血吸虫病疫情与地理环境因子的多元相关分析

探索鄱阳湖血吸虫病典型疫区的社会、经济、环境因子与血吸虫病疫情的相互关系及其相关程度。采用经典统计学中单相关、偏相关和复相关系数研究南昌县43个行政村血吸虫病感染人数与疫水接触指数、耕牛存栏数、行政村水域面积、行政村湖边边界长度和行政村到鄱阳湖边界的距离的内在联系和相互关系。所选5个因子与感染人数的简单相关系数都达到了005置信水平，固定疫水分布各因子计算疫水接触各因子与“感染人数”的偏相关系数，与固定疫水接触各因子计算疫水分布各因子与“感染人数”的偏相关系数，都小于简单相关系数，说明疫水分布因子与疫水接触因子具有内在关联；“感染人数”与所有5个因子的复相关系数为0.948，达到了0.005的极显著置信水平。所选的村级宏观因子都与血吸虫病疫情显著相关

MULTIPLE CORRELATION ANALYSIS BETWEEN SCHISTOSOMIASIS EPIDEMICS AND ENVIRONMENTAL FACTORS ON THE BASIS OF EMPIRICAL STUDY IN THE ADMINISTRATIVE VILLAGES OF NANCHANG COUNTY

The purpose of this study was to explore the relationship between the schistosomiasis epidemicity and the social, economic, environmental factors in a typical schistosomiasis epidemic area of the Poyang Lake region. We used simple correlation coefficient, partial correlation coefficient and multiple correlation coefficient, to study the correlations and the interrelationships among the number of infected persons and the five factors of 43 typical schistosomiasis epidemic administrative villages in Nanchang county, Jiangxi province. The five factors were divided into two portions, Infected Water Contact factors (including water contact index, lake border length and distance to the Poyang Lake) and Infected Water Distribution factors (including cattle stock, waters area). The previous studies of water contact index calculation were based on contact ways, contact frequency, the body area exposed and the lasting time without considering susceptible seasons, susceptible time and exposing spots. In the study,we tried to include these important elements into the computation of water contact index in forms of contact way, contact season, the number of contact days, contact time periods in a day, the number of the persons of different contact ways and contact spots. The lake border length and the waters area for each administrative village werederived from a TM image of the Poyang Lake region in June 2009; the distance to the Poyang Lake for each administrative village was measured by length of geometric center of village to the lake border; the cattle stock data was from a social economic statistic of the Schistosomiasis Control Department of Nanchang county. The simple correlation coefficients between the number of infected persons and the selected 5 factors reached 005 significance level，among which the water contact factors (including lake boundary length and water contact index) hadhighest correlation coefficients (0747 and 0813 respectively); the partial correlation coefficients between either the number of infected persons and the water contact factors when fixing the Infected waters factors (including cattle stock, waters area and distance to the Poyang Lake), or the number of infected persons and the infected waters factors when fixing the water contact factors were lower than their simple correlation coefficients, implying there existed mutual interrelationship between the infected waters factors and the water contact factors; the multiple correlation coefficient between the number of infected persons and the whole 5 factors was 0948 (P<0005), accounting for 79% of the total variance of the Number of infected persons. Conclusions can be drawn that the selected 5 environmental factors were significantly correlated with the number of infected persons; the infected waters factors and the water contact factors were indispensable for epidemic occurrence and there are interrelationship between these 2 group factors; the 5 macro environmental factors can explain most variance of the number of infected persons.