With purified Japanese encephalitis (JE) virion, an indirect ELISA was developed to detect antibody of IgG class against JE. This method was more sensitive than conventional HI and IFA, and its specificity was 93.3%. 666 serum specimens of various age groups from both urban and rural areas of Shanghai were assayed by ELISA. In children under 10 years of age, about 50% showed JE antibody with no difference between rural and urban areas, whereas in teenagers the positive rates were 30.1% in city area and 77.8% in the countryside. Of urban residents aged from 20 to over 60, 65.9-89.7% were seropositive for JE antibody while in rural dwellers of the same age almost all possessed JE antibody. Factors that may influence the fluctuation of JE antibody prevalence rates in different ages and areas are discussed. These factors include JE vaccination and JE prevalence pattern in the past.
Shanghai Medical Journal