The United States Department of Agriculture (USDA) has announced a comprehensive initiative to address the threat posed by the New World Screwworm (NWS), a pest that can infest livestock, pets, wildlife, and occasionally humans. The NWS was eradicated from the U.S. in the 1960s but began spreading northward into Mexico in November 2024.
On May 11, USDA announced the closure of the southern border to imports of cattle, bison, and horses from Mexico. Since then, there has been no notable increase in reported NWS cases in Mexico, and its northward movement has stalled. To date, there have been no cases of NWS in the United States.
To combat the potential spread of NWS towards the U.S., USDA unveiled a five-pronged plan on June 18, 2025:
1. **Stop the Pest from Spreading in Mexico**: USDA is enhancing international sterile fly production with a $21 million investment to retrofit a fruit fly facility in Mexico. Surveillance will be improved with additional traps and lures supplied along with technical assistance for effective deployment and maintenance. Animal movement may be limited if necessary.
2. **Protect the U.S. Border at All Costs**: Efforts include intercepting stray and illegally introduced livestock at the border with Mexico and collaborating with state wildlife agencies for wildlife surveillance and monitoring. Enhanced inspection of live animals at ports of entry from Mexico will continue.
3. **Maximize our Readiness**: USDA is partnering with state animal health officials to update emergency management plans and continue training federal and state responders for potential outbreaks. Regulatory hurdles are being addressed by working with EPA, FDA, and others to ensure access to effective treatment products.
4. **Take the Fight to Screwworm**: Construction will begin on an $8.5 million sterile insect dispersal facility at Moore Air Base in South Texas to disperse sterile flies along the border and Northern Mexico. Options are being explored for a domestic sterile fly production facility as well as validating modular rearing facilities for future surge capacity.
5. **Innovate Our Way to Continued Success**: Innovative research into improving sterile insect technology is underway, including exploring modified strains or genetically engineered organisms. Partnerships with land-grant universities aim to facilitate local training, trap deployment, surveillance validation, and stakeholder outreach while exploring next-generation treatments for screwworm effects should it enter the country.
For more details on USDA's policy brief regarding this initiative...