In a bid to shield U.S. livestock and secure the agricultural supply chain, the HHS has authorized the FDA to issue Emergency Use Authorizations (EUAs) for animal drugs intended to combat the New World screwworm, a parasitic fly whose larvae burrow into live tissue, causing extensive damage to warm-blooded animals.

Though eradicated from the U.S. for decades, the screwworm is now inching closer-recently detected just 370 miles from the U.S.-Mexico border, triggering an immediate halt on Mexican cattle imports. To sustain defense until sterile-fly production ramps up-a complex process expected to take 2 to 3 years-veterinarians and ranchers will now have access to animal medications not yet FDA-approved for screwworm, including foreign or alternate-use drugs.

Why this matters: The infestation risk, while still low for human health, poses a significant threat to animals, livestock productivity, and food prices. The FDA, under the new EUA framework, can authorize off-label or foreign-approved products temporarily-just as it did during the COVID-19 pandemic.

Voices from leadership:

• HHS Secretary Robert F. Kennedy Jr. emphasized that this "decisive action ... equips FDA to act quickly, limit the spread of New World Screwworm, and protect America's livestock."

• FDA Commissioner Marty Makary, M.D., M.P.H., reaffirmed the urgency: "FDA is acting swiftly and responsibly to help ensure we have the necessary tools to prevent and control New World Screwworm, minimizing risks to agriculture and public health."

Longer-term strategy: The USDA has allocated up to $750 million for a sterile-fly production facility in Texas, a proven pest control measure based on decades-old sterile-insect techniques. Still, construction and ramp-up may take several years-making the EUA route a critical interim measure.

Industry response: R-CALF USA urged FDA to permit the preventive use of ivermectin, citing its prior success controlling cattle-fever ticks. The FDA is currently reviewing scientific literature and international drug profiles for effectiveness against screwworm.

Policy context:

• Historical threat: The screwworm was effectively eliminated from the U.S. by the early 1990s, largely thanks to the sterile-fly method championed by USDA and international partners.

• Current risk: Rising cases throughout Central America and recent incursions into Southern Mexico have weakened regional defenses, prompting renewed vigilance.

Implications for agriculture:

• Rapid access to emergency treatments may avert outbreaks, preserving commodity prices, yields, and livestock health.

• Preventing screwworm's spread supports sustainable agriculture, reduces input costs, and strengthens supply chain resilience.

• The measure aligns with broader farm bill goals centered on animal disease preparedness and safeguarding rural economies.

As the season unfolds, all eyes are on the FDA's forthcoming guidance to veterinarians and producers, including protocols for authorized product use and updates to regulatory pathways for full approval of screwworm treatments.