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Agriculture Secretary Brooke Rollins told members of the Senate Agriculture Committee Wednesday that the Biden administration’s handling of the southern border created conditions that allowed the New World screwworm — a parasite absent from U.S. soil for six decades — to take hold again in American livestock territory.
Why It Matters
New World screwworm poses a serious threat to the American cattle and livestock industry, including ranching operations across the Mountain West and Idaho. The parasite, a fly that deposits eggs in living animals, produces larvae that consume flesh and can kill the host animal if untreated. A widespread outbreak could have severe consequences for agricultural producers who depend on healthy livestock herds.
Rollins sought to reassure the public about the food supply, stating plainly: “The food supply is 100% safe. This is not a disease. It’s not a virus. It’s a fly.” But she made clear the threat to livestock is real and demands immediate action.
What Happened
Six confirmed cases of New World screwworm have been identified in the United States — five in South Texas and one in New Mexico. The parasite had been successfully eliminated from the country in 1966 through a sustained federal eradication program, making its return a significant agricultural biosecurity concern.
Testifying before the Senate Agriculture Committee, Rollins attributed the reemergence to what she described as lax border enforcement during the previous administration. “Everyone took their eye off the ball years ago, and unfortunately, because of the border policies, it’s coming our way,” she said.
The USDA responded by closing all ports along the southern border to livestock trade last summer in an effort to slow the parasite’s northward spread. The agency has also dramatically expanded its dedicated prevention workforce, growing from just 10 full-time screwworm prevention staff at the start of last year to more than 120 today.
By the Numbers
- 6 confirmed U.S. cases of New World screwworm (5 in South Texas, 1 in New Mexico)
- $1.3 billion allocated by the USDA to combat the screwworm threat
- 100 million sterilized flies produced per week currently — but 500 million per week are needed to achieve full eradication
- 120+ full-time screwworm prevention staff currently, up from 10 at the beginning of last year
- 21,000+ total USDA employees lost since President Trump returned to office in January 2025
Staffing Concerns Raised
The hearing also surfaced concerns about whether recent workforce reductions at the USDA could undermine eradication efforts. The agency’s Animal and Plant Health Inspection Service lost roughly 25% of its staff, including more than 300 veterinary services employees. Overall, the department has shed more than 21,000 workers since Trump took office last year.
Sen. Amy Klobuchar (D-Minn.) raised questions about whether those staffing cuts could hamper the department’s ability to eliminate the parasite before it spreads further. Rollins defended the department’s readiness, pointing to the rapid expansion of the screwworm-specific prevention team and the $1.3 billion funding commitment as evidence of the administration’s seriousness.
Zoom Out
The screwworm situation reflects a broader federal debate over how border security intersects with agricultural biosecurity. As federal programs distribute rural health and agricultural support dollars under recent legislation, livestock producers across Idaho and the Mountain West are watching closely to see whether the USDA can scale up its sterilized fly production — which must increase fivefold from current levels — before the parasite establishes a wider foothold.
The primary eradication method involves releasing large numbers of sterile male flies to disrupt the parasite’s reproductive cycle, a technique that proved effective in the original 1966 campaign. Matching that success today will require a significant increase in production capacity, something Rollins indicated the agency is actively working to achieve.
What’s Next
The USDA faces the challenge of ramping up sterile fly production from roughly 100 million to 500 million per week while managing a reduced overall workforce. Congressional oversight is likely to continue as lawmakers on both sides of the aisle monitor how quickly the department can contain the outbreak and whether the southern border livestock trade restrictions remain in place.
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