U.S.-Mexico Border to Reopen for Cattle Imports After Screwworm Scare

MEXICO CITY — Mexico and the United States are set to begin gradually reopening the United States border to cattle imports from Mexico next week, ending a suspension that began in May over fears of the spread of a parasitic fly that threatens livestock and wildlife.

Agriculture officials in both countries said the border opening would begin Monday.

U.S. Agriculture Secretary Brooke Rollins said via social media that "key progress" had been made in the U.S. against the New World screwworm. She noted that more than 100 million sterile flies were being dispersed weekly in Texas and there had been no northward spread in eight weeks.

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The U.S. restricted Mexican cattle shipments in late November after detection of the pest, but lifted the ban in February after protocols were put in place to evaluate the animals prior to entry into the country. But after an "unacceptable northward advancement" of the screwworm, the U.S. Department of Agriculture said in May it was suspending shipments of cattle, horses and bison from Mexico.

Mexican President Claudia Sheinbaum described the move as "unfair" and said she worried the suspension would result in another economic blow for her country, which was already scrambling to offset tariff threats by U.S. President Donald Trump.

"We do not agree with this measure," she said at the time. "The Mexican government has been working on all fronts from the very first moment we were alerted to the screwworm."

Its impact isn't hypothetical. Texas A&M AgriLife said the parasite wreaked havoc on the Texas livestock industry 50 years ago, with recovery taking years. If it entered the U.S. again, A&M AgriLife said, the parasite could cause losses of $2.1 billion to cattle and $9 billion to the hunting/wildlife industry in Texas.

Mexico Agriculture and Rural Development Secretary Julio Berdegué said Monday that he had participated in a virtual meeting with Rollins and that the border opening would start early next week.

Rollins and Berdegué applauded close cooperation between both governments.

The screwworm is a larva of the Cochliomyia hominivorax fly that can invade the tissues of any warm-blooded animal, including humans. The parasite enters the skin, causing serious and life-threatening damage and lesions. It is most notorious for laying eggs in open wounds. Once hatched, the larvae feed on the living tissue of the host.