在2010年代,出现了几种不寻常的轮状病毒毒株,在全世界造成流行病。本研究报告了基于全基因组分析的日本轮状病毒的全面分子流行病学研究。2014年至2019年,共鉴定出489份轮状病毒阳性粪便标本,和相关的病毒基因组通过下一代测序进行分析。这些菌株的基因型星座分为九种模式(G1P[8](Wa),G1P[8]-E2,G1P[8](DS-1),G2P[4](DS-1),G3P[8](Wa),G3P[8](DS-1),G8P[8](DS-1),G9P[8](Wa),和G9P[8]-E2)。主要流行基因型因年份而异,包括2014年的G8P[8](DS-1)(当年分离株的37%),2015年的G1P[8](DS-1)(65%),2016年的G9P[8](Wa)(72%),2017年的G3P[8](DS-1)(66%),2018年的G1P[8]-E2(53%)和2019年的GG1P[8]-E2菌株(G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1)在不连续的年份(2015年和2018年)中分离出,是新出现的NSP4单重配菌株。根据贝叶斯进化分析的结果,假设G1P[8]-E2和G9P[8]-E2是由不同的独立基因组间重组事件产生的。本研究中检测到的G1菌株分为多个簇,取决于检测年份。VP7表位的预测氨基酸序列的比较显示,在不同年份中检测到的G1菌株编码具有不同突变的VP7表位。这些突变可能导致免疫逃逸和流行菌株的年度变化。
In the 2010s, several unusual rotavirus strains emerged, causing epidemics worldwide. This study reports a comprehensive molecular epidemiological study of rotaviruses in Japan based on full-genome analysis. From 2014 to 2019, a total of 489 rotavirus-positive stool specimens were identified, and the associated viral genomes were analyzed by next-generation sequencing. The genotype constellations of those strains were classified into nine patterns (G1P[8] (Wa), G1P[8]-E2, G1P[8] (DS-1), G2P[4] (DS-1), G3P[8] (Wa), G3P[8] (DS-1), G8P[8] (DS-1), G9P[8] (Wa), and G9P[8]-E2). The major prevalent genotype differed by year, comprising G8P[8] (DS-1) (37% of that year\'s isolates) in 2014, G1P[8] (DS-1) (65%) in 2015, G9P[8] (Wa) (72%) in 2016, G3P[8] (DS-1) (66%) in 2017, G1P[8]-E2 (53%) in 2018, and G9P[8] (Wa) (26%) in 2019. The G1P[8]-E2 strains (G1-P[8]-I1-R1-C1-M1-A1-N1-T1-E2-H1) isolated from a total of 42 specimens in discontinuous years (2015 and 2018), which were the newly-emerged NSP4 mono-reassortant strains. Based on the results of the Bayesian evolutionary analyses, G1P[8]-E2 and G9P[8]-E2 were hypothesized to have been generated from distinct independent inter-genogroup
reassortment events. The G1 strains detected in this study were classified into multiple clusters, depending on the year of detection. A comparison of the predicted amino acid sequences of the VP7 epitopes revealed that the G1 strains detected in different years encoded VP7 epitopes harboring distinct mutations. These mutations may be responsible for immune escape and annual changes in the prevalent strains.