What is the New World Screwworm (NWS)?
The New World Screwworm (Cochliomyia hominivorax) is a deadly parasitic fly that targets warm-blooded animals. Its larvae burrow into living tissue, causing severe wounds, infections, and in some cases, death.
- Hosts: Livestock (cattle, sheep, goats), pets (dogs, cats), wildlife, and rarely, humans.
- Health Impact: Tissue damage, infections, high treatment costs, reduced livestock productivity.
- Food Supply Threat: Large-scale infestations can devastate meat and dairy industries, posing a risk to national food security.
Although the pest was eradicated from North and Central America decades ago, it has resurfaced since 2022, spreading northward and now nearing the U.S.–Mexico border.
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Why This Emergency Declaration Matters
HHS Secretary Robert F. Kennedy, Jr. stated:
“Today we act with urgency to shield America’s food supply from this advancing threat. This emergency declaration equips FDA with authority to move swiftly, stem the spread of the screwworm, and safeguard our herds and flocks.”
Currently, no FDA-approved drugs exist in the U.S. for NWS. This EUA will allow:
- Faster access to animal medicines approved abroad but not in the U.S.
- Emergency use of drugs already authorized for other conditions.
- Immediate support for farmers, veterinarians, and animal health workers.
This move ensures that America’s livestock producers have the tools needed to protect their animals and defend the nation’s food supply.
The Threat: New World Screwworm Overview
What Makes This Parasite So Dangerous
The New World Screwworm (Cochliomyia hominivorax) is not your typical parasite:
- Larvae consume living tissue (not dead tissue like other flies)
- Rapid reproduction cycle (females lay 200-400 eggs at a time)
- Can kill adult cattle in 7-10 days if untreated
- Causes $20,000+ losses per infected herd
Current Spread Pattern
| Year | Location | Impact |
|---|---|---|
| 2022 | Reappeared in Central America | Initial outbreaks |
| 2023 | Spread through Mexico | Major livestock losses |
| 2024 | Northern Mexico border states | Emergency preparations |
| 2025 | Approaching US border | Emergency declaration |
Emergency Response Measures
FDA Emergency Powers Activated
- Emergency Use Authorizations (EUAs) for veterinary drugs
- Fast-track approval of international treatments
- Emergency protocols for field veterinarians
- Border monitoring enhancements
USDA Action Plan
✔ Enhanced surveillance at all southern border crossings
✔ Quarantine protocols for infected animals
✔ Producer education programs launching September 2025
✔ Treatment stations being established in high-risk areas
Economic Impact Assessment
Potential Consequences if Unchecked
- $1.2 billion in annual livestock losses possible
- 15-20% increase in meat prices projected
- Export restrictions likely from trading partners
- 20,000+ jobs at risk in meat processing industry
Historical Success Gives Hope
- 1950s-1960s: US completely eradicated screwworm
- Sterile insect technique proved highly effective
- 2000: Declared eradicated from North America
- Proven methods exist for control and elimination
Agriculture Secretary Brooke L. Rollins commended the move:
“I extend gratitude to Secretary Kennedy and Commissioner Makary for rallying to this urgent cause. This emergency clearance grants us another formidable instrument to repel the New World Screwworm. Our ranchers and producers entrust this administration with their livelihoods. This is not merely a pest control matter—it is a national security imperative. Together, across President Trump’s cabinet, we are united in defending our borders and protecting our producers from ruin.”
FDA Commissioner Marty Makary, M.D., M.P.H., emphasized the agency’s dual mission:
“Our foremost duty is to defend animal health while preserving the nation’s food security. The FDA is acting decisively yet responsibly, ensuring we deploy the right tools to intercept and suppress the spread of New World Screwworm while minimizing risks to agriculture and public well-being.”
In the coming weeks, the FDA will release additional instructions for veterinarians and agricultural stakeholders regarding the appropriate and judicious use of any emergency-authorized products. Updates will also be furnished through the FDA’s New World Screwworm: Information for Veterinarians resource hub.
