This is the sixth short news article written by students, during the professional development class of Spring 2025, about each other's research.
Paige Alexander, PhD student
Student Spotlight: Paige Alexander
By Faith Mihalick
As the majestic white-tail deer of Pennsylvania leap through our forests, an unseen war rages on their skin. Two tick species battle for dominance: the lone star tick, which emerges earlier in the season than other ticks, and the blacklegged tick, an infamous tick known for spreading Lyme disease. Paige Alexander, a PhD student studying veterinary entomology in Erika Machtinger's research group, believes that understanding the co-feeding between these two tick species can help prevent the spread of Lyme disease.
"Previous work in other hosts has shown that when the lone star tick feeds before the blacklegged tick, an immune reaction can occur. This reaction then reduces the ability of the blacklegged tick to thrive on its host, which could reduce Lyme spread" Alexander explained.
The blacklegged tick is a widespread tick in Pennsylvania that spreads Lyme disease. Lyme disease can begin as a fever, headache, and distinctive bull's eye rash. If left untreated, it can spread to joints, the heart, and the nervous system, having life-long effects on humans. Its main host is the white-tail deer, an important reservoir for tick reproduction and spread.
Normally, when the blacklegged tick feeds on deer, deer are fairly permissive, which allows the tick to feed and successfully reproduce. Unlike the blacklegged tick, the lone star tick has been shown to cause an immune response in animals such as guinea pigs. When fed on by the lone star tick, guinea pigs showed classic signs of immune response such as scabbing over the tick to prevent it falling off and abnormal cell growth. Additionally, it was seen in these guinea pigs that when the lone star tick feeds before the blacklegged tick, the blacklegged ticks trigger an immune response. Now, Alexander is investigating if this same phenomenon happens in deer, which could greatly reduce people's exposure to Lyme disease by arming the immune system of one of the ticks most important hosts: the white-tailed deer.
Preliminary results from the Machtinger lab suggest that the deer also show a strong immune response to the blacklegged tick following lone star tick bites. The deer showed raised skin and scabbed over ticks, which could reduce tick fitness in the blacklegged tick. If their fitness is reduced, their reproduction and spread will be decreased, leading to less humans being exposed to Lyme disease.
This encouraged Alexander to test her hypothesis again this summer. At Penn State's deer barn, one of the only academic deer research facilities in the country, she will infest deer with the lone star tick followed by the blacklegged tick. Then she will test for an array of deer-specific immune responses by taking skin biopsies and blood samples from the deer and evaluate impacts to life history characteristics of the ticks after feeding. All this work contributes to Alexander's main goal in life: to help others.
"My main goal in life is to help other people. And I have seen how people avoid nature for fear of getting Lyme disease, so I am dedicating my work to reducing that risk. If my work led to one less person getting Lyme disease, then all my hard work would have been worth it" Alexander says.
Paige Alexander is a PhD student in the research group of Erika Machtinger in the Department of Entomology at Penn State University. Alexander's research is supported by funding from McIntire-Stennis Capacity Funds Program.
