RAPID DIAGNOSIS OF JAPANESE ENCEPHALITIS BY USING AN IMMUNOGLOBULIN-MDOT ENZYME-IMMUNOASSAY

Japanese encephalitis (JE) occurs in rural settings in southern and ea stern Asia, where diagnostic facilities are Limited. For the diagnosis of JE virus (JEV) infection, we developed a nitrocellulose membrane-b ased immunoglobulin M (IgM) capture dot enzyme immunoassay (MAC DOT) t hat is rapid, simple to use, requires no specialized equipment, and ca n distinguish JEV from dengue infection. In a prospective field study in southern Vietnam, 155 cerebrospinal fluid (CSF) and 341 serum sampl es were collected from 111 children and 83 adults with suspected encep halitis, The JEV MAC DOT, performed on site, was scored visually from negative to strongly positive by two observers, and the results were c ompared subsequently with those of the standard IgM capture enzyme-lin ked immunosorbent assay. For the 179 patients with adequate specimens, the MAC DOT correctly identified 59 of 60 JEV-positive patients and 1 18 of 119 JEV-negative patients (sensitivity [95% confidence intervals ], 98.3% [92.1 to 99.9%]; specificity, 99.2% [95.9 to 100.0%]; positiv e predictive value, 0.98; negative predictive value, 0.99), The MAC DO T also correctly identified three patients with dengue encephalopathy, Admission specimens were positive for 73% of JE patients, Interobserv er agreement for MAC DOT diagnosis was excellent (kappa = 0.94), The J EV MAC DOT is a simple and reliable rapid diagnostic test for JE in ru ral hospitals.