Photo by Monica Moriak June 09, 2020
Doctoral candidate Casey Johnson applies innate scientific mind to combat animal disease
Whether the topic is molecular biology or the day’s news, University of Delaware doctoral candidate Casey Johnson speaks a mile a minute. She employs her seemingly limitless energy in the Department of Animal and Food Sciences, where she’s working on research projects to fight animal diseases.
“I like everything that I’ve worked on,” Johnson said with a chuckle. “I don’t do as well with hypotheticals. I like working on real-world diseases and problems.”
Casey’s path to a doctorate has been circuitous. While pursuing her UD undergraduate degree in pre-veterinary medicine, Johnson connected with Kali Kniel, a professor of microbial food safety — her first exposure to academic research.
“I found it to be an amazing experience,” said Johnson, who is currently pursuing her doctorate in Animal and Food Sciences with a concentration in molecular biology and biotechnology. “Dr. Kniel taught me a lot and really made me love research.”
But as graduation approached, Casey wasn’t convinced that moving on to graduate school was for her. Equipped with another degree in accounting, Johnson began her career as an auditor. But, after a couple of years, the research bug was back.
“I reached out to Dr. Carl Schmidt, one of my undergraduate professors,” Johnson said. “He encouraged me to find a principal investigator whose research fit with my interests.”
Her timing was supreme; the College of Agriculture and Natural Resources had recently hired Ryan Arsenault, assistant professor of animal science, who focuses on gut health and disease pathogenesis. His work included antibiotic alternatives for chickens. Looking to do disease research on the molecular level, Johnson found those research projects right up her alley. And with his first UD graduate student, Arsenault found himself a kindred spirit in scientific curiosity.
“Casey is an excellent graduate student researcher because she has an innate scientific mind,” Arsenault said. “She has an intuitive sense of experimental design and can readily conceptualize data and appropriate data analysis techniques. She’s a critical thinker with the skepticism that is important in a good scientist.”
Johnson has investigated diseases in pigs, ducks and chickens, but her primary focus is necrotic enteritis (NE), a common and financially devastating disease that hits chickens hard. Unlike some more well-known diseases like avian influenza, NE is not caused by a specific pathogen. It’s what is known as a multifactorial disease; multiple components must come together before the disease shows itself. And researchers across the country don’t agree on how the infection manifests.
“NE is coming back because of the removal of in-feed antibiotics, which were taken away in 2017,” Johnson said. “I’m looking at all of these different pathogens, viruses, bacteria and environmental and physiological factors. We’re also investigating antibiotic alternatives to see how we can prevent the disease in the first place.”
Johnson is first author on a recently published paper describing how a postbiotic — what many scientists consider a more promising intervention than probiotics — helps a chicken's immune system to fight bacteria that cause NE.
Johnson credits her department for not only the wide array of research opportunities, but also for actively listening to its graduate students. For prospective graduate students, Johnson said, UD more than likely does research on their topic of interest in the Department of Animal and Food Sciences.
“The research perspectives are so broad — both on the animal and food side,” Johnson said. “And even if you don’t find something that interests you initially, the professors are willing to listen to your ideas and consider implementing them. Even if you have a random idea that’s completely outside of your research project, you are going to be able to find a professor to help flesh it out.”