Molecular epidemiology and spatiotemporal dynamics of norovirus associated with sporadic acute gastroenteritis during 2013–2017, Zhoushan Islands, China

Abstract

A total of 1 590 fecal swabs and stool samples from sporadic acute gastroenteritis patients of all ages were collected from January 2013 to March 2018 in the Zhoushan Islands, China, with 99 (6.23%) samples subsequently identified as human norovirus (HuNoV) positive. Phylogenetic analysis of partial RdRp and VP1 gene regions identified 10 genotypes of the GII genogroup and 3 genotypes of the GI genogroup. The predominant genotype was GII.P17-GII.17 (42.86%, 33/77), followed by GII.Pe-GII.4_Sydney 2012 (24.68%, 19/77) and GII.P16-GII.2 (12.96%, 10/77). However, the prevailing genotype in the Zhoushan Islands has shifted on three separate occasions. The GII.Pe-GII.4_Sydney_2012 strain was dominant in 2013–2014, the GII.P17-17 strain was dominant in 2015–2016, and the GII.P16-GII.2 strain was dominant in 2017. Divergence analysis showed that the re-emerging GII.P16-GII.2 strains clustered with the Japanese 2010–2012 GII.P16-GII.2 strains, and the time of the most recent common ancestor was estimated to have occurred in 2012 to 2013. The evolutionary rates of the RdRp gene region of the GII.P16 genotype and the VP1 gene region of the GII.2 genotype were 2.64 × 10−3 (95% HPD interval, 2.17–3.08 × 10−3) and 3.36 × 10−3 (95% HPD interval, 2.66–4.04 × 10−3) substitutions/site/year, respectively. The migration pattern of the HuNoV GII.2 genotype in China demonstrated that the re-emerging GII.P16-GII.2 strains were first introduced into Hong Kong from Japan, and then spread from Hong Kong to other coastal areas. Our results also showed that the GII.P16-GII.2 strains in the Zhoushan Islands were likely introduced from Jiangsu Province, China, in 2016.

Prevalence of noroviruses in children hospitalized for acute gastroenteritis in Hohhot, China, 2012-2017

“…GII.4/Sydney 2012 was first identified in Australia, France, and New Zealand, and subsequently isolated in the United States, Belgium, Denmark, Scotland, Japan, and China. Of note, after 2012, the GII.4/Sydney 2012 variant was the dominant epidemic strain in Hohhot and most other regions of China, both in sporadic NV cases and NV outbreaks [19,21]. Previous studies show GII.4 usually caused epidemics in adult populations, whereas GII.3 NV was prevalent in young children and infants [45,46].…”

“…China is a vast country, and the prevalence of NV varies by region [1,19,21,22]. However, reports and knowledge of routine sporadic NV disease in northern China have been limited.…”

Genetic Diversity and Epidemiology of Norovirus in Children with acute sporadic gastroenteritis in Shanghai, China, 2012-2017

“…Interestingly, this type was mainly observed in Asia-Pacific region, implying that the pandemic of GII.P12/GII.3 may have regional characteristics [17,47,48]. GII.P7/GII.6, as the second prevalent genotype in 2014, was reported with a few cases elsewhere [46,49]. Besides, many other rare RdRp/Capsid strains were detected in our study, such as GII.Pe/GII.3 and GII.P16/GII.2.…”

Genetic Diversity and Epidemiology of Genogroup II Noroviruses in Children with Acute Sporadic Gastroenteritis in Shanghai, China, 2012-2017

“…Interestingly, this genotype was mainly observed in the Asia-Pacific region, implying that the GII.P12/GII.3 pandemic may have regional characteristics [17,47,48]. GII.P7/GII.6, as the second most prevalent genotype in 2014, was reported in a few cases elsewhere [46,49]. In addition, many other rare RdRp/capsid strains, such as GII.Pe/GII.3 and GII.P16/GII.2, were detected in our study.…”