SILVER SPRING, Md., July 15, 2026
The U.S. Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for Ivermectin Liquid for Horses (ivermectin oral solution) to provide short-term prevention of New World Screwworm (NWS) infestations, also known as myiasis, in horses. The authorization marks another significant step in the U.S. government’s efforts to protect the nation’s livestock and equine populations from the highly destructive parasitic pest. The emergency authorization permits veterinarians to administer the prescription-only oral solution within 24 hours of birth or during initial wound care to reduce the risk of screwworm infestations in horses. The FDA emphasized that the authorization applies only to horses and is intended exclusively for preventive use, not for treating existing infestations. The decision represents the agency’s 11th Emergency Use Authorization issued to support preparedness against the growing threat posed by New World Screwworm to American agriculture.
FDA Expands Emergency Measures Against New World Screwworm
New World Screwworm is a parasitic fly whose larvae feed on the living tissue of warm-blooded animals, creating severe and potentially life-threatening wounds if left untreated. Newly born animals with healing umbilical cords and horses with open wounds are particularly vulnerable because female screwworm flies deposit eggs directly into exposed tissue. According to the FDA, available scientific evidence indicates that Ivermectin Liquid for Horses may effectively provide short-term protection against NWS when administered according to the emergency authorization. Regulators concluded that the known and potential benefits outweigh the known and potential risks, allowing emergency access while federal agencies continue implementing broader biosecurity measures. The authorization forms part of an ongoing national response designed to safeguard horses, livestock, wildlife, and the broader agricultural economy from potential outbreaks.
Prescription-Only Prevention With Important Usage Limitations
The FDA stressed that Ivermectin Liquid for Horses is not approved to treat active screwworm infestations and should only be used as a preventive measure during the first 24 hours after birth or immediately following initial wound care. Horses that develop infestations despite preventive treatment should receive prompt veterinary evaluation to determine appropriate therapeutic options. The clear oral solution may be administered either as an oral drench or through a nasogastric tube by or under the direction of a licensed veterinarian. Officials also emphasized that the product should never be administered to species other than horses and should be combined with additional preventive practices, including proper wound bandaging, fly repellents, and comprehensive fly-control strategies, to maximize protection against NWS exposure. The emergency authorization will remain active until federal authorities determine that the public health emergency no longer justifies emergency access to the product.
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Strengthening U.S. Veterinary Preparedness and Animal Health Protection
The emergency authorization highlights the FDA’s continued commitment to protecting animal health, supporting veterinary medicine, and strengthening national preparedness against emerging agricultural threats. Sponsored by Alberta Vet Labs Ltd., the authorized ivermectin formulation provides veterinarians with an additional preventive tool while federal agencies coordinate broader surveillance and response measures against New World Screwworm. As livestock producers and horse owners face increasing concerns over the spread of the parasite, rapid regulatory action helps improve readiness and reinforces ongoing efforts to minimize disease risk across the United States. The FDA’s decision demonstrates how emergency regulatory pathways can accelerate access to important veterinary medicines during evolving animal health emergencies while maintaining scientific oversight. Continued monitoring, responsible veterinary use, and integrated pest management will remain essential to protecting equine health and preserving the stability of the nation’s agricultural sector.
Source: FDA press release
