Follow-Up: New World Screwworm Confirmed in a Beef Cow in Otero County, New Mexico; Infested Zone of at Least 20 km Set Around the Site
The New Mexico Department of Agriculture said on October 21 that state animal health officials have confirmed a case of New World screwworm in a beef cow in Otero County, New Mexico, in the southwestern United States. It was another new U.S. case confirmed the same day: the U.S. Department of Agriculture (USDA) had announced earlier that day the first detection of the parasite in U.S. wildlife, in an elk on a game ranch in Pecos County, Texas.
According to Reuters, the New Mexico Department of Agriculture said state and federal officials were continuing to expand surveillance and fly trapping around the affected locations to identify any additional cases and determine whether the pest had spread beyond the affected animals. Officials have established a minimum 12.4-mile (20 km) radius infested zone around the affected animal's location, and within the zone animals must be inspected and, if necessary, treated before moving within or out of the area.
In Texas, the Texas Animal Health Commission will modify a previously established infested zone, and the USDA and the Texas Parks and Wildlife Department are conducting additional wildlife surveillance in the area.
The New World screwworm is a parasitic fly whose larvae feed on the living tissue of warm-blooded animals, threatening livestock and wildlife. Eradicated from the United States decades ago, the pest has surged north from Central America through Mexico. The United States halted livestock imports from Mexico for more than a year to keep it out, resuming trade in August at an Arizona port under a phased reopening plan; the halt tightened U.S. cattle supplies and pushed beef prices to record highs.
Source: GSM · USA (original Chinese edition)
Photo: 牧场上的肉牛（资料图）。照片：Mahfuzur Rahman Nafi 摄，CC0，经 WordPress Photo Directory。 / Beef cattle on pasture (file photo). Photo: Mahfuzur Rahman Nafi, CC0, via WordPress Photo Directory
- 2026-10-18New World Screwworm Returns to the Southern U.S. as USDA Builds $750 Million Sterile Fly Plant in Edinburg, Texas
- 2026-10-20Follow-Up: USDA Continues Phased Reopening of Southern Border Ports, With Columbus, New Mexico Resuming Cattle Imports From Mexico on October 26
- 2026-10-21Follow-Up: New World Screwworm Confirmed in a Pecos County, Texas Elk, a First Detection in U.S. Wildlife
- 2026-10-22Follow-Up: New World Screwworm Confirmed in a Beef Cow in Otero County, New Mexico; Infested Zone of at Least 20 km Set Around the SiteThis story
- 2026-10-23Follow-Up: Texas Modifies New World Screwworm Infested Zone 12.A, Easing Livestock and Pet Movement Rules in Parts of the Zone
- 2026-10-24Follow-up: New Mexico Confirms New World Screwworm in a Hidalgo County Calf on Oct. 23, Setting a 12.4-Mile Infested Zone
- 2026-10-27Follow-Up: Two New World Screwworm Cases Confirmed in Doña Ana County, New Mexico; Livestock Board Expands Surveillance and Trapping
- 2026-10-28Follow-Up: First New World Screwworm Detection in Arizona Confirmed in a Cochise County Dog, USDA Sets 20-km Infested Zone
