FDA Approves New Oral Treatment for Poultry Mites

A new approach to controlling northern fowl mites, a common parasite in poultry, has received approval from the U.S. Food and Drug Administration (FDA)—and Penn State researchers played a key role in the process.

The treatment, known as EXZOLT, is added to drinking water, making it the first systemic solution for fowl mites in U.S. poultry production. Unlike traditional topical treatments, EXZOLT works throughout the bird’s body by targeting the parasite’s nervous system, similar to flea and tick chewable medications for dogs.

“Current treatments are all topical, and mites have developed resistance to many of their active chemicals,” said Erika Machtinger, associate professor of entomology and lead researcher on the project. “This new approach ensures the medication reaches all parts of the bird.”

A Collaborative Effort with Industry Impact

The product was developed by Merck Animal Health, but approval required extensive studies following FDA protocols. Penn State’s College of Agricultural Sciences was selected to conduct large-scale trials evaluating EXZOLT’s effectiveness in both broiler breeders and layer chickens.

“These kinds of studies showcase how Penn State works with industry to deliver science-based solutions to real-world problems,” said Troy Ott, dean of the college.

Behind the Research

The Penn State team raised more than 1,000 birds for two separate studies. Once the birds reached 20 weeks of age, they were infested with mites and treated with EXZOLT.

The trials followed strict scientific protocols, including blinded mite counts, weekly weight monitoring, and detailed health records. Birds receiving EXZOLT had over 90% fewer mites compared to control groups.