WASHINGTON, D.C.- The U.S. Department of Agriculture (USDA) has announced the immediate shutdown of southern border ports to livestock trade following the discovery of a new case of New World Screwworm (NWS) in eastern Mexico.
The infected site, located in Ixhuatlán de Madero in the state of Veracruz, lies approximately 370 miles south of the U.S.–Mexico border. It is also about 160 miles beyond the current sterile fly dispersal grid aimed at controlling the pest. This latest detection follows similar reports in northern Veracruz and Oaxaca over the past two months and has raised concerns about the accuracy of prior data shared by Mexican authorities.
As a result, Agriculture Secretary Brooke L. Rollins has suspended the phased reopening of five border ports that had been scheduled to resume accepting cattle, bison, and horses from Mexico between July 7 and September 15.
“The United States has promised to be vigilant — and after detecting this new NWS case, we are pausing the planned port reopenings to further quarantine and target this deadly pest in Mexico,” said Secretary Rollins in a statement. “We must see additional progress combatting NWS in Veracruz and other nearby Mexican states in order to reopen livestock ports along the Southern border.”
The USDA had previously implemented a phased reopening strategy after closing the ports on May 11, 2025. That initial closure was triggered by the spread of NWS to areas within 700 miles of the U.S. border.
To support containment efforts, the USDA is continuing site inspections in Mexico and requiring animal movement controls, surveillance, and trapping. Plans are also moving forward for a sterile fly dispersal facility in South Texas and the design of a domestic sterile fly production center to help reinforce pest control efforts in cooperation with Arizona, New Mexico, and Texas.
The USDA emphasized that its actions are part of a broader strategy to protect U.S. livestock herds and the national food supply from NWS, a pest known to cause severe tissue damage in warm-blooded animals.
No timeline was provided for when the southern ports might reopen. The USDA stated it will monitor developments in Mexico and assess readiness before making further decisions.
