Amy Murillo and Alec Gerry, entomologists at University of California, Riverside, explain that the return of the New World screwworm fly to Texas is a serious treat because its larvae feed on the living tissue of animals and occasionally humans. They say federal and state agencies are responding with surveillance, quarantines, and releases of sterile male flies, a method that previously eradicated the pest from the United States. The sterile-fly technique works because female screwworms mate only once, so mating with a sterile mate prevents reproduction. Murillo notes that California could be at risk if infected animals transport the parasite into the state, especially given its large livestock industry. both researchers emphasize that early detection and rapid response are the best ways to prevent the screwworm from spreading.