An Emerging Cause of Arboviral Encephalitis in Pennsylvania.

Powassan virus (POWV) is a rare neuroinvasive flavivirus transmitted through the bite of an infected Ixodes scapularis tick. Although infections are infrequent, they have become increasingly recognized in recent years, particularly in the northeastern United States. With the expanding geographic range of Ixodes ticks due to climate change, the risk of POWV transmission is rising, making awareness of the virus crucial for timely diagnosis and effective management. Preventive measures, such as avoiding tick exposure, using repellents, and performing thorough tick checks, are essential in reducing the risk of infection. Here, we present a case of POWV encephalitis in western Pennsylvania, highlighting some of the diagnostic challenges.