Atsushi YamanakaMami MatsudaTamaki OkabayashiPannamthip PitaksajjakulPongrama RamasootaKyoko SaitoMasayoshi FukasawaKentaro HanadaTomokazu MatsuuraMasamichi MuramatsuTatsuo ShiodaRyosuke SuzukiFaculty of Tropical Medicine, Mahidol UniversityThe Jikei University School of MedicineNational Institute of Infectious DiseasesResearch Institute for Microbial DiseasesUniversity of Miyazaki2022-08-042022-08-042021-08-01mSphere. Vol.6, No.4 (2021), 1-12237950422-s2.0-85115040385https://repository.li.mahidol.ac.th/handle/20.500.14594/76074Thailand is a hyperendemic country for flavivirus infections in Southeast Asia. Although the reporting system for flavivirus surveillance in Thailand is well established, syndromic surveillance tends to underestimate the true epidemiological status of flaviviruses due to the majority of infections being asymptomatic. To accurately understand the prevalence of flaviviruses in endemic regions, we performed neutralization tests against multiple flaviviruses using 147 serum samples from healthy donors collected from four distinct regions in Thailand. Single-round infectious particles (SRIP) for six flaviviruses, dengue virus types 1 to 4 (DENV-1 to -4), Japanese encephalitis virus (JEV), and Zika virus (ZIKV), were used as antigens for developing a safe, high-throughput neutralization assay. Titers of neutralizing antibodies (NAbs) against the six flaviviruses revealed that DENV-1 and DENV-2, followed by ZIKV were the predominant circulating flaviviruses in a total of four regions, whereas the prevalence of NAbs against JEV varied among regions. Although the seroprevalence of ZIKV was low relative to that of DENV-1 and DENV-2, the findings strongly suggested that ZIKV has been circulating at a sustained level in Thailand since before 2012. These findings not only demonstrated the application of an SRIPneutralization test in a serological study, but also elucidated the circulation and distribution trends of different flaviviruses in ThailandMahidol UniversityBiochemistry, Genetics and Molecular BiologyImmunology and MicrobiologyArticleSCOPUS10.1128/mSphere.00339-21