Comparing electron microscopy and a competitive blocking ELISA in the detection of rotaviruses in porcine faeces

Analysis of 476 faecal samples from diarrhoeic piglets was performed using electron microscopy (EM) and a competitive blocking (CB)-ELISA based on monoclonal antibodies to the VP6 protein of group A rotavirus. Rotavirus was detected by EM and/or CB-ELISA in 111 (23.3%) samples. Of these, all groups of rotavirus were identified in 83 (74.8%) samples by EM (EM+), while group A rotavirus was identified in 90 (81.1%) samples by CB-ELISA (ELISA+). However, only 62 (55.9%) of samples were positive using both detection methods. The finding of 28 (25.2%) EM−/CB-ELISA+ samples illustrated the high sensitivity of the CB-ELISA method. On PCR analysis, groups B and C rotavirus was found in 3 and 16 of 19 EM+/CB-ELISA− samples, respectively. Although the study illustrates the high sensitivity of a CB-ELISA in rotavirus detection, the findings highlight the need to use a range of diagnostic methods in detecting these viruses in clinical samples.