Objective To explore the effects of extreme low temperatures on respiratory hospital admissions in Guangdong Province and effect modification of different regions and age groups. Methods Based on the time-series data of respiratory hospital admissions and meteorological variables in Panyu District (developed region) and Xingning County (underdeveloped region) of Guangdong Province during 2006-2011, the relationship between extreme low temperatures (below the 5th percentile of daily average temperature distribution) and respiratory hospital admissions was analyzed with distributed lag non-linear model, and stratified analysis by sex and age group was also conducted.Results The mean of daily average temperature was 22.7 ℃ in Panyu, and the total respiratory hospital admissions were 24 216 in Panyu Central Hospital with a daily average of 11.1 during 2006-2011. The mean of daily average temperature was 21.9 ℃ in Xingning, and the total respiratory hospital admissions were 19 934 in Xingning People’s Hospital with a daily average of 9.1 in the same period. The effect of daily average temperature on respiratory hospital admissions was non-linear, and low temperatures had significant lagged effects for the 2 regions, with the RRs reaching the maximum of 1.04 (95% CI:1.02-1.06) at 6.4 ℃ on lagged 13 days for Xingning and 1.03 (95% CI:1.02-1.04) at 9.9 ℃ on lagged 10 days for Panyu, respectively. For the cumulative lagged effects during the 25 lagged days, the RR s were 1.48 (95% CI:1.13-1.94), 1.45 (95% CI:1.12-1.82) and 1.29 (95% CI:1.10-1.51) respectively at the 5th percentile (10.9 ℃), 10th percentile (14.3 ℃) and 25th percentile (18.2 ℃) of daily average temperature distribution for Panyu, and were 1.61 (95% CI:1.17-2.21), 1.45（95% CI:1.08-1.96）and 1.11 (95% CI:0.94-1.35) for Xingning. The change of effects (RRs) associated with extreme low temperatures along the lagged days showed a similar trend of converse “U” shape for various sub-groups, with the effects emerging on 2-4 days after exposure, growing up later, and decreasing after reaching the peak. The effect of extreme low temperatures had the greatest impact on ≥65 age group in Xingning with an RR of 1.86（95% CI:1.04-3.31）. Conclusion Extreme low temperatures can significantly impact on respiratory hospital admissions for the elderly, especially in underdeveloped regions.

Objective To study the awareness of HIV/AIDS and syphilis related knowledge among early pregnant women and to understand its influencing factors on accepting screening tests. Methods Early pregnant women, who were residents in Yuexiu District of Guangzhou, were surveyed with questionnaire from February 2012 to January 2013. The contents of questionnaire included demographic characteristics，awareness of HIV/AIDS and syphilis transmission related knowledge，prevention, attitude and behavior on screening test for pregnant women．Chi-square test and multivariate logistic regression were used for data analysis. Results A total of 6 012 pregnant women were surveyed. Their average age was（29.07±3.57）years, 60.83% of them were bachelor degree, and 38.31% of their jobs were cadre or staff. Of them, 81.74% understood general knowledge of HIV/AIDS and syphilis, 76.72% understood the transmission route of AIDS and syphilis, 78.69% knew the mother-to-child transmission（MTCT）, and awareness rate of preventive measures was 80.82%. Although 81.90% of the respondents expressed their willingness to participate in the free screening tests of HIV and syphilis antibodies, only 55.19% of them had their blood tested for free testing on anti-HIV and treponema pallidum particle agglutination (TPPA). Multivariate regression showed that pregnant women who did not have premarital medical check-up had more possibility to accept the related testing compared with those who did (OR =1.207) , pregnant women who had never detected HIV antibodies had higher possibility to accept HIV antibodies detected than those who previously had HIV antibodies detected (OR =1.805), and the possibility of accepting free testing in those who expressed unwilling to accept the free test was 0.548 times compared with those who expressed willing to do it. Conclusion The awareness rate of HIV and syphilis MTCT knowledge of pregnant women is relatively low. Health education should be strengthened in early pregnant women to improve their awareness level of MTCT and preventive measures. Multi-level testing service system should be established to promote test rate during the first and second trimesters of pregnancy to prevent MTCT.

Objective To explore risk factors of primary hepatocellular carcinoma (PHC) in Guangzhou so as to provide scientific basis for effective prevention of PHC. Methods A 1∶1 matching case-control study was conducted. In the study, 100 pairs of cases (diagnosed in 2013 and lived in Guangzhou for ≥10 years) and controls (matched by community, sex, and age, but no blood kinship) were selected. Study participants were asked to complete a questionnaire about their life style, habits, and diseases. Univariate and multivariate logistic regression models were used to analyze the data. Results There were 86 male pairs and 14 female pairs among the 100 cases-control pairs. The average age of the hepatocellular carcinoma cases was（50.58±11.66）years and that of the controls was（51.37±12.54） years. Age structures in the two groups were consistent (P ＞0.05). Multivariate logistic regression showed that alcohol (OR:33.142, 95% CI:5.729-245.367), viral hepatitis (OR:70.385, 95% CI:13.452-408.274), and family history of cancer (OR:33.218, 95% CI:6.745-212.403) were risk factors for PHC (all P <0.01). Drinking tea (OR:0.016, 95% CI:0.002-0.071), eating beans (OR:0.038, 95% CI:0.005-0.621), and dark green vegetables (OR:0.007, 95% CI:0.001-0.053) were protective factors for PHC (P <0.05 or <0.01). Conclusion PHC is a comprehensive result of multiple factors. Controlling risk factors such as alcohol consumption and viral hepatitis, and intake of tea, beans, and dark green vegetables can reduce the occurrence of PHC.

Objective To survey and confirm the invasion, breeding, and distribution of Biomphalaria straminea in mainland of China so as to provide scientific basis for prevention and control of the spread of schistosomiasis mansoni. Methods According to report clues, Biomphalaria straminea habitat characteristics, water system, and geographical position, breeding and distribution of Biomphalaria straminea , vegetation, and water quality were surveyed and analyze by the method of field investigation from 1981 to 1982 and 2012 to 2013. Results Snails collected in a fish pond in Luohu, Shenzhen City were confirmed as the Biomphalaria straminea in 1981, as the first report in mainland of China. From 1981 to 1982, about 4 030 m2 of Biomphalaria straminea breeding places were found in six fish ponds and one sewage pond, 300 m long in three ditches interlinked with Shenzhen river, 1 000 m away from the junction of Shenzhen Luohu and the New Territories of Hong Kong to Shenzhen river, and 1 000 m away from the junction to Shenzhen People's Park, but not found in the other 9 communes (towns, streets) and 11 counties of Shenzhen. Analysis of the water quality showed neutral and alkaline water was suitable for the breeding of Biomphalaria straminea . Chloride content was 9.0-94.0 mg/L, total hardness was 44.8-142.8 mg/L, and ammonia nitrogen was 0.02-1.50 mg/L in the water with more alive Biomphalarias . Most of them lived in the pond, ditch, and river with rich humus, along the waterside, attached to the floating object, and were mainly found in lower river section and at the outlet with slow water flow. In 2012 and 2013, alive biomphalaria straminea were found at 9 rivers, including rivers of Yantian, Kuicong, and Dasha in Shenzhen, Shima River in Dongguan, and Danshui River in Huiyang, etc. Conclusion Biomphalaria straminea breeding was first confirmed in Shenzhen, China in 1981 with limited area; as spreading along the rivers of surrounding areas, it has now spread to part rivers in cities of Dongguan and Huizhou adjacent to Shenzhen.

Objective To explore the intention of quitting smoking and its influencing factors among workers of enterprises so as to provide scientific evidence for developing effective tobacco control measures. Methods Smoking workers were selected by convenient sampling method from ten enterprises in Sanxiang Town of Zhongshan City. They were asked to complete a structured questionnaire on socio-demographic characteristics, smoking-related knowledge and attitudes, smoking behaviors, past quitting experiences and quitting intentions. Univariate and multiple logistic regressions were employed to test associations between intention to quit smoking and independent variables of interest. Results A total of 1 573 smokers were surveyed (1 353 males and 174 females). Of them, 664 (42.2%) had tried to quit smoking and 676 (43.0%) intended to quit smoking. The average scores of smoking-related knowledge and attitudes were (11.5±3.9) and (77.0±9.9) points, respectively, and the average score of nicotine dependence was (3.5±2.5) points. Multiple logistic regression indicated that those with the experience of ever quitting (OR =2.56), confidence of quitting smoking (OR =14.47), higher scores of smoking-related knowledge (OR =1.05) and attitudes (OR =1.05) inclined to have greater intentions to giving up smoking; compared with people with monthly income of 2 000 Yuan or less, those with monthly income more than 4 000 Yuan were less likely to stop smoking（OR =0.48）. Conclusion The score of smoking-related knowledge was low among the workers in enterprises. For tobacco control in enterprises， health education, including correct Methods of quitting smoking, should be strengthened for tobacco control in enterprises.

Objective To investigate hygienic status of dental clinic water in departments of stomatology in Guangzhou so as to provide scientific basis for control of nosocomial infection. Methods Samples of dental source water, dental mouth wash, washing water, and hand-piece water in self-purifying-typed and storage-typed dental unit waterlines of medical institutions at different levels were collected by multi-stage stratified random sampling method and general survey. Bacteria of water samples were isolated, identified and evaluated based on health standard for disinfection in hospitals (GB 15982-2012) and health standards for drinking water quality (GB 5749-2006). Total bacteria counts were expressed by the median (P25 and P75). Results A total of 204 water samples were collected from self-purifying-typed dental unit waterlines (68 samples for each of dental mouth wash, washing water, and hand-piece water) and the total bacteria counts were 40.00 (10.50-373.50) CFU/mL in mouth wash, 1 141.50 (185.00-2 995.00) CFU/mL in washing water, and 3 302.00 (1 397.75-5 601.25) CFU/mL in hand-piece water. There were statistically significant differences in total bacteria counts among different treatment water samples of self-purifying-typed dental unit waterlines (P <0.01). Meanwhile, 66 water samples were collected from storage-typed dental unit waterlines (22 samples for each of dental source water, washing water, and hand-piece water) and the total bacteria counts were 225.00 (17.50-1 619.75) CFU/mL in dental source water，2 160.00 (440.00-3 652.00) CFU/mL in washing water, and 2 665.50(252.00-5 636.00) CFU/mL in hand-piece water, respectively. Significant differences were found in total bacteria counts among different treatment water samples in storage-typed dental unit waterlines (P <0.05). Dominant bacteria were Sphingomonas paucimobilis, Cupriavidus pauculus, Burkholderia cepacia, and Ralstonia pickettii . Conclusion The dental unit waterlines were contaminated seriously in departments of stomatology in medical institutions of Guangzhou. Regular monitoring and disinfection measures should be strengthened to prevent and control nosocomial infection.

Objective To investigate epidemiological characteristics of other infectious diarrhea other than cholera，dysentery，typhoid and paratyphoid in Qingyuan City and discuss the control and prevention strategy. Methods Epidemiological characteristics of other infectious diarrhea reported by China Information System for Disease Control and Prevention in Qingyuan from 2008 to 2012 were analyzed by descriptive research method. Results From 2008 to 2012, a total of 21 730 cases of other infectious diarrhea were reported and the annual incidence rates ranged from 88.69/100 000 to 141.17/100 000. The annual average incidence rate was 120.90/100 000. The cases distributed in 8 counties. Top 4 counties with the most cases were Qingcheng (8 877 cases), Qingxin (3 960), Lianzhou (3 346), and Yingde (1 642), which together accounted for 82.03% of the total cases. Cases were reported every months, but 42.65% of them were reported from October to December. Among the cases, 13 320 were male and 8 410 were female, and the incidence rate of male was higher than that of female (P <0.01), and 13 792 cases were children below 3 years old, accounted for 63.47% of the total cases. Main occupation of the cases was scattered children (14 531 cases), accounted for 66.87% of the total cases. Conclusion Other infectious diarrhea was main epidemic in scattered children below 3 years old and winter was the epidemic peak.

Objective To understand epidemic intensity and trend of hand, foot, and mouth disease (HFMD) in Liping County so as to provide the basis for developing control strategies. Methods Descriptive epidemiological method was used to analyze outbreaks of HFMD in Liping County from 2009 to 2012. Results A total of 504 cases of HFMD were reported and the average annual incidence rate was 23.91/100 000. Of all reported cases, 7 were severe cases (rate of severe cases, 1.39%) and 3 deaths (mortality rate, 0.14/100 000); 368 were male and 136 were female, with a sex ratio of 2.7∶1; 426 (84.52%) cases aged at 1-3 years; 460 (91.27%) were scattered children. Clear seasonality of HFMD occurrence was observed. Epidemic peaks were in April-June (180 cases, 35.71%) and November-December (137, 27.18%). Conclusion Incidence of HFMD was relatively low in Liping County during 2009-2012 and mainly occurred in scattered children aged 1-3 years. HFMD prevention and control should be strengthened for the scattered children.

Objective To investigate the hand, foot, and mouth disease (HFMD) epidemic characteristics in Buji Street, Longgang District so as to provide the basis for HFMD prevention and control.Methods Data of HFMD of Buji street from 2010 to 2012 were collected through the National Disease Surveillance Information Reporting System and epidemiological analysis was conducted. Results A total of 9 112 HFMD cases were reported from 2010 to 2012, including 6 severe cases and 1 death. The average annual incidence rate was 314.1/100 000. Of all cases, 5 711 were male and 3 401 were female, with a sex ratio of 1.68∶1; 8 627 cases (94.68%) were children aged 5 years or below; 8 737 cases (95.88%) were scattered and kindergarten children. Epidemic peak was from May to September, when 6 011 cases (65.97%) were reported. Of 53 samples collected, 17 were positive for enteric virus (positive rate, 32.08%), including 10 strains of EV 71 and 6 of CV A16. Conclusion Obvious seasonality and differences in age and gender were observed in HMFD cases of Buji Street, Longgang District, Shenzhen City. HFMD surveillance should be strengthened and more attention should be paid to the prevention and control for scattered and kindergarten children.

Objective To establish a method of ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for determination of residues of eight penicillins in milk products. Methods Samples of milk products were extracted by water in super-sonic instrument. Proteins in the extract were precipitated by acetonitrile and degreased by n-hexane with liquid-liquid extraction, then the purified solution was concentrated by nitrogen, dissolved with acetonitrile-water (10+90,v/v) and cleaned by 0.22 μm millipore filter. The filtrate was separated on a Endeavorsil C18 column by gradient elution in 13 minutes with acetronitrile-water (containing 0.1% formic acid) as mobile phase. Eight penicillins in milk products were detected by UHPLC-MS/MS, identified by electrospray ionization in positive mode using multiple reaction monitoring, and quantified with external standards. Results The calibration curves of residues of eight penicillins showed good linearity in the range of 1.0-100.0 μg/kg with correlation coefficient in the range of 0.999 2-0.999 8. The detection limit of the method was from 0.03 μg/kg to 0.15 μg/kg. The recoveries at three spiking levels ranged from 91.0% to102.3%, and relative standard deviations in the range of 1.02%- 6.13% were obtained. A total of 78 samples of milk powder, liquid milk, fresh milk, and milk beverage were analyzed. Three samples were proved to contain penicillin G in the range of 0.2-1.6 μg/kg. Conclusion The method was applied to determine residues of eight penicilins in milk products by UPLC-MS/MS and proved to be simple, rapid, and accurate, and meet the requirements of monitoring of penicillin in milk products.