The U.S. Department of Agriculture (USDA) is urging Mexico to lift restrictions that are slowing critical efforts to contain the spread of New World Screwworm (NWS) in southern Mexico.
In a letter sent today to Mexico’s Secretary of Agriculture, U.S. Secretary Brooke Rollins stressed that the situation has reached a critical point. Rollins warned that delays in action are allowing the outbreak to expand, increasing the risk that the pest could spread beyond the Isthmus of Tehuantepec and reach the U.S. border.
New World Screwworm is a deadly parasitic fly that infests warm-blooded animals, causing severe wounds that can lead to death if left untreated. While NWS was eradicated from the U.S. and Mexico decades ago, new detections in Mexico highlight the urgent need for a coordinated response. An outbreak in the United States would severely impact the livestock industry and the nation’s food supply.
The USDA’s emergency response relies heavily on the use of sterile insect technique (SIT), a proven method that involves daily aerial releases of sterile flies to suppress the pest population. However, Mexican aviation authorities have placed limits on Dynamic Aviation, a USDA-contracted carrier. Current restrictions allow only a temporary 60-day permit and limit flight operations to six days per week—falling short of the seven days per week needed for an effective response.
Rollins also raised concerns about Mexican customs authorities imposing significant import duties on essential supplies, including aircraft parts, dispersal equipment, and sterile fly shipments. These materials, fully funded by the U.S. government, are critical for stopping the spread of NWS. The added costs and delays are hampering efforts at a time when rapid action is crucial.
In her letter, Rollins called on Mexico to take immediate steps, including:
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Granting Dynamic Aviation full operational clearance for at least one year, preferably longer.
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Waiving customs duties on all NWS-related equipment and sterile fly shipments.
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Appointing a senior liaison to work directly with USDA’s Animal and Plant Health Inspection Service (APHIS) to resolve operational barriers quickly.
Rollins warned that if the issues are not addressed by April 30, the U.S. will move to restrict imports of live cattle, bison, and equines originating from or passing through Mexico to protect American agriculture.
To strengthen coordination, the USDA has also proposed a joint U.S.-Mexico meeting involving government officials, technical experts, and operational partners to align on an effective aerial dispersal strategy.
The USDA emphasized its commitment to working with Mexico to resolve the situation and maintain the progress made in protecting livestock, wildlife, and agriculture across the region.
