FDA approves first oral solution for the treatment and control of northern fowl mites in poultry

Photo: Anton Dios/Adobe Stock

On July 17, 2025, the FDA approved fluralaner oral solution (Exzolt; MSD Animal Health) for the treatment and control of Ornithonyssus sylviarum, also known as northern fowl mites, in laying hens and replacement chickens. The parasiticide is the first FDA-approved therapy for the treatment and control of northern fowl mites in poultry and is also the first oral solution of its kind.¹

Fluralaner oral solution also treats Dermanyssus gallinae (red mites).² According to MSD Animal Health, the product is more than 99% effective.²

The product works by systematically treating birds by adding it to their drinking water. Specifically, veterinarians administer the solution to laying hens and replacement chickens via drinking water through 2 single doses of 0.5 mg fluralaner/kg (0.227 mg/lb) body weight, which is equivalent to 0.05 mL of Exzolt/kg body weight (0.023 mL/lb). The doses should be administered 7 days apart. Each dose should be consumed over a period of 6 to 24 hours.

The parasiticide is only available through prescription from a licensed veterinarian. “Professional expertise is required to monitor the safe and effective use of this product,” the FDA wrote in its announcement.¹

The FDA noted that care should be taken when handling the product. When administering fluralaner oral solution, people should wear protective gloves and avoid exposing the skin and eyes to the product. Accidental exposure to the skin or eye may cause irritation.³

In a release announcing the product’s approval, the FDA said consuming poultry treated with fluralaner oral solution is not considered a public health risk provided the product is used according to the label. “In addition to establishing that fluralaner is safe and effective in laying hens and replacement chickens, the FDA determined that residues in edible tissues or eggs from birds treated with Exzolt will not represent a public health concern when the product is used according to the label,” wrote the FDA.¹

Two dose confirmation studies and 2 field studies demonstrated the effectiveness of fluralaner oral solution. Its target animal safety, meanwhile, was evaluated in 4 studies. No clinically significant adverse effects were observed.³

At the time, the product is not at risk of developing antimicrobial resistance.³

References

1. FDA Approves First Oral Product for Treatment and Control of Northern Fowl Mites in Laying Hens and Replacement Chickens. News release. US Food and Drug Administration. July 17, 2025. Accessed September 5, 2025. https://www.fda.gov/animal-veterinary/cvm-updates/fda-approves-first-oral-product-treatment-and-control-northern-fowl-mites-laying-hens-and
2. Exzolt Fluralaner. MSD Animal Health. Accessed September 5, 2025. https://www.exzolt.com/
3. Freedom of information summary. US Food and Drug Administration. July 17, 2025. Accessed September 5, 2025. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/17210