The United States has suspended the importation of live cattle, horses, and bison from Mexico through all southern border ports, effective immediately, due to the threat posed by the New World Screwworm (NWS), a dangerous flesh-eating parasite.

This decision, announced by U.S. Agriculture Secretary Brooke Rollins this weekend, is intended to protect the U.S. livestock industry from a pest that, in the past, took three decades to eradicate and caused severe economic damage.

“I am announcing the suspension of live cattle, horse, & bison imports through U.S. southern border ports of entry effective immediately,” Rollins said. “The last time this devastating pest invaded America, it took 30 years for our cattle industry to recover. This cannot happen again.”

Her Mexican counterpart, Julio Berdegue, swiftly rebuked the action, but said he hoped the two countries could soon come to an agreement over the pest, known as NWS.