WASHINGTON, D.C. — The U.S. Food and Drug Administration last week granted emergency authorization for Zoetis Inc.’s Simparica TRIO to treat New World screwworm infestations in dogs and puppies, expanding veterinary treatment options as federal officials monitor detections in parts of Texas and New Mexico.
The Emergency Use Authorization applies to treatment of New World screwworm myiasis and does not authorize Simparica TRIO for prevention, the FDA stated.
The agency said most dogs in the U.S. currently face low exposure risk because of their geographic location. Animals that live in, travel to or return from areas where state or federal animal-health officials have identified screwworm, including certain countries south of the U.S. border, warrant closer monitoring.
Signs of infestation can include visible maggots or foul odors coming from wounds or body openings such as the eyes, ears, nose or mouth. The FDA advised owners to seek immediate veterinary care if infestation is suspected.
New World screwworm has currently been detected only in specific areas of Texas and New Mexico in the U.S., according to the agency.
“The FDA continues to authorize products to give veterinarians and pet owners multiple treatment options, in the unlikely event animals under their care become infested with New World screwworm,” Acting FDA Commissioner Kyle Diamantas stated.
The FDA concluded, based on the available scientific evidence, that it is reasonable to believe Simparica TRIO may be effective against screwworm myiasis when used under the terms of the authorization and that its potential benefits outweigh known and potential risks.
Simparica TRIO was originally approved by the FDA in 2020 for heartworm, flea and tick-related indications in dogs and puppies.
One of its active ingredients, sarolaner, belongs to the isoxazoline class of antiparasitic drugs. The FDA noted that while those products are commonly used and considered safe for most dogs, they have been associated with neurologic adverse reactions including tremors, loss of coordination and seizures.
Because those reactions can require professional monitoring and treatment, Simparica TRIO remains available only by prescription from a licensed veterinarian.
“We want dog owners to be informed, not alarmed,” Timothy Schell, director of the FDA’s Center for Veterinary Medicine, stated. He urged owners to watch for signs of infestation and consult veterinarians if they have concerns.
The emergency authorization will remain in effect until the FDA revokes it or the Health and Human Services secretary terminates the underlying emergency declaration supporting use of animal drugs against New World screwworm.
Simparica TRIO is sponsored by Kalamazoo, Michigan-based Zoetis.
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