Objective To study the clinical and the epidemiological features of hospitalized children with influenza virus infection. Methods Two hundred and fifty-three inpatients with laboratory-confirmed influenza virus infection from 1999 to 2008 were reviewed for analyzing the clinical and epidemiological characteristics. Type A and B influenza viruses in the nasopharyngeal aspirates were detected by immunofluorescence assay. Mann-Whitney U test were performed for comparing the median age and the length of hospitalization. Chi-square test was performed for comparing the proportion of patients with fever and cough. Results Among 253 hospitalized children aged between 5 days and 127 months, 182 (71.9%) were boys and 71 (28. 1%) were girls. The median age was 18 months. Fifty-three cases were infants younger than 6 months. 95 cases were children aged between 6 months and 2 years, 85 cases were aged between 2 years and 5 years and 20 cases were older than 5 years. The diagnosis of influenza-related admission included pneumonia (190 cases), bronchitis (49 cases) and upper respiratory tract infection (14 cases). Eleven cases developed febrile convulsion, 6 cases had acute exacerbation of asthma and 3 cases had concomitant viralencephalitis. Twenty-nine cases had basic diseases. Cough and fever were the most common symptoms. Two hundred and thirty-eight cases presenting cough and 209 case presenting fever. Sixty-seven percent (140/209) had high fever with body temperature higher than 39 ℃. The average duration of fever was (5. 0 ±2. 9) days. Fever and cough were both more common in children older than6 months (X2 = 22. 895,P<0. 01; X2 = 16. 992,P<0. 01, respectively). Febrile convulsion occurred in children older than 2 years. Fifteen point five (39/251) developed leukocytopenia. Conclusions Children younger than 5 years old are at high risk of influenza-related hospitalization. We should emphasize influenza vaccination in previously healthy children aged between 6 months and 5 years and children with underlying diseases.

Objective To understand the clinical characteristics of pediatric patients who developed H1N1 influenza A virus-associated pneumonia during the outbreak of H1N1 influenza A in Shanghai. MethodsA dcscriptivc study was done to analyze the clinical and epidemiologic characteristics of 30 hospitalized children who developed complicated pneumonia caused by H1N1 influenza A virus infection in 2009 in Shanghai. The comparison of medians was done using rank sum test and comparison of rates was done using exact chi-square test. Results Among thirty pediatric patients with H1N1 influenza A virus-associated pneumonia, the median age was 5.9 years old, five cases (16.7 %) had pre-existing medical conditions. Twenty cases (66.7 % ) had been exposed to the classmates or family membcrs with fever. All cases had fever and cough. Eleven cases (36.7 %00 ) had tachypnca and ten (33.3%) had wheeze. Eleven cases (36.7%) showed white blood cell (WBC)＜4.0 × 109/L and 2 (6. 7%) had thrombocytopenia. All patients had bilateral or unilatcral patchy infiltrates in the lung indicated by chest X-ray and four (13. 3%) had extensive infiltrates with the evidence of pulmonary edema. One (3. 3%) critically ill child with pneumonia, chest computed tomography scan revealed lung fibrosis 3 months and 9 months after illness onset. Three(10. 0%) cases had pneumomediastinum and subcutaneous emphysema. Six cases (20. 0%) were complicated with acute respiratory failure, three (10. 0%) with acute asthmatic attack and one (3. 3%) with encephalitis. All patients were treated with oseltamivir plus antibiotics and four required mechanical ventilation. All patients survived. The median duration of fever in group with oseltamivir given within 2 days of fever onset was statistically shorter than that in group with oseltamivir given 2 days after fever onset (2 days vs 5 days, Z= -8. 015, P<0. 01). Conclusions Both pre-school age and schoolage children may develop complicated severe respiratory diseases after H1N1 influenza A virus infection. Early initiation of oseltamivir may shorten the duration of fever and reduce the occurrence of severe complications.

ObjectiveTo understand the clinical epidemiology of enterovirus 71 (EV71) in children with hand,foot,and mouth disease (HFMD) in Shanghai during 2010 to 2011.Methods The demographic,etiological and clinical data of children with HFMD were analyzed retrospectively.EV71 was tested in stool samples by one-step quantitative reverse transcription-polymerase chain reaction (RT-PCR).The date were analyzed by Chi-square test.ResultsEV71 was detected in 820 (54.45％) of 1506 inpatients in 2010 and in 924 (59.84％) of 1544 inpatients in 2011,respectively.The detection rates in severe cases and uncomplicated cases were 86.31％ and 46.67％ (x2 =247.146,P＜0.01) in 2010 and 88.78％ and 48.75％ (x2 =201.664,P＜0.01) in 2011,respectively.The detection rate of EV71 was the highest (60％- 67 ％) during May and June when HFMD peaked.Among 1744 EV71-infected HFMD inpatients,the male-to-female ratio was 1.78 ∶ 1 ; the proportion of cases was the lowest in infant ＜6 months of age (0.46％,8/1744),and the highest in children 1 years of age (34.92％,609/1744); children aged 1-3 years accounted for 76.78％ (1339/1744);and migrant children accounted for 72.76 ％ (1269/1744).The demographic characteristics in severe cases were similar to those in general EV71-infected children.Nine severe cases of pulmonary edema/hemorrhage were all infected with EV71.Conclusions EV71 was a major pathogen causing the outbreaks of HFMD and severe complications in Shanghai in 2010 and 2011.Most severe cases and all critically severe cases were associated with EV71 infection.

Objective To monitor the epidemic pattern of influenza in children during the 2011-2012 season in Shanghai and to evaluate the socioeconomic burden of influenza in children.Methods We carried out a prospective surveillance program on influenza among children who visiting the outpatient clinic for influenza-like illness (ILI) between June 2011 and May 2012.Respiratory samples as well as related demographic and clinical data were obtained from the enrolled cases.Socio-economic burden was evaluated using the questionnaires for some of the confirmed cases during the outbreak.Results Out of the 1 119 enrolled cases,influenza viruses were virologically confirmed,using the RT-PCR in 370 (33.1％) otherwise healthy children.Among them,109 (9.7％) were positive for influenza A/H3N2 viruses,and 279 (24.9％) were positive for influenza B viruses.The 2011-2012 seasonal outbreak of influenza among children with Shanghai residency started with the major outbreak of influenza B during December 2011-Feburary 2012,followed by the smaller outbreak of influenza A/H3N2 during March-April,2012.A total of 69 influenza A/H3N2-infected cases and 163 influenza B-infected cases were surveyed to evaluate the influenza-associated disease burden.The average costs per case were 706.10 Yuan and the average indirect costs per case incurred by the work loss of family members were 293.80 Yuan,with the total average costs per case were 999.90 Yuan.Mean visits to medical settings were 2.7,with antibiotics used in 67.2％ of the cases.Secondary household cases were seen in 21.1％ of the cases.Pneumonia was diagnosed in 5.6％ of the cases.The burden of disease increased from both influenza A/H3N2 and influenza B but without significant differences between them.Conclusion Influenza A/H3N2 and influenza B viruses caused outbreaks of influenza in children with Shanghai residency during the 2011-2012 season.Socioeconomic burden of influenza in children showed significantly direct impact on the sick children and an indirect impact on their families.Influenza vaccination should be recommended in children to reduce the disease burden.

Objective:To monitor the epidemiological characteristics of viral etiology in children with influenza-like illness and to guide the prevention and management of acute respiratory tract infections in childhood.Methods:Nasopharyngeal swabs were collected from the outpatient children seeking medical care in Children′s Hospital of Fudan University, Shanghai for influenza-like illness between January 2015 and December 2018. Multiplex real-time polymerase chain reaction was performed to detect respiratory syncytial virus (RSV), influenza virus (Flu), adenovirus (ADV), parainfluenza virus (PIV, type Ⅰ to type Ⅳ) and enterovirus (EV), and the epidemiological data were analyzed. Chi-square test was used for statistical analysis.Results:A total of 2 271 patients with influenza-like illness were enrolled, age range from two months to 182 months old, 1 280 cases(56.4%) were positive for the target respiratory viruses tested on respiratory samples. The detection rates of FluA, FluB, PIV, EV, ADV, RSV were 15.1%(343/2 271), 12.5%(284/2 271), 8.4%(191/2 271), 7.8%(177/2 271), 5.1%(116/2 271) and 6.7%(152/2 271), respectively.The detection rates of influenza virus were statistically different among the age groups ( χ2=39.33, P<0.05), which showed an increasing trend with the increasing ages. The detection rate of RSV was 9.7%(35/361) in infant group from zero to 12 months old, which was higher than other age groups. Usually, FluA had two epidemic peaks during the winter and summer seasons, the epidemics of FluB and RSV peaked during the winter season, and EV and PIV were more prevalent in the summer season. Conclusions:Influenza virus remains the most common viral pathogen responsible for childhood influenza-like illness in Shanghai.Influenza virus has high incidence in winter.Widely influenza vaccination is highly recommended for the effective prevention the influenza outbreaks.Continuous monitoring the epidemic trend of viral respiratory infections is imperative for the prevention and control of diseases.

OBJECTIVETo monitor the epidemiology of norovirus infection in diarrheal children in Shanghai between 2009 and 2011 and characterize the genotypes of norovirus strains.

METHODThe stool samples were collected from children visiting outpatient clinic for acute non-dysenteric diarrhea between 2009 and 2011.One step real-time RT-PCR was used for screening norovirus genogroups GI and GII. The genotypes of norovirus genogroup GII were classified based on the nucleotide sequences of both partial capsid and polymerase fragments.

RESULTA total of 2 288 outpatient children with acute diarrhea were included in this study, out of whom, 531 (23.1%) were positive for norovirus in the fecal specimens based on real-time RT-PCR test.Norovirus was prevalent throughout the year and an increased activity of norovirus infection was usually observed between July and October. Children <4 years of age accounted for 95.2% of norovirus-infected cases, and the detection rate of norovirus was significantly higher in diarrheal children <4 years than in those ≥ 4 years (24.4% vs. 10.7%,χ(2) = 10.66, P < 0.05).Of 531 norovirus-positive specimens, 4 (1.7%) were positive for genogroup GI and 527 (98.3%) positive for genogroup GII. Seven distinct capsid genotypes were identified in 234 norovirus strains, including 153 (64.4%) GII.4 (9 belonging to 2010 variants and 145 belonging to 2006b variants), 66 (27.6%) GII.3, 7 (2.9%) GII.2, 6 (2.5%) GII.6, 4 (1.7%) GII.12, 1 (0.4%) GII.7 and GII.14 in each. Seven polymerase genotypes were identified in 244 norovirus strains, including 189 (77.5%) GII.4 (14 belonging to 2010 variants and 175 belonging to 2006b variants), 47 (19.3%) GII.12, 2 (0.8%) GII.16, GII.b and GII.g in each, 1 (0.4%) GII.2 and GII.6 in each. A new GII.4-2010 (New Orleans) variant was first detected in June 2010 and sporadically circulated afterwards.Of 198 norovirus strains in which both polymerase and capsid genotypes were determined, 56 showed discordant results, indicating potential norovirus recombinants. The common discordant combinations of the polymerase and capsid genotypes were GII.12/GII.3 (69.6%) and GII.4/GII.3 (8.9%).

CONCLUSIONNorovirus is a common causative agent responsible for diarrhea in Shanghai children over the three years and norovirus-associated diarrhea was epidemic year round with high activity in late summer and autumn in Shanghai.Infants and young children are susceptible to norovirus infection. The circulating norovirus showed genetic diversity. The GII.4-2006b variant continued to predominate in Shanghai during the period of 2009-2011 despite the emergence of the novel GII.4-2010 (New Orleans) variant.

Adolescent ; Caliciviridae Infections ; epidemiology ; virology ; Capsid Proteins ; genetics ; Child ; Child, Preschool ; China ; epidemiology ; Diarrhea ; epidemiology ; virology ; Feces ; virology ; Female ; Gastroenteritis ; epidemiology ; virology ; Genetic Variation ; Genotype ; Humans ; Infant ; Male ; Molecular Epidemiology ; Norovirus ; classification ; genetics ; isolation & purification ; Prevalence ; RNA, Viral ; genetics ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Sequence Analysis, DNA