Seroprevalence of severe fever with thrombocytopenia syndrome using specimens from the Korea National Health & Nutrition Examination Survey

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is an acute febrile disease caused by bites from ticks infected with the SFTS virus. In Korea, SFTS patients are observed nationwide, including Jeju Island, but there are currently no data regarding the national prevalence of SFTS, including that of residents of 16 cities and provinces. This study aimed to investigate the seroprevalence of SFTS in Korea. METHODOLOGY/PRINCIPAL FINDINGS: A total of 1500 participants were selected through random sampling from the 2014–2015 Korea National Health and Nutrition Examination Survey (KNHANES). An indirect immunofluorescence antibody assay (IFA) was performed to assess immunoglobulin (Ig) G and IgM antibody titers against SFTS virus. RESULTS: Of the 1500 participants, 55 (3.7%) tested positive for IgG and 1 (0.1%) tested positive for IgM, with antibody titer of ≥ 1:32. Approximately 3.9% and 2.5% of participants in urban and rural areas, respectively, had a positive titer of ≥ 1:32. There was a significant correlation between SFTS incidence per 100,000 population and seroprevalence using an IgG titer ≥ 1:64 as the cut-off value. CONCLUSION: This is the first study to investigate national SFTS seroprevalence in all 16 cities and provinces representing Korea. Our study will also provide useful guidelines for the development of preventive measures against SFTS.