REDFIELD, Iowa (DTN) -- Ports will remain open for livestock imports from Mexico to the U.S. following an agreement between the two countries about how to combat New World Screwworm (NWS).

On Saturday, U.S. Secretary of Agriculture Brooke Rollins sent a letter to Mexico Secretary of Agriculture and Rural Development Julio Antonio Berdegue Sacristan, warning that the outbreak of NWS "continues to expand in southern Mexico" and "we are now at a critical inflection point in our shared campaign against this pest, and I am very concerned about our collaboration."

On Wednesday, making the deadline set in the letter, Rollins announced in a statement that Mexico committed to eliminate restrictions on USDA aircraft and waive customs duties on eradication equipment aiding in the response to the spread of NWS.

"Due to this agreement the ports will remain open to livestock imports, however if at any time these terms are not upheld, port closure will be revisited," she said.

PEST IS A THREAT

NWS are fly larvae that infest mammals and birds, feeding as they go like a screw being driven into wood. Symptoms in these animals include irritated behavior, head shaking, smell of decay, evidence of fly strike and presence of fly larvae in the wounds, according to the Animal and Plant Health Inspection Service (APHIS). NWS can cause serious damage and even kill an animal.

APHIS says the best prevention of NWS in the U.S. is by avoiding infestation. Eradicating NWS is only possible through the sterile insect technique. Since the female fly only mates once, this helps eliminate the problem.

"I am happy to share Mexico has continued to partner in emergency efforts to eradicate the New World Screwworm. 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," Rollins added.

Year-to-date, Mexico has exported more than 178,240 cattle to the U.S., mostly feeder cattle. That is about 38% of what Mexico sent to the U.S. in the same period of 2024. The U.S. temporarily banned Mexican cattle imports on Nov. 22, 2024, and reopened the border to those cattle on Feb. 1, 2025.

"At USDA we are working every day to keep pests and disease from harming our agricultural industry. I thank our frontline USDA staff and their counterparts in Mexico for their work to ensure the screwworm does not harm our livestock industry," Rollins said.

Also see, "Rollins Warns Mexico Over Screwworm," https://www.dtnpf.com/…

See, "APHIS Expands Biological Barrier Into Mexico to Help Prevent Screwworm Spread," https://www.dtnpf.com/…

Jennifer Carrico can be reached at jennifer.carrico@dtn.com

Follow her on social platform X @JennCattleGal

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