U.S. to allow limited livestock imports from Mexico as outbreak from flesh-eating screwworm parasite eases, but total eradication will take time

At daybreak, rancher Martín Alfonso Ibarra takes advantage of the cooler hours in northern Mexico’s desert to oversee the milking of his cows and tend to 16 prized calves.

Soon, he hopes, they will be headed north to the United States as a yearlong ban on Mexican cattle imports comes to an end.

The ban, imposed over concerns about a flesh-eating parasite known as the New World screwworm fly , dealt a blow to cattle and beef industries on both sides of the border, exacerbating a livestock shortage in the U.S. and hurting a Mexican ranching sector already weakened by drought and a cattle export business that generated $1.2 billion for Mexico last year.

Now, the U.S. is set to resume livestock imports from Mexico beginning Aug.

24 at the Douglas, Arizona, border crossing, which borders Agua Prieta in Mexico’s Sonora state.

If the reopening goes smoothly, the U.S.

Department of Agriculture could allow imports through additional ports, though shipments will initially be subject to restrictions aimed at preventing the spread of the parasite — which has already crossed the border, with authorities battling cases in Texas and New Mexico .

The screwworm gets its name from the maggots’ habit of burrowing — or screwing — into a wound, according to the USDA Animal and Plant Health Inspection Service.

Any warm-blooded animal, including wildlife, pets and occasionally even humans, can be infested.

In Mexico, the screwworm outbreak was detected in November 2024 and has spread to 30 of the 32 states — most recently in Sonora, where the first case was reported Wednesday in the community of Munihuasa, near the borders with Chihuahua and Sinaloa, states where infections have also proliferated.

To date, Mexico has 1,969 active screwworm cases, which represent less than half of the infections reported a year ago, a decline that authorities say shows progress in containing the outbreak.

Still, they acknowledge eradication will take time.

New US controls are expected to slow shipments Against that backdrop, Ibarra and thousands of other ranchers in the northern state of Sonora are preparing to resume live cattle exports.

But optimism is tempered by new U.S. controls expected to slow shipments across the border.