Epidemic Features Analysis of 106 Cases of Epidemic Encephalitis Type B in Qiandongnan Prefecture of Guizhou Province in 2004

Objective The epidemic features of epidemic encephalitis type B in Qiandongnan Prefecture of Guzhou Province in 2004 were analyzed to provide scientific evidence for the control and prevention of encephalitis type B．Methods Questionnaires were adopted to survey the re-ported encephalitis type B cases in the responsible area．Case database was established with the aid of Microsoft Excel and was analyzed by applying the descriptive epidemiology method．EIA was employed to test the anti encephalitis type B antibody IgM in the serum for the patients in acute stage．Results Of the 106 cases infected with encephalitis type B reported in the whole prefecture，90.57％ occurred in countries and 88.68％ of the countries were not inoculated with encephalitis type B vaccine in the recent 3 years．The immunization rate of children among ages of 0 to 9 was 14.66％ and there were 91 children under the age of 9 infected with the diseases，accounting for 85.85％ of all infected patients．Of the 28 serum samples，the positive rate of the anti-encephalitis type B antibody IgM was 78.57％．Conclusion In Qiandongnan Prefecture of Guizhou Province，encephalitis type B displayed a strict seasonal mode with an age characteristic．The main reason for the epidemic was the poor sanitation condition，which was suitable for the reproduction of mosquitoes and other insects，and the low immunization rate．It is recommended to enhance the inoculation of encephalitis type B vaccine in the countries and to involve encephalitis type B into the children'S expanded program on immunization．