Studies on the serological cross-reaction between dengue and Japanese encephalitis.

Antibody responses of sero-confirmed flavivirus-infected patients were investigated by hemagglutination-inhibition (HI) tests against acute phase sera (S1) and convalescent phase sera (S2) using JE virus (JEV) JaGAr# 01 strain antigen (J-Ag) and dengue virus (DV) type 1 Hawaiian strain antigen (D-Ag). Analysis of the test results showed that depending on the combinations of HI responses to both antigens, the sero-confirmed patients could be divided into five classes: primary JE, secondary JE, primary D (JEV-uncontracted), primary D(JEV-contracted), and secondary D(JEV-contracted) patients. The diagnostic combinations of responses to HI tests for the infections were discussed and defined in this paper.