Objective To characterize the antimicrobial resistance to ciprofloxacin in Salmonella isolates from diarrhea cases in Guangdong Province from 2009 to 2013. Methods All Salmonella strains isolated by ESS project between 2009 and 2013 were serotyped. Antimicrobial resistances to ciprofloxacin and nalidixic acid were determined by disk diffusion method and main serotypes resistant to ciprofloxacin were molecular typed by PFGE. Results In all 2 939 Salmonella strains isolated from diarrhea cases, 253 (8.61%) were resistant to ciprofloxacin and 665 (22.63%) were intermediately resistant to ciprofloxacin. Patients aged less than 7 years accounted for 73.52%（186/253）of total patients carrying the resistant strains and 76.84%（511/665）of the all patients with moderately sensitive strains, respectively. Increasing trends of resistance to ciprofloxacin were observed from 2009 to 2013（P<0.01）. Drug resistant strains isolated from cities of Dongguan, Foshan, Guangzhou, Zhongshan, and Zhuhai accounted for 86.96% (220/253) of the total strains of the province. Salmonella typhimurium, Salmonella 4,5,12:i:,Salmonella enterica,and Salmonella stanley,and Salmonella Derby were major serotypes among the resistant strains. The PFGE patterns of resistance strains from the predominant serotypes had different clonal lineage and showed significant genetic diversity. Conclusion The resistance to ciprofloxacin in isolates of Salmonella typhi was low in Guangdong Province, but gradually increasing from 2009 to 2012. The PFGE typing analysis appeared high genetic diversity in resistant strains.

Objective To learn status and influential factors of internet addiction disorder of Yi and Han junior middle school students in Panzhihua City. Methods Students were selected from Dahe and Minzu middle schools in Panzhihua City by stratified cluster random sampling to investigate internet addiction disorder through self-designed questionnaire. Chi-square test, rank sum test and logistic regression were used to explore influential factors of internet addiction disorder of the students. Results A total of 1 000 questionnaires were distributed and 963 were recovered (recovery rate, 96.3%). Excluding 63 neither Han nor Yi students, the valid questionnaires were 900 (416 males and 484 females, averagely aged 13.4 years), of whom 628 were Han students and 272 were Yi students. The rates of internet use and internet addiction of the students were 83.7% and 8.3%, respectively. The internet addiction rates were 8.6% for Han students and 7.7% for Yi students. There was no significant difference in the internet addiction rates between Yi and Han students. In the multiple logistic regression model, high level education of mother (OR=1.428), unhappy in school life (OR=1.424), bad relationship with families (OR=1.810), psychological inversion (OR=2.636), being bantered maliciously (OR=1.920), and being made fun pornographically (OR=2.240) were risk factors, while female (OR=0.412) and good achievement (OR=0.692) were protective factors for internet addiction.Conclusion The internet is in common use among students of junior middle schools and many factors are associated with internet addiction disorder. Teachers of the schools and parents of students should pay attention to the influential factors of internet addiction disorder to prevent and control the internet addiction of the students.

Objective To investigate the epidemiological characteristics and analyze the risk factors of an infectious diarrhea outbreak in a factory in Shenzhen City, so as to provide scientific evidence for decision-making in the prevention and control of diarrhea outbreaks. Methods All cases were screened according to the case definition. The epidemiologic characteristics were described to facilitate proposing etiological hypothesis, followed by retrospective cohort study and case-control analyses to determine the risk factors. Anal swabs of patients and cooks, and samples of the outer environment were collected for pathogenic detection. The real time fluorescent quantitative RT-PCR was used for detection of virus nucleic acid and the PCR amplified products were sequenced to identify the virus genotyping. Results A total of 76 cases were found from 17 to 21 January 2013, with an attack rate of 18.12%（76/414）. The attack rates in general staff, middle-level staff, and senior staff were 26.28% (72/274), 2.96% (4/135）, and 0.00%（0/5）, respectively（P<0.01）. The retrospective cohort study analysis showed that the attack rate in middle-level staff who ate meals serving for the general staff was 11.43%（4/35）, while there was no case in middle-level staff who didn’t (0/75）（P<0.01）. Case-control study showed that on January 15th, the proportions of cases who ate the first round vegetables for lunch and dinner were 64.00%（32/50）and 70.83%（34/48）respectively in the case group, and those were 41.67%（35/84）and 50.00% (40/80) in the control group, and the ORs were 2.489（95%CI: 1.209-5.125）and 2.429（95%CI: 1.134-5.199）, respectively, indicating the exposure to the first round vegetables of the lunch and dinner was a risk factor for the outbreak. Sixty-four samples of rectal swabs of patients and cooks,vomit, feces,hand swabs, food, spices, kitchen utensils, and water were collected. Pathogenic bacteria were negative in 56 samples detected. Among the 51 samples for detection of norovirus nucleic acid, 13 rectal swabs of patients, 2 rectal swabs of cooks, 2 feces of patients and 1 patient vomit were positive for the norovirus nucleic acid and all were identified as the GII-4 norovirus Sydney 2012 strain. Conclusion This infectious diarrhea outbreak may be caused by vegetables contaminated with the new GII-4 norovirus Sydney 2012 strain. Health education should be strengthened among food-processing workers.

Objective To rapidly detect and identify an outbreak of hand, foot, and mouth disease (HFMD) caused by CV-A6 enterovirus in Heyuan City in May 2013 with molecular biological technology. Methods Specimens of stool and throat swabs of HFMD cases and close contacts were collected and detected for pan-EV, EV-A71, CV-A16, and CV-A6 by real-time PCR. VP1 genetic partial fragments of the positive samples were amplified with semi-nested PCR, and were adopted for sequencing and genetic analysis. Results In this outbreak, 96.15% of cases (25/26) and 28.95% of close contacts (11/38) were pan-EV positive; 96.15% of cases (25/26) and 18.42% of close contacts (7/38) were CV-A6 positive. All samples were negative for EV-A71 and CV-A16 nucleic acid. Partial fragments of VP1 were amplified from 10 samples of 7 cases and 3 close contacts by using semi-nested PCR. Sequence analysis showed that the nucleotide homology of all partial VP1 was 100.0% homologous with CV-A6. Conclusion The outbreak in a kindergarten in Heyuan City of Guangdong Province was caused by enterovirus CV-A6. Combining the real-time PCR and semi-nested PCR can be an effective way for rapid detection and identification of CV-A6 enterovirus.

Objective To investigate the water quality and sanitary conditions of oyster aquaculture water in Changsha Bay of Guangdong Province and explore the relationship between the fecal coliform bacteria (FCB) and primary physicochemical indexes in oyster aquaculture water. Methods Samples of seawater were collected monthly from five sites of the oyster aquaculture area in Changsha Bay during November 2013 to October 2014 and determined for the physicochemical parameters, including temperature, pH, salinity, turbidity, and dissolved oxygen according to GB 17378.4-2007 as well as the number of FCB according to GB 17378.7-2007. Results A total of 60 seawater samples were collected during the investigation. The FCB number in seawater taken from the oyster aquaculture area ranged from 10 MPN/L to 1.26×106 MPN/L with a geometric mean of 3.8×103MPN/L. Of the samples, 60.0% (36/60) exceeded the Sea Water Quality Standard (GB 3097-1997) for FCB in grade II seawater. During the study period, water temperature ranged from 13.1 to 32.5 ℃, pH ranged from 6.8 to 9.2, salinity ranged from 0.1 ‰ to 24.9 ‰, turbidity ranged from7.0 to 140.0 NTU, and dissolved oxygen ranged from 2.9 to 12.5 mg/L. Negative correlations were found between FCB and salinity as well as dissolved oxygen(r=-0.266、-0.505). A positive correlation was observed between FCB and turbidity(r=-0.425). Conclusion The exceeding standard rate of FCB in seawater was relatively high in Changsha oyster aquaculture area. The salinity, turbidity, and dissolved oxygen have some effects on the FCB number in seawater.

Objective To investigate the influenza epidemic trends and pathogenic characteristics in Kaifeng City from 2012 to 2013 so as to provide a basis for developing influenza prevention and control measures. Methods Data of influenza surveillance were obtained from the Chinese National Influenza Surveillance Information System. Descriptive epidemiology methods were used to analyze the data. Results A total of 1 591 cases of influenza-like illness (ILI) were reported from 2012 to 2013. The average percentage of outpatient visits for ILI was 0.47% (426/91 202) in 2012, 1.20% (1 165/97 285) in 2013, and 0.84% (1 591/188 487) averagely for the two years. The highest proportion of ILI was found in the 0-4 age group (597 cases, 37.52%). The positive isolation rate for influenza virus was 9.09%（30/330) in 2012. Of the 30 strains, 12 strains were type B and 18 were the seasonal A (H3). In 2013, the positive isolation rate for influenza virus was 11.87% (71/598). Among the 71 strains, 28 strains were type B, 12 were the seasonal A (H3), and 31 were the A (H1N1). Conclusion The predominant strains of the influenza virus were type B, seasonal A (H3), and A (H1N1) in Kaifeng City from 2012 to 2013.

Objective To analyze epidemic characteristics of influenza in Mianyang from 2010 to 2013 so as to provide basis for making prevention and control strategy. Methods Influenza-like illness (ILI) surveillance data, pathogen testing results and influenza virus outbreak information were collected in Mianyang from 2010 to 2013 for analysis. Results A total of 50 277 ILI cases were reported by three surveillance hospitals in 2010-2013, accounting for 2.47% of the total outpatients. The percentages of ILI were 2.71%, 1.83%, 2.72%, and 2.55% from 2010-2013, respectively. Most cases were children aged 0-4 years, accounting for 47.59% of the total cases. A total of 3 213 specimens of ILI cases were detected by real time RT-PCR and 314 specimens were positive nucleic acid of influenza virus, with a positive rate of 9.77%. Of influenza virus positive stains, 110 were A/H1N1, 16 were A (unclassified), 109 were A/H3, and 79 were B. Conclusion Influenza activity was relatively stable in Mianyang from 2010 to 2013, presenting many types and subtypes of influenza virus.

Objective To analyze the HIV/AIDS related knowledge, behavior, infection status of HIV, and acceptance of HIV/AIDS related services of men who have sex with men (MSM) in Foshan, so as to provide reference for integrated control and prevention. Methods HIV/AIDS sentinel surveillance data of MSM were collected from 2009 to 2013 and analyzed using descriptive epidemiological methods. Results A total of 1 522 MSM were monitored. The awareness rate of HIV/AIDS related knowledge was 85.1%（1 295/1 522）. In the past six months, 81.1%（1 235/1 522）of the MSM had anal sex and 45.0%（556/1 235）of them used condom each time. The total HIV antibody positive rate was 10.4% (159/1 522) and appeared a rising trend（P<0.01）. The HIV antibody positive rate increased from 2.9% in 2009 to 12.7% in 2013, increased by 337.9%. Single factor analysis showed that HIV antibody positive rates were related with the age, degree of education, frequency of condom use, history of drug abuse, history of sexually transmitted diseases, acceptance of condom use promotion education, and HIV/AIDS counseling and testing (P<0.05 or P<0.01). Conclusion The condom using rate among MSM in Foshan City is low and HIV prevalence showed a rising trend. The condom use should be vigorously promoted to reduce the HIV infection among MSM.

Objective To explore influencing factors of HIV/AIDS-related knowledge and behavior among male clients of STD clinics in Dongguan and analyze risk factors so as to provide the evidence for intervention. Methods HIV surveillance data from 2010 to 2012 among male clients of STD clinics in Dongguan were collected and analyzed. Content of the investigation contained demographic data, HIV/AIDS related knowledge, extramarital sex, drug use behavior, homosexual sex, and STDs. Venous blood samples were taken to detect antibodies of HIV and treponema (TP). Results A total of 1 200 male clients of STD clinics were surveyed. The HIV/AIDS related knowledge awareness rate was 48.42%（581/1 200). In the past three months, 31.75%（381/1 200）of the survey participants admitted extramarital sex. Men who had injecting drug use behavior and homosexual sex accounted for 1.00%（12/1 200） and 0.33%（4/1 200） of the all clients, respectively. Positive rates of antibodies of HIV and TP were 0.58%（7/1 200）and 8.25%（99/1 200）, respectively. The awareness rate of HIV/AIDS-related knowledge was significantly associated with age (OR=0.761), household register（OR=2.090）, ethnicity（OR=4.378）, and STD within last year（OR=2.010）. The sexual acts with non-spouse partners were correlated with the STD within last year (OR=7.208) and the aware of the HIV-related knowledge (OR=1.906). Conclusion The awareness rate of HIV/AIDS related knowledge was low among male clients of STD clinics in Dongguan and unsafe sex is still common.

Objective To investigate the effect of the national health city project on health literacy among residents in Meizhou City from 2008 to 2012 so as to provide scientific basis for health literacy intervention．Methods Using multi-stage stratified random cluster sampling method, urban and rural residents aged 15-74 years were selected from each 3 villages (neighborhood committees) of 1 town and 1 street office which were selected from 3 towns and 3 street offices as the survey points in Meijiang District with 90 villages (neighborhood committees). Participants were intervened by“Sixty-six for health literacy of citizens”. The health literacy assessment was analyzed before and after the interventions．Results Before and after the interventions, 1 270 and 1 280 residents were investigated respectively and there were no significant differences in the distribution of urban and rural areas, gender, age, and educational levels of the participants (P>0.05 for all). The rates with total health literacy, basic knowledge and concept，healthy life style, and basic skills increased from 9.5%, 11.8%，10.5%，and 14.6% before the intervention to 19.4%, 17.3%，14.8%，and 33.6% after the intervention among residents in Meizhou City（P<0.01 for all）．After the intervention，the correct answer rates of five health literacy problems were 19.4% for scientific health view，32.9% for infectious disease prevention, 22.3% for chronic disease prevention, 48.8% for security and emergency，and 15.2% for primary medical care，significantly increased compared with those (9.5%，24.5%，12.8%，22.2%，and 9.4%) before intervention（P<0.01 for all）．Conclusion Health literacy knowledge and skills were significantly promoted among residents in Meizhou City through the national health city project．