The Department of Agriculture (USDA) announced it will begin reopening ports along the U.S.–Mexico border for imports of live cattle, bison, and horses, following what officials described as significant progress in controlling the spread of New World screwworm (NWS) in Mexico.

A phased reopening will begin July 7, starting with the Douglas, Arizona port, followed by Columbus, New Mexico (July 14), Santa Teresa, New Mexico (July 21), Del Rio, Texas (Aug. 18), and Laredo, Texas (Sept. 15), according to a press release from the USDA.

The USDA acknowledges Mexico’s progress in controlling animal movement and surveillance but emphasizes that further improvements are needed to reopen all U.S. ports, such as strengthening measures against illegal animal movements and expanding screwworm monitoring.

Agriculture Secretary Brooke Rollins stated that the USDA prioritized efforts to stop the spread of New World Screwworm in Mexico. She noted that the United States and Mexico have made meaningful progress by enhancing pest surveillance and increasing the release of sterile flies.

To combat the outbreak, the USDA deployed more than 100 million sterile screwworm flies per week across key areas. Officials also conducted on-the-ground assessments in collaboration with Mexico.

Mexico has started renovating its sterile fly facility in Metapa, aiming for completion by July 2026. Once upgraded, the facility will produce 60–100 million sterile New World Screwworm flies weekly—an important step toward the long-term goal of generating 400–500 million flies per week to rebuild the screwworm barrier at the Darien Gap.

“We are continuing our posture of increased vigilance and will not rest until we are sure this devastating pest will not harm American ranchers,” stated Rollins.

The decision to reopen the ports marks a big shift from the USDA’s position on May 11, when it stopped all imports of live cattle, horses, and bison from Mexico. Screwworm infestations reached as far north as Oaxaca and Veracruz—about 700 miles from the U.S. border. The closure was described as a national security measure to protect American livestock and the food supply chain.

The National Cattlemen’s Beef Association CEO Colin Woodall supported the original ban and said it was “necessary to prevent economic and ecological catastrophe,” according to an earlier report from NTD.

Screwworms are dangerous parasites. The larvae, or maggots, burrow into the flesh of living animals, often causing severe—and sometimes fatal—injuries. NWS can infest livestock, pets, wildlife, and occasionally birds, with rare cases reported in humans, according to the USDA.

The Centers for Disease Control and Prevention (CDC) warns that travelers with open wounds in affected regions are also at risk.

According to the USDA, screwworm is endemic in countries such as Cuba, Haiti, the Dominican Republic, and across much of South America. In recent years, the parasite has also been detected in Central American nations including Costa Rica, Nicaragua, Honduras, Guatemala, Belize, El Salvador, and Mexico.

Source - https://www.ntd.com