Powassan Virus Seroprevalence in a U.S. Servicemember Population at High Risk for Tick Exposure

Powassan virus (POWV) is an emerging tick-borne flavivirus that can cause severe encephalitis in humans. Currently no vaccines or therapeutics are approved to treat POWV. POWV is spread by the deer tick, Ixodes scapularis , which is ubiquitous across the Northeastern United States. To better understand POWV prevalence in high-risk populations, we examined POWV seroprevalence in Cadets at United States Military Academy (USMA) in West Point, New York. Cadets at USMA, located in a heavily wooded area, are at high risk for tick exposure during outdoor military training. 1,051 serum samples from the Cadet class of 2017 were screened for POWV seropositivity using a POWV Envelope (E) DIII ELISA. A seropositivity rate of 1.3% was determined. Several ELISA-positive samples were also able to neutralize both reporter virus particles bearing the POWV E protein and authentic POWV. This study demonstrates populations at risk for tick exposure may have significant seroprevalence of POWV.