US Halts Mexican Cattle Imports Over New World Screwworm Fears

The U.S. Department of Agriculture has announced a temporary halt on the import of live cattle from Mexico following the detection of the flesh-eating New World screwworm in some Mexican cattle. This decision comes after an initial suspension in November 2024, which was lifted in February, but the recent discovery of the parasite has prompted renewed concerns about the spread of this dangerous pest.

The New World screwworm, a parasitic fly that feeds on the living flesh of warm-blooded animals, was previously eradicated from the U.S., Mexico, and Central America. However, its recent detection about 700 miles from the U.S. border in Mexico has raised alarms. The parasite has been known to cause significant harm to livestock and, in rare cases, has even infected humans. The U.S. Secretary of Agriculture, Brooke Rollins, suspended live cattle imports from Mexico on May 11, 2025, as a precautionary measure to prevent the spread of the screwworm into the U.S.

This development has significant implications for both the U.S. and Mexican cattle industries. For the U.S., the ban on Mexican cattle imports aims to protect its livestock from the potentially devastating effects of the New World screwworm. The parasite can cause severe wounds and even death in infected animals, leading to substantial economic losses for farmers and ranchers. The U.S. has a robust system in place for monitoring and controlling pests and diseases, and this ban is a proactive step to ensure that the screwworm does not establish a foothold in the country.

For Mexico, the ban represents a setback for its cattle industry, which relies heavily on exports to the U.S. The suspension of trade will likely result in financial losses for Mexican cattle producers and could disrupt supply chains. However, it also provides an opportunity for Mexico to strengthen its pest control measures and ensure that its livestock is free from the screwworm before trade resumes.

The ban on Mexican cattle imports is a reminder of the ongoing challenges posed by pests and diseases in the global livestock industry. It underscores the importance of vigilant monitoring and swift action to prevent the spread of harmful parasites. As both countries work to address this issue, it is crucial that they collaborate to develop effective strategies for controlling the New World screwworm and protecting their livestock industries.

Mexico exported just over one million head of cattle to the United States in 2024, according to official estimates. The trade was halted briefly that year for the same reason. The cattle standoff comes amid heightened tensions between the two neighbors over the Trump administration’s hardline immigration policy and trade tariffs.

“The United States has promised to be vigilant — and after detecting this new NWS case, we are pausing the planned port reopening’s to further quarantine and target this deadly pest in Mexico,” Secretary Brooke Rollins said in a statement on Wednesday. “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 official said.