A new way to treat poultry for fowl mites was approved by the U.S. Food and Drug Administration (FDA) in July, thanks in part to a team of researchers in Penn State's College of Agricultural Sciences.
The treatment, called EXZOLT, can be added to the animals' drinking water and is used to control northern fowl mites, a blood-feeding parasite that can lead to health problems and lower egg production in chickens and other poultry.
Erika Machtinger, associate professor of entomology and researcher on the project, said the product - which works by targeting the parasite's nervous system - is novel due to its delivery method.
"Current treatments are all topical, and additionally, mites have developed resistance to many of their active chemicals," Machtinger said. "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."
While the product itself was developed by Merck Animal Health, Machtinger said it needed to go through a rigorous study process to be approved for use in the U.S. The study took place at Penn State, helmed by a team including Machtinger; John Boney, assistant professor of poultry science; Scott Kephart, manager of Penn State's Poultry Education and Research Center; and many others.
Troy Ott, dean of the College of Agricultural Sciences, said the project is a good example of how the college partners with industry to bring real-world solutions to the public.
"This work is just another example of how Penn State uses science to solve problems in Pennsylvania and beyond," Ott said. "The poultry industry is an economic driver of the Pennsylvania economy and our scientists, working closely with industry stakeholders, focus on delivering science-based solutions to the challenges they face."
The research began with initial studies conducted at the University of California, Riverside. Following FDA protocols that require multiple trials with different investigators and mite populations, Merck needed to identify an additional testing site, Machtinger explained.
Penn State was selected to conduct the study to evaluate efficacy with broiler breeders. Based on that positive experience, Merck also chose to have the team at Penn State perform the second study in layer chickens to assess if the treatment would work for both production classes.
For both studies, the research team raised more than 1,000 broiler breeder and layer chicks, a task that Kephart said was one of the biggest challenges of the project. Once the birds reached 20 weeks of age, they were infested with northern fowl mites and then treated with the experimental product.
"A project of this size was a huge undertaking, especially with other projects taking up some of the available space," he said. "However, my team was determined and worked together to troubleshoot and make the project a success."
Throughout the study period, researchers maintained rigorous monitoring protocols. They counted mites twice a week to track population changes, weighed birds weekly for nutritional management, and kept detailed health and treatment records. Birds in the treatment group received two doses of the product seven days apart, while control birds received only water.
To ensure scientific rigor, personnel conducting mite counts were blinded to the treatment status of each bird. The team monitored mite populations for 28 days following treatment to evaluate the product's effectiveness.
Additionally, Machtinger said the study process involved developing new systems for medication administration and figuring out housing systems and bird welfare protocols that would work for the teams' specific needs. There was also a training aspect, with students and staff learning techniques they'd never done before.
"This project really showcases what makes Penn State special: We can take on these complex, high-stakes studies because we have the facilities, the expertise and the flexibility to innovate when we need to," she said. "That's something not every institution can offer industry partners."
The researchers found that, compared to the control groups, the treatment groups had more than 90% reduction in mites. Following completion of the study, the data went through a thorough and rigorous quality control review before being sent to the FDA for final review and approval, Machtinger said.
For Machtinger, the project is an example of how collaborating with industry can be a win-win that advances both science and practical solutions.
"There's nothing more satisfying than working on something that will genuinely help producers," she said. "And for the college, these collaborations bring in funding, give our students hands-on experience with cutting-edge projects, and strengthen our reputation as a place where industry knows they can come to solve tough problems. Plus, it creates this pipeline where our graduates are already connected to industry and understand their needs."
