Evaluation of diagnostic methods for the detection of Bovine Coronavirus and Rotavirus in faeces of diarrhoeic calves

The purpose of the present study was to evaluate the efficacy of Enzyme-Linked Immunosorbent Assay (ELISA), immunochromatographic (ICG), and reverse transcription-polymerase chain reaction (RT-PCR) methods for the detection of rotavirus (RV) and bovine coronavirus (BCV). Faeces samples were collected from 90 diarrhoeic calves (male and female) up to one month of age and the immune response against RV and BCV infection was as-sessed by using AgELISA, ICG, and RT-PCR. To determine the performance and accuracy of each diagnostic method in comparison to the diagnostic gold standard (RT-PCR) method, different statistical tests including receiver operating characteristic curve (ROC) and concordance correlation were used. Results revealed the prevalence of RV and BCV and RV+BCV according to RT-PCR were equal to 8.89 (95% CI: 6.64-10.07), 14.44 (95% CI: 11.23-6.90), and 2.22 (95% CI: 0.89-3.72), respectively. The best agreement and the highest sensitivity and specificity were obtained be-tween the RT-PCR and AgELISA (100% and 94.3%), and also the ICG test (95% and 94.3%) was less accurate method in comparison to ELISA method for identifying RV and BCV, but a good correlation and concordance between ICG diagnostic techniques and RT-PCR were observed. To put it in a nutshell, our results demonstrate that the AgELISA is the most accurate technique in comparison to RT-PCR, however the ICG assay can help improve the speed of diagnosis RV and BCV infections in dairy field. New scientific strategies for promoting accuracy and transparency of ICG-based technique in early diagnosis of the cause of calf diarrhoea should be used. Altogether, we suggest that positive ICG samples should be tested by AgELISA or RT-PCR techniques to avoid false results in farm animals.