title: Usefulness of RT-PCR for the diagnosis of Japanese encephalitis in clinical samples.
abstract: The present study was carried out between July 2003 and December 2005 in PGIMER, Chandigarh, India and aimed to compare IgM capture ELISA and nested RT-PCR for the diagnosis of Japanese encephalitis (JE). The samples collected were cerebrospinal fluid and blood from 40 febrile patients with encephalitis (n=40, group I) and blood samples from febrile patients without encephalitis residing in JE endemic areas (n=45, group II). Overall, in CSF samples JE specific RNA was detected in 9/40 (22.5%), while 7/28 (25%) patients showed the presence of specific IgM antibodies. Only 28 CSF samples could be subjected to both RT-PCR and IgM and, among these, 13 cases were found to be confirmed JE based on IgM and/or RT-PCR positivity. Among the confirmed cases, 6 (6/13, 46.5%) could be detected by RT-PCR alone, 4 (4/13, 30.7%) by IgM capture ELISA and 3 (3/13, 23.1%) patients were positive by both the methods. All the RT-PCR positive cases had presented within 5 d of onset of illness. The serum samples of only 16 patients in group I could be tested for IgM antibodies and 5 (31.25%) were found to be positive, while in group II, 11.1% (5/45) positivity was observed. JE specific RNA could not be detected in serum samples of either group of patients. This study highlights the need for carrying out RT-PCR in CSF samples, compared to IgM antibody detection, for the early detection of JEV.
authors.affiliation: Department of Virology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Reena
authors.initials: R
authors.lastname: Swami
authors.forename: Radha Kanta
authors.initials: RK
authors.lastname: Ratho
authors.forename: Baijayantimala
authors.initials: B
authors.lastname: Mishra
authors.forename: Mini P
authors.initials: MP
authors.lastname: Singh
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood / Q000134:cerebrospinal fluid; D016009:Chi-Square Distribution; D002675:Child, Preschool; D004664:Encephalitis Virus, Japanese / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D004672:Encephalitis, Japanese / Q000175:diagnosis* / Q000276:immunology / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood / Q000134:cerebrospinal fluid; D007194:India; D007223:Infant; D008297:Male; D012367:RNA, Viral / Q000134:cerebrospinal fluid*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*
chemical_list: D000914:Antibodies, Viral; D007075:Immunoglobulin M; D012367:RNA, Viral