[Variation characteristics of total gaseous mercury at Wuzhi mountain (Wuzhishan) background station in Hainan].

Total gaseous mercury (TGM) was continuously monitored at Wuzhi mountain (Wuzhishan) using the high-resolution automatic atmospheric mercury vapor analyzer (Tekran 2537B) from May 2011 to May 2012. The annual geometric mean TGM concentration was (1.58 ± 0.71) ng x m(-3), suggesting that the atmosphere was not obviously polluted. The TGM level at WuZhi mountain remained low from June to August in 2011 and from March to May in 2012, while higher values were observed from September in 2011 to January in 2012. Tropical monsoons played an important role in the monthly variation of TGM. TGM concentrations showed a clear diurnal trend with the minimum concentration occurring at 09:00 AM and the peak concentration at 19:00 PM due to the combined impact of the long-range transport of atmospheric mercury and local meteorological conditions. The temporal trend of TGM highlighted the impact of long-range transport from the mainland of China on the distribution of TGM in ambient air at Wuzhi mountain by the results of backward trajectory analysis using HYSPLIT.

Risk factors for hepatitis B and C infection among blood donors in five Chinese blood centers.

BACKGROUND: Few studies were conducted on hepatitis B and C virus (HBV and HCV, respectively) risk factors among Chinese blood donors in recent years since voluntary donors replaced commercial donors. STUDY DESIGN AND METHODS: A case-control survey was conducted in HBV- or HCV-positive and -negative donors from five blood centers in China between September 2009 and April 2011. Case status was defined by having a reactive result on Monolisa HBsAg Ultra (Bio-Rad) for HBV and Ortho anti-HCV EIA 3.0 (Johnson & Johnson) for HCV. Controls were randomly selected qualified blood donors matched to cases by donation month and blood center. Specific test-seeking, medical-related, and behavioral risk factors were compared by HBV and HCV status using chi-square tests or Fisher's exact tests with Bonferroni correction. RESULTS: A total of 364 HBV cases, 174 HCV cases, and 689 controls completed the survey; response rates were 66.2, 47.3, and 82%, respectively. HCV-positive donors were significantly more likely to report having a blood transfusion history (23.4% vs. 3.0%, p < 0.0001) and ever living with a person with illegal drug injection (6.0% vs. 0.5%, p < 0.0001) than controls. Having intravenous and intramuscular injections in the past 12 months and ever having a tattoo are marginal risk factors for HCV (p values < 0.01). No specific risk factor for HBV was identified. CONCLUSION: History of previous transfusion and living with illegal drug users are risk factors for HCV infection among Chinese blood donors from five regions. Test-seeking behavior is not associated with HBV or HCV infections.

[Investigation on the risk factors for reported rising of measles incidence during November, 2011 to February, 2012, in some areas of Hubei province].

OBJECTIVE: To identify the risk factors for reported sudden rise of measles incidence in November, 2011, in some areas of Hubei province. METHODS: We analyzed all measles patients reported in the measles surveillance system from November 2011 to February 2012 in two prefectures with highest attack rates and their vaccination history by reviewing vaccination records. We interviewed patients' parents by telephone to obtain the history of visiting health care within 7 to 21 days before onset. We also used case-crossover study to estimate the relative risk (RR) of hospital acquired infection and to compare the exposure to health care between 7-21 days before onset to 37-51 days before onset among measles patients. RESULTS: Totally 140 patients were reported in the two prefectures. Reported measles incidence rates among the population aged <8 m(69/100 000) and 8 m to 17 m (72/100 000) were higher than other age groups (rang from 0 to 5.8 per 100 000). Among the population aged 8 m to 17 m, estimated vaccination coverage was lower than 75%, and it was lower than 90% among those aged 18 m to 3 yrs. During 7-21 days before onset, 58% (29/50) of the patients had an exposure to health care settings, compared to 14% (7/50) of patients during 37 to 51 days before onset (MH RR = 5.4, 95% confidence interval = 2.1-14.0). CONCLUSION: Under the condition of measles vaccination coverage lower than 95%, iatrogenic infection was a risk factor for measles in Hubei.

An analysis of risk factors for human immunodeficiency virus infection among Chinese blood donors.

BACKGROUND: Information regarding the risk factors for human immunodeficiency virus (HIV) infection among Chinese donors is important for understanding the trend of HIV transmission routes and for developing effective donor behavioral screening policies. STUDY DESIGN AND METHODS: In 2009 to 2011, a total of 77 HIV-positive and 649 HIV-negative consented donors who screened nonreactive for hepatitis B virus, hepatitis C virus, syphilis, and alanine aminotransferase in four Retrovirus Epidemiology Donor Study-II Chinese regions received and completed a questionnaire by mail regarding their recent and past medical procedures, drug use, and sexual behaviors, etc. Exploratory and confirmatory factor analyses grouped questions into three risk factors. Multivariable logistic regression analysis examined the relationship between risk factors and HIV status adjusting for center, age, sex, and education. RESULTS: The three risk factors were test-seeking tendency, medical-related risks, and behavioral risks. In multivariable logistic regression analysis, greater test-seeking tendency and behavioral risks were associated with HIV infection, with the adjusted odds ratios (ORs) being 2.2 (95% confidence interval [CI], 1.2-4.1) and 3.8 (95% CI, 1.8-7.9), respectively, but medical risks were not (OR, 1.2; 95% CI, 0.6-2.2). In comparison to less high school education, high school and more education was associated with lower risks for HIV infection, with the ORs being 0.35 (95% CI, 0.17-0.70) and 0.17 (95% CI, 0.09-0.33), respectively. CONCLUSIONS: Test-seeking tendency and high-risk sexual behaviors are important predictors of HIV infection in Chinese blood donors, suggesting that the health history inquiry used in donor selection process needs improvement to defer high-risk donors more effectively.

Effect of conjugated linoleic acid on Cyprinus carpio var. Jian regarding growth, immunity, and disease resistance to Aeromonas hydrophila.

The present study was performed to investigate the effect of dietary conjugated linoleic acid (CLA) on the growth performance, immune parameters and disease resistance to Aeromonas hydrophila of juvenile Jian carp. A total of 900 juvenile Jian carp (10.71 +/- 0.02 g) were randomly allocated into six groups of each three replicates, feeding isonitrogenous (35% crude protein) and isolipidic (7.8% crude fat) diets containing graded amounts of CLA (0, 0.5, 0.8, 1.4, 1.7, and 2.0%) for 60 days. After a 60-day growth test, a challenge trial was conducted by intraperitoneal injection of Aeromonas hydrophila to determine the effect of CLA on disease resistance of juvenile Jian carp. The results showed that diets incorporated with a proportion of up to 2.0% CLA without effect on weight gain, feed intake, and feed conversion ratio, but improved immune parameters and disease resistance of juvenile Jian carp. The dietary CLA level of optimal disease resistance to Aeromonas hydrophila was estimated to be 1.7% in juvenile Jian carp using broken-line analysis.