Abstract
During the years 1959 to 1966, about 10, 500 sera were collected in Gunma Prefecture and antibody to Japanese encephalitis virus was measured by both hemaggultination-inhibition and neutralization tests. The neutralization test employed for this study was the recently described plaque reduction method of Oya.
From the data of the distribution of antibody to Japanese encephalitis virus in various age groups in 3 geographically different areas, the effect of antibody patterns in human populations on attack rate was suggested. The method of the neutralization test was most sensitive for detection of anitbody and it seemed to be an effective laboratory tool for serum survey because of the ease and inexpense of performance.
