Etiological and epidemiological characteristics of Vibrio cholerae in Beijing, 2015-2021 / 中华流行病学杂志

Objective: To analyze the etiological and epidemiological characteristics of Vibrio cholerae in Beijing during 2015-2021 and provide evidence for the prevention and control of cholera. Methods: The V. cholerae strains isolated in Beijing during 2015-2021 were analyzed by serotyping and virulence genes detection. Pulsed field gel electrophoresis (PFGE) was performed for the molecular typing of the strains. Based on the collected epidemiological and clinical data of cholera cases,the epidemiological characteristics of cholera were analyzed by descriptive epidemiology method. Results: A total of 76 Vibrio cholerae O1 strains were isolated in Beijing during 2015-2021, including 61 strains from human, 10 strains from environment and 5 strains from seafood. The 76 strains consisted of 68 Ogawa strains and 8 Inaba strains. Six Ogawa strains isolated from sporadic cases carried ctxAB. After NotⅠ digestion, 76 strains were divided into 33 PFGE patterns. From 2015 to 2021, a total of 38 cholera epidemics were reported in Beijing, most of them were sporadic ones, accounting for 92.11% (35/38). A total of 45 cases were reported, and the cases occurred during June-September accounted for 97.78% (44/45). Cholera cases occurred in 9 districts of Beijing, and the cases reported in Chaoyang district accounted for 42.22% (19/45) and in Changping district accounted for 31.11% (14/45). The age of the cholera cases ranged from 19 to 63 years. Except for one case with unknown clinical symptoms, 44 cases had diarrhea symptoms with 84.09% (37/44) of the cases reporting diarrhea (3-9 times/day), followed by yellow watery stool (95.45%, 42/44), abdominal pain (68.18%, 30/44), nausea and vomiting (40.91%, 18/44) and fever (36.36%, 16/44). Conclusion: Vibrio cholerae strains isolated in Beijing during 2015-2021 were mainly O1 serotype Ogawa,most of which were non-toxigenic. The PFGE of the strains varied. Cholera epidemics occurred in 9 districts of Beijing, but most were sporadic ones with incidence peak during June-September.

Epidemiological characteristics of imported COVID-19 cases in Beijing / 中华流行病学杂志

Objective: To analyze the epidemiological characteristics of imported COVID-19 cases and the effect of vaccination on virus load and disease severity of the cases in Beijing. Methods: The data of the imported COVID-19 cases in Beijing were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and Epidemiology investigation. The data were processed and analyzed by Excel 2010 and SPSS 22.0. Results: From June 1 to September 30, 2021, a total of 171 imported COVID-19 cases were reported in Beijing, of which 66.67% (114/171) were asymptomatic. The cases were mainly from the Philippines, the United Arab Emirates, the United Kingdom and the Russian Federation, accounting for 67.84% (116/171). The male to female ratio of the cases was 2∶1 (114∶57). The median age M (Q1, Q3) of the cases was 28 (23, 36) years. The cases of Chinese accounted for 80.12% (137/171). The sequencing of the whole genome of the virus in 47 imported COVID-19 cases showed that the proportion of Delta variant was 76.60% (36/47). The COVID-19 vaccination coverage rate in the cases was 60.82% (104/171), but the full vaccination coverage rate was 53.80% (92/171). In the imported COVID-19 cases, 13.53% (23/170) were screened to be SARS-CoV-2 nucleic acid positive on the day when they arrived in Beijing, and all the cases were positive for 2019-nCoV nucleic acid within 28 days. The severity of the disease was higher in the unvaccinated group than in the partially vaccinated group and fully vaccinated group (P<0.001). In the unvaccinated group, there were 1 severe case and 1 critical case. The median Ct values M (Q1, Q3) of N gene and ORFlab gene in unvaccinated group were 32.51 (23.23, 36.06) and 32.78 (24.00, 36.38), respectively. There was no significant difference in the median of double-gene Ct value between the partially vaccinated group and the fully vaccinated group. Conclusions: During the study period, most of the imported COVID-19 cases in Beijing were asymptomatic. No matter vaccinated or not, the viral loads in the COVID-19 cases were similar, but the vaccination could reduce the severity of the disease.

Etiological detection of severe hand-food-mouth disease and related genetic characteristics of enterovirus type 71 infection in Beijing,2010 / 中华流行病学杂志

Objective To study the etiological detection on samples from severe hand-footmouth disease (HFMD) cases and the genetic characteristics of enterovirus type 71 (EV71) isolates lrom severe patients in Beijing,2010.Methods Real-time RT-PCR was used to detect EV71 and Coxsackievirus A16 (CoxA16) and RD cells were used to separate virus strains from samples.Homogeneity of EV71 isolated strains were also analyzed. Results Four hundred and fourty-two severe cases were detected and 253 were positive,taking up 57.24％ of the total (253/442).The overall positive detection rate on EV71 was 54.55％ (138/253),with CoxA16 as 5.93％(15/253),and with other enterovirus group was 39.53％(100/253).The nucleotide homogencity of VP1 within these 12 strains was 97.2％ 100.0％,and with Beijing strains in 2007-2010,Shandong strains in 2007 and Anhui Fuyang strains in 2008 and the Guangdong strains in 2008 as 94.0％-99.9％.Conclusion Severe HFMD cases were most oftenly caused by EV71 but less caused by CoxA16 or other cnterovirus.The HFMD in 2010 in Beijing was mainly caused by EV71 subgenotype C4a with 4 transmission chains.Twclve isolated EV71 strains had high homogeneity with strains isolated from severe cases in Anhui Fuyang in 2007.

Etiological surveillance and analysis of infectious diarrhea in Beijing in year 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>To explore the pathogenic form, epidemic features and serotype distribution of the pathogenic bacteria causing infectious diarrhea in Beijing.</p><p><b>METHODS</b>A total of 2118 samples of rectal swabs and stool specimens of diarrheal patients were collected from 6 surveillant intestinal tract clinics during the period between April and October, 2010. Enteric multiple pathogens including Vibrio cholerae, Vibrio parahaemolyticus, Salmonella, Shigella and diarrheagenic Escherichia coli were detected by the isolation culture, biochemical identification and serotyping methods. The population distribution, temporal distribution and serotype distribution of the above pathogenic bacteria were analyzed by descriptive statistical methods.</p><p><b>RESULTS</b>478 strains isolated from the total 2118 specimens were positive for pathogen detection, accounting to 22.6%. Among the 478 strains of pathogenic bacteria, Shigella accounting for 40.8% (195/478) was the most frequent pathogen, followed by Vibrio parahaemolyticus accouting for 23.8% (114/478), Salmonella accounting for 19.0% (91/478) and diarrheagenic Escherichia coli accounting for 4.8% (23/478). Enteric pathogenic bacteria spread mainly among adults aging between 20 and 39; and the distribution was different among different age groups, while the highest detected rate was in 30 - 39 age group, accounting for 27.2% (92/338). The detected rate of pathogenic bacteria showed evident seasonal variations, with a peak from July to October, whose detected rates were 23.5% (114/486), 32.8% (176/536), 36.1% (90/249) and 25.9% (29/112) respectively. The detected rates in other months were all under 16.0%. Shigella Sonnei was the dominant serotype, accounting for 83.1% (162/195). O3:K6 was the dominant serotype among Vibrio parahaemolyticus, accounting for 63.2% (72/114). Salmonella Enteritidis and Salmonella Typhimurium were dominant serotypes among Salmonella, accounting for 13.2% (12/91) and 12.1% (11/91) separately. Enterpathogenic Escherichia coli and enterotoxigenic Escherichia coli were the dominant serotypes among Diarrheagenic Escherichia coli, accounting for 69.6% (16/23) and 30.4% (7/23) respectively.</p><p><b>CONCLUSION</b>The three main pathogenic bacteria causing infectious diarrhea in Beijing are Shigella, Vibrio parahaemolyticus, Salmonella; and there are obvious changes in the serotype distribution of Shigella and Samonella compared to previous years.</p>

Analysis on the etiological and molecular epidemiological characteristics of Vibrio parahaemolyticus in Beijing / 中华流行病学杂志

Objective To understand the etiological and molecular-epiderniological characteristics of Vibrio parahaemolyticus in Beijing.Methods Stool specimens from sporadic diarrheal patients were collected during April to December,2010.Culture and serotyping were used to detect the Vibrio parahaemolyticus from the 2118 specimens.All the positive strains were tested for drug sensitivity by Kirby-Bauer method.Real-time PCR was used to detect the existence of three virulence genes tlh,tdh and trh.Molecular typing on Vibrio parahaerrolyticus isolates was completed by pulsed field gel electrophoresis(PFGE).Results 114 out of the 2118 specimens were Vibrio parahaemolyticus positive,with the positive rate as 5.38％.114 isolates belonged to 23 serotypes,with the dominant (63.16％)serotype as O3:K6.Strains isolated from clinical manifestation patients were resistant to antibiotics-ampicillin and gentamicin,while with high sensitivity to amoxicillin,ceftriaxone,chloromycetin,imipenem,nalidixic acid and tetracycline.Virulence gene detection was positive to tlh for all the strains,but most to tdh,while only one strain to trh.The positive rate oftdh among O3:K6 strains(98.61％)was higher than that in those non-O3:K6 strains(85.71％)(P=0.0098).114 isolates were discriminated into 54 different PFGE patterns,while 72 O3:K6 strains into 34 patterns without the clustering characteristic.Conclusion Vibrio parahaemolyticus strains isolated from diarrheal patients in Beijing were dominated by O3:K6 strains,with stronger virulence.The positive rates of genes tlh and tdh were high.Vibrio parahaemolyticus strains showed high sensitivity to most antibiotics.The prevalent Vibrio parahaemolyticus strains in Beijing had various sources of clones.

Comparisons of epidemiological and clinical characteristics in children with hand-foot-mouth disease caused by Enterovirus 71 and Coxackievirus A16 / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To compare the differences of epidemiological and clinical characteristics in children with hand-foot-mouth disease (HFMD) caused by Coxsackievirus A16 (CA16) and Enterovirus 71 (EV71).</p><p><b>METHODS</b>The samples of vesicle fluid and throat swabs of 108 children with HFMD were collected and detected for enterovirus by RT-PCR. The clinical data of children with EV71 and CA16 infection were retrospectively reviewed and compared.</p><p><b>RESULTS</b>The total positive rate of enterovirus was 97.2% (105/108). Of the 105 cases, 56 cases were positive for EV71 (51.9%), 39 cases were positive for CA16 (36.1%), 2 cases were positive for other enterovirus (1.9%), and 8 cases were co-infected by EV71 and CA16 (7.4%). There were no significant differences in age and sex between EV71 and CV16 infected cases. The univariate analysis showed that the incidences of herpes of mouth, erythra of knees, and nose running in children infected by CA16 were higher than in those infected by EV71. The multivariate logistic regression analysis showed that the HFMD children who had erythra of knees had higher probability of CA16 infection.</p><p><b>CONCLUSIONS</b>EV71 should be considered as the pathogen in children with HFMD who have no herpes of mouth, erythra of knees, and nose running.</p>

A survey on serological epidemiology of influenza A (H1N1) 2009 in Beijing / 中华流行病学杂志

Objective To investigate the immunological level against influenza A (H1N1)2009 in Beijing and provide evidence to evaluate the developing trend of the disease. Methods Between Nov. 27,2009 and Dec. 23,2009, subjects were randomly selected from patients in hospitals (infectious and respiratory diseases related departments were excluded) ,volunteers in blood donation center and healthy subjects attending the physical examination center. Questionnaire survey was conducted and serum samples were collected to detect the hemagglutination-inhibition (HI) antibody against influenza A(H1N1) 2009 virus. Results 856 subjects participated in this survey, and 127 showed positive HI antibody to this pandemic virus. The proportions of sero-positivity among 0-5 ,was no significant difference in the sero-positivity between males and females (P=0.693). The analysis, factors as age, acute respiratory symptoms and the rate of pandemic (H1N1) 2009 vaccination were significantly associated with sero-positivity of HI antibody to the influenza A (H1N1) 2009 virus. Conclusion Above 15% of the population in Beijing showed protective antibody against influenza A (H1N1) 2009 virus, indicating the development of immunological barrier to this disease had been formed, to some extent.