RESUMEN
Background & objectives: Dengue fever (DF) is associated with significant morbidity and mortality in the tropical and sub-tropical regions of the world. Since there are no effective antiviral drugs for treatment, clinicians often rely on the accurate diagnosis of dengue fever to begin supportive therapy at early stages of the illness. The objective of this study was to develop an in-house dengue virus serotype 2 (DENV-2) non-structural protein- 5 (NS5) based indirect ELISA. Methods: DENV-2 was raised in Vero cells and the viral proteins were separated and subsequently the NS5 protein was eluted. Serum samples from primary and secondary dengue fever patients; and acute and convalescent samples from Japanese encephalitis (JE) and West Nile virus (WNV) cases were used to validate the ELISA. Results: The assay was found to be 100 per cent specific in detecting DENV-2 specific antibodies from patient’s serum. However, in terms of sensitivity, the assay could detect IgM antibodies only from 90 per cent of the primary dengue samples. The IgM/IgG ratio of the primary and secondary samples was 7.24 and 0.64, respectively. Interpretation & conclusions: The results indicate that the DENV-2 NS5 ELISA is dengue group specific and can be used to differentiate dengue infection from other circulating Flavivirus infections. This NS5 ELISA can also be used to distinguish between primary and secondary dengue fever on the basis of IgM/IgG ratios. Further studies with larger sample sizes and different DENV serotypes are required to validate the ELISA.
RESUMEN
In this study, we report the evaluation of In-house fl avi virus immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA), which can be used as a screening test to determine the infecting fl avivirus serotype over the current serological methods. A panel of 88 sera (inclusive of well characterized dengue, Japanese Encephalitis (JE) and West Nile virus (WNV) positive and negative samples tested and confi rmed by commercial kit) was used for evaluation of the kit. The sensitivity and specifi city of the In-house capture assay versus the commercial kit for the sero-diagnosis of dengue was 100% and 87% respectively, for JE IgM, it was found to be 90% and 100% respectively, and for West Nile it was 87.5% and 90.9%. Based on the study, we concluded that this fl avivirus-serotyping ELISA provides rapid results and may be used as an accurate alternate to other serological tests for the specifi c diagnosis of fl avivirus infections.