Source: U.S. Food and Drug Administration
The U.S. Food and Drug Administration (FDA) has issued its first-ever Emergency Use Authorization (EUA) for an animal drug, approving Credelio (lotilaner) chewable tablets to treat New World screwworm (NWS) infestations in dogs and puppies. Based on available evidence, the FDA determined that Credelio may be effective and that its potential benefits outweigh known risks. The authorization follows the August 2025 declaration by the Secretary of Health and Human Services that NWS poses a significant public health threat.
Although eradicated decades ago, NWS—an invasive parasite that causes severe tissue damage in warm-blooded animals—has reemerged since 2022, threatening livestock, pets, and wildlife near the U.S.–Mexico border. Originally approved in 2018 for flea and tick control, Credelio’s active ingredient, lotilaner, is an isoxazoline antiparasitic drug. The FDA is also reviewing additional NWS-related EUAs for other animal species. Credelio remains prescription-only, requiring Veterinary supervision due to possible neurologic side effects.