US reports five New World screwworm cases in Texas, NM

A parasitic pest that was eradicated from the United States six decades ago has returned, with five confirmed cases of New World screwworm detected in Texas and New Mexico within a single week. The first case was identified in a calf in Zavala County, Texas, on June 3, 2026, marking the first domestic detection since 1966. Subsequent cases were confirmed in a second calf in Zavala County, a calf in La Salle County, a goat in Gillespie County, and a dog residing in Lea County, New Mexico.

The screwworm is the larva of a parasitic fly that lays its eggs in the open wounds of warm-blooded animals. The larvae then feed on living flesh, causing severe injury and death if left untreated. While the parasite can infect pets, wildlife, and, in rare cases, humans, the primary threat is to livestock. Officials have established quarantine zones, designated as "infested areas," around the detection sites, restricting the movement of animals without inspection and treatment.

The outbreak has triggered a significant political debate. Agriculture Secretary Brooke Rollins has publicly linked the parasite's northward spread from Central America to border and immigration policies under the...