Wuhan Wuchang Hospital, Wuchang Hospital Affiliated to Wuhan University of Science and Technology, Wuhan, 430063, China.
Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, China.
BMC Infect Dis. 2021 Oct 30;21(1):1122. doi: 10.1186/s12879-021-06746-9.
Norovirus (NoV) is the main cause of non-bacterial acute gastroenteritis (AGE) outbreaks worldwide. From September 2015 through August 2018, 203 NoV outbreaks involving 2500 cases were reported to the Shenzhen Center for Disease Control and Prevention.
Faecal specimens for 203 outbreaks were collected and epidemiological data were obtained through the AGE outbreak surveillance system in Shenzhen. Genotypes were determined by sequencing analysis. To gain a better understanding of the evolutionary characteristics of NoV in Shenzhen, molecular evolution and mutations were evaluated based on time-scale evolutionary phylogeny and amino acid mutations.
A total of nine districts reported NoV outbreaks and the reported NoV outbreaks peaked from November to March. Among the 203 NoV outbreaks, 150 were sequenced successfully. Most of these outbreaks were associated with the NoV GII.2[P16] strain (45.3%, 92/203) and occurred in school settings (91.6%, 186/203). The evolutionary rates of the RdRp region and the VP1 sequence were 2.1 × 10 (95% HPD interval, 1.7 × 10-2.5 × 10) substitutions/site/year and 2.7 × 10 (95% HPD interval, 2.4 × 10-3.1 × 10) substitutions/site/year, respectively. The common ancestors of the GII.2[P16] strain from Shenzhen and GII.4 Sydney 2012[P16] diverged from 2011 to 2012. The common ancestors of the GII.2[P16] strain from Shenzhen and previous GII.2[P16] (2010-2012) diverged from 2003 to 2004. The results of amino acid mutations showed 6 amino acid substitutions (*77E, R750K, P845Q, H1310Y, K1546Q, T1549A) were found only in GII.4 Sydney 2012[P16] and the GII.2[P16] recombinant strain.
This study illustrates the molecular epidemiological patterns in Shenzhen, China, from September 2015 to August 2018 and provides evidence that the epidemic trend of GII.2[P16] recombinant strain had weakened and the non-structural proteins of the recombinant strain might have played a more significant role than VP1.
诺如病毒（NoV）是全球非细菌性急性肠胃炎（AGE）暴发的主要原因。从 2015 年 9 月至 2018 年 8 月，深圳市疾病预防控制中心报告了 203 起涉及 2500 例的诺如病毒暴发。
收集了 203 起暴发的粪便标本，并通过深圳市 AGE 暴发监测系统获得了流行病学数据。通过测序分析确定基因型。为了更好地了解深圳市 NoV 的进化特征，基于时间尺度进化系统发生树和氨基酸突变评估了分子进化和突变。
共有 9 个区报告了诺如病毒暴发，报告的诺如病毒暴发高峰出现在 11 月至 3 月。在 203 起诺如病毒暴发中，有 150 起成功测序。这些暴发大多与 NoV GII.2[P16]株（45.3%，92/203）有关，发生在学校（91.6%，186/203）。RdRp 区和 VP1 序列的进化率分别为 2.1×10（95%HPD 区间，1.7×10-2.5×10）取代/位/年和 2.7×10（95%HPD 区间，2.4×10-3.1×10）取代/位/年。深圳 GII.2[P16]株和 GII.4 Sydney 2012[P16]株的共同祖先于 2011 年至 2012 年分化。深圳 GII.2[P16]株和之前的 GII.2[P16]（2010-2012 年）株的共同祖先于 2003 年至 2004 年分化。氨基酸突变的结果表明，只有在 GII.4 Sydney 2012[P16]和 GII.2[P16]重组株中发现了 6 个氨基酸取代（*77E、R750K、P845Q、H1310Y、K1546Q、T1549A）。
本研究阐明了 2015 年 9 月至 2018 年 8 月期间中国深圳的分子流行病学模式，并提供了证据表明 GII.2[P16]重组株的流行趋势已经减弱，重组株的非结构蛋白可能比 VP1 发挥更重要的作用。
