Epidemiologic characteristics of outbreaks of three norovirus genotypes (GII.2, GII.17 and GII.4 Sydney) in Guangzhou, China, from 2012 to 2018

Abstract

To compare the epidemiologic features (e.g. settings and transmission mode) and patient clinical characteristics associated with outbreaks of different norovirus (Nov) strains, we retrospectively analysed data of Nov outbreaks occurring in Guangzhou, China from 2012 to 2018. The results suggested that outbreaks of Nov GII.2, GII.17 and GII.4 Sydney exhibited different outbreak settings, transmission modes and symptoms. GII.2 outbreaks mainly occurred in kindergartens, elementary and high schools and were transmitted mainly through person-to-person contact. By contrast, GII.4 Sydney outbreaks frequently occurred in colleges and were primarily associated with foodborne transmission. Cases from GII.2 and GII.17 outbreaks reported vomiting more frequently than those from outbreaks associated with GII.4 Sydney.

Prevalence of GII.4 Sydney Norovirus Strains and Associated Factors of Acute Gastroenteritis in Children: Winter 2019-2020 in Guangzhou

“…Our study revealed October and November as the months when the norovirus infections were most prevalent in Guangzhou in the winter 2019-2020, which is different from the previous research that November to March of the following year is the prevalent month [27]. Research by Marshall et al showed that the prevalence is positively related to the humidity and the amount of rainfall [28].…”

“…In this study, male patients were more among the infected than females (103:65), which is consistent with previous studies [26,27]. That the innate and acquired immunity in females are inherently stronger than in males may be the reason [31].…”

“…Vomiting and diarrhoea were the main symptoms of norovirus infection in our study. Compared with patients infected with non-GII.4 norovirus, patients with GII.4 were more likely to present with diarrhoea [20,27]. In this study, we found that the duration of diarrhoea was signi cantly longer and the maximum frequency per day in patients with GII.4 infection was more (P<0.05) than that of other genotypes.…”

Prevalence of GII.4 Sydney Norovirus Strains and Associated Factors of Acute Gastroenteritis in Children: 2019/2020 Season in Guangzhou, China

“…GII.2[P16] was the major epidemic strain in Guangdong Province in August 2016 and continued to circulate in 2017(Ao et al, 2018 ). The main epidemic strains were GII.4 Sydney[P31] (78.0%) and GII.4 Sydney[P16] (11.9%) in this study, which was different from previous years in Guangzhou(Wang et al 2019a ). This suggests that the norovirus epidemic trend may have changed in Guangzhou in the 2019/2020 season, but further studies are needed to verify it.…”

“…According to the norovirus surveillance network in China, more than 80% of norovirus outbreaks occurred during the winter season (November to March) from 2006 to 2018 (Jin et al, 2020 ; Qin et al, 2017 ; Wang et al 2019a ). However, our data revealed that the majority (75.60%) of norovirus cases presented from October and November in Guangzhou in 2019/2020 season, which was slightly earlier than the previous data of Guangzhou (Wang et al 2019a ). Marshall et al revealed that meteorological factors may be able to play a role in the seasonal pattern of norovirus epidemics (Marshall & Bruggink, 2011 ).…”