Flesh-eating parasite found in Texas elk and New Mexico beef cow

By the Editorial Team · Monday, October 26, 2026

Federal and state authorities have confirmed the first detection of the New World screwworm parasite in U.S. wildlife after larvae were found in an elk in West Texas. This discovery has prompted expanded surveillance and control efforts as officials work to prevent the parasite’s reestablishment and protect livestock and wildlife populations.

Federal and state officials have confirmed the presence of the New World screwworm (NWS) parasite in U.S. wildlife for the first time, following the identification of larvae in an elk harvested in West Texas. The detection was reported on October 21 by the U.S. Department of Agriculture (USDA) and the Texas Parks and Wildlife Department. Laboratory analysis verified NWS larvae in the elk, which was killed on a game ranch in Pecos County and reported by the hunter. This marks the initial documented case of the flesh-eating parasite affecting wildlife within the United States.

Simultaneously, the New Mexico Department of Agriculture confirmed a separate case of NWS infestation in a beef cow in Otero County. Both states have expanded surveillance and trapping efforts to track the parasite’s spread in the surrounding regions. As of October 22, the USDA reported a total of 61 NWS cases across Texas and New Mexico, including the first U.S. case in decades—a 3-week-old calf in Texas identified in June.

The New World screwworm is a parasitic fly whose larvae feed on living tissue of warm-blooded animals, including livestock, wildlife, pets, and occasionally humans and birds. Adult female flies lay eggs in open wounds or natural body openings, and the hatched larvae burrow into the tissue, causing painful infestations. The parasite was previously eradicated in the United States during the 1960s through sterile fly release programs, but recent outbreaks in Central America and Mexico have raised concerns about its northward expansion.

In response to the latest findings, the Texas Animal Health Commission announced plans to adjust an existing infested zone. Federal and state agencies are conducting intensified wildlife surveys to assess the extent of the infestation. Officials emphasize the importance of hunters and landowners in early detection, urging the public to inspect harvested animals during the fall hunting season. Warning signs in affected animals include behavioral irritation, loss of appetite, head shaking, isolation, foul odors, and visible maggots in wounds.

The USDA noted that hunters frequently serve as the first line of defense in identifying NWS presence, highlighting the need for careful inspection of eyes, ears, nose, mouth, genital areas, and any injuries post-harvest.

Efforts to control the parasite’s spread have included a suspension of livestock imports from Mexico for over a year, lifted with a phased reopening starting in August. This restriction contributed to tightened cattle supplies and increased beef prices domestically. With the parasite’s confirmed presence in multiple animals, officials continue to monitor and implement measures aimed at preventing the reestablishment of NWS in the United States.

This article was reported by synthesizing coverage from multiple independent news outlets to present a balanced, unbiased account. Read about our editorial standards. Spotted an error? Let us know.