| 研究実績の概要 |
I analyzed molecular characterization of HRSV in Biliran Island, Philippines over three seasons in 2013, 2014, and 2015. Nasopharyngeal swabs were collected from hospitalized children with severe pneumonia at the Biliran Provincial Hospital. Samples were screened by using real-time polymerase chain reaction (PCR). Genotypes were determined using conventional PCR and sequencing of the 2nd hypervariable region (HVR) of the G gene. Of 1,240 sample tested, 356 (28.7%) were positive for HRSV including 183 (51.4%) HRSV-A and 173 (48.6%) HRSV-B. HRSV-A were further divided into two genotypes; NA1 and ON1. Both NA1 and ON1 were co-circulating in 2013, only ON1 remained to be circulating in 2014. A novel ON1 variant, which was phylogenetically distinct from other ON1 strains, was detected in 2014. These novel ON1 viruses possess three unique amino acid substitutions (K212R, K213G, and K223G) in the 2nd HVR of the G gene, which had not been found in other countries. All HRSV-B viruses were identified as genotype BA9 except two samples identified as GB2. Both HRSV-A and -B were co-circulating in 2013 and 2014 seasons, but most of HRSV detected in 2015 season were HRSV-B. Most of amino acid sites of the 2nd HVR of the G gene were under purifying/negative selection. This study can build on the molecular characterization to contribute the advance of molecular genetics on HRSV in the Philippines. Moreover, I made the manuscript of complete genome sequences of HRSV-A in the Philippines that I did last year.
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