Epidemiology of norovirus infections among diarrhea outpatients in a diarrhea surveillance system in Shanghai, China: a cross-sectional study

Abstract

BackgroundNorovirus is an important cause of gastroenteritis both in children and adults. In China, few studies have been conducted on adult populations. This study aimed to determine the contribution of norovirus to gastroenteritis, characterize the features of norovirus infections, compare them with other pathogens, and test the effectiveness of the surveillance system.MethodsA citywide surveillance network on diarrhea patients was established. Samples were collected with intervals from both children and adults among diarrhea outpatients in hospitals and tested for viruses using rRT-PCR and for bacteria in CDCs. Patient information was acquired through interviews and recorded into a dedicated online system. The Pearsonχ2 test, multivariate logistic regression models and discriminant models were fitted into its comparisons with the non-norovirus group and other pathogens.ResultsNorovirus was detected in 22.91% of sampled diarrhea patients. The seasonal distribution of norovirus infections was different from non-norovirus patients (p < 0.001), with a half-year peak. Higher proportions of males (p = 0.001, OR = 1.303, 95% CI = 1.110-1.529), local citizens (p < 0.001) and officials/clerks (p = 0.001, OR = 1.348, 95% CI = 1.124-1.618) were affected with norovirus when compared with non-norovirus patients. Diarrhea patients affected with norovirus featured nausea (p < 0.001, OR = 1.418, 95% CI = 1.176-1.709) and vomiting (p < 0.001, OR = 1.969, 95% CI = 1.618-2.398), while fewer manifested fever (p = 0.046, OR = 0.758, 95% CI = 0.577-0.996) and abdominal pain (p = 0.018, OR = 0.815, 95% CI = 0.689-0.965). Children were more vulnerable to rotavirus (p = 0.008, OR = 1.637, 95% CI = 1.136-2.358) and bacteria (p = 0.027, OR = 1.511, 95% CI = 1.053-2.169) than norovirus. There was a seasonal difference between the GI and GII genotypes (p < 0.001). Officials or clerks were more easily affected with GI than GII (p = 0.006, OR = 1.888, 95% CI = 1.205-2.958).ConclusionsThis study was based on a citywide hospital-sentinel surveillance system with multiple enteric pathogens included. Norovirus was recognized as the most prevalent enteric pathogen in Shanghai. The seasonal peak was from October to April. Males had a higher prevalence than females. Local citizens and officials/clerks were more vulnerable to norovirus than other pathogens. Compared with rotavirus and bacteria, children were less frequently affected by norovirus. Nausea and vomiting were typical of norovirus, whereas fever and abdominal pain were uncommon symptoms of this pathogen. GI and GII infections were centered in different seasons. Officials and clerks were more easily affected by GI than GII.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-0922-z) contains supplementary material, which is available to authorized users.

Norovirus diarrhea in Bangladesh, 2010–2014: prevalence, clinical features, and genotypes

“…Norovirus was detected in a quarter of all diarrheal samples from two sites in Bangladesh which is one of the most densely populated countries worldwide. These rates are comparable to what has been reported previously [Caracciolo et al, ; Liu et al, ; Nahar et al, ; Wu et al, ; Xue et al, ]. In fact, several case‐control studies including the Global Enteric Multicenter Study in Bangladesh site reported that norovirus was as prevalent in children with diarrhea as in healthy controls and frequently identified as co‐infections with other diarrheal pathogens [Kotloff et al, ].…”

“…In contrast, fever, dehydration and frequency of stool output per day were lower in norovirus patients compared to patients with other bacterial pathogens. Some of these findings were inconsistent with those reported from other studies [Rahman et al, ; Nahar et al, ; Tang et al, ; Xue et al, ].…”

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

“…This finding may imply that gender is not a predisposing factor for NoV infection in children less than 5 years old. In accordance with previous studies that concluded that noroviruses mainly peaked in cold seasons [20,22,[26][27][28], our study demonstrated that most NoV infections were detected in autumn and winter. However, in some other areas, NoVassociated diarrhoea had a summer peak or no apparent seasonal peak, which may be connected with an increase in contaminated water and food or other unknown reasons [21,29].…”

Human calicivirus occurrence among outpatients with diarrhea in Beijing, China, between April 2011 and March 2013

“…However, no significant difference was found between age groups, which indicates that age may not influence HuCV infection. In this study, most detected HuCVs were NoVs, and most HuCV‐positive patients were adults, whereas higher incidences of NoV in adults who had diarrhea were also found in Wuhan and Shanghai, China [Wang YH et al, ; Xue Y et al, ]. These results suggest that NoV is an important cause of adult sporadic diarrhea in China.…”