Journal Article

Powassan and Eastern Equine Encephalitis Virus Seroprevalence in Endemic Areas, United States, 2019–2020

Gould, Carolyn V., Staples, J. Erin, Wolujewicz, Karen Ann A., Brown, Catherine M., Grimm, Kacie, Dinh, Emily T.N., Basavaraju, Sridhar V., Esponda-Morrison, Brenda, Stramer, Susan L., Lee, Xia, Osborne, Matthew, Boroughs, Karen, Biggerstaff, Brad J., Saá, Paula, Ledermann, Jeremy P., Lehman, Jennifer A., Brault, Aaron C., Stobierski, Mary Grace, Wozniak, Ryan J., Krysztof, David, Raetz, Janae, Schiffman, Elizabeth K., Townsend, Rebecca L., Huang, Claire Y.-H., Garvin, Alex, Osborn, Rebecca A., Mossel, Eric C., Padda, Hannah, Martin, Stacey W., Hopkins, Brandi

2025

Overview

Powassan virus (POWV) and Eastern equine encephalitis virus (EEEV) are regionally endemic arboviruses in the United States that can cause neuroinvasive disease and death. Recent identification of EEEV transmission through organ transplantation and POWV transmission through blood transfusion have increased concerns about infection risk. After historically high numbers of cases of both viruses were reported in 2019, we conducted a seroprevalence survey using blood donation samples from selected endemic counties. Specimens were screened for virus-specific neutralizing antibodies, and population seroprevalence was estimated using weights calibrated to county population census data. For POWV, median county seroprevalence in 4 states was 0.84%, ranging from 0% (95% CI 0%-2.28%) to 11.5% (95% CI 0.82%-40.9%). EEEV infection was identified in a single county (estimated seroprevalence 1.62% [95% CI 0.04%-8.75%]). Although seroprevalence estimates in sampled areas were generally low, additional investigation of higher-prevalence areas could inform risk for transmission from asymptomatic blood and organ donors.

• Publisher: U.S. National Center for Infectious Diseases,Centers for Disease Control and Prevention
• Subject: Adolescent / Adult / Age groups / Antibodies / Antibodies, Viral - blood / Arbovirus diseases / Arboviruses / Asymptomatic / Blood & organ donations / blood donor / Blood donors / Blood transfusion / Censuses / Disease / Disease transmission / Distribution / Eastern equine encephalitis virus / Encephalitis / Encephalitis Virus, Eastern Equine - immunology / Encephalitis Viruses, Tick-Borne - immunology / Encephalitis, Tick-Borne - epidemiology / Encephalitis, Tick-Borne - history / Encephalitis, Tick-Borne - virology / Encephalomyelitis, Eastern Equine - epidemiology / Encephalomyelitis, Eastern Equine - virology / Endemic Diseases / Epidemics / Equine encephalomyelitis / Estimates / Fatalities / Female / Health aspects / Health risks / Health surveillance / History, 21st Century / Humans / Infections / Male / Middle Aged / Permethrin / Population / Powassan and Eastern Equine Encephalitis Virus Seroprevalence in Endemic Areas, United States, 2019–2020 / Powassan virus / Risk factors / Seroepidemiologic Studies / Serology / serosurvey / Statistics / Surveys / Transplantation of organs, tissues, etc / United States - epidemiology / vector-borne infections / Viral antibodies / Viruses / West Nile virus / Young Adult