Evaluation of reverse-transcriptase PCR as a diagnostic tool to confirm Japanese encephalitis virus infection

Japanese encephalitis (JE) is a serious central nervous system infection and major public health problem in several countries of Southeast Asia including India. This study evaluated the use of IgM, ELISA and reverse-transcriptase (RT)-PCR in blood and cerebrospinal fluid (CSF) samples from acute encephalitis patients for the detection of Japanese encephalitis virus (JEV). Forty-four children suffering from acute encephalitis were enrolled, and 36 were selected from whom both CSF and serum samples were available. Twenty-two of the 36 CSF samples were positive for JEV by IgM ELISA and all were negative by RT-PCR. Twenty-three of the 36 serum samples were positive by IgM ELISA while 28 were positive by RT-PCR. Total positivity for JEV infection in CSF and serum samples was 66.7% (24/36) and 83.3% (30/36) respectively by one or both tests. The overall positivity for JEV infection was 86.1% (31/36). We suggest that the use of RT-PCR in serum samples during the early days of JEV infection may be helpful in confirming diagnosis in those cases which are negative for JEV-specific IgM antibodies in both serum and CSF samples. (C) 2009 Published by Elsevier Ltd on behalf of Royal Society of Tropical Medicine and Hygiene.