WASHINGTON — After sending a letter to her Mexican counterpart earlier in the week,  Agriculture Secretary Brooke Rollins confirmed that the United States and Mexico agreed to move on handling the spread of New World screwworm (NWS).

According to the agency, Mexico committed to eliminating restrictions for USDA aircraft and waiving customs duties on eradication equipment, which are assisting with stopping the spread of these flies.

“I am happy to share Mexico has continued to partner in emergency efforts to eradicate the New World screwworm,” Rollins said. “This pest is a devastating threat to both of our economies, and I am pleased to work together with Mexico in good faith to protect the livelihoods of our ranchers and producers who would have been hurt by this pest. I thank our frontline USDA staff and their counterparts in Mexico for their work to ensure the screwworm does not harm our livestock industry.”

In Rollins’ previous letter, closing ports was a possibility, but this new update allows ports to remain open to livestock imports. The United States usually imports more than one million cattle a year from Mexico.

NWS are fly larvae that infest the living tissue of warm-blooded animals, causing infection. According to the Animal and Plant Health Inspection Service (APHIS), the maggots can infest livestock and other warm-blooded animals, including people.

In November 2024, the chief veterinary officer of Mexico notified APHIS of a positive NWS detection in the southern Mexico state of Chiapas, near the border of Guatemala.

The next month, APHIS provided $165 million in funding to stop NWS.