First confirmed case of Powassan neuroinvasive disease in Rhode Island

Abstract

The Powassan Virus is the arthropod-borne vector responsible for Powassan neuroinvasive disease. The virus was first isolated in 1958 and has been responsible for approximately 100 cases of neuroinvasive disease. Rates of infection have been on the rise over the past decade with numerous states reporting their first confirmed case; New Jersey, New Hampshire and Connecticut all reported their first case within the last five years. We present here the first confirmed case of Powassan neuroinvasive disease in the nearby state of Rhode Island. A previously healthy 81-year-old female with known tick exposure presented with fever, altered sensorium, seizures and focal neurological deficits. After an extensive work-up that was largely unrevealing Powassan encephalitis was suspected. The diagnosis was confirmed with serological testing consisting of Powassan IgM enzyme-linked immunosorbent assay and Powassan plaque reduction neutralization testing. The case study provides evidence for the increasing spread of Powassan neuroinvasive disease and reinforces the importance of requesting focused testing for Powassan Virus in patients from an endemic area with a clinically compatible syndrome. Keywords: Powassan encephalitis, Tick-borne disease, Viral encephalopathy