Gastroenteritis and Respiratory Viruses Laboratory Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
J Clin Microbiol. 2010 Jan;48(1):168-77. doi: 10.1128/JCM.01622-09. Epub 2009 Oct 28.
Human noroviruses (NoVs) of genogroup II, genotype 4 (GII.4) are the most common strains detected in outbreaks of acute gastroenteritis worldwide. To gain insight into the epidemiology and genetic variation of GII.4 strains, we analyzed 773 NoV outbreaks reported to the CDC from 1994 to 2006. Of these NoV outbreaks, 629 (81.4%) were caused by GII viruses and 342 (44.2%) were caused by GII.4 strains. The proportion of GII.4 outbreaks increased from 5% in 1994 to 85% in 2006, but distinct annual differences were noted, including sharp increases in 1996, 2003, and 2006 each associated with newly emerging GII.4 strains. Sequence analysis of the full-length VP1 gene of GII.4 strains identified in this study and from GenBank segregated these viruses into at least 9 distinct subclusters which had 1.3 to 3.2% amino acid variation between strains in different subclusters. We propose that GII.4 subclusters be defined as having >5% sequence variation between strains. Our data confirm other studies on the rapid emergence and displacement of highly virulent GII.4 strains.
人类诺如病毒（NoV）属基因群 II、基因型 4（GII.4）是全球急性胃肠炎暴发中最常见的检测到的菌株。为了深入了解 GII.4 株的流行病学和遗传变异，我们分析了 1994 年至 2006 年向疾病预防控制中心报告的 773 起 NoV 暴发。在这些 NoV 暴发中，629 起（81.4%）由 GII 病毒引起，342 起（44.2%）由 GII.4 株引起。GII.4 暴发的比例从 1994 年的 5%增加到 2006 年的 85%，但每年都有明显的差异，包括 1996 年、2003 年和 2006 年的急剧增加，每次都与新出现的 GII.4 株有关。对本研究和 GenBank 中鉴定的 GII.4 株全长 VP1 基因的序列分析将这些病毒分为至少 9 个不同的亚群，不同亚群中株间的氨基酸变异为 1.3%至 3.2%。我们建议将 GII.4 亚群定义为株间序列差异>5%。我们的数据证实了其他关于高毒力 GII.4 株快速出现和取代的研究。
