As warming climates push tick populations into new territories, a little-known but devastating virus is quietly rising in the American disease landscape. Powassan virus, carried by the same blacklegged ticks responsible for Lyme disease, inflames the brain and leaves survivors with lasting neurological harm — yet no vaccine or treatment exists to meet it. Georgia State University researchers are now publishing a trio of studies that illuminate how the virus damages the brain at the molecular level, how the body attempts to defend itself, and what mechanisms allow the infection to persist long
Georgia researchers advance understanding of rare Powassan virus amid rising tick-borne cases
Powassan virus causes severe brain inflammation, encephalitis, meningitis, and lasting neurological complications in infected individuals.
No vaccine, no specific treatment, but now we know how it damages the brain
Mark
Why does Powassan virus matter more now than it did five years ago?
Mimi
The case count jumped to 49 in 2023—the highest since 2004. That's a real signal that something is changing. Warming temperatures are expanding tick habitats, and there's no vaccine or specific treatment available.
Luke
But 49 cases is still rare, right? How does that compare to Lyme disease or other tick-borne illnesses?
Mimi
It is rare, and that's the point—we don't have good epidemiological data yet. But the CDC and NIH have flagged tick-borne diseases as a growing public health concern, and Powassan can cause encephalitis or meningitis, which are serious outcomes.
Mark
What did these Georgia State studies actually discover that we didn't know before?
Mimi
Three separate findings: first, they mapped how the virus disrupts brain microRNAs—the molecules that regulate cell function. Second, they built an animal model showing how the virus crosses the blood-brain barrier and causes persistent neurological damage. Third, they identified type I interferon as a critical immune defense.
Luke
So they've identified the problem and one piece of the immune response. But do they have a treatment yet?
Mimi
No. These studies are foundational work. They're building the scientific framework that could eventually guide antiviral development. It's not a cure, but it's the groundwork.
Mark
What happens to people who survive Powassan infection?
Mimi
The research shows persistent neurological changes long after the acute phase. The studies don't specify exactly what those look like in patients, but the animal models showed lasting brain damage.
Luke
And we still don't know how many people are actually infected but asymptomatic, or how many cases go unreported?
Mimi
That's a real gap. The 49 cases in 2023 are confirmed cases. The actual prevalence could be higher, but we don't have that data yet.
The Pulse
- Powassan virus cases reached a two-decade high of 49 in 2023, and with no vaccine or treatment available, every new infection is a reminder of how exposed the public remains.
- Warming temperatures are steadily expanding tick habitats, meaning the window for this rare disease to become a more common threat is quietly closing.
- Three new Georgia State University studies are attacking the problem from different angles — mapping molecular disruption in the brain, modeling how the virus breaches the blood-brain barrier, and identifying the immune pathway most critical to survival.
- The discovery that neurological damage persists long after the acute infection ends raises urgent questions about long-term outcomes for survivors.
- Identifying type I interferon as a key line of defense opens a concrete direction for antiviral therapy development, giving researchers a target where none clearly existed before.
- The science is still foundational, but the trajectory is toward treatment — and researchers warn that building this knowledge now is essential before case counts climb further.
As warming climates push tick populations into new territories, a little-known but devastating virus is quietly rising in the American disease landscape. Powassan virus, carried by the same blacklegged ticks responsible for Lyme disease, inflames the brain and leaves survivors with lasting neurological harm — yet no vaccine or treatment exists to meet it. Georgia State University researchers are now publishing a trio of studies that illuminate how the virus damages the brain at the molecular level, how the body attempts to defend itself, and what mechanisms allow the infection to persist long after its acute phase. In a moment when the distance between scientific ignorance and clinical need is measured in human suffering, this foundational work represents the careful, unglamorous labor that precedes any hope of remedy.
Tick populations are expanding across America, and with them comes a virus most people have never encountered but that scientists are watching with growing unease. Powassan virus, transmitted by the same blacklegged ticks that carry Lyme disease, causes severe brain inflammation and can leave survivors with lasting neurological damage. Unlike Lyme disease, it does not respond to antibiotics, and no vaccine or specific treatment exists. In 2023, the United States recorded 49 cases — the highest annual count since 2004 — and the trend is moving upward as warming temperatures widen the range of infected ticks.
Georgia State University researchers are working to close the gap between rising cases and scientific understanding. Three recent studies from the university map how Powassan virus damages the brain, how the immune system responds, and what molecular changes unfold as infection progresses. Associate professor Mukesh Kumar frames the mission directly: build the scientific foundation needed to understand this emerging virus and identify new ways to prevent or treat the neurological disease it causes.
The first study, published in Viruses, found that brain microRNAs — tiny molecules that regulate cell function by controlling protein production — were widely disrupted during Powassan infection. The altered regulators were linked to pathways governing inflammation, cell death, immune response, and tissue repair, offering new insight into the molecular mechanisms behind neurological damage and potential targets for future therapies.
A second study, in Frontiers in Immunology, developed an animal model that closely mirrors human Powassan infection. It demonstrated how the virus crosses the blood-brain barrier, triggers widespread neuroinflammation, damages neurons, and — critically — persists in the brain long after the acute illness ends, revealing a mechanism for the long-term neurological complications seen in survivors.
The third study, published in Frontiers in Microbiology, identified type I interferon as a vital line of defense against the virus. When this immune pathway is disrupted, the virus spreads rapidly and triggers excessive inflammation — a finding that points toward a concrete direction for antiviral therapy development.
Together, the three studies give researchers a clearer picture of how Powassan virus moves through the body, evades defenses, and causes lasting harm. Kumar notes that ticks and mosquitoes are often dismissed as nuisances, but they carry pathogens that pose serious risks — particularly for older adults. The more scientists understand about Powassan now, the better positioned medicine will be when the next threshold is crossed.
Tick populations are spreading across America, and with them comes a virus that most people have never heard of but that scientists are increasingly watching with concern. Powassan virus, transmitted by the same blacklegged ticks that carry Lyme disease, causes severe brain inflammation and can leave survivors with lasting neurological damage. Unlike Lyme disease, which responds to antibiotics, Powassan has no vaccine and no specific treatment. In 2023, the United States recorded 49 cases—the highest number in a single year since 2004—and the trend is climbing as warming temperatures expand the habitats where infected ticks thrive.
The gap between rising cases and scientific understanding is what Georgia State University researchers are working to close. Three recent studies from the university are mapping how Powassan virus actually damages the brain, how the body's immune system tries to fight it, and what molecular changes occur as the infection progresses. Mukesh Kumar, an associate professor in the Department of Biology and director of the Molecular Basis of Disease program at Georgia State, frames the work plainly: the goal is to build the scientific foundation needed to understand this emerging virus and ultimately identify new ways to prevent or treat the severe neurological disease it causes.
The first study, published in the journal Viruses, examined what happens to brain microRNAs during Powassan infection. MicroRNAs are tiny molecules that regulate how cells function by controlling protein production. The research team, led by doctoral student Amany Elsharkawy, found that these 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—a finding that offers new insight into the molecular mechanisms driving neurological damage and could help identify biomarkers of disease progression and point to new targets for future therapies.
A second study, published in Frontiers in Immunology, took a different approach. Researchers developed and characterized a comprehensive animal model that closely mirrors many of the neurological features observed in human Powassan virus infection. The model demonstrated how the virus crosses the blood-brain barrier, triggers widespread neuroinflammation, damages neurons, and persists in the brain long after the initial infection. Notably, the research revealed persistent neurological changes long after the acute phase of illness—a finding that offers critical insight into how Powassan virus causes long-term disease. Co-first authors Heather Pathak and Amany Elsharkawy led the study, with Kumar providing research oversight. Both researchers have since moved to Emory University School of Medicine, where they continue their work in biomedical research.
The third study identified a key player in the body's defense against the virus. Published in Frontiers in Microbiology, the research showed that type I interferon—a critical part of the immune system's antiviral response—plays a vital role in controlling Powassan virus infection. When this 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 insight that could guide the development of future antiviral therapies.
Together, these three 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 provide a foundation for testing potential treatments. As cases increase and tick habitats continue to expand, building that scientific understanding now could prove increasingly important for anticipating and responding to emerging infectious diseases. Kumar notes that 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. The more scientists learn about Powassan virus now, the better positioned they will be for threats in the future.
Notable Quotes
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 causes.— Mukesh Kumar, Georgia State University
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.— Mukesh Kumar, Georgia State University
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