Molecular epidemiology of genogroup II norovirus infections in acute gastroenteritis patients during 2014-2016 in Pudong New Area, Shanghai, China

Prevalence and associated factors of norovirus infections among patients with diarrhea in the Amhara national regional state, Ethiopia

BACKGROUND

Noroviruses (NoVs) are the leading cause of diarrheal disease among all age groups worldwide, with an increased burden in developing countries. As there is no surveillance, epidemiological data is limited in Ethiopia. Hence, this study aimed to investigate the prevalence and associated factors of NoV infection among patients with diarrhea in the Amhara National Regional State, Ethiopia.

METHODS

A prospective health facility-based cross-sectional study was conducted from May 2021 to November 2021. A total of 550 study participants of all age groups with symptoms of diarrhea were proportionately assigned to the four study areas, area with three health facilities. Study participants were systematically sampled in each health facility. A fecal sample from each case was collected. The RNA was extracted and tested for NoV by one-step RT-PCR. Sociodemographic and other variables were gathered using a pre-tested questionnaire. A descriptive analysis was performed. Both binary and multiple logistic regressions were utilized to identify factors associated with NoV infection. Variables with a p-value < 0.05 in the final model were considered statistically significant.

RESULTS

Five hundred nineteen out of 550 samples were analyzed (94.4% response rate). The overall prevalence of NoV was 8.9% (46/519). The positivity rates were higher among the elderly (33.3%) and under-5 children (12.5%). Both genogroup I and genogroup II (GII) were identified, with GII being the predominant, at 82.6% (38/46). Of all participants, only 20% reported a history of vomiting. Norovirus infection was more prevalent among participants from Debre Tabor (AOR = 4, 95%CI: 1.2-14) and Bahir Dar areas (AOR = 3.6, 95%CI: 1.04-11) compared to Debre Markos. Additionally, older adults (AOR = 7, 95% CI: 2-24) and under-5 children (AOR = 3.5, 95% CI: 2.8-12) were disproportionately affected compared to adults. The previous history of diarrhea (AOR = 3.6, 95% CI: 1.7-7) was a significant factor contributing to NoV infections. Moreover, the odds of NoV infection were higher among individuals with a high frequency of diarrhea (AOR = 15.3, 95%CI: 7.6-43) and vomiting (AOR = 3.5, 95%CI: 1.5-8).

CONCLUSIONS

The prevalence of NoV was considerably high, with the predominance of NoV-GII. The positivity rate was higher among the extreme age groups and varied across the study areas. To obtain a comprehensive understanding of the virus`s epidemiology and its genetic diversity, further research is warranted.

Global prevalence of norovirus gastroenteritis after emergence of the GII.4 Sydney 2012 variant: a systematic review and meta-analysis

Introduction

Norovirus is widely recognized as a leading cause of both sporadic cases and outbreaks of acute gastroenteritis (AGE) across all age groups. The GII.4 Sydney 2012 variant has consistently prevailed since 2012, distinguishing itself from other variants that typically circulate for a period of 2-4 years.

Objective

This review aims to systematically summarize the prevalence of norovirus gastroenteritis following emergence of the GII.4 Sydney 2012 variant.

Methods

Data were collected from PubMed, Embase, Web of Science, and Cochrane databases spanning the period between January 2012 and August 2022. A meta-analysis was conducted to investigate the global prevalence and distribution patterns of norovirus gastroenteritis from 2012 to 2022.

Results

The global pooled prevalence of norovirus gastroenteritis was determined to be 19.04% (16.66-21.42%) based on a comprehensive analysis of 70 studies, which included a total of 85,798 sporadic cases with acute gastroenteritis and identified 15,089 positive cases for norovirus. The prevalence rate is higher in winter than other seasons, and there are great differences among countries and age groups. The pooled attack rate of norovirus infection is estimated to be 36.89% (95% CI, 36.24-37.55%), based on a sample of 6,992 individuals who tested positive for norovirus out of a total population of 17,958 individuals exposed during outbreak events.

Conclusion

The global prevalence of norovirus gastroenteritis is always high, necessitating an increased emphasis on prevention and control strategies with vaccine development for this infectious disease, particularly among the children under 5 years old and the geriatric population (individuals over 60 years old).

Development and Evaluation of a Rapid GII Norovirus Detection Method Based on CRISPR-Cas12a

Norovirus is highly infectious and rapidly transmissible and represents a major pathogen of sporadic cases and outbreaks of acute gastroenteritis worldwide, causing a substantial disease burden. Recent years have witnessed a dramatic increase in norovirus outbreaks in China, significantly higher than in previous years, among which GII norovirus is the predominant prevalent strain. Therefore, rapid norovirus diagnosis is critical for clinical treatment and transmission control. Hence, we developed a molecular assay based on RPA combined with the CRISPER-CAS12a technique targeting the conserved region of the GII norovirus genome, the results of which could be displayed by fluorescence curves and immunochromatographic lateral-flow test strips. The reaction only required approximately 50 min, and the results were visible by the naked eye with a sensitivity reaching 102 copies/μl. Also, our method does not cross-react with other common pathogens that cause intestinal diarrhea. Furthermore, this assay was easy to perform and inexpensive, which could be widely applied for detecting norovirus in settings including medical institutions at all levels, particularly township health centers in low-resource areas.

Association of China's two-child policy with changes in number of births and birth defects rate, 2008-2017

Background

In October 2015, China’s one-child policy was universally replaced by a so-called two-child policy. This study investigated the association between the enactment of the new policy and changes in the number of births, and health-related birth outcomes.

Methods

We used difference-in-difference model to analyse the birth record data in Pudong New Area, Shanghai.The design is descriptive before-and-after comparative study.

Results

The data covered three policy periods: the one-child policy period (January 2008 to November 2014); the partial two-child policy period (December 2014 to June 2016); the universal two-child policy period (July 2016 to December 2017). There was an estimate of 7656 additional births during the 18 months of the implementation of the universal two-child policy. The trend of monthly percentage of births to mothers aged ≥35 increased by 0.24 percentage points (95% confidence interval 0.19 to 0.28, p < 0.001) during the same period. Being a baby boy, preterm birth, low birth weight, parents with lower educational attainment, and assisted delivery were associated with a higher risk of birth defects.

Conclusions

The universal two-child policy was associated with an increase in the number of births and maternal age. Preterm birth, low birth weight, and assisted delivery were associated with a higher risk of birth defects, which suggested that these infants needed additional attention in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12839-0.

Molecular epidemiology of norovirus infections in children with acute gastroenteritis in 2017-2019 in Tianjin, China

Norovirus (NoV) is the leading cause of acute gastroenteritis (AGE) worldwide. Globally, the GII.4 Sydney 2012 strain has predominated since 2012, although GII.4 variant strains have caused AGE outbreaks in China. Recent patterns of NoV genotype distributions in 6011 children with AGE in Tianjin, China were investigated. NoV was detected using real-time reverse-transcriptase polymerase chain reaction and sequencing of partial sequences of the viral capsid gene. NoV genotypes were determined, and phylogenetic analysis was conducted. Epidemiological and clinical data were compared between children infected with different NoV genotypes. NoV was detected in 27.6% of the specimens tested. GII.4 strains comprised 49.4% infections, followed by GII.3 at 39.9%. Genotypes GII.2, GII.13, GII.17, GII.1, GII.6, and GII.14 were also detected. NoV was detected during most of the year, with a peak season of cases in the winter. Diarrhea, vomiting, fever, abdominal pain, and dehydration were present in patients with NoV infection. The main genotypes were GII.4 and GII.3, with a slight increase in GII.2, beginning in March 2017. Among the GII.4 strains, GII.4 Sydney 2012 was the only epidemic strain in Tianjin. Patients with GII.4 genotypes were more likely to present with diarrhea and vomiting than those with GII.3. Children with GII. Others were prone to suffered from dehydration and abdominal pain than those with GII.3. NoV GII has become the main cause of viral AGE in Tianjin, China. The predominant genotypes of NoV were GII.4 and GII.3. Identification of emerging genotypes is crucial for the prevention and control of NoV-caused AGE.

Epidemiology and evolution of Norovirus in China

Norovirus (NoV) has been recognized as a leading cause of gastroenteritis worldwide. This review estimates the prevalence and genotype distribution of NoV in China to provide a sound reference for vaccine development. Studies were searched up to October 2020 from CNKI database and inclusion criteria were study duration of at least one calendar year and population size of >100. The mean overall NoV prevalence in individuals with sporadic diarrhea/gastroenteritis was 16.68% (20796/124649, 95% CI 16.63-16.72), and the detection rate of NoV was the highest among children. Non-GII.4 strains have replaced GII.4 as the predominant caused multiple outbreaks since 2014. Especially the recombinant GII.P16-GII.2 increased sharply, and virologic data show that the polymerase GII.P16 rather than VP1 triggers pandemic. Due to genetic diversity and rapid evolution, predominant genotypes might change unexpectedly, which has become major obstacle for the development of effective NoV vaccines.

Molecular epidemiology and genetic diversity of norovirus infection in children with acute gastroenteritis in Bangladesh, 2014-2019

Acute gastroenteritis (AGE) is one of the most common diseases in children, and it continues to be a significant cause of morbidity and mortality worldwide. Norovirus is one of the major enteropathogens associated with both sporadic diarrhea and outbreaks of gastroenteritis. This study aims to investigate genotype diversity and molecular epidemiology of norovirus in Bangladesh. A total of 466 fecal specimens were collected from January 2014 to January 2019 from children below 5 years old with AGE in Bangladesh. All samples were analyzed by reverse transcriptase polymerase chain reaction to detect norovirus, and sequence analysis was conducted if found positive. Norovirus was detected in 5.1% (24 of 466) fecal specimens. Norovirus genotype GII.7 was predominant (62.5%, 15 of 24), followed by GII.3 (37.5%, 9 of 24). Coinfection between rotavirus and norovirus was found in 7 of 24 positive cases. Diarrhea (93.7%) and dehydration (89%) were the most common symptoms in children with AGE. About 80% of the positive cases were detected in children aged under 24 months. One seasonal peak (87.5% infection) was detected in the winter. This study suggests that norovirus continues to be one of the major etiologies of children AGE in Bangladesh. This study will provide a guideline to assess the burden of norovirus infection in Bangladesh, which will assist to combat against AGE.

Predominance of norovirus GI.4 from children with acute gastroenteritis in Jambi, Indonesia, 2019

Norovirus (NoV) is one of the most important viral causes of acute gastroenteritis (AGE) in children worldwide. Only a few studies have reported AGE with NoV-positive in some cities in Indonesia. This study aimed to investigate the incidence and clinical characteristic of NoV infection, and also genotype distribution of NoV in children with AGE in Jambi, as the capital and the largest city of Jambi province, Indonesia. Stool samples were collected from children (≤15 years of age) with AGE at three participating hospitals in Jambi from February to April 2019. The detection of NoV and its genotyping were carried out by reverse-transcriptase polymerase chain reaction and direct sequencing. Of the 91 stool samples collected, 14 (15.4%) were positive for NoV. Fever, vomiting, and severe diarrhea were commonly observed in AGE with NoV, while level of dehydration was statistically significant difference between children with NoV-positive and those with NoV-negative. The most prevalent genotype was GI.4 (42.9%), followed by GII.6 (28.6%) and some other genotypes. Interestingly, this study found the predominance of GI.4, differed from previous reports in Indonesia. Continuously investigation of the circulating genotype is needed to control the NoV-infected AGE.

Molecular epidemiology of GII noroviruses in outpatients with acute gastroenteritis in Shandong Province, China

Noroviruses have been recognized as the most important causative agents of acute gastroenteritis. The present study was carried out to investigate the molecular epidemiological features of genotype II (GII) norovirus in outpatients with acute gastroenteritis in Shandong province in China from July 2017 to June 2018. In total, 151 (10.30%) samples were positive for NoV GII strains by RT-PCR. Eight genotypes were detected: GII.2, GII.3, GII.4, GII.6, GII.7, GII.12, GII.13 and GII.17. GII.4 (43.71%) was the most prevalent genotype, and the dominant strains belonged to the group of Sydney-2012 strains. GII.17 (27.15%), which has become the main cause of outbreaks of acute gastroenteritis in China, also accounted for a high proportion. Meanwhile, three recombinant types (GII.P17-GII.7, GII.P3-GII.4 and GII.P12-GII.4) were observed and authenticated using Simplot software. The results showed that GII norovirus was the main cause of acute gastroenteritis in Shandong province. GII.4 and GII.17 were the dominant genotypes. Continuous observation and identification of emerging genotypes are necessary for understanding the evolution of the virus, control of infection, and development of vaccines.

Surveillance of the 'bud event of norovirus-associated gastroenteritis' in schools: does it work in the prevention of norovirus infection outbreaks in Shanghai?

Outbreaks of norovirus-associated gastroenteritis have been reported in schools in recent decades in China. For early warning and response to infectious disease outbreaks, the Shanghai Infectious Diseases Bud Event Surveillance System (IDBESS) was established in 2016. Bud event is a term used for the early sign of a potential infectious disease outbreak in public settings when the first few cases appear. This study aimed to describe the epidemiological characteristics of Norovirus-associated gastroenteritis bud events from June 2016 to December 2017 and to understand factors influencing the severity of events. Data were extracted from the IDBESS, supplemented by field investigations and school absence surveillance. In total, 189 bud events of Norovirus-associated gastroenteritis were reported in schools and kindergartens, affecting 3827 individuals and 52.38% happened in primary schools. The attack rate of Norovirus-associated gastroenteritis was 3.82% on average in students in the affected schools. In each event, case numbers varied between 5 and 148, with a median of 16. The duration of bud events lasted for 2 days on average. School absence happened in 47.93% (1797/3749) of affected students and the average duration of absence was 3.07 days. It was found that a longer delay before reporting was associated with a longer-lasting duration of bud event (OR = 2.25, 95% CI: 1.65, 3.07). In conclusion, ascribed to the sensitive threshold for alerting and the timely field investigation, the surveillance of bud events of Norovirus-associated gastroenteritis is effective in the control of Norovirus infection among preschool children and students in Shanghai.

Genetic diversity and epidemiology of Genogroup II noroviruses in children with acute sporadic gastroenteritis in Shanghai, China, 2012-2017

BACKGROUND

Noroviruses (NoVs) are considered an important cause of acute gastroenteritis (AGE) across all age groups, especially in children under 5 years of age. We investigated the epidemiology of noroviruses in outpatient children from the Children's Hospital of Fudan University in Shanghai, China.

METHODS

Stool specimens were collected between January 2012 and December 2017 from 1433 children under 5 years of age with acute gastroenteritis. All samples were analysed by conventional reverse transcription-polymerase chain reaction (RT-PCR) for genogroup II NoVs amplifying both the RNA-dependent RNA polymerase (RdRp) and partial capsid genes. The Norovirus Genotyping Tool v.2.0 ( https://www.rivm.nl/mpf/typingtool/norovirus/ ) was used for genotyping the strains, and phylogenetic analyses were conducted by MEGA 6.0.

RESULTS

From 2012 to 2017, GII NoVs were detected in 15.4% (220/1433) of the samples, with the highest detection rate in children aged 7-12 months (19.2%, 143/746). The seasons with the highest prevalence of GII NoVs infection were autumn and winter. Based on genetic analysis of RdRp, GII.Pe (74.5%%, 137/184) was the most predominant RdRp genotype from 2013 to 2017, while GII.P4 played a dominant role in 2012 (55.6%, 21/36). Among the capsid genotypes, the most prevalent NoV genotype from 2012 to 2017 was GII.4 (74.1%, 163/220). On the basis of genetic analysis of RdRp and capsid sequences, the strains were clustered into - 19 RdRp/capsid genotypes, and 12 of them were discordant, such as GII.Pe/GII.4-Sydney_2012, GII.P12/GII.3, GII.P7/GII.6, GII.Pe/GII.3, and GII.P16/GII.2. Starting with 2013, GII.Pe/GII.4-Sydney_2012 had completely replaced the pandemic GII.P4-2006b/GII.4-2006b subtype and was detected in children across all age groups.

CONCLUSIONS

The present study shows high detection rates and the genetic diversity of circulating NoV GII genotypes in paediatric AGE samples from Shanghai. The findings emphasize the importance of continuous molecular surveillance of emerging NoV strains.

Epidemiological and clinical differences between sexes and pathogens in a three-year surveillance of acute infectious gastroenteritis in Shanghai

Acute infectious gastroenteritis cases in Shanghai, reported over three years, were analyzed. Pathogens were identified in 1031 patients; of these, 725 and 306 were bacterial and viral cases, respectively. Vibrio parahemolyticus and Salmonella were the dominant bacteria, and Caliciviridae and Reoviridae were the dominant viral families in the local area. The acute gastroenteritis epidemic peaks appeared in August and January, which represented the active peak periods of bacteria and viruses, respectively. Logistic regression analyses with sex stratification showed that abdominal pain, fever and ingestion of unsafe food at restaurants were independent factors more frequently associated with bacterial gastroenteritis irrespective of sex; red cell-positive fecal matter was associated with bacterial gastroenteritis with an odds ratio (OR) of 3.28 only in males; and white blood cell count was associated with bacterial gastroenteritis with an OR of 1.02 only in females. Pathogen stratification showed that age, vomiting and red cell-positive fecal matter were associated with males with ORs of 0.99, 0.61 and 1.71, respectively, in bacterial gastroenteritis; and the migrant ratio was higher in males with an OR of 2.29 only in viral gastroenteritis. In conclusion, although bacterial and viral gastroenteritis shared many features, epidemiological and clinical factors differed between sexes and pathogens.

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

BACKGROUND

Noroviruses (NVs) are an important cause of acute gastroenteritis (AGE) worldwide. There are limited data on the prevalence and molecular characterization of NVs in children in Hohhot, China.

METHODS

Between January 2012 and December 2017, 1863 stool samples were collected at Maternal and Child Health Hospital in Hohhot. All samples were screened for NVs by real-time reverse transcription polymerase chain reaction (real-time RT-PCR).

RESULTS

NVs were detected in 24.15% of these inpatient cases, ranging from 12.78 to 32.92% in different years. NV was detected throughout the year, with a peak in winter. Based on sequence analysis of the partial VP1 gene, the 306 identified NV strains were divided into six genotypes: GII.3 (71.24%), GII.4 (23.53%), and GII.2, GII.5, GII.6, and GII.13 (total 5.23%). Based on further sequence analysis of the RNA-dependent RNA polymerase (RdRp), GII.P12/GII.3, GII.Pe/GII.4, and GII.P4/GII.4 were identified as predominant genotypes, accounting for 92.6% of genotyped strains. The median age of the children with NV infection was 8.0 (range 0-59) months. However, children infected with GII.3 were younger (median 7.0 months) than GII.4-positive patients (median 10.0 months).

CONCLUSION

NV contributed greatly to AGE among hospitalized children in Hohhot in China. Continuous surveillance is important for understanding the local prevalence and characterization of NV.

Variation of human norovirus GII genotypes detected in Ibaraki, Japan, during 2012-2018

Background

Human norovirus (HuNoV) is the major cause of viral acute gastroenteritis for all age groups in various countries. HuNoV GII in particular accounted for the majority of norovirus outbreaks, among which GII.4 caused repeated outbreaks for a long time. Besides GII.4, other norovirus genotypes, GII.2, GII.6, and GII.17, have also been prevalent in various contexts in recent years, but few detailed epidemiological studies of them have been performed and are poorly understood. We thus conducted an epidemiological analysis of HuNoV GII in Ibaraki Prefecture, Japan, by performing surveillance in the six seasons from September 2012 to August 2018.

Results

HuNoV GI occurred almost sporadically for all genotypes; however, each genotype of GII exhibited its typical epidemiological characteristics. Although the number of outbreaks of GII.4 decreased season by season, it reemerged in 2017/2018 season. The timing of the epidemic peak in terms of number of cases for GII.17 differed from that for the other genotypes. The patients age with GII.2 and GII.6 were younger and outbreak of GII.17 occurred frequently as food poisoning. Namely, the primarily infected outbreak group differed for each genotype of HuNoV GII. Moreover, the viral load of patients differed according to the genotype.

Conclusions

Various HuNoV genotypes including GII.2, GII.4, GII.6, and GII.17 were shown to be associated with various types of outbreak sites (at childcare and educational facilities, involving cases of food poisoning, and at elderly nursing homes) in this study. These genotypes emerged in recent years, and their prevalence patterns differed from each other. Moreover, differences in outbreak sites and viral load of patients among the genotypes were identified.

Age, primary symptoms, and genotype characteristics of norovirus outbreaks in Shanghai schools in 2017

Sixty norovirus outbreaks that occurred in Pudong District, Shanghai in 2017 and affected 959 people were summarised. Of the outbreaks, 29 (48.3%), 27 (45.0%), and 4 (6.7%) occurred in kindergartens, primary schools, and middle schools, respectively. Although the total number of outbreaks peaked in March (13/60, 21.7%), outbreaks in kindergartens and primary schools peaked in April (6/29, 20.7%) and March (8/27, 29.6%), respectively. Primary schools had the highest median number of cases per outbreak (19) and the highest proportion of cases (54.6%). The male-to-female case ratio differed among school classifications, with the highest male case ratio (69.2%) occurring in middle schools. Primary symptoms also differed across the school classifications. Molecular virology analysis showed that a single viral strain caused each outbreak at each school. In turn, 50.6, 28.8, and 20.6% of cases were infected by GII.4, GII.2, and GII.17, respectively. Vomiting was seen in 98.2, 97.3, and 88.6% of the subjects infected with noroviruses GII.17, GII.4, and GII.2, respectively, and nausea in 73.6, 43.9, and 39.0%. In conclusion, noroviruses mainly affect primary school and kindergarten students. GII.4, GII.2, and GII.17 are the main epidemic strains in the local area, and the primary symptoms differed by age and genotype.