U.S. Shuts Down Livestock Trade at Southern Border Over Screwworm Threat
New World Screwworm edges closer to U.S.; emergency action taken to protect livestock
Washington, D.C. – In a swift and decisive move, the United States Department of Agriculture (USDA) has closed all livestock ports of entry along the southern border with Mexico after a new case of New World Screwworm (NWS) was confirmed in Veracruz — significantly north of previously reported detections.
According to USDA Press Release No. 0160.25, the newly detected case in Ixhuatlán de Madero, Veracruz—located just 370 miles from the U.S. border and 160 miles north of the sterile fly dispersal grid—raises serious concerns about the pest’s northward movement. In response, Secretary of Agriculture Brooke L. Rollins ordered an immediate halt to livestock trade, reversing earlier plans to reopen ports between July and September.
What is the New World Screwworm?
The New World Screwworm (Cochliomyia hominivorax) is a dangerous parasite. The female fly lays eggs in wounds of warm-blooded animals. When the larvae hatch, they begin consuming live flesh, causing deep, infected wounds that can lead to death if untreated.
Though eliminated in the U.S. in the 1980s, the screwworm remains endemic in parts of Latin America. A reintroduction would pose a multi-billion-dollar threat to American livestock production and food security.
This latest detection in Veracruz undermines the phased reopening strategy USDA had announced just days earlier. Originally, livestock ports were closed in May 2025 after cases were detected in Oaxaca and southern Veracruz. However, a risk-based reopening was scheduled to begin on July 7. That plan has now been suspended indefinitely.
“The United States has promised to be vigilant — and after detecting this new NWS case, we are pausing the planned port reopenings,” said Secretary Rollins.
“We must see additional progress in combatting NWS in Veracruz and surrounding states before reopening any livestock ports along the border.”
USDA’s Bold Response Plan as outlined in the USDA press release, the agency has launched a multi-pronged containment strategy, including:
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Continued surveillance and site inspections in Mexico -
Construction of a sterile fly dispersal facility in South Texas -
Design of a domestic sterile fly production plant for emergency response -
Coordination with Texas, New Mexico, and Arizona for cross-agency monitoring
USDA is also holding Mexican authorities accountable for implementing robust animal movement controls and containment measures to stop the spread of the pest.
While this incident is specific to North America, the broader lesson applies globally. Countries like Pakistan with thriving livestock sectors must stay alert, enforce biosecurity protocols, and increase awareness about emerging parasitic threats.
Vet News & Views will continue to monitor USDA updates and provide verified coverage for both English and Urdu readers.
This report is based on USDA Press Release No. 0160.25, issued July 9, 2025. Official source: www.usda.gov