Investigation of Japanese Encephalitis Virus Infections in Three- to Six-Year-Old Children in Rural Taiwan
1995 Vol.11 NO.9
To understand the distribution of Japanese encephalitis antibodies among preschool children in rural Taiwan, all three- to six-year-old children residing in Hsinchu, Taichung, Pingtung and Hualien Counties were selected for sero-epidemiological investigation. The plaque reduction neutralization test (PRNT) was used with a total of 2,281 children. The total positive rate of Japanese encephalitis neutralization antibodies found was 67% (1,520/2,281). After a series of three doses of Japanese encephalitis vaccine, the four-year-old children of all four counties showed the lowest neutralization antibody positive rate: these were 45% (56/125) in Hsinchu; 51% (57/111) in Taichung; 30% (39/128) in Pingtung and 66% (67/102) in Hualien. These figures are significantly lower than those for the other age group of the children immunized in each county. (p=:O.000l, Chi-square test). Whether or not children had been immunized against Japanese encephalitis, the neutralization antibody positive rate went up after age five, reaching the highest rate (around 82 to 91%) at age six. This shows that in the areas of study, spontaneous infection with Japanese encephalitis generally existed. The antibody positive rate of the 47 nod-immunized children also went up with age.