Prompt Urgent Action

The New World screwworm fly has been confirmed in cows, goats, and dogs in the United States. The fly deposits eggs in open wounds or orifices, and the larvae consume the animal’s tissue.

On June 8, 2026, the U.S. Department of Agriculture reported three new cases of New World screwworm. These include the first instances in dogs and goats, raising the total number of cases in the country to five. The department announced plans to boost efforts to manage this parasitic fly, considered eradicated in the 1960s.

Federal and Texas state officials mentioned during a briefing that they are utilizing AI technology to track screwworm populations. They are also training ranchers to detect infections in livestock and increasing sterile fly production facilities. The sterile fly method is a primary countermeasure against screwworms.

There is also discussion of an emergency authorization for a new genetically engineered fly strain, which may improve the efficiency of sterile fly production.

“We prevented and eradicated this pest before. We can do it again,” stated Texas Governor Greg Abbott during the briefing.

Recently, authorities identified new cases in a calf in La Salle County, Texas, a goat in Gillespie County, Texas, and a dog in Lea County, New Mexico. Officials are uncertain whether the dog contracted the parasite domestically, as its travel history remains unclear.

The first two cases, involving calves in Zavala County, Texas, were reported the previous week. Secretary of Agriculture Brooke Rollins remarked that the reemergence of the screwworm was not unforeseen.