Elucidation of prevalence of group B human rotavirus in Asia

本研究在印度（4086份标本中9株）、孟加拉国（1151份标本中14株）和中国（769份标本中2株）检测到B族轮状病毒，主要来自散发性成人腹泻病例标本。对印度的CAL-1株、中国的Wh683株和孟加拉国的Bang373、Bang544、Bang334和Bang402株进行遗传分析。2000年在武汉市获得的中国毒株Wh683与1982年发现的人类B群轮状病毒原型株ADRV（序列同源性为98 ~ 99%）的遗传相似性比与cal1或Bang373（同源性为90 ~ 95%）的遗传相似性更接近，说明中国B群轮状病毒具有高度保守性。孟加拉国B群轮状病毒的VP7基因序列几乎完全相同，与印度CAL-1毒株（98%）和中国ADRV毒株（92%）的同源性也很高，而与牛和鼠病毒的同源性很低（60-63%）。Bang373和Bang544编码VP2、VP4、VP6和NSP1 ~ NSP5的其他基因与cal - 1的序列同源性（97.7 ~ 99.4%）也高于ADRV（89.9 ~ 93.9%）。对Bang373、CAL-1和ADRV之间核苷酸替换的表征表明，所有基因片段可能以相似的突变率中性进化。综上所述，在孟加拉国检测到的以Bang373为代表的B组轮状病毒与印度的CAL-1病毒被认为是几乎相同的病毒，在遗传上与ADRV不同，并且表明Bang373 （CAL-1）样B组轮状病毒（孟加拉毒株）可能主要分布在孟加拉湾周围。

In the present study, group B rotaviruses were detected in India (9 strains in 4086 specimens), Bangladesh (14 strains in 1151 specimens), and China (2 strains in 769 specimens), mostly in specimens from sporadic diarrheal cases of adult patients. Genetic analysis was done for CAL-1 strin in India, Wh683 strain in China, and four strains (Bang373, Bang544, Bang334, and Bang402) in Bangladesh. The Chinese strain Wh683 which was obtained in Wuhan city in 2000 was genetically extremely closeer (sequence identity was 98-99%) to the ADRV strain (a prototype of human group B rotacirus detected in 1982) than to CAL-1 or Bang373 (identities of 90-95%), indicating that group B rotaviruses in China are highly conserved. In contrast, VP7 gene sequences of the Bangladeshi group B rotaviruses were almost identical each other and showed also high sequence identity to Indian strain CAL-1 (98%) and also to Chinese strain ADRV (92%), while identities to bovine and murine viruses were considerably low (60-63%). Other genes of Bang373 and Bang544 encoding VP2, VP4, VP6, and NSP1〜NSP5 showed also extremely high sequence identities to those of CAL-l (97.7-99.4%) than those of ADRV (89.9-93.9%). Characterization of nucleotide substitutions among Bang373, CAL-1, and ADRV suggested that all the gene segments might have evolved neutrally at similar mutaton rates. In conclusion, group B rotaviruses detected in Bangladesh represented by Bang373 and the Indian virus CAL-1 were considered as virtually identical viruses which are genetically distinct from ADRV, and it was suggested that Bang373 (CAL-l)-like group B rotavirus (Bengali strains) might have been primarily distributed to an are around the Bay of Bengal.