OBJECTIVE: To clarify the epidemiological characteristics and spatial distribution patterns of human norovirus outbreaks in China, identify high-risk areas, and provide guidance for epidemic prevention and control. METHODS: This study analyzed 964 human norovirus outbreaks involving 50,548 cases in 26 provinces reported from 2012 to 2018. Epidemiological analysis and spatiotemporal scanning analysis were conducted to analyze the distribution of norovirus outbreaks in China. RESULTS: The outbreaks showed typical seasonality, with more outbreaks in winter and fewer in summer, and the total number of infected cases increased over time. Schools, especially middle schools and primary schools, are the most common settings of norovirus outbreaks, with the major transmission route being life contact. More outbreaks occurred in southeast coastal areas in China and showed significant spatial aggregation. The highly clustered areas of norovirus outbreaks have expanded northeast over time. CONCLUSION By identifying the epidemiological characteristics and high-risk areas of norovirus outbreaks, this study provides important scientific support for the development of preventive and control measures for norovirus outbreaks, which is conducive to the administrative management of high-risk settings and reduction of disease burden in susceptible areas.
Humans ; Gastroenteritis/epidemiology* ; Norovirus ; Caliciviridae Infections/epidemiology* ; Disease Outbreaks ; China/epidemiology* ; Genotype

Rabbit haemorrhagic disease virus (RHDV) and myxoma virus (MYXV), are two pathogens that have harmful effect on rabbit breeding and population decline of European rabbits in their native range, causing rabbit haemorrhagic disease (rabbit fever) and myxomatosis, respectively. The capsid protein VP60 of the RHDV represents the major antigenic protein. To develop a recombinant bivalent vaccine candidate that can simultaneously prevent these two diseases, we used the nonessential gene TK (thymidine kinase) of MYXV as the insertion site to construct a recombinant shuttle vector p7.5-VP60-GFP expressing the RHDV major capsid protein (VP60) and the selectable marker GFP. Then the shuttle vector p7.5-VP60-GFP was transfected into rabbit kidney cell line RK13 which was previously infected with MYXV. After homologous recombination, the recombinant virus expressing GFP was screened under a fluorescence microscope and named as rMV-VP60-GFP. Finally, the specific gene-knock in and expression verification of the vp60 and gfp genes of the recombinant virus was confirmed by PCR and Western blotting. The results showed that these two genes were readily knocked into the MYXV genome and also successfully expressed, indicating that the recombinant MYXV expressing the vp60 of RHDV was generated. Protection against MYXV challenge showed that the recombinant virus induced detectable antibodies against MYXV which would shed light on development of the effective vaccine.
Animals ; Blotting, Western ; Caliciviridae Infections/veterinary* ; Hemorrhagic Disease Virus, Rabbit/immunology* ; Rabbits ; Vaccines, Synthetic/immunology* ; Viral Structural Proteins/genetics*

OBJECTIVE: To investigate the molecular epidemiological characteristics of norovirus (NoV) among children with acute gastroenteritis in Tianjin in 2017. METHODS: A total of 758 stool specimens were collected from the children with acute gastroenteritis possibly caused by viral infection in Tianjin Children's Hospital between January and December, 2017. Quantitative real-time RT-PCR was used for primary screening of NoV, and conventional RT-PCR was used for gene amplification, sequencing and genotype identification of the VP1 region of capsid protein in positive specimens. RESULTS: Among the 758 specimens, 241 (31.8%) were found to have GII NoV. Sequencing of the VP1 region of capsid protein in positive specimens showed that among the 241 specimens with GII NoV, 69 (28.6%) had GII.4 subtype, 51 (21.2%) had GII.3 subtype, 24 (10.0%) had GII.2 subtype, and 18 (7.5%) had other subtypes. There was a significant difference in NoV detection rate between different age groups (P=0.018), and the 1- <4 years group had the highest NoV detection rate (37.3%). There was also a significant difference in NoV detection rate across seasons (P<0.001), and there was a highest NoV detection rate in winter (48.1%). Twenty-seven children (3.6%) had co-infections with NoV and rotavirus. CONCLUSIONS NoV is one of the major pathogens of the children with acute gastroenteritis from Tianjin in 2017. GII genotype, especially GII.4 subtype, is the prevalent strain. NoV infection is commonly seen in children less than 4 years and reaches the peak in winter. Some children are found to have co-infections with rotavirus.
Caliciviridae Infections ; Child ; China ; epidemiology ; Feces ; Gastroenteritis ; epidemiology ; Genotype ; Humans ; Molecular Epidemiology ; Norovirus ; Phylogeny ; RNA, Viral ; Sequence Analysis, DNA

Objective: To understand the epidemiological and etiological characteristics of outbreaks on acute gastroenteritis caused by sapovirus (SaV) worldwide. Methods: Literature about the outbreaks on acute gastroenteritis caused by SaV were retrieved from the databases including WanFang, CNKI, PubMed and Web of Science after evaluation. Time, geography, setting and population distributions of outbreaks, transmission mode, SaV genotype and clinical characteristics of the patients were analyzed. Results: A total of 34 papers about SaV were included, involving 146 outbreaks occurred between October 1976 and April 2016. In these papers, 138 outbreaks were reported on the related months. All these outbreaks occurred in northern hemisphere. SaV outbreaks occurred all year around, but mainly in cold season, the incidence was highest in December (25 outbreaks) and lowest in in August (2 outbreaks). Most outbreaks were reported by Japan, followed by Canada, the United States of America and the Netherlands. There were 141 outbreaks for which the occurring settings were reported, child-care settings were most commonly reported setting (48/141, 34.04%), followed by long-term care facility (41/141, 29.08%) and hospital (16/141, 11.35%). Clinical symptoms of 1 704 cases in 31 outbreaks were reported, with the most common symptom was diarrhea (1 331/1 704, 78.12%), followed by nausea (829/1 198, 69.20%), abdominal pain (840/1 328, 63.25%), vomiting (824/1 704, 48.36%) and fever (529/1 531, 34.53%). Genotypes of SaV were determined for 119 outbreaks. GⅠ(51/119, 42.86%) and GⅣ (45/119, 37.82%) were predominant. The outbreaks of GⅣ SaV increased suddenly in 2007, and the outbreaks of GⅠ SaV mainly occurred in 2008 and during 2011-2013. Conclusions: SaV outbreaks were reported mainly by developed countries, with most outbreaks occurred in cold season, in child-care settings and long term care facility. GⅠ and GⅣ were the most common genotypes of SaV. Prevention and control of SaV outbreak in China seemed relatively weak, and it is necessary to conduct related training and to strengthen the SaV outbreak surveillance in areas where service is in need.
Caliciviridae Infections/virology* ; Child ; China/epidemiology* ; Disease Outbreaks ; Feces/virology* ; Gastroenteritis/virology* ; Genotype ; Humans ; Phylogeny ; RNA, Viral/genetics* ; Sapovirus/isolation & purification* ; Sequence Analysis, DNA

Objective: To analyze the genetic characterization of norovirus isolated in an outbreak of gastroenteritis in Jiangsu province. Methods: Extracted viral RNA from the swab samples of cases of acute gastroenteritis outbreak in Jiangsu province on December 16-27, 2016 was reversely transcribed to cDNA, and partial RNA-dependent RNA polymerase sequence and complete capsid sequence (VP1) were amplified by RT-PCR. Amplification products were sequenced for the analysis of genetic characteristics. Results: Based on sequence alignment, the variant shared a high level of identity with the strain GⅡ.g isolated in Spain and Finland (98.7%) in the RNA-dependent RNA polymerase region, and with the strain GⅡ.1 isolated in American (99.4%) in the VP1. The recombination was determined by using software Simplot, and the breakpoint of recombination was located in the ORF1/2 overlap region at position 5 106 of VP1. The result of amino acids alignment in capsid region showed that there were no mutations in the amino acids of the predicted epitopes and receptor binding site Ⅰ-Ⅲ, but a unique amino acid change was detected at position 132 (N-S). Conclusion: The norovirus isolated in the outbreak of gastroenteritis in Jiangsu province was a rare recombinant norovirus variant GⅡ.g-GⅡ.1.
Caliciviridae Infections/epidemiology* ; Capsid Proteins ; Disease Outbreaks ; Gastroenteritis/epidemiology* ; Genotype ; Humans ; Norovirus/isolation & purification* ; Phylogeny ; RNA, Viral/genetics* ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Analysis, DNA

Objective: To understand the epidemiologic characteristics of outbreaks, caused by norovirus-GⅡ.2、GⅡ.17 and GⅡ.4/Sydney in Guangdong Province from 2013 to 2017 and to provide scientific evidence for epidemic prevention and control. Methods: Incidence data of norovirus outbreaks in Guangdong from January 1(st) 2013 to November 30(th) 2017 were collected from Public Health Emergency Management Information System. RT-PCR was performed for every case of each outbreak to detect norovirus nucleic acid and gene sequencing was conducted to identify the genotype of norovirus. Characteristics of norovirus GⅡ.2, GⅡ.17 and GⅡ.4/Sydney outbreaks were analyzed. Directly standardized method was used to calculate the proportion of symtoms as diarrhea and vomitting. Results: From January 1(st) 2013 to November 30(th) 2017, a total of 167 norovirus outbreaks were reported in Guangdong, and 115 outbreaks were caused by norovirus GⅡ.2, GⅡ.17 and GⅡ.4/Sydney respectively. The outbreaks caused by norovirus GⅡ.2 accounted for 39.68% (25/63) in primary schools, 28.57% (18/63) in child care settings, 25.40% (16/63) in middle schools and 6.35% (4/63) in universities. Outbreaks caused by norovirus GⅡ.17 accounted for 41.03% (16/39) in middle schools, 20.51% (8/39) at workplaces, 15.38% (6/39) in primary schools, 12.82% (5/39) in universities, 5.13% (2/39) in communities and child care settings respectively. The outbreaks caused by norovirus GⅡ.4/Sydney accounted for 53.85% (7/13) in universities, 15.38% (2/13) in child care settings and at workplaces respectively, 7.69%(1/13) in primary schools and middle schools respectively. The outbreaks caused by norovirus GⅡ.2 had 77.78% (49/63) of contact transmission, 17.46% (11/63) of food-borne transmission. The outbreaks caused by norovirus GⅡ.17 showed 53.85% (21/39) of food-borne transmission, 15.38% (6/39) of contract transmission, 12.82% (5/39) of water-borne transmission. The outbreaks caused by norovirus GⅡ.4/Sydney had 53.85% (7/13) of food-borne transmission, 38.46% (5/13) of the contact transmission. In terms of the clinical manifestations, the standardized proportion of vomit was 73.76% and the proportion of diarrhea was 42.85% in cases infected with norovirus GⅡ.2, the proportion of standardized of vomit was 76.37% and the proportion of diarrhea was 51.40% in cases infected with norovirus GⅡ.17, with the standardized proportion of vomit was 54.10% and the proportion of diarrhea was 55.95% in cases infected with norovirus GⅡ.4/Sydney. Conclusions: The outbreaks caused by norovirus GⅡ.2 through contact transmission mainly occurred in primary schools, child care settings and middle schools. The outbreaks caused by norovirus GⅡ.17 through food-borne transmission mainly occurred in middle schools and at workplaces. The outbreaks caused by norovirus GⅡ.4/Sydney food-borne transmission and contact mainly occurred in universities.
Adolescent ; Caliciviridae Infections/epidemiology* ; Child ; Child, Preschool ; Diarrhea/etiology* ; Disease Outbreaks ; Epidemics ; Gastroenteritis/epidemiology* ; Genotype ; Humans ; Norovirus/isolation & purification* ; Reverse Transcriptase Polymerase Chain Reaction ; Sentinel Surveillance ; Vomiting/etiology*

Objective: To understand the epidemiological and molecular characteristics of a norovirus- borne outbreak caused by GⅡ.4 Sydney 2012 in a university of Guangzhou to provide evidence for the prevention and control strategy on norovirus-caused epidemics. Methods: A self-designed questionnaire was used to collect clinical information from the patients as well as other data related to the epidemic. Pathogen detections were performed through anal swab specimens from the patients, kitchen workers and samples from the environment. Positive samples were further sequenced for phylogenetic analysis. A case-control study was employed to identify the risk factors related to this outbreak. Results: A total of 226 cases of norovirus-borne infection were identified between September 17 and 21, 2017, including 223 students, with an attack rate of 0.73% (223/30 711), and 3 kitchen workers. Students staying in the A dormitory area had the highest attack rate (1.73%, 164/9 459). No clustering was found in different colleges or classes. Results from the case-control study revealed that people who ate at the canteen in A dormitory area during September 18 to 20 was at risk for the onset of illness (OR=10.75, 95%CI: 5.56-20.79). The highest risk was related to the dinner on September 18. Another significant risk factor (OR=3.65, 95%CI: 1.92-6.94) was close personal contact in the same room of the dorm. The 3 norovirus infected kitchen workers were all from the canteen in A dormitory area where the positive rate of norovirus identified in kitchen workers was 26.67% (12/45). Positive samples were sequenced and sub-typed with results showing that the GⅡ.4 Sydney 2012 variant and the nucleotide sequences of cases and kitchen workers were 100% identical. Conclusions: The outbreak was caused by norovirus GⅡ.4 Sydney 2012 variant at campus. Similar outbreaks had been seen since 2013, with the routes of transmission most likely due to food-borne or personal contact.
Adolescent ; Adult ; Caliciviridae Infections/epidemiology* ; Case-Control Studies ; China/epidemiology* ; Disease Outbreaks ; Female ; Foodborne Diseases/virology* ; Gastroenteritis/virology* ; Humans ; Male ; Norovirus/isolation & purification* ; Phylogeny ; Surveys and Questionnaires

Caliciviridae Infections ; prevention & control ; therapy ; Disease Outbreaks ; prevention & control ; Humans ; Norovirus ; Practice Guidelines as Topic

OBJECTIVETo investigate the epidemiological and clinical features of calicivirus-associated diarrhea in hospitalized children in Chengdu, China in recent years.

METHODSThe clinical data of 267 children with calicivirus-associated diarrhea aged <5 years who were hospitalized in Chengdu Women and Children's Central Hospital (the only sentinel hospital for sample collection of pediatric viral diarrhea in Chengdu, Sichuan) between January 2012 and December 2014 were retrospectively studied.

RESULTSAmong the 267 children, 200 (74.9%) were aged less than 1 year. The infection rate of calicivirus was 28.4%, 21.6%, and 27.1% in 2012, 2013, and 2014, respectively. Calicivirus was prevalent in summer and autumn (August to October). The detection rate of Norovirus II was 85.8% (229/267), and 244 children (91.4%) experienced an acute clinical course. Watery stool was the most common change in stool properties (82.0%, 219 children), and some specimens showed mucus and/or blood. Most children had moderate to severe fever. One hundred and thirty-eight children (53.9%) experienced a reduced serum prealbumin level. One hundred and fifty-nine children (59.6%) experienced flora imbalance.

CONCLUSIONSCalicivirus has become one of the major pathogens for diarrhea in children aged <5 years in Chengdu, with Norovirus II as the dominant strain. Calicivirus is prevalent in summer and autumn. Infants aged <1 year are the main population affected by calicivirus-associated diarrhea, with watery stool as the most common manifestation.

Adolescent ; Caliciviridae Infections ; epidemiology ; Child ; Child, Hospitalized ; Child, Preschool ; China ; epidemiology ; Diarrhea ; epidemiology ; Female ; Humans ; Infant ; Male ; Time Factors

Norovirus (NoV) is a pathogen that commonly causes viral diarrhea in children. Studies indicate that NoV recognizes human histo-blood group antigens (HBGAs) as cell attachment factors. In order to explore the correlation between of NoV infection and HBGAs, a cross-sectional study was conducted in children less than five years old who were hospitalized with diarrhea in two areas of China between November 2014 and February 2015. Of the paired stool and saliva samples taken from 424 children, NoV was detected in 24 (6%) children, with viral genotypes GII.3 (n=5), GII.4 (n=14), GII.12 (n=1), and GII.17 (n=4). All of the individuals having NoV infection were either secretors (Lea-b+/Lex-y+) or partial secretors (Lea+b+/Lex+y+) except one GII.3 infection of a non-secretor (Lea+b-/Lex+y-). These results suggest that secretor positive is associated with NoV infection, although non-secretors are not absolutely protected from NoV infection.
Blood Group Antigens ; genetics ; Caliciviridae Infections ; blood ; complications ; virology ; Child, Preschool ; China ; Cross-Sectional Studies ; Diarrhea ; blood ; etiology ; virology ; Feces ; virology ; Gastroenteritis ; blood ; virology ; Genotype ; Humans ; Infant ; Norovirus ; physiology