Mexico’s President, Claudia Sheinbaum, accused the United States of overreacting after officials reimposed a ban on Mexican livestock imports due to a deadly outbreak of New World screwworm, a pest capable of killing both animals and humans, Breitbart reported.
Sheinbaum is pushing back against the Trump administration’s latest decision to close the border to cattle shipments, calling it an "exaggerated" reaction to a confirmed outbreak of New World screwworm in southern Mexico.
“From our viewpoint, she took a totally exaggerated decision to shut down the border again,” Sheinbaum said during her daily news briefing, referencing U.S. Secretary of Agriculture Brooke Rollins.
Rollins announced earlier this week that all livestock crossings from Mexico into the United States would be suspended due to the discovery of a new screwworm infection just 350 miles south of the U.S.-Mexico border.
The move aims to "quarantine and target this deadly pest in Mexico," Rollins said in a prepared statement. “We must see additional progress combating NWS (New World Screwworm) in Veracruz and other nearby Mexican states in order to reopen livestock ports along the Southern border.”
The United States Department of Agriculture (USDA) had initially shut down livestock imports from Mexico in May 2025 after confirmed screwworm cases appeared in areas previously considered safe. A case found 160 miles north of an established buffer zone prompted the renewed suspension. That zone had been fortified with the release of sterile flies to control the parasite's spread.
In a notice explaining the closure, Rollins said the USDA was holding Mexico accountable by demanding more decisive action against the pest.
The New World screwworm, spread through flies, poses a lethal risk to livestock and wildlife and, in rare cases, humans. Although it was eradicated in Mexico in the 1990s —with the last outbreak reported in 1993 — officials believe widespread corruption has allowed contaminated livestock to be smuggled through the country’s porous southern border.
Concerns escalated in November 2024 when U.S. authorities warned of growing infections spreading north from states like Oaxaca and Veracruz. In response, the USDA ramped up containment and prevention efforts.
The May 11, 2025, suspension halted imports of live cattle, horses, and bison at all southern U.S. ports of entry. At the time, the pest had already been detected roughly 700 miles south of the border.
While Mexico has publicly criticized the renewed shutdown, U.S. officials insist the measures are essential to safeguarding American agriculture and public health.
In mid-June, Rollins announced the launch of an $8.5 million sterile fly dispersal facility in South Texas as part of a sweeping five-part strategy to enhance the USDA’s capabilities in fighting the parasite.
“These urgent actions are necessary to finish the fight against NWS and protect the United States,” Rollins said.
Jim Thomas ✉
Jim Thomas is a writer based in Indiana. He holds a bachelor's degree in Political Science, a law degree from U.I.C. Law School, and has practiced law for more than 20 years.