Recently I visited a ranch in Texas where New World screwworm, a parasitic fly larva, was discovered in a calf on June 3, 2026. Though the calf is now recovering, ranchers are still on high alert. Since that first confirmed case of infection, my colleagues at the U.S. Department of Agriculture (USDA) have confirmed 41 more within our borders, warranting public vigilance—but not panic. The Trump administration is well-prepared to defend our producers from this pest, which must be seen in the context of our entire effort to restore American preeminence in the Western Hemisphere.
Simply put, the eradication of New World screwworm from the United States sixty years ago, and its elimination from the North American continent two decades later, depended on a Western Hemisphere in which American leadership was active, respected, and effective. The reappearance of New World screwworm in the past five years required exactly the opposite: a Western Hemisphere in which American leadership was inactive, disrespected, and ineffective.
The culprits for that are many. They include the decades-long rise of cartels, cartel-corrupted governments in Latin America, and American leadership that took a holiday from history—and abandoned its responsibility to protect Americans and American livelihoods first. More recently, the Biden administration’s open border policies and refusal to crack down on trafficking allowed screwworm to move north through the Darién Gap and toward our southern border.
As a result, every model showed the pest entering our country by late summer of 2025. The good news is that’s not what happened, because now we have a president who takes the fight seriously. We’re back in it—and we’re going to win.
President Trump took immediate action to defend America from New World screwworm once he returned to office, rapidly strengthening border protections and increasing oversight of containment efforts in Mexico, buying us critical time to prepare. Over the past 17 months, we have deployed over $1 billion in preparation for this moment, centered around three crucial actions.
First, we have sharpened our best tool against the pest by expanding sterile fly production and dispersal capacity in record time. By mating with wild female screwworm, the male sterile fly brings its reproductive cycle to an abrupt halt. Dispersing millions of sterile flies in an infected area collapses the screwworm population, which is why this spring we opened a new sterile fly dispersal facility and broke ground on a sterile fly production facility, both at Moore Air Base in Texas. Last week, a production facility we helped upgrade in Metapa, Mexico officially opened. This is on top of a facility we support in Panama that is currently producing sterile flies at fivefold its planned capacity.
Second, we are advancing next-generation tools and technologies. For example, our USDA scientists recently developed a novel strain of fly for sterile screwworm that will soon double our production output.
Finally, we have strengthened surveillance and detection. We are actively monitoring over 8,000 surveillance traps along the U.S.-Mexico border and have examined over 78,000 fly samples and wildlife specimens since January 2025. And we are demanding that Mexico fully implement in-country animal movement protocols to slow screwworm’s northward spread.
Our whole of government approach entails unprecedented teamwork across the entire Cabinet, as well as with Texas Governor Greg Abbott, the Texas Animal Health Commission, and the Texas Parks and Wildlife Department. As soon as we confirmed cases in the U.S., our state partners established a 20-kilometer movement control zone around the detections. We have also expedited a targeted release of sterile flies in the affected areas and are increasing trapping for screwworm along the border and just outside of the dispersal areas.
In short, we are using every tool at our disposal to respond in a manner that is sweeping but not monolithic. After all, this fight is also a cartel phenomenon. It’s also a trafficking phenomenon. It’s also a border-crisis phenomenon. The Trump administration is solving this as the multi-layered crisis that it is, together with our local, state, and binational partners who have been waiting for American leadership to finally arrive on the scene. We have.
The reappearance of New World screwworm isn’t a leading indicator. It isn’t a harbinger of terrible things to come. It’s a lagging indicator, a last manifestation of American neglect and complacency that is long since over. When we beat it—and we will—that win will be the real harbinger of our future and of the future of our hemisphere.
