Fatal Multiorgan Powassan Virus Infection in a Liver Transplant Recipient

A fatal Powassan virus case in a Pennsylvania transplant recipient reveals systemic risks

A 38-year-old woman in southeastern Pennsylvania died from a disseminated Powassan virus (POWV) infection, a case that highlights the severe risks faced by immunosuppressed individuals. According to a report from the Centers for Disease Control and Prevention (CDC), the infection was not limited to the brain but involved multiple organs, including the lungs and kidneys.

The patient, who had recently undergone an orthotopic liver transplant due to alcohol-associated cirrhosis, sought emergency care just six weeks after her surgery. She presented with malaise, headache, fever, and leukocytosis. Her condition rapidly deteriorated into multiple generalized seizures, and imaging later revealed significant neurological damage, including hydrocephalus and progressive enhancement of the brainstem and spinal cord. While doctors initially suspected rabies due to the speed of her neurological decline, postmortem testing confirmed the presence of Powassan virus lineage 2, also known as deer tick virus.

This case is particularly significant because it demonstrates that Powassan virus—a tickborne flavivirus—can cause widespread systemic damage beyond the central nervous system. While the virus is primarily known for causing severe encephalitis, autopsy findings in this patient showed the virus was present in the bronchiolar epithelial cells of the lungs and in circulating mononuclear cells, contributing to lung and kidney injury. This aligns with how other flaviviruses, such as West Nile or yellow fever, can disrupt pulmonary and renal functions.

The complexity of transmission and detection

Investigating how the patient contracted the virus proved difficult because no definitive tick bites were recorded. The Pennsylvania Department of Health noted in a communication on April 20, 2026, that the patient had several potential exposure points, including visits to a public garden, local campgrounds, and walks with her dog in nature. Despite these opportunities, a direct link to a tick bite remained unconfirmed.

The diagnostic process was also complicated by the limits of early testing. An earlier metagenomic sequencing of the patient’s cerebrospinal fluid was negative for the virus, a result the CDC suggests may have been due to a low viral load or the detection limits of the technology at that time. It was only through postmortem testing—using immunohistochemistry and PCR on brain samples—that the presence of the virus was definitively established.

This case adds to a growing body of evidence regarding how vulnerable transplant recipients are to arboviral diseases. For context, PubMed documentation of similar cases, such as a 2018 incident in Indiana, has explored alternative routes of infection. In that instance, a kidney transplant recipient developed encephalitis following a blood transfusion from an asymptomatic donor, leading researchers to investigate transfusion-transmitted Powassan virus. While the Pennsylvania case was investigated for organ-related transmission, testing of the donor liver at the time of transplant was negative for both Powassan and rabies.

Powassan Virus (POWV) Clinical Trends in the United States:

Metric	Data Point
Confirmed US Cases (2024)	60
Confirmed US Deaths (2024)	9
Neuroinvasive Disease Rate	94% of confirmed cases
Fatality Neuroinvasion Rate	98% of fatalities

Vulnerability in the immunosuppressed population

The intersection of tickborne illness and transplant medicine creates a high-stakes environment for clinicians. Because transplant recipients must take medications to prevent organ rejection, their immune systems are intentionally suppressed, making them less capable of fighting off even rare pathogens. The CDC report notes that severe systemic manifestations of flaviviruses are frequently observed in these populations, often resulting in multiorgan failure.

There is a delicate balance for medical professionals managing these patients. While the primary clinical manifestation of Powassan is meningoencephalitis, the ability of the virus to migrate to the kidneys and lungs suggests that doctors must monitor for systemic failure even when neurological symptoms are the primary focus. The rarity of the virus means that clinical suspicion must be high, especially in regions like Pennsylvania where transmission has been documented in every district since 2011.

As the geographic range of the Ixodes scapularis tick—the primary vector for this virus—continues to shift, the medical community faces a moving target. The question remains whether current screening protocols for blood and organ donations are sufficient to catch asymptomatic carriers of lineage 2 Powassan virus before they reach highly vulnerable populations.