Full Breakdown
New World Screwworm Returns to the United States as USDA Prepares to Reopen a Major Mexican Cattle Port
By Drooid · · How we work
Core Event: Recent Screwworm Confirmation and Port Reopening Plans
On September 17, U.S. officials confirmed a New World screwworm infestation in a horse in Grant County, New Mexico. The case triggered a 12.4-mile “infested zone” with movement restrictions for warm-blooded animals. The USDA announced that the Santa Teresa livestock port of entry on the New Mexico-Mexico border will reopen on September 24, resuming cattle imports halted to contain the parasite.
Background & Context
The New World screwworm (*Cochliomyia hominivorax*) was eradicated from the United States in the 1960s using the sterile insect technique. Since the 1950s the fly’s range has been limited to Mexico and Central America, but northward movement was noted in 2023. Recent detections in Texas and now New Mexico signal a resurgence.
Data & Statistics
- USDA reports three active screwworm cases in the United States (horse in New Mexico, horse and dog in Texas).
- Nationwide, 48–50 cases have been confirmed since the outbreak began.
- Approximately 500,000 cattle passed through Santa Teresa in 2024, about 40 % of U.S. cattle imports from Mexico.
- USDA has invested more than $1.3 billion in the response, including the release of over 1 billion sterile flies along the border.
Official Statements & Responses
U.S. Secretary of Agriculture Brooke Rollins said “protecting American livestock will always come first” and linked the port reopening to a phased plan that began with the Douglas, Arizona crossing. New Mexico Agriculture Secretary Jeff Witte noted coordination among state and federal agencies, industry groups, and universities to prepare for the port’s return.
On-the-Ground Reports
State officials established a quarantine zone centered near Mimbres, with towns such as Santa Clara, Bayard, Hurley, Pinos Altos and Lake Roberts on its perimeter. Animals may not leave the zone without inspection and authorization from the New Mexico Livestock Board. A broader surveillance ring includes Silver City, Tyrone and Faywood, where owners are urged to monitor livestock and pets for open, non-healing wounds, maggots, swelling, discharge, foul odor, lethargy or abnormal behavior. Suspected cases should be reported to the Grant County Extension Office, a veterinarian, the Livestock Board, or the state’s screwworm website.
Conflicting Reports & Gaps
- Active case count: Reuters cites three active U.S. cases, while KFOX TV reports two and none in New Mexico.
- Total confirmed cases: USDA statements mention 48 confirmed nationwide, whereas TTNews references 50.
- Source of infection: The origin of the Grant County horse infestation remains under investigation.
Verbatim Quotes
- “Traditional reporting mechanisms for public health are often delayed,” — Seema Shah
- “The tool gives you a sense of where you might expect to see cases next,” — Mark Beatty
- “We are working closely with the California Department of Food and Agriculture to connect local veterinarians with screwworm resources for surveillance in our region,” — Emily Trumbull
- “Protecting American livestock will always come first,” — Brooke Rollins
- “We’ve got a lot of work to do, but it’s going to get done,” — Jeff Witte
What’s Next
The Santa Teresa port is scheduled to resume operations on September 24, pending verification that inspection and treatment protocols are functioning. USDA officials indicated that the Columbus, New Mexico crossing could be the next port to reopen if Santa Teresa’s reopening proceeds without incident. Ongoing surveillance, fly-trapping, and sterile-fly releases will continue along the border to monitor and contain further spread.