ATLANTA — Tick populations are expanding across the U.S., driving an increase in tick-borne diseases. Among them is Powassan virus, a rare but increasingly reported infection that can cause severe brain inflammation and lasting neurological complications.
Although reported cases are growing, scientists still know relatively little about the virus and how it causes serious illness. In three recent studies, Georgia State University researchers are filling that gap, from developing new laboratory models to identifying how the body’s immune system fights the infection and uncovering changes in the brain that could help point to future treatments.
Powassan virus is transmitted by the same blacklegged ticks that spread Lyme disease. Unlike Lyme disease, which is caused by bacteria and can be treated with antibiotics, Powassan virus has no specific treatment or vaccine. In severe cases, an infection can cause encephalitis or meningitis.
As warming temperatures and expanding tick habitats contribute to rising case numbers, the National Institutes of Health and the Centers for Disease Control and Prevention have identified tick-borne diseases as a growing public health concern.
Most reported U.S. cases of Powassan virus occur in the Northeast and Great Lakes regions. In 2023, 49 cases were reported in the U.S., the most in a single year since 2004, according to the CDC.
“Our goal is to build the scientific foundation needed to better understand this emerging virus and ultimately identify new ways to prevent or treat the severe neurological disease it can cause,” said Mukesh Kumar , an associate professor in the Department of Biology and director of the Molecular Basis of Disease program at Georgia State. “Each of these studies adds another important piece to that puzzle.”
Pioneering Study Maps Molecular Changes
In the first study of its kind , published in the journal Viruses , a Georgia State research team characterized changes in brain microRNAs during Powassan virus infection. MicroRNAs are tiny, natural molecules that help regulate how cells function by controlling protein production. The researchers found that these important regulators were widely disrupted as the infection progressed.
The altered microRNAs were associated with pathways involved in inflammation, cell death, immune regulation and tissue repair, providing new insight into the molecular mechanisms driving neurological damage. The findings could help identify biomarkers of disease progression and point to new targets for future therapies.
The study was led by Amany Elsharkawy (Ph.D. ’25), who conducted the research as a doctoral student at Georgia State.
Comprehensive Disease Model Reveals Brain Damage
In another study , published in the journal Frontiers in Immunology , researchers developed and characterized a comprehensive animal model that closely mirrors many of the neurological features observed in human Powassan virus infection. The researchers demonstrated how the virus crosses the blood-brain barrier, triggers widespread neuroinflammation, damages neurons and persists in the brain long after the initial infection.
The research also underscores Georgia State’s role in training the next generation of biomedical researchers. Co-first authors Heather Pathak (Ph.D. ’25) and Elsharkawy led the study, with Kumar providing research oversight.
The models also revealed persistent neurological changes long after the initial infection, offering critical insight into how Powassan virus causes long-term disease. Together, this provides a valuable foundation for testing future antiviral treatments and therapeutic strategies.
Both Elsharkawy and Pathak are now research scientists at Emory University School of Medicine, continuing their work in biomedical research.
Key Immune Defense Identified
Researchers also found that a key part of the body’s immune system, called type I interferon, plays a vital role in controlling Powassan virus infection in preclinical models.
Led by the same Georgia State research team, this study , published in Frontiers in Microbiology , showed that when this critical antiviral pathway is disrupted, the virus spreads rapidly throughout the body and triggers excessive inflammation. By identifying one of the body’s most important defenses against Powassan virus, the findings provide valuable insight that could help guide the development of future antiviral therapies.
Together, the studies are giving researchers new tools and a clearer picture of how Powassan virus moves through the body, interacts with the immune system and damages the brain. That knowledge could help provide a foundation for testing potential treatments.
As cases increase, building that scientific understanding now could prove increasingly important for anticipating and responding to emerging infectious diseases.
“Mosquitoes and ticks are often viewed as little more than a nuisance, but they can carry pathogens that pose significant health risks, especially for older adults,” said Kumar. “The more we learn about Powassan virus now, the better positioned we will be for threats in the future.”
Viruses