Objective:To understand the gene characteristics of Sapovirus from diarrhea cases in diarrhoeal disease clinics in Beijing.Methods:In 2019, stool samples were collected from diarrhea cases in diarrhoeal disease clinics in Beijing. The samples were used for the detection of nucleic acid of Sapovirus with real-time RT-PCR. Different RT-PCR methods were used for the partial gene segment amplification in the capsid protein VP1 region and the polymerase RdRp region, and sequencing was conducted for amplified positive products. The sequences were aligned with software BioEdit 7.0.9.0 and analyzed with software Mega 6.06.Results:The overall detection rate of Sapovirus was 2.89% (44/1 522), the detection rate in children under 5 years old was 3.34% (18/539) and 2.64% (26/983) in children aged ≥5 years. The capsid protein VP1 region was sequenced in 23 strains belonging to 8 genotypes (GⅠ.2 had 6 strains, GⅠ.1 and GⅡ.3 had 5 strains, respectively, GⅠ.3 and GⅡ.5 had 2 strains, respectively, GⅠ.5, GⅡ.1 and GⅣ.1 had 1 strain, respectively). A total of 16 strains were detected in the cases aged ≥5 years, and the proportion of GⅠ.2 was highest (37.50%, 6/16), and 7 strains were detected in the cases under 5 years old, the proportions of GⅠ.1 and GⅡ.3 were highest (both 42.86%, 3/7); The internal similarity of each genotype was 95.5%-100.0%, and the similarity with the 51 reference strains of human or sewage sources in different years and different countries was 92.2%-100.0%. The polymerase RdRp region was sequenced in 25 strains belonging to 8 genotypes (GⅡ.P3 had 9 strains, GⅠ.P3 had 4 strains, GⅠ.P1, GⅠ.P2 and GⅡ.P1 had 3 strains, respectively, GⅠ.P5, GⅡ.P5 and GⅣ.P1 had 1 strain, respectively). Fifteen strains were detected in the cases aged ≥5 years, and GⅡ.P3 had the highest proportion (40.00%, 6/15). Ten strains were detected in the cases under 5 years old, and the proportions of GⅠ. P1, GⅡ.P1 and GⅡ.P3 were highest (all 30.00%, 3/10); The internal similarity of each genotype was 94.0%-100.0%, and the similarity with the 39 reference strains of human or sewage sources in different years and different countries was 90.2%-99.1%.Conclusions:Sapovirus is one of the pathogens among diarrhea cases in Beijing. The main genome is GⅠ and GⅡ, and the genotypes are diverse and dispersed. The main genotypes of diarrhea cases in people aged ≥5 years and less than 5 years are different.

Objective:To provide evidence for clinical diagnosis, prevention and control of group A rotavirus (RVA) diarrhea, the clinical characteristics of RVA diarrhea in children in Beijing from 2011 to 2018 were analyzed.Methods:From January 2011 to December 2018, 4 819 stool samples from children under 5 years old with diarrhea were collected monthly from 3 hospitals in Beijing. General information, clinical characteristics and other information of children were collected. RVA was detected by enzyme-linked immunosorbent assay (ELISA), genotype was identified by multiple semi-nested RT-PCR. The Vesikari clinical severity score was used to define the severity of diarrhea in children. Dichotomous unconditional logistic regression was used to analyze clinical symptoms and other differences between RVA positive and negative cases. Chi-square and Fisher direct probability tests were used to compare the composition among different groups.Results:A total of 4 819 fecal samples were collected, 953 were positive for RVA, the positive detection rate was 19.78%. The positive rate of RVA was high in the younger age group, and the incidence was high in winter and spring. RVA-positive children had more risk on diarrhea ≥5 times a day, vomiting symptoms, fever, mild dehydration, and Vesikari score ≥11. The positive rate of RVA in watery stool samples (26.13%, 214/819) and infectious diarrhea cases (42.20%, 265/628) was the highest respectively. There were no significant differences in clinical symptoms, clinical diagnoses and fecal traits among children with different RVA genotypes.Conclusions:The clinical symptoms of RVA diarrhea were severe in children. RVA genotype did not affect the clinical symptoms. Stool traits (watery stools) and Vesikari score can assist physicians in diagnosing RVA diarrhea.

Objective:To study the prevalence of Norovirus infection among kitchen workers in Beijing, and the contamination status of Norovirus in catering companies and train station.Methods:A cross-sectional survey was conducted to collect anal swab specimens and environmental specimens from catering companies in 16 districts of Beijing and in 3 big train stations. Norovirus nucleic acid was detected by fluorescence quantitative PCR. The contamination status of Norovirus in the environment and the asymptomatic infection status of kitchen workers was analyzed in this study.Results:A total of 650 catering companies were investigated. 1 302 anal swabs or stool specimens and 2 600 environmental swabs were collected and tested. Among the 644 catering companies out of train stations, 1 290 anal swabs or stool specimens and 2 576 environmental swabs were collected and tested. The asymptomatic infection rate of Norovirus was 0.85% (11/1 290) among kitchen workers of the catering companies out of the train stations, while the positive rate of norovirus contamination in the environment was 0.04% (1/2 576). Norovirus was not detected in the specimens collected from the kitchen workers and the environment of the catering companies in train stations.Conclusion:During the non-epidemic season of Norovirus in 2019, the infection rate of Norovirus among kitchen workers in Beijing is low, and the environment is contaminated by Norovirus.

Objective:To study the prevalence of Norovirus infection among kitchen workers in Beijing, and the contamination status of Norovirus in catering companies and train station.Methods:A cross-sectional survey was conducted to collect anal swab specimens and environmental specimens from catering companies in 16 districts of Beijing and in 3 big train stations. Norovirus nucleic acid was detected by fluorescence quantitative PCR. The contamination status of Norovirus in the environment and the asymptomatic infection status of kitchen workers was analyzed in this study.Results:A total of 650 catering companies were investigated. 1 302 anal swabs or stool specimens and 2 600 environmental swabs were collected and tested. Among the 644 catering companies out of train stations, 1 290 anal swabs or stool specimens and 2 576 environmental swabs were collected and tested. The asymptomatic infection rate of Norovirus was 0.85% (11/1 290) among kitchen workers of the catering companies out of the train stations, while the positive rate of norovirus contamination in the environment was 0.04% (1/2 576). Norovirus was not detected in the specimens collected from the kitchen workers and the environment of the catering companies in train stations.Conclusion:During the non-epidemic season of Norovirus in 2019, the infection rate of Norovirus among kitchen workers in Beijing is low, and the environment is contaminated by Norovirus.

Objective:To investigate the contamination of ball lettuce sold by norovirus and rotavirus in Beijing.Methods:From November 2015 to October 2016, 54 samples were collected at a market stall in Beijing. The potentially existing viruses were eluted and concentrated from the ball lettuce leaves using centrifugation and direct methods corresponding to three kinds of eluants. Norovirus and rotavirus were detected by real time RT-PCR. The partial VP1 gene of norovirus was amplified by semi-nested RT-PCR. The PCR product was sequenced directly, the sequence alignment was performed using the BioEdit 7.0.9.0 software, the phylogenetic tree was constructed with the MEGA 6.06 software.Results:Among 54 pieces of ball lettuce, rotavirus was detected negative, and the detection rate of norovirus was 11.11% (6/54). Of these NoV-positive specimens, 3 (50.0%) were NoV GII, 1 (16.7%) was NoV GI, and 2 (33.33%) were a mix of NoV GI and GII, The detection rates in spring, summer, autumn and winter were 8.3% (1/12), 0.0% (0/8), 28.6% (4/14) and 5.0% (1/20), respectively. One strain was sequenced successfully and identified as GII.3 genotype. The strain shares 100.0% nucleotide identity with strain KY348698 isolated from human in Guangdong in 2014.Conclusions:Human norovirus contamination existed in some ball lettuce sold in Beijing, eating raw unwashed ball lettuce may indicate a risk of viral acute gastroenteritis.

Objective: To analyze the influencing factors of acute gastroenteritis outbreaks caused by norovirus in Beijing from 2014 to 2018. Methods: Data of acute gastroenteritis events caused by norovirus in Beijing from April 2014 to March 2018 were collected. Unconditional logistic regression model was conducted to identify the risk factors of the outbreaks. Results: A total of 765 acute gastroenteritis epidemics caused by norovirus were reported in Beijing, in which 85.88% (657/765) were cluster events and 14.12% (108/765) were outbreaks. Among the outbreaks, 70.37% (76/108) were reported in 2017; 84.26% (91/108) were reported in winter and spring; 88.89% (96/108) were reported in kindergartens, primary or secondary schools; 81.48% (88/108) were through person-to-person transmission; 93.52% (101/108) were caused by norovirus GⅡ infection. The risk of outbreaks in suburban and out suburb area were 1.84 times (95%CI: 1.13-3.02) and 3.78 times (95%CI: 1.62-8.82) as high as that in urban area, respectively. The risks of outbreaks in primary, secondary schools and other institutions were 6.26 times (95%CI: 3.53-11.10), 14.98 times (95%CI: 6.23-36.01) and 8.71 times (95%CI: 3.07-24.71) as high as that in kindergartens, respectively. The risk of outbreak in which patients having lower hospital visiting rate than the median rate of all events was 2.29 times than that in the context of having higher hospital visiting rate (95%CI:1.42-3.68). The risk of foodborne outbreak was 14.55 times as high as that transmitted through person-to-person (95%CI: 3.15-67.07). Conclusion Measures such as strengthening the prevention and control of norovirus outbreaks in suburbs, primary schools, secondary schools and other institutions, promoting patients to visit the hospital actively, improving the management of foodborne events and kitchen workers should be taken to reduce the incidence of acute gastroenteritis outbreaks caused by norovirus.

Objective To investigate the clinical and imaging features of the aquaporin-4 (AQP4)antibody-negative binocular optic neuritis and to analyze the predictive factors of visual function outcome.Methods Fifty-eight patients with AQP4-negative binocular optic neuritis were reviewed and followed up from January 2014 to December 2015.Patients at baseline and at the end of follow-up were evaluated for visual function and neurological examination.All patients underwent optic nerve and brain MRI, cerebrospinal fluid and routine laboratory tests.Results AQP4 antibody-negative binocular optic neuritis accounted for 9.4%(58/615)of the total optic neuritis in the same period.At baseline, 99 eyes (85.3%,99/116)had best corrected visual acuity<0.1.At the end of follow-up, 31 eyes(26.7%,31/116) had best corrected visual acuity < 0.1. There were 43 cases (74.1%, 43/58) with multi-segment involvement of optic nerve at the baseline.Baseline visual acuity(P=0.005), early treatment response (P=0.011), and segment numbers of optic nerve involvement(P=0.025)were independently associated with end-point outcome of visual function.Forty-nine patients(84.5%,49/58)showed monophasic course in (3.1 ± 0.9) years follow-up period, 7 cases (12.1%, 7/58) had recurrence, and 2 cases (3.4%, 2/58) converted to neuromyelitis optic spectrum disorder (NMOSD). Conclusions AQP4 antibody-negative binocular optic neuritis is common and the recovery of visual function is not satisfied. Baseline visual function and the length of optic lesion in MRI is related to the end-point prognosis. Most patients performs the single phase course during the follow-up period.

Objective: To analyze the infection characteristics of patients in acute gastroenteritis outbreaks caused by noroviruses. Methods: Between April 2014 and March 2016, the clinical data and samples were collected from the patients in acute gastroenteritis outbreaks caused by noroviruses in Beijing. Noroviruses were detected and genotyped using real time RT-PCR, and the infection characteristics of norovirus gastroenteritis were analyzed using the descriptive epidemiological method. Results: A total of 1743 clinical diagnosed cases of norovirus gastroenteritis were collected, and children under 12 years old accounted for 77.68% (1354/1743). The detection rate of noroviruses was 73.98% (509/688). The detection rates of noroviruses in fecal, swab and vomitus samples were gradually decreased (χ²=67.798, P<0.001). Among these clinical diagnosed cases, vomiting was the most common symptom (93.98%), followed by abdominal pain (40.34%), diarrhea (30.35%) and fever (27.94%). The most common symptom of patients under 6 years old was vomiting(98.14%), whereas diarrhea was most common among over 18 years old patients (68.12%). With the increase of age of the patients, the incidence of vomiting was gradually decreased (χ²=100.913, P<0.001), whereas the incidence of diarrhea was gradually increased (χ²=261.164, P<0.001). There was no statistical difference in vomiting, diarrhea and abdominal pain symptoms between patients infected with genogroup Ⅰ and Ⅱ noroviruses, and patients infected with genogroup Ⅱ (34.49%, 149/432) had the higher incidence rate of fever than that of genogroup Ⅰ (18.18%, 14/77) (χ²=7.985, P<0.01). Conclusions Noroviruses mainly infected children under 12 years old in acute gastroentertis outbreaks. The most common symptom of patients with acute gastroenteritis caused by noroviruses was vomiting, and the incidences of vomiting and diarrhea were significantly correlated with age of the patients. Patients infected with genogroup Ⅱ had the higher incidence rate of fever than genogroup Ⅰ infection.

Objective To investigate the rotavirus contamination in commercial oysters in Beijing. Methods Between February 2014 and March 2015, a total of 280 oysters were collected in a large aquatic market in Beijing, and 5 oysters per stall were collected and classified as one sample.The samples were processed using three kinds of methods:direct treatment, PEG ( polyethylene glycol) 8 000 precipitation and proteinase K digestion-PEG 8 000 precipitation.Group A rotaviruses were detected by real time RT-PCR, and G/P genotyping was performed using the semi-nested RT-PCR.The VP7 and VP4 genes of positive samples were amplified, sequenced, and the phylogenetic tree was constructed using the maximum likelihood method with MEGA software ( version 6.06 ) .Results The detection rates of group A rotaviruses of three methods (direct treatment, PEG 8 000 precipitation and proteinase K digestion-PEG 8 000 precipitation) were 3.57%(2/56), 7.14%(4/56) and 5.38% (3/56), respectively.Rotaviruses were detected in 8 oysters samples ( 14.29%) , which were collected during autumn and winter . The G/P genotype combination included G9/P[8] (2 strains) and G9/P[N] (6 strains).The VP7 genes of 3 strains and the VP4 gene of one strain were sequenced successfully, and the phylogenetic analyses demonstrated that these strains had the highest similarity to those G9/P[8] strains prevailing in recent years in China.Conclusion Group A rotaviruses were detected in some commercial oysters during autumn and winter in Beijing, indicating a risk of foodborne illness.

Objective To evaluate the efficiency of a rapid immunochromatographic test kit for noroviruses of different genotypes in fecal specimens.Methods Between April 2011 and May 2015,101 norovirus-positive fecal specimens were collected from patients with diarrhea.Noroviruscs of genogroup Ⅰ (G Ⅰ) or Ⅱ (G Ⅱ) were detected using the real time RT-PCR.The capsid genes of noroviruses were amplified using the RT-PCR,and genotypes were identified through the phylogenetic analysis.The results of real-time RT-PCR and genotyping were employed as the reference,then the rapid immunochromatography test kit (RIDA(R) QUICK Norovirus) was evaluated.Results Among 101 specimens,8 strains of GⅠ and 93 strains of G Ⅱ were identified by real time RT-PCR,whereas 1 strains of GⅠ and 57 strains of G Ⅱ were identified by RIDA(R) QUICK Norovirus,with the coincidence rate of 57.4％.RIDA(R) QUICK Norovirus could detect GⅠ.9,G Ⅱ.3,G Ⅱ.4,G Ⅱ.6,G Ⅱ 7,G Ⅱ.13,G Ⅱ.17,G Ⅱ.21 and G Ⅱ.N,and it failed to detect GⅠ.2,GⅠ.6,GⅠ.N and G Ⅱ.2.The detection rates for G Ⅱ.4 strains and new G Ⅱ.17 variants were 77.8％ (28/36) and 38.1％ (8/21) respectively.Conclusion This assay was effective for common GⅡ noroviruses,but less reliable for new G Ⅱ.17 variants.