Federal officials have confirmed the first case of New World screwworm in U.S. wildlife, after a hunter in West Texas harvested an elk carrying the flesh-eating parasite, the U.S. Department of Agriculture said Wednesday.

The elk was taken on a game ranch in Pecos County, and the sample was confirmed at the USDA's screwworm laboratory in Kerrville, according to CBS News. The Texas Parks and Wildlife Department said it received the lab confirmation the same day. Until now, every confirmed U.S. case of the parasite — including a three-week-old calf in Texas this past June and a beef cow found in New Mexico the same week as the elk case — had been in livestock, not wild animals.

Expanded quarantine, new hunter warnings

New World screwworm fly larvae burrow into the living tissue of warm-blooded animals, feeding on the wound and often killing the host if untreated. The parasite poses a serious threat to cattle and other livestock and, in rare cases, can infect humans.

In response, the Texas Animal Health Commission is redrawing the boundaries of its existing New World Screwworm Infested Zone, which already covers parts of ten counties including Kerr, Uvalde and Val Verde. Animals inside the zone generally cannot be moved out without inspection and, if necessary, treatment. The USDA and Texas Parks and Wildlife Department are also expanding wildlife surveillance in the area around the new detection, according to a Texas Parks and Wildlife Department release.

INSPECT BEFORE YOU FIELD DRESS

State officials are urging hunters across the region to check harvested animals before field dressing or transporting a carcass, watching for warning signs that include visible maggots in wounds, foul-smelling injuries, and animals that appear unusually weak or distressed. The Texas Animal Health Commission handles suspected livestock cases, while the Department of State Health Services fields any reports involving humans.

The news comes as USDA has ramped up screwworm monitoring nationwide after confirming the pest's return to Texas livestock earlier this year — the first U.S. livestock cases in decades. The agency has since launched a dedicated screwworm.gov information portal to centralize federal guidance for ranchers, hunters and veterinarians.

Pecos County sits roughly 180 miles from the site of the original Texas livestock detection, underscoring how far the parasite has already spread since first reappearing domestically. Wildlife biologists say elk, deer and other game animals could serve as a reservoir for the parasite even if livestock-focused containment efforts succeed, complicating eradication.

Officials have not said how many additional wildlife samples are being tested in the area, or how long the expanded surveillance effort is expected to run.