Epidemiology and risk analysis of Powassan virus infection, New York state, USA, 2013–2023

Powassan virus (POWV), a tick-borne flavivirus, is an emerging public health threat in the United States. In New York State (NYS), incidence of human POWV infection has increased in recent years. We describe the epidemiology of confirmed and probable POWV infection cases reported in NYS from 2013 to 2023. A total of 44 human cases were reported over the study period, with the highest incidence rates in Columbia and Putnam counties. Most cases occurred in White, non-Hispanic males over age 50. Hospitalization was reported in 91% of cases, and 11% were fatal. Human case data and tick surveillance results were analysed to assess spatiotemporal patterns of disease emergence. Spatial analysis revealed clustering of human cases in the Capital and Metropolitan regions of NYS. The prevalence of POWV in adult tick populations increased significantly statewide, and entomological risk was positively but modestly correlated to disease incidence at the ZIP code level. These findings suggest that POWV infection is emerging in geographically concentrated areas of NYS, highlighting the need for enhanced surveillance and targeted prevention efforts in high-risk regions.