The U.S. Food and Drug Administration has approved EXZOLT (fluralaner oral solution), marking the first systemic oral treatment for northern fowl mites in chickens. Developed by Merck Animal Health, this innovative parasiticide represents a significant advancement in poultry health management, offering producers a more effective alternative to traditional topical treatments.
Novel Mechanism and Administration
EXZOLT works by targeting the parasite's nervous system, killing mites that have taken a blood meal while remaining safe for the host animal. The treatment is administered through drinking water, eliminating the stress associated with spray applications and reducing chemical exposure for both workers and birds.
"This new treatment is a veterinary-prescribed drug that works systemically, so it gets to all parts of the bird. Think of it like those flea and tick chewable tablets people give their dogs — it's the same concept," explained Erika Machtinger, associate professor of entomology at Penn State, who led the pivotal efficacy studies.
Addressing Industry Challenges
Northern fowl mites pose substantial economic threats to poultry operations, causing increased stress levels, reduced weight gain, and diminished egg quality and production in affected birds. Current treatments face significant limitations, as mites have developed resistance to many active chemicals in topical formulations.
"Northern fowl mites pose a significant threat to poultry, leading to increased stress levels, reduced weight gain and diminished egg quality and production in affected birds. They are also a major source of economic loss for layer and pullet operations," said Jim Stockam, D.V.M., poultry technical services at Merck Animal Health.
Rigorous Clinical Testing
The approval followed extensive studies conducted at Penn State's College of Agricultural Sciences, where researchers evaluated the treatment's efficacy in both broiler breeders and layer chickens. The team raised more than 1,000 birds for the studies, implementing rigorous monitoring protocols throughout the research period.
Birds received two doses of EXZOLT seven days apart, while control groups received only water. Researchers maintained blinded mite counting procedures and monitored populations for 28 days following treatment. The studies demonstrated over 90% reduction in mite populations compared to control groups.
"A project of this size was a huge undertaking, especially with other projects taking up some of the available space," noted Scott Kephart, manager of Penn State's Poultry Education and Research Center. "However, my team was determined and worked together to troubleshoot and make the project a success."
Safety Profile and Withdrawal Periods
EXZOLT maintains an excellent safety profile for laying hens and replacement chickens. The treatment features a zero-day withdrawal period for eggs, meaning eggs from treated chickens are immediately safe for consumption. The meat withdrawal period is 11 days following the last treatment.
Commercial Availability
EXZOLT is now available in 1-liter and 4-liter presentations for commercial poultry operations. The product requires veterinary prescription and represents Merck Animal Health's commitment to advancing poultry health solutions.
"EXZOLT is more impactful than traditional spray products for rapidly and dramatically decreasing infestation burdens," Stockam added. "With a zero-day withdrawal period, eggs from chickens treated with EXZOLT are safe to consume, making it ideal for maintaining the health, performance and welfare of flocks."
