Phan Tung Gia, Kuroiwa Toshimasa, Kaneshi Kunio, Ueda Yuichi, Nakaya Shigekazu, Nishimura Shuichi, Yamamoto Atsuko, Sugita Kumiko, Nishimura Tadashi, Yagyu Fumihiro, Okitsu Shoko, Müller Werner E G, Maneekarn Niwat, Ushijima Hiroshi
Department of Developmental Medical Sciences, Institute of International Health, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
J Med Virol. 2006 Jul;78(7):971-8. doi: 10.1002/jmv.20649.
A total of 402 fecal specimens collected during July 2003-June 2004 from infants and children with acute gastroenteritis, encompassing five localities (Maizuru, Tokyo, Sapporo, Saga, and Osaka) of Japan, were tested for the presence of norovirus by RT-PCR. It was found that 58 (14.4%) fecal specimens were positive for norovirus. Norovirus infection was detected throughout the year with the highest prevalence in December. Norovirus GII was the most predominant genogroup (98.3%; 57 of 58). The genotypes detected in this study were GI/4, GII/2, GII/3, GII/4, and GII/6. Of these, NoV GII/3 (known as the Arg320 virus cluster) was the most predominant genotype (43.9%), followed by NoV GII/4 (the Lordsdale virus cluster; 35.1%) and others. Two norovirus strains clustered with a "new variant designated GIIb" and a "new variant of GII/4" were found circulating in Japan for the first time. It was interesting to note that NoV GIIb and NoV GII/3 appeared to be the recombinant strains and the recombination site was demonstrated at the overlap of ORF1 and ORF2. The majority (96%) of the dominant norovirus strains were identified as the recombination of GII/3 capsid and GII/12 polymerase. The recombination in the NoV GIIb capsid gene at the breakpoint located at P1 domain was also identified. Obviously, NoV GIIb isolate in Japan had double recombination. This is the first report demonstrating the existence of different "new variants" co-circulating in Japanese infants and children with acute gastroenteritis.
2003年7月至2004年6月期间，从日本五个地区（舞鹤、东京、札幌、佐贺和大阪）患有急性肠胃炎的婴幼儿中总共采集了402份粪便样本，通过逆转录聚合酶链反应（RT-PCR）检测诺如病毒的存在。结果发现，58份（14.4%）粪便样本诺如病毒呈阳性。全年均检测到诺如病毒感染，12月患病率最高。诺如病毒GII是最主要的基因组（98.3%；58份中的57份）。本研究中检测到的基因型为GI/4、GII/2、GII/3、GII/4和GII/6。其中，NoV GII/3（称为Arg320病毒簇）是最主要的基因型（43.9%），其次是NoV GII/4（Lordsdale病毒簇；35.1%）及其他基因型。首次发现两种诺如病毒株，一种与“指定的GIIb新变种”聚集，另一种与“GII/4新变种”聚集，在日本传播。值得注意的是，NoV GIIb和NoV GII/3似乎是重组株，重组位点在ORF1和ORF2的重叠处得到证实。大多数（96%）优势诺如病毒株被鉴定为GII/3衣壳和GII/12聚合酶的重组体。还鉴定出NoV GIIb衣壳基因在位于P1结构域的断点处发生重组。显然，日本的NoV GIIb分离株有双重重组。这是第一份证明在患有急性肠胃炎的日本婴幼儿中存在不同“新变种”共同传播的报告。
