Authorities confirmed a case of New World screwworm in a Texas calf, marking the first detection in U.S. livestock in decades.
The re-emergence of this flesh-eating parasite threatens the stability of cattle herds and could potentially drive up beef prices for consumers.
The infection was discovered in a three-week-old calf [2] in La Pryor, located in Zavala County, Texas. This area sits near the U.S.–Mexico border [3, 4]. Reports said the case was identified in April 2024 [3, 5].
This discovery is significant because it is the first time the parasite has been found in U.S. livestock since the species was eradicated in 1966 [6]. The New World screwworm is a parasite that targets living tissue, which can lead to severe infestations if left untreated.
Experts said a single case could be the precursor to a larger outbreak. Because the parasite can infect livestock, pets, and, in rare instances, humans, the detection in a border region suggests a need for heightened surveillance [4].
Agricultural officials are monitoring the situation to prevent the parasite from spreading further into the interior of the country. The potential for widespread infection puts thousands of head of cattle at risk, which could disrupt the national food supply [3].
“First U.S. livestock case since eradication in 1966”
The return of the New World screwworm represents a significant biosecurity breach. Since the parasite was eradicated decades ago, the U.S. livestock industry has operated without the need for the intensive screening and treatment protocols required to manage the pest. A widespread outbreak would not only cause animal suffering but would create economic volatility in the beef market by reducing supply and increasing production costs.
