
The U.S. Department of Agriculture has suspended live animal imports from Mexico to prevent the northward spread of the deadly New World screwworm, reigniting tensions over cross-border biosecurity.
At a Glance
- USDA halts imports of cattle, horses, and bison from Mexico due to screwworm outbreak
- The flesh-eating parasite has been detected as far north as Oaxaca and Veracruz
- The import suspension will be reviewed monthly, with enhanced inspections at border ports
- Mexico disputes the fairness of the suspension, calling it economically damaging
- U.S. cattle industry groups support the move to protect domestic livestock
USDA Acts to Shield U.S. Livestock
On May 11, the U.S. Department of Agriculture announced a full suspension of live cattle, horse, and bison imports through the southern border, citing new outbreaks of the New World screwworm. This parasitic fly, whose larvae feed on living tissue, has been confirmed in Oaxaca and Veracruz, raising alarm about its advance toward U.S. territory.
The agency, under Secretary Brooke Rollins, said the suspension is a necessary step to protect American herds and prevent a biosecurity disaster. Although initially limited to 15 days, the USDA will review the policy monthly and adjust based on regional containment efforts and new data.
Watch a report: USDA Suspends Live Animal Imports Through Ports of Entry Along Southern Border.
Industry Backs Precautionary Measures
Major ranching groups are standing by the USDA’s move. The National Cattlemen’s Beef Association praised the decision as a proactive defense of U.S. agriculture. CEO Colin Woodall pointed to Mexican regulatory delays as a critical failure that helped fuel the parasite’s spread.
Similarly, Texas and Southwestern Cattle Raisers Association President Carl Ray Polk Jr. acknowledged the temporary economic hit but emphasized the long-term need to keep the pest from crossing the border. He called the USDA’s action “an unfortunate but necessary measure” to protect the national herd from collapse.
Mexico Pushes Back Against Suspension
Not everyone agrees. Mexican President Claudia Sheinbaum condemned the U.S. suspension as “unfair,” warning that the 15-day ban could severely impact Mexico’s livestock economy. She emphasized her country’s willingness to collaborate on eradication strategies and pushed for a science-based, bilateral response.
Despite ongoing cooperative programs between the two nations, including a sterile fly release initiative, the screwworm’s northward expansion has continued largely unabated. The USDA has confirmed increased surveillance and monitoring along the southern border, including deployments of pest control personnel and port inspections.
A Renewed Biosecurity Battle
Once eliminated in the U.S. by 1966 through massive campaigns, the New World screwworm has resurfaced in Mexico and Central America since early 2023. Its resurgence prompted renewed concern among epidemiologists and prompted the USDA’s Animal and Plant Health Inspection Service to accelerate sterile insect deployment strategies in southern Mexico.
As the situation unfolds, U.S. officials are balancing trade relations with an uncompromising stance on agricultural safety. The next monthly review will test how effectively both governments can contain the outbreak and prevent a repeat of past screwworm disasters—ones that cost billions and took decades to defeat.