ABSTRACT
<p><b>OBJECTIVE</b>To study the prevalent situation of Japanese encephalitis (JE) virus among healthy people in Heilongjiang province and to analyze its risk factors.</p><p><b>METHODS</b>7 national surveillance counties were selected and divided into 5 age groups as 1-2, 3-5, 6-10, 11-20 and 21-59 years and randomly sampled 7 person in each age group per county with the sample size as 1050. Quantitative Elisa test was used to detect Japanese encephalitis antibody IgG.</p><p><b>RESULTS</b>The adjusted standard antibody positive rate of people on 1-59 year olds was 70.62%, with lowest in 3-5 age group, and increasing by age (chi2 for trend test = 40.52, P < 0.001). The overall titer of IgG was low in general population but was different with age (Kruskal-Wallis test chi2 = 76.9, P < 0.001). Older age and lower latitude seemed to be two risk factors on JE antibody IgG.</p><p><b>CONCLUSION</b>JE virus infection had a long-term effect with low level, among general population. Age and latitude were two risk factors which suggesting the necessarily of strengthening the surveillance system for JE cases at risk in the prevalent areas on Heilongjiang province.</p>