FDA authorizes emergency fluralaner use for screwworm infestations in dogs

A parasitic threat most U.S. veterinarians have only read about in textbooks now has a cleared treatment protocol. The FDA issued an Emergency Use Authorization November 3 for "Bravecto (fluralaner) chewable tablets to treat New World screwworm" infestations, or myiasis, in dogs and puppies, according to Veterinary Practice News.

What the authorization clears

The FDA said the EUA "is based on scientific evidence indicating the drug may be effective when used as directed, with its potential benefits outweighing known and potential risks." The agency noted that "fluralaner belongs to the isoxazoline class of antiparasitic drugs commonly used in dogs" and that it had "previously approved Bravecto for the treatment of flea and tick infestation in canine patients."

The authorization removes the prescribing gray area for a condition that, while rare in most U.S. regions, now has a cleared protocol. A veterinarian who sees a confirmed screwworm case now has regulatory cover to use a drug already on the shelf, rather than navigating off-label use without that backing.

Where exposure risk sits and what to watch for

The FDA said "exposure risk remains low for most U.S. dogs." According to the agency, dogs "living in or traveling to areas with confirmed cases should be monitored for signs such as visible maggots or foul odors in wounds or body openings." The U.S. Department of Agriculture maintains a "dashboard of confirmed detections of New World screwworm" for up-to-date U.S. case information.

The issuance of an EUA means the agency determined the potential benefits outweigh the known and potential risks for this use. The authorization provides a treatment pathway for a condition that remains uncommon but serious when it occurs.

Our read on what this changes in practice

For the associate: If you see a wound with visible maggots or a foul odor in a dog with recent travel history or residence near a confirmed-case region, screwworm is now on the differential with a cleared treatment option. The drug handling and client education are the same as for flea and tick use, so there's no new learning curve. Document the clinical suspicion and the EUA basis in the record.

For the owner: The inventory you already carry for ectoparasites now has emergency-use coverage for a rare but serious condition. No new supplier relationships, no new stocking decisions. The liability question for off-label use in a screwworm case is answered. If your practice sees dogs that travel to areas with confirmed cases, brief your team on the signs to flag and the fact that a protocol now exists.

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The limits of an EUA and the geographic-complacency risk

An EUA is not the same as a full approval. It's a regulatory tool for situations where the potential benefit justifies use despite incomplete evidence. We'd treat it as a cleared pathway for a rare case, not as a standing protocol to apply broadly. If the case is ambiguous or the maggots are not confirmed as screwworm, the standard diagnostic and treatment algorithm still applies.

The other risk is geographic complacency. Low exposure risk for most U.S. dogs is not the same as zero. A practice that has never seen a screwworm case may see one, and the time to know the protocol exists is before the client is in the room.

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