Comparison of polymerase chain reaction and monoclonal antibodies for G-typing of group A bovine rotavirus directly from fecal material.

A reverse transcriptase and polymerase chain reaction (RT-PCR)-based assay for G-typing of bovine rotaviruses (BRV) was compared with a monoclonal antibody-based immunoassay (MAbs-ELISA) in the characterization of BRV field strains obtained from calves in different regions of Quebec between 1992 and 1994. The strains were analysed for two G types (G6 and G10) which are the most predominate BRV field strains. Fecal samples positive for BRV by polyacrylamide gel electrophoresis (n = 74) were typed by both methods revealing 77% correlation. RT-PCR detected 10 more G6 and 2 more G10 serotypes than MAbs-ELISA. Nine of the 12 discrepant samples could be cultivated and were confirmed as G6 (8) or G10 (1) by both methods. RT-PCR was able to efficiently detect artificial mixes of G6 and G10 and detected two mixed field infections. Four additional infections considered as mixed by MAbs-ELISA and as only G6 by RT-PCR were possibly MAbs-ELISA cross-reactions. RT-PCR provided a very sensitive method for typing BRV field isolates.