Epidemic Situation And Spatial Analysis Of Leptospirosis In Hunan Province

Objective:This essay is to study the three-dimension distrubution of leptospirosis (Leptospirosis, Leptospirosis for short) and the changes in density, species and the rate of virus carriers of the main transmission hosts (rodents) of leptospirosis at the different time and areas. By using the spatial analysis method,it reveals the spatial distribution of leptospirosis and investigates the space-time aggregation of leptospirosis in order to provide new research tools and basis for the future prevention and treatment of leptospirosis in Hunan Province.Methods:Use Excel software to make maps and tables to describe on the leptospirosis's epidemiological data and rodents'monitoring data in Hunan Province in 2003-2008 and use chi-square test to analyze their difference; use Kriging Interpolation Analysis to form Leptospirosis Distribution Forecast Map and Prediction Error Map; by the analysis of the use of scan statistics, its clustering time, regions and the relative risk of this disease in various counties in different years are obtained and then realize their visualization.Results:Both morbidity and mortality rate of Leptospirosis in Hunan Province are generally exhibited on the decline during the study period, but they rebounded in 2007.In total, there're 703 cases of leptospirosis reported from 2003 to 2008 in Hunan, the average incidence rate was 0.180/100 000.41 patients died with an average mortality rate of 0.011/10 million, fatality rate 5.832/10 million. The disease has obvious seasonal features, although the peak incidence between different years was preceded and delayed to some extent, but it basically focused on from June to October, the general distribution was a single peak, but the individual years manifested as a bimodal distribution. Case Report dominated by agricultural workers, followed by students whose ages focused on 10-59 years, more men than women; host animal epidemiological survey displayed that the highest rat density and carrier rate of mice was the Year 2007,monitoring points for the highest rat density was the Yuanjiang City,the same for the highest carrier rate of mice was Shuangfeng County. Rat density and the carrier rate of mice have statistics significance(P<0.0001)between different years and monitoring sites. The dominant species of leptospirosis rodents in Hunan Province is apodemus agrarius,occupied 45.85% of the total captured number,followed by Mus and Rattus norvegicus which were 25.69%, 22.32%.The difference of rodents constitution between different years and monitoring points has statistics significance (P<0.0001).The results of Kriging Interpolation Data Exploration Analysis showed that in the average incidence rate which was came by the second-order extract kriging interpolation method based on spherical model, maps have the highest accuracy,and according to the formula of spherical model,we know that changing within the range of 123994, the average incidence rate of leptospirosis of Hunan Province was associated with Moderate Autocorrelation, thereamong the variation caused by spatial autocorrelation accounted for 49.97% of the total.The outcome of space-time scan statistics analysis revealed the incidence of leptospirosis in Hunan Province are not randomly distributed in the study period,there are three space-time clustering areas of statistical significance (P <0.00001).Forecast maps of leptospirosis in Hunan Province and the results of Scan Statistics analysis indicated that:The high incidence areas of leptospirosis were mainly located in the central and eastern hills zone, northwest and southwest mountains areas, of which the annual risk map could be expressioned as follows:The overall distribution of high-risk areas and low-risk areas was relatively fixed, in some areas,high-risk areas and low-risk areas distributed alternately and high-risk waves unevenly distributed between years and areas.Conclusion:The epidemic situation of leptospirosis of Hunan Province overall displayed a downtrend from 2003 to 2008, the onset of leptospirosis in men was more than women,to young adults based on farmers for more, it are showed significant seasonal nature. Rat density, dominant species distribution and bacterial bearing rate were all different between different time and monitoring points. Leptospirosis was not a random distribution in Hunan Province with the time-space clustering, its high incidence areas were mainly located in the central and eastern hills zone, northwest and southwest mountains areas.