Comparative efficacy of immunological, molecular and culture assays for detection of group A rotavirus from faecal samples of buffalo (Bubalus bubalis) calves.

Group A rotaviruses play an important role in causing gastroenteritis and mortality in buffalo (Bubalus bubalis) calves. A number of assays like RNA-polyacrylamide gel electrophoresis (RNA-PAGE), enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction (RT-PCR) and virus isolation have been employed for rotavirus diagnosis. We evaluated the comparative efficacy of different assays for detection of group A rotavirus in buffalo calves. A total of 455 faecal samples collected from five organized farms in northern India were screened by monoclonal antibody based ELISA, 33 (7.25%) samples were positive for group A rotavirus. The percent positivity ranged from 3.22% to 28% in different organized farms. The same samples were also tested by RNA-PAGE, which revealed classical 11 segments with 4:2:3:2 migration patterns in 14 faecal samples showing 3.08% positivity. Virus isolation was successfully done from 21 (4.61%) samples. However, only 15 (3.3%) samples yielded a specific product of 864 and 1,011 bp for VP4 and VP7 genes, respectively, by RT-PCR. The sensitivity and specificity of ELISA, RNA-PAGE and RT-PCR was 100%, 66.67% and 71.43% and 97%, 100% and 100%, respectively, considering virus isolation as standard test. ELISA being simple, fast and sensitive assay can be used as routine laboratory test for the diagnosis of group A rotavirus and field epidemiological studies.