Deadly Screwworm Pest Revives Old Fears on Texas Ranches

June 6, 2026, 1:24 AM UTC

The Nieto family hasn’t had to fight the New World screwworm in decades.

Lupe Nieto, 80, battled the deadly pest with a team of 30 cowboys on the HP El Sauz Ranch in the 1960s and 1970s. They started every day with full saddlebags: In one pocket, they carried lunch, and in the other, putrid supplies of medication used to treat cattle infested with screwworm larvae, which can kill an animal in weeks.

The parasitic fly was eradicated from Texas in the 1970s, but now it has returned. USDA inspectors earlier this week detected larvae in a three-week-old calf in ...

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