A three-week-old calf [2] on a ranch in southern Texas was confirmed to be infected with New World Screwworm larvae.
The discovery marks the first case of the parasite in the U.S. since 1966 [1]. Because the parasite can cause severe disease and death if left untreated, the emergence of the larvae threatens a livestock industry already facing significant pressure.
U.S. Department of Agriculture Secretary Brook Rollins said the situation during a briefing on April 4, 2024 [1]. The infection was identified the night before the briefing at a ranch near Lafayette, Texas [1].
The New World Screwworm, known scientifically as Cochliomyia hominivorax, is a parasite that feeds on the living tissue of warm-blooded animals. The return of the larvae after approximately 60 years [1] creates a precarious situation for American farmers, especially as U.S. cattle herd numbers are currently at a historic low [1].
Agricultural officials said that an uncontrolled outbreak could further deplete cattle populations. Such a loss of livestock could drive beef prices higher for consumers as the supply of cattle continues to dwindle [1].
USDA officials are monitoring the site in southern Texas to prevent the spread of the larvae to other animals. The agency is coordinating efforts to contain the parasite and protect the remaining cattle herds from further infection [1].
“First U.S. case of New World Screwworm infection since 1966”
The reappearance of the New World Screwworm after six decades represents a significant biosecurity breach. With the U.S. cattle herd already at record lows, the industry has little margin for error; any widespread loss of livestock to this parasite could trigger a sharp increase in beef prices and destabilize domestic meat supply chains.
