Evaluation of three immunoglobulin M antibody capture enzyme-linked immunosorbent assays for diagnosis of Japanese encephalitis.

Japanese encephalitis (JE) virus is a major cause of neurologic infection in Asia, but surveillance has been limited. Three JE immunoglobulin M (IgM) antibody capture enzyme-linked immunosorbent assay kits have recently been developed. The aim of this study was to evaluate their sensitivity, specificity, and usability using 360 acute-phase serum samples containing JE, dengue, or neither IgM antibody. The kits, manufactured by Panbio Limited, Inbios International, Inc., and XCyton Diagnostics Ltd, had high sensitivities of 89.3%, 99.2%, and 96.7%, respectively. The specificities were 99.2%, 56.1%, and 65.3%, respectively. When dengue IgM-positive samples were excluded, the kits had specificities of 98.4%, 96.1%, and 96.1%, respectively. The Panbio kit includes both JE and dengue antigens and appears to have an advantage in settings where dengue virus co-circulates, although further assessments in clinical settings are needed. This information is helpful in considering options for strengthening the laboratory component of JE surveillance.