Capstar’s New Role in Fighting New World Screwworm
Capstar, a flea tablet that has long been used on cats and dogs, is now authorized by the FDA to treat and prevent New World screwworm infestations in pets.
The FDA issued an Emergency Use Authorization on September 3 2026 for nitenpyram tablets, allowing the product to be used off-label for this purpose. New World screwworm is a fly (Cochliomyia hominivorax) whose larvae burrow into living tissue, causing extensive damage and potentially life-threatening wounds.
The parasite has been detected in the United States and Mexico. USDA is conducting surveillance and has established infestation zones in Texas. Historical outbreaks have had large economic impacts, such as the 1976 Texas outbreak that cost producers an estimated $132.1 million (about $740 million in 2024 dollars) and recent disruptions to Mexican cattle exports costing around $1.8 billion.
Veterinarians can use Capstar under the EUA, not its standard FDA-approved use. The product should not become routine parasite prevention for all cats. Owners of pets in or traveling to affected areas should be aware of the risk, know preventive options, and recognize signs of infestation.
Key takeaways
- Capstar tablets are now authorized to treat and prevent New World screwworm in cats, kittens, dogs, and puppies.
- The fly’s larvae feed on living tissue, causing serious wounds.
- The FDA issued the Emergency Use Authorization on September 3 2026.
- USDA monitors infestations, especially in Texas.
- Capstar should only be used under the EUA, not as routine flea prevention.
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Originally reported by Catster. Read the full article.
Cover photo by Sole Montaner via Pexels.
