RESUMO
The nucleotide alignment of all 11 genes of human Rotavirus A (RVA) strains revealed suitability of NSP2, NSP3 and VP6 genes for the development of real time PCR (qRT-PCR). Evaluation of qRT-PCR assays using known rotavirus ELISA positive and negative fecal specimens showed non-overlapping ranges of Mean ±3SD cycle threshold (Ct) values for NSP3 and VP6 based assays. Using serial dilutions of purified RVA, high sensitivity of VP6 qRT-PCR assay (1.95 × 10-5 pg/µL of RNA) was recorded as compared to NSP2 and NSP3 qRT-PCR assays (1.95 × 10-4 pg/µL of RNA). Further, evaluation of the VP6 qRT-PCR assay involving 266 fecal specimens and frequency polygon analysis of the data indicated cut-off value of 35 for Ct with high sensitivity (126/131, 96%) and specificity (12/12, 100%). This VP6 qRT-PCR assay will be a useful diagnostic tool to evaluate clinical presentations in rotaviral gastroenteritis under different conditions such as breast feeding and administration of rotavirus vaccines.
