National Institute of Virology, 130/1, Sus Road, Pashan, Pune-411 021, India.
Abstracts of the papers presented at the XVIII National Conference of Indian Virological Society at Post Graduate Institute of Medical Education and Research, Chandigarh, India, December 11–13, 2008.
Hepatitis E virus (HEV), a major cause of enterically transmitted acute hepatitis of adults in developing nations, occurs in sporadic and epidemic forms. It is a non-enveloped, single-stranded, positive sense RNA virus (∼7.2 kb), consisting of 3 open reading frames (ORFs). ORF2 protein is the major target for vaccine development and diagnostic assays. In the present study, ELISAs based on complete ORF2 protein (1–660 amino acids, cORF2p) and the region corresponding to minimum neutralizing epitopes (rNEp) within cORF2p of HEV were compared. The performance of these 2 assays was validated by commercially available ELISA. Serum samples of outbreak (n=109) and sporadic (n=60) cases of acute viral hepatitis, apparently healthy children (n=138) and 4 sequential samples each from 10 hepatitis E patients were tested for anti-HEV IgM antibodies. Serum samples of outbreak and sporadic patients were tested with commercial ELISA. A concordance of 93.5% was observed between the ORF2 and NE assays for detection of anti-HEV IgM antibodies in outbreak and sporadic patients. The OD values were comparable (r=0.974). Specificity of both the indigenous assays (100% concordance) in detecting IgM antibodies in healthy children was comparable. Similar results were obtained for sequential sera of hepatitis E patients. The ORF2 assay shared a concordance of 87% (P>0.05) and 75% (P>0.05), whereas for NE assay the concordance was 82.4% (P>0.05) and 77.3% (P>0.05) with the commercial assay for outbreak and sporadic cases respectively. Bacterially expressed NE protein was equally useful for diagnosis of HEV.
