Iritani N, Seto Y, Haruki K, Kimura M, Ayata M, Ogura H
Department of Health and Epidemiology, Osaka City Institute of Public Health and Environmental Sciences, Tennoji-ku, Osaka 543-0026, Japan.
J Clin Microbiol. 2000 Jul;38(7):2649-54. doi: 10.1128/JCM.38.7.2649-2654.2000.
In Osaka City, Japan, between April 1996 and March 1999, a total of 350 fecal specimens from 64 outbreaks of acute nonbacterial gastroenteritis were examined to investigate infection by "Norwalk-like viruses" (NLVs). By reverse transcription (RT)-PCR, 182 samples (52.0%) from 47 outbreaks (73.4%) were NLV positive. During those three years, the incidence of NLV-associated outbreaks showed seasonality, being higher during January to March (winter to early spring). The ingestion of contaminated oysters was the most common transmission mode (42.6%). The amplicons of the 47 outbreak strains that were NLV positive by RT-PCR were tested using Southern hybridization with four probe sets (Ando et al., J. Clin. Microbiol. 33:64-71, 1995). Forty of the outbreak strains were classified as 4 probe 1-A (P1-A) strains, 6 P1-B strains, 10 P2-A strains, 17 P2-B strains, and 3 untypeable strains, and the other 7 outbreaks were determined to be mixed-probe-type strains. Probe typing and partial sequence analysis of the outbreak strains indicated that a predominant probe type of NLVs in Osaka City had drastically changed; P2-B strains (77.8%) with multiple genetic clusters were observed during the 1996-97 season, the P2-A common strain (81.3%) related to the Toronto virus cluster was observed during the 1997-98 season, and P1-B strains (75.0%) with a genetic similarity were observed during the 1998-99 season. For the three untypeable outbreak strains (96065, 97024, and 98026), the 98026 outbreak strain had Southampton virus (SOV)-like sequences, and each of the other outbreak strains had a unique 81-nucleotide sequence. Newly designed probes (SOV probe for the 98026 outbreak strain and the 96065 probe for the 96065 and 97024 outbreak strains) were hybridized with relative strains and without other probe type strains. The prevalent NLV probe types in Osaka City during those three years were classified in six phylogenetic groups: P1-A, P1-B, P2-A, P2-B, SOV, and 96065 probe types.
1996年4月至1999年3月期间，在日本大阪市，对64起急性非细菌性胃肠炎疫情的350份粪便标本进行了检测，以调查“诺如病毒样病毒”（NLVs）感染情况。通过逆转录（RT）-PCR检测，47起疫情（73.4%）中的182份样本（52.0%）呈NLV阳性。在这三年中，NLV相关疫情的发病率呈现季节性，1月至3月（冬季至早春）发病率较高。食用受污染的牡蛎是最常见的传播方式（42.6%）。对通过RT-PCR检测呈NLV阳性的47起疫情菌株的扩增产物，使用四组探针进行Southern杂交检测（安藤等人，《临床微生物学杂志》33:64 - 71，1995年）。40起疫情菌株被归类为4探针1-A（P1-A）型菌株，6起为P1-B型菌株，10起为P2-A型菌株，17起为P2-B型菌株，3起为无法分型的菌株，另外7起疫情被确定为混合探针类型菌株。对疫情菌株进行探针分型和部分序列分析表明，大阪市NLV的主要探针类型发生了显著变化；1996 - 97年期间观察到具有多个基因簇的P2-B型菌株（77.8%），1997 - 98年期间观察到与多伦多病毒簇相关的P2-A常见型菌株（81.3%），1998 - 99年期间观察到具有基因相似性的P1-B型菌株（75.0%）。对于3起无法分型的疫情菌株（96065、97024和98026），98026疫情菌株具有南安普顿病毒（SOV）样序列，其他每起疫情菌株都有独特的81个核苷酸序列。新设计的探针（针对98026疫情菌株的SOV探针以及针对96065和97024疫情菌株的96065探针）与相关菌株以及其他探针类型菌株进行杂交。这三年大阪市流行的NLV探针类型分为六个系统发育组：P1-A、P1-B、P2-A、P2-B、SOV和96065探针类型。
