Emergence and predominance of norovirus GII.17 in Huzhou, China, 2014–2015

Abstract

BackgroundNorovirus (NoV) has been recognized as the leading cause of both outbreaks and sporadic cases of acute gastroenteritis in children and adults worldwide. Stool samples collected from outpatients with clinical symptoms of acute gastroenteritis in all age groups at the First People’s Hospital in Huzhou, Huzhou, China between March 2014 and February 2015 were analyzed to gain insight into the epidemiology and genetic variation in NoV strains circulating in China.MethodReal-time RT-PCR (qPCR) was performed for Norovirus detection. RT-PCR were used for genomic amplification and sequencing. Genogroup and genotype were assigned using the NoV Noronet typing tool and the strains were named according to the time of isolation. The phylogenetic analysis was conducted using MEGA 5.ResultsOf the 809 specimens, 193 (23.9 %) were positive for NoV, with GII.4 and GII.17 the most commonly identified strains. Phylogenetic analysis confirmed the presence of five recombinant strains in Huzhou. Recombinants GII.P13/GII.17 and GII.P12/GII.4 were newly detected in China. The GII.P13/GII.17 recombinant was first identified in October 2014 and steadily replaced GII.Pe/GII.4 (GII.4 Sydney 2012) as the predominant circulating NoV genotype.ConclusionThis is the first report of the detection of GII.17 in the Huzhou area and of a NoV genotype being detected in greater numbers than GII.4. Furthermore, our results indicated that following the emergence of GII.17 in October 2014, it steadily replaced the previous circulating GII.4 Sydney2012 strain, which was the dominant circulating genotype for the past 2 years. As norovirus are the important cause of nonbacterial gastroenteritis, continuous and comprehensive study of the norovirus strains involved in large and cost-effective acute gastroenteritis would help understanding the molecular epidemiology of norovirus infections and development of improved prevention and control measures.

Clinical and molecular analyses of norovirus-associated sporadic acute gastroenteritis: the emergence of GII.17 over GII.4, Huzhou, China, 2015

“…1. In the winter of 2014–2015, the new GII.P17/GII.17 variant first emerged in Huzhou and began to replace GII.Pe/GII.4 Sydney_2012 as the predominant strain [10]. From January to March, the GII.P17/GII.17 variant continued to predominate and kept increasing; it then declined in April and May.…”

“…In the winter of 2014–2015, a novel variant of NoV GII.17 emerged and became predominant in Huzhou, and steadily replaced the previously circulating GII.4 Sydney 2012 strain [10]. At the same time, GII.17 emerged and became predominant in the United States [11], Europe [12], and other places in Asia [13–16].…”

Norovirus, the Next Target for Vaccine Development in China

“…It attacked Beijing, Guang--dong, Hebei, Jiangsu, Zhejiang, Taiwan and Hongkong [20][21][22][23][24][25][26][27][28][29][30][31][32] . Besides, other rare prevalent genotypes were also confirmed, including GII.6 [33,34] and GIV.1 [35] .…”

“…China [15,[20][21][22][23][24][25][26][27][28][29][30][31][32] . It attacked Beijing, Guang--dong, Hebei, Jiangsu, Zhejiang, Taiwan and Hongkong [20][21][22][23][24][25][26][27][28][29][30][31][32] .…”

The novel norovirus genotype GII.17 is the predominant strain in diarrheal patients in Shanghai, China

“…Starting in November 2014, Guangdong [2], Jiangsu [3], and Zhejiang [4] in China, and Japan [5] reported diarrheal disease outbreaks that were caused by a novel NoV genotype GII.17. Chen et al [6] reported this novel genotype collected from sporadic patients in Shanghai during the winter of 2014–2015 has evolutionary relationships with other reported genotypes [2, 5].…”