July 15, 2026 - FDA Issues Emergency Use Authorization for Drug for Short-Term Prevention of New World Screwworm in Horses

To advance the Trump administration's actions to safeguard American agriculture, the U.S. Food and Drug Administration today issued an Emergency Use Authorization (EUA) for Ivermectin Liquid for Horses (ivermectin oral solution) for the short-term prevention of New World screwworm (NWS) infestations (myiasis) in horses. The product is authorized for use when administered within 24 hours of birth or at the time of initial wound care. Ivermectin Liquid for Horses is not for use in species other than horses.

"The Trump administration will use every available tool to stop New World screwworm from threatening America's horses and livestock," said U.S. Health and Human Services Secretary Robert F. Kennedy, Jr. "This EUA expands our defenses, strengthens our preparedness, and helps protect the animals, producers, and communities that drive American agriculture."

"President Trump has directed his entire administration to do what it can to combat and stop the spread of New World screwworm. We at USDA have been working with our federal partners to prepare for any potential infestation of animals that may occur as a result of New World screwworm, and today's announcement is another step in the right direction," said U.S. Department of Agriculture Secretary Brooke L. Rollins. "HHS and FDA have stepped up to the plate and have moved at Trump speed to authorize as many treatments as needed to protect our livestock, wildlife, and companion animals. I am thankful to Secretary Kennedy for getting this authorization across the finish line and ensuring our horse population has access to preventative measures, should they need it."

NWS is a parasitic fly whose larvae feed on the living tissue of warm-blooded animals. Newborn animals with healing umbilical wounds and animals with open wounds are particularly vulnerable to infestations, as NWS flies are attracted to these sites to lay their eggs. Left untreated, infestations can be severe and life-threatening.

Based on the totality of the scientific evidence available, the FDA has concluded it is reasonable to believe that Ivermectin Liquid for Horses may be effective in the short-term prevention of NWS myiasis in horses when used as authorized, and the known and potential benefits of the product outweigh its known and potential risks.

"The Trump administration is leaving no stone unturned in our fight to shield American ranchers, livestock producers, and the agricultural economy from this threat," said Acting FDA Commissioner Kyle A. Diamantas, J.D. "This marks the FDA's 11th Emergency Use Authorization deployed against New World screwworm, and we will continue to use all available authorities, act with maximum speed, and deliver tools to protect animals in the U.S."

This EUA authorizes Ivermectin Liquid for Horses only for short-term prevention of NWS myiasis, not treatment. If a wound is already infested, or if an infestation develops after administering Ivermectin Liquid for Horses, contact a veterinarian to discuss treatment options.

"This authorization provides a short-term prevention option for horses, but owners and veterinarians should be aware of the limitations," said Timothy Schell, Ph.D., director of the FDA's Center for Veterinary Medicine. "This product's window of prevention lasts no more than 24 hours, so it is important that the product be used alongside other preventive measures such as bandaging, repellents, and other fly-control methods."

Ivermectin Liquid for Horses is a clear, ready-to-use solution and can be administered as an oral drench or via a tube going from a horse's nose to its stomach. This product is available only by prescription from a licensed veterinarian. Do not use this product in species other than horses.

Detailed product information about Ivermectin Liquid for Horses can be found in the Fact Sheet: Emergency Use Authorization of Ivermectin Liquid for Horses (ivermectin oral solution) for New World Screwworm (NWS).

This EUA will be effective until it is revoked or the HHS Secretary terminates the declaration that the potential public health emergency presented by NWS justifies the emergency use authorization of animal drugs for NWS.

Ivermectin Liquid for Horses is sponsored by Alberta Vet Labs Ltd. based in Canada.

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