A nested polymerase chain reaction test for bovine coronavirus diagnosis bases on the RNA-dependent RNA-polymerase gene

ABSTRACT

Bovine coronavirus (BCoV) causes enteritis and respiratory iIIness in calves and dysentery in cows. Difficulties found in the production of large amounts of BCoV in cel! culture and those regarding envelope integrity pose a major problem to antigen, hyperimmune sera and monoclonal antibodies production. This study aimed at the development of a polymerase chain reaction for BCoV detection in fecal samples of calves targeted to the gene of the RNA-dependent RNApolymerase, and the comparison of this test with the hemagglutination/ hemagglutination inhibition test (HA/HI). Both tests were applied to 203 fecal samples. HA/HI resulted in an individual-levei BCoV frequency of 35.47% and a farm-Ievel frequency of 73.68%, while the proposed PCR resulted in an individual-levei BCoV frequency of 25.12% and a farm-Ievel frequency of 52.63%. Both Kappa and Youden's tests revealed a low agreement between PCR and HA/HI. Hypotheses are suggested to explain such a disagreement. The PCR proposed is a useful toei forthe detection of BCoV, for epidemiological surveys and as a screening test for studies focused on other BCoV genes, such as the spike gene.