Molecular analysis of Brazilian strains of bovine coronavirus (BCoV) reveals a deletion within the hypervariable region of the S1 subunit of the spike glycoprotein also found in human coronavirus OC43

Bovine coronavirus (BCoV) causes enteric and respiratory dis- orders in calves and dysentery in cows. In this study, 51 stool samples of calves from 10 Brazilian dairy farms were analysed by an RT-PCR that amplifies a 488-bp fragment of the hypervariable region of the spike glycoprotein gene. Maximum parsimony genealogy with a heuristic algorithm using sequences from 15 field strains studied here and 10 sequences from GenBank and bredavirus as an outgroup virus showed the existence of two major clusters (1 and 2) in this viral species, the Brazilian strains segregating in both of them. The mean nucleotide identity between the 15 Brazilian strains was 98.34%, with a mean amino acid similarity of 98%. Strains from cluster 2 showed a deletion of 6 amino acids inside domain II of the spike protein that was also found in human coronavirus strain OC43, supporting the recent proposal of a zoonotic spill- over of BCoV. These results contribute to the molecular characterization of BCoV, to the prediction of the efficiency of immunogens, and to the definition of molecular markers useful for epidemiologic surveys on coronavirus-caused diseases.