1988 Volume 62 Issue 3 Pages 235-241
During the preepidemic and epidemic seasons of Japanese encephalitis, ELISA IgM titers of viral antibodies in pigs were measured and compared with HI titers. Sera were collected serially at intervals from ten pigs and subjected to assay of antibody titers. In the preepidemic period, ELISA IgM titerswere less than 103 and no HI antibody was detected. When HI IgM antibody was demonstrated, the sera showed ELISA IgM titers of more than 104. ELISA IgM antibodies continued to be detected for about 2 weeks. Later the titers decreased to around 103, but the HI reaction was observed due to the presence of IgG antibody.
Twenty pigs were selected periodically at each time when they were brought to market, and subjected to assay of antibody titers. In the nonepidemic and preepidemic seasons, the ELISA IgM titers were less than 103. At the early stage of the epidemic period when the HI IgM antibody appeared, the sera showed ELISA IgM titers of more than 104. ELISA IgM antibodies were detected for about one month in a group of pigs as a whole. Although sera showing ELISA IgM titers of 2-4×103 contained HI IgM antibodies in some specimens, ELISA IgM titers more than the cut off value of 3×103 well correlated with IgM antibodies detected in the HI reaction.
