Article ID: JJID.2014.266
The available literature for epidemiological studies of human coronaviruses (HCoVs) in Japan is limited to descriptions representing a maximum of one year. We conducted a 4-year study of HCoVs by analyzing 4,342 respiratory specimens obtained in Yamagata, Japan, between January 2010 and December 2013. A pan-coronavirus reverse-transcription PCR screening assay was performed and all HCoV-positive specimens were subsequently identified by sequencing of the PCR products. We detected in 332 (7.6%) HCoV strains during the study period, comprising 133 (3.1%) HCoV-NL63, 83 (1.9%) HCoV-HKU1, 78 (1.8%) HCoV-OC43, and 38 (0.9%) HCoV-229E strains. HCoV detection per year ranged from 3.5% to 9.7%. HCoVs were detected mainly in winter, with January (28.5%) and February (25.3%) 2011, and December 2012 (14.6%) being the only months in which HCoV-NL63 detection per month exceeded 10.0%. HCoV-HKU1 displayed clear biennial peaks in January (18.3%) and February (10.7%) 2010, and in February (18.8%) and March (14.7%) 2012. The peak detection of HCoV-OC43 was 13.6% in November 2010, while that for HCoV-229E was 10.8% in March 2013. Our results indicate that there may be yearly variations in the circulation of individual HCoVs. Further long-term surveillance is necessary to clarify HCoV prevalence and circulation patterns in Japan.
