A total of 3499 cases of influenza A (H1N1) were included in this study for analysis.Epidemiological and clinical data of these cases were input into EpiData software and analyzed by SPSS software. Throat swabs were collected from the cases and detected for nucleic acid of influenza A ( H1N1 )virus using real-time polymerase chain reaction (RT-PCR) with fluorescence quantitative method, and time of viral excretion and clinical features of the cases were analyzed. Results showed that 0. 37% of the cases were in-apparent and asymptomatic and the most common symptom of the cases was fever (86. 77% ).Throat swabs converted to negative on the sixth day of onset in average, and no factors related to the time of conversion was found with logistic regression analysis.

Objective To understand the distribution of virulence gene and the epidemiological characteristics of diarrheagenic Escherichia(E.) coli (DEC) from diarrheal patients in Beijing. Methods Stool specimens from diarrheal patients were cultured which were collected from the hospitals under sentinel surveillance program,during 2012-2013. DNA was examined by real-time PCR. Results 253 out of 6 370 specimens were positive for DEC detection with the rate as 4.0%. A total number of 262 DEC strains were isolated. Two different pathotypes of DEC strains with mixed infection,were isolated from 9 specimens. Different pathotypes would show the following profiles:42.8% for enteropathogenic E. coli (EPEC) including 42.0% atypical and 0.8% typical;38.9% for enterotoxigenic E. coli(ETEC)including 24.8%st positive,9.9%lt positive and 4.2%st and lt both positive;15.3% for enteroaggregative E. coli(EAEC);2.7% for enteroinvasive E. coli(EIEC);one strain STEC with serotype O26 ∶ K60. ETEC had obvious characteristics on age. All kinds of DEC were isolated throughout the year with seasonal fluctuation. Conclusion DEC isolates from diarrheal patients in Beijing were dominated by EPEC and ETEC,with atypical ones accounted for the majority of EPEC. One specimen was found under mixed infection. Pathotypes DEC were found to have different age and seasonal distributions.

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.

OBJECTIVETo understand the distribution of virulence gene and the epidemiological characteristics of diarrheagenic Escherichia(E.) coli (DEC) from diarrheal patients in Beijing.

METHODSStool specimens from diarrheal patients were cultured which were collected from the hospitals under sentinel surveillance program, during 2012-2013. DNA was examined by real-time PCR.

RESULTS253 out of 6 370 specimens were positive for DEC detection with the rate as 4.0%. A total number of 262 DEC strains were isolated. Two different pathotypes of DEC strains with mixed infection, were isolated from 9 specimens. Different pathotypes would show the following profiles: 42.8% for enteropathogenic E. coli (EPEC) including 42.0% atypical and 0.8% typical; 38.9% for enterotoxigenic E. coli (ETEC) including 24.8% st positive, 9.9% lt positive and 4.2% st and lt both positive;15.3% for enteroaggregative E. coli(EAEC);2.7% for enteroinvasive E. coli (EIEC); one strain STEC with serotype O26:K60. ETEC had obvious characteristics on age. All kinds of DEC were isolated throughout the year with seasonal fluctuation.

CONCLUSIONDEC isolates from diarrheal patients in Beijing were dominated by EPEC and ETEC, with atypical ones accounted for the majority of EPEC. One specimen was found under mixed infection. Pathotypes DEC were found to have different age and seasonal distributions.

China ; epidemiology ; Diarrhea ; microbiology ; Enteropathogenic Escherichia coli ; genetics ; isolation & purification ; Enterotoxigenic Escherichia coli ; genetics ; isolation & purification ; Epidemics ; Escherichia coli ; genetics ; isolation & purification ; Escherichia coli Infections ; epidemiology ; microbiology ; Genotype ; Humans ; Virulence