The challenge of managing screwworm populations during the warmer months is critical to preventing their spread further north, according to experts. In Kansas, the cold winter temperatures are sufficient to eliminate the screwworm threat, but increased vigilance is necessary as summer approaches.
Levendofsky emphasized the importance of monitoring the situation: “In Kansas, it gets cold enough in the wintertime that it does kill the screwworm, but these summer months are going to be pretty crucial for tracking it and ensuring that we can stay ahead of it.”
Earlier this week, the USDA identified a screwworm case just 25 miles south of the Texas-Mexico border. The agency assured the public that it is prepared to respond should the fly cross into the United States.
Rollins, during a press call, noted, “We are preparing to implement the very moment the fly makes it into our country. USDA and our state partners will work hand in hand to address the incident, and we will communicate every step of the process with the public.”
Shortly thereafter, the anticipated situation materialized. A comprehensive 29-page response playbook was released to guide monitoring efforts and control the spread among animals.
Adherence to animal movement guidelines by producers is crucial to containing the outbreak within the quarantine zone. Rollins explained, “This fly typically moves great distances because humans move animals. These flies do not fly to new areas on their own.” He added that minimizing disruptions to commerce and the livelihood of livestock producers is essential, emphasizing the collective responsibility of respecting animal movement restrictions.
To tackle the infestation, sterile flies will be released in affected areas to decrease the screwworm population.
In response to the threat, imports of Mexican cattle were suspended in May 2025, a measure that continues to be in effect. Rollins highlighted the importance of collaboration with Mexico to mitigate future outbreaks, stating, “We’ve conducted extensive audits and verification missions throughout Mexico to assess their surveillance, movement controls, prevention, and response activities. There obviously was a lot to be desired in the Mexican response, but we made some progress, and we will continue.”
Meanwhile, a leading meat industry group in Mexico reported to Reuters that the country is increasing domestic beef processing as a countermeasure to the import ban, which has resulted in a $1.8 billion loss to Mexico’s livestock sector.
Rollins recognized the economic repercussions in the U.S. stemming from the border closure but stressed that the potential damage from screwworms would be more severe, stating, “We will obviously keep the ports closed until further notice.”
This story was produced in partnership with Harvest Public Media, a collaboration of public media newsrooms in the Midwest and Great Plains. It reports on food systems, agriculture, and rural issues.
