Yong Long

Fourth Military Medical University, Xi’an, Liaoning, China

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Publications (9)14.98 Total impact

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    ABSTRACT: Current baseline data regarding the prevalence of hepatitis B virus (HBV) infections and the immune status in hyperendemic areas is necessary in evaluating the effectiveness of ongoing HBV prevention and control programs in northwest China. This study aims to determine the prevalence of chronic HBV infections, past exposure rates, and immune response profiles in Wuwei City, northwest China in 2010. Cross-sectional household survey representative of the Wuwei City population. 28,579 participants were interviewed in the seroepidemiological survey ≥1 year of age. House to house screening was conducted using a standard questionnaire. All serum samples were screened by enzyme-linked immunoassays for the presence of hepatitis B surface antigen, antibodies against HBV surface antigen, and antibodies to the hepatitis B core antigen. Among individuals ≥1 year of age, 7.2% (95%CI: 6.3-8.1%) had chronic HBV infections, 43.9% (CI: 40.4-47.4%) had been exposed to HBV, and 23.49% (CI: 21.6-25.3%) had vaccine-induced immunity. Multi-factor weighted logistic regression analysis showed that having household contact with HBV carriers (OR = 2.6, 95%CI: 2.3-3.0) and beauty treatments in public places (OR = 1.2, 95%CI: 1.1-1.3) were the risk factors of HBV infection in whole population. Having household contact with HBV carriers (OR = 3.8, 95% CI: 2.2-6.5) and lack of hepatitis vaccination (OR = 2.0, 95% CI: 1.4-3.3) were the risk factors for HBV infection in children aged 1-14 years. Hepatitis B infection remains a serious public health problem in northwest China. Having household contact with HBV carriers and beauty treatments in public places represented HBV infection risk factors. Hepatitis B vaccine immunization strategies need further improvement, particularly by targeting the immunization of rural migrant workers.
    PLoS ONE 01/2014; 9(5):e97474. · 3.53 Impact Factor
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    ABSTRACT: BACKGROUND: Wuwei City has the highest prevalence of hepatitis B virus (HBV) in China. From 2007 to 2011, the average reported incidence rate of hepatitis B was 634.56/100,000 people. However, studies assessing the epidemic features and risk factors of HCV in the general population of Wuwei City are limited. METHODS: A total of 7189 people were interviewed and screened for HCV antibodies. HCV RNA and HCV genotypes were analyzed by PCR. Relevant information was obtained from the general population using a standardized questionnaire, and association and logistic regression analyses were conducted. RESULTS: The anti-HCV prevalence was 1.64% (118/7189), and HCV-RNA was detected in 37.29% (44/118) of the anti-HCV positive samples. The current HCV infection rate was 0.61% (44/7189) in the Wuwei general population. Hepatitis C infection rate was generally higher in the plains regions (χ(2) = 27.54,P<0.05), and the most predominant HCV genotypes were 2a (59.1%) and 1b (34.1%). The concurrent HCV and HBV infection rate was 1.37%, and a history of blood transfusion (OR = 17.9, 95% CI: 6.1 to 52.6, p<0.001) was an independent risk factor for HCV positivity. CONCLUSIONS: Although Wuwei is a highly endemic area for HBV, the anti-HCV positive rate in the general population is low. More than one-third of HCV-infected people were unaware of their infection; this may become an important risk factor for hepatitis C prevalence in the general population. Maintaining blood safety is important in order to help reduce the burden of HCV infection in developing regions of China.
    PLoS ONE 01/2013; 8(1):e54815. · 3.53 Impact Factor
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    ABSTRACT: Hainan Province is the main area threatened by malaria in China. However, the epidemiologic patterns of malaria in this region are not yet defined. In this study, we determined the spatio-temporal distribution and variation of Plasmodium falciparum and Plasmodium vivax malaria in Hainan during 1995-2008 by using wavelet and cluster quantitative approaches. The results indicated a decreasing secular trend and obvious seasonal fluctuation of malaria in Hainan. In addition, the characteristic annual peak of malaria could not be detected after 2005. The southcentral region of Hainan has remained an area of relatively high malaria risk, but the incidence of P. falciparum malaria increased significantly in the southeast and southwest regions during 2002-2008. These findings identify epidemic patterns of malaria in Hainan, and are applicable for designing an effective and dynamic public health campaign to combat malaria in this region.
    The American journal of tropical medicine and hygiene 08/2012; 87(4):646-54. · 2.53 Impact Factor
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    ABSTRACT: Our purpose was to explore the relationship between hepatitis B virus (HBV) gene heterogeneity and maternal vertical transmission. HBsAg-positive mothers and their neonates were selected and classified into a vertical infection neonate group (group N), a vertical infection mother group (group M) and a control group (group C). Serum HBsAg and HBeAg were examined. HBV gene fragments, including the pre-S1, and pre-S2 and S coding regions, were amplified and sequenced, and the genotype and serotype of the sequences were identified. Mutation sites and frequency of mutations were then compared between group N and group C. A total of 104 HBV clone sequences were obtained. All obtained sequences belonged to genotype C and serotype adr. Upon comparing sequences between group N and group C, 4 nonsynonymous mutations were found with significant difference in mutation frequency (p < 0.05). When the mothers were both HBsAg and HBeAg positive, 10 nonsynonymous mutations were found. The frequencies of these mutations were significantly lower in group N than in group C (p < 0.05). The 10 HBV mutations were negatively associated with vertical transmission when maternal HBeAg was positive. Furthermore, the species that were vertically transmitted to the fetus were mainly wild-type.
    Intervirology 01/2011; 54(3):122-30. · 1.89 Impact Factor
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    ABSTRACT: Hainan is one of the provinces most severely affected by malaria epidemics in China. The distribution pattern and major determinant climate factors of malaria in this region have remained obscure, making it difficult to target countermeasures for malaria surveillance and control. This study detected the spatiotemporal distribution of malaria and explored the association between malaria epidemics and climate factors in Hainan. The cumulative and annual malaria incidences of each county were calculated and mapped from 1995 to 2008 to show the spatial distribution of malaria in Hainan. The annual and monthly cumulative malaria incidences of the province between 1995 and 2008 were calculated and plotted to observe the annual and seasonal fluctuation. The Cochran-Armitage trend test was employed to explore the temporal trends in the annual malaria incidences. Cross correlation and autocorrelation analyses were performed to detect the lagged effect of climate factors on malaria transmission and the auto correlation of malaria incidence. A multivariate time series analysis was conducted to construct a model of climate factors to explore the association between malaria epidemics and climate factors. The highest malaria incidences were mainly distributed in the central-south counties of the province. A fluctuating but distinctly declining temporal trend of annual malaria incidences was identified (Cochran-Armitage trend test Z = -25.14, P < 0.05). The peak incidence period was May to October when nearly 70% of annual malaria cases were reported. The mean temperature of the previous month, of the previous two months and the number of cases during the previous month were included in the model. The model effectively explained the association between malaria epidemics and climate factors (F = 85.06, P < 0.05, adjusted R(2) = 0.81). The autocorrelations of the fitting residuals were not significant (P > 0.05), indicating that the model extracted information sufficiently. There was no significant difference between the monthly predicted value and the actual value (t = -1.91, P = 0.08). The R(2) for predicting was 0.70, and the autocorrelations of the predictive residuals were not significant (P > 0.05), indicating that the model had a good predictive ability. Public health resource allocations should focus on the areas and months with the highest malaria risk in Hainan. Malaria epidemics can be accurately predicted by monitoring the fluctuations of the mean temperature of the previous month and of the previous two months in the area. Therefore, targeted countermeasures can be taken ahead of time, which will make malaria surveillance and control in Hainan more effective and simpler. This model was constructed using relatively long-term data and had a good fit and predictive validity, making the results more reliable than the previous report. The spatiotemporal distribution of malaria in Hainan varied in different areas and during different years. The monthly trends in the malaria epidemics in Hainan could be predicted effectively by using the multivariate time series model. This model will make malaria surveillance simpler and the control of malaria more targeted in Hainan.
    Malaria Journal 01/2010; 9:185. · 3.49 Impact Factor
  • Yong Long, Yi-yang Li, De-zhong Xu
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 08/2008; 29(7):631.
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    ABSTRACT: Using the indirect economic burden of stroke in a rural population to develop rational allocation of future health resources, in Hanzhong area. Cluster sampling which involved 53 natural villages with a total number of 75,000 people selected from the 'stroke monitoring base' of rural population was adopted in this study in the Hanzhong area. All of the 164 stroke cases were studied through a self-designed questionnaire. In calculating disability-adjusted life years (DALYs), fixed value was used in accordance with the value of GBD. The disability assessment was simplified in DALYs calculation and modified Barthel's ADL was used in disability assessment of stroke patients. In indirect economic burden analysis, the human capital method combined with DALYs was adopted with the formula as: indirect economic burden = GNP per capita x DALYs x productivity weight. The total DALYs were 598.88, with an average DALY of stroke as 3.65 per case. The total indirect economic burden of stroke patients in rural areas was 1,993,977.8 RMB and the average of indirect economic burden of stroke was 12,158.4 RMB per case with the largest seen in the 45-59 age group, accounted for 74.4%. In our study, the use of method in combining the human capital with DALYs was the first time being adopted in calculation of the indirect economic burden of stroke in rural population in China. The burden seemed to be much lower than literature cited from other countries. It was reasonable to evaluate indirect economic burden of stroke using method in integrating DALYs with human capital, but it was difficult to calculate the DALYs.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 08/2007; 28(7):708-11.
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    ABSTRACT: The purpose of this study was to describe survival status and risk factors of mortality on inpatients with ischemic stroke. 617 patients with continuous ischemic stroke cases were collected from January 2002 to June 2005 retrospectively in the Department of Neurology, Xijing Hospital, Fourth Military Medical University. In order to perceive relevant information on survival and the cause of death. All patients were followed through phone calls or mailing. The follow-up program was completed in January 2006. Kaplan-Meier methods were used for survival description. Monovariant and multivariant Cox's proportional hazard regression model were used to analyze prognostic factors on mortality. The longest time in the follow-up program was 47 months with 59 dropped-out cases, making the dropout rate as 9.5%. Of these patients, 80 cases died during the period of study(60 for ischemic stroke,3 for cerebral hemorrhage, 10 for cardiac disease, 7 for other cause). The median survival time was 42. 16 months. The survival rates of one-year, two-year and three-year period were 91.9%, 89.4% and 85.3%, respectively. Monovariant and multivariant Cox's proportional hazard regression model showed that the risk factors associated with mortality were old age (RR = 1.043, 95% CI: 1.013-1.074), lower Glasgow scores (RR = 0.855, 95% CI: 0.742-0.985) ,poor conscious levels(RR = 4.085, 95% CI: 2.128-7.844) and having complication (RR = 1.765, 95% CI: 1.108-2.812). The results of this study suggested that the risk factors were old age, lower Glasgow scores, poor conscious levels and having complication on mortality of ischemic stroke.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 05/2007; 28(4):390-3.
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    ABSTRACT: To analyze the direct economic burden of stroke in rural areas of Hanzhong. Plan on primary interview was made after the purpose of the study had been informed to the managers of the 'surveillance field base', heads and members of the monitor assistants and detailed information was collected in the fields. Every single patient of stroke was then interviewed by the above said interviewers,using a self-designed questionnaire. 164 patients with stroke were interviewed in 53 villages with 75,000 persons lived there. The main items involved in the questionnaire would include: costs for inpatient or outpatient, reaching-out fees, fee for accommodation during treatment as outpatient, costs for treatment at home, long term medicine, caregivers and funerals as well as average income. The median of annual direct economic burden was 3100 Yuan for each patient in Hanzhong rural area. There were no significant differences seen between males and females or among age groups (P > 0.05). The proportion of patients with medians of annual direct economic burden of: 1000 Yuan and below, 1001-5000 Yuan, 5001-10,000 Yuan, 10,001-20,000 Yuan and over 20,001 Yuan, were 29.2%, 36.0%, 18.3%, 9.8% and 6.0% respectively. The median of annual direct economic burden of first episode stroke was 5500 Yuan for each patient, and that of stroke was 1700 Yuan for each chronic patient. The direct economic burden of first episode was significantly higher than that of stroke (P < 0.01). The costs of hospitalization, accommodation of hospitalization and treatment at home of middle-aged patients were significant higher than that of old age patients (P < 0.05). In this study, the direct economic burden of stroke was 2.9 times of the annual personal average income, which was contrary to the reports from other countries. However, the State Health Bureau bore 87.1% of the direct economic burden for urban patients, but patients in the rural areas had to pay from their own pockets. The direct economic burden of stroke was heavy in Hanzhong rural region, which called for measures to be made to decrease the direct economic burden of stroke in the region.
    Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi 08/2005; 26(7):494-7.