Bovine coronaviruses associated with enteric and respiratory diseases in Canadian dairy cattle display different reactivities to anti-HE monoclonal antibodies and distinct amino acid changes in their HE, S and ns4.9 protein

Abstract

Bovine coronavirus isolates associated with recent outbreaks of respiratory disease in Ontario and Quebec dairy farms were compared to reference strains known to be responsible for neonatal calf diarrhea (NCD) or winter dysentery (WD) of adult cattle. In respect to their hemagglutinating properties and their higher RDE activities with rat erythrocytes, WDBCoV strains differed from NCDBCoV strains and respiratory bovine coronaviruses RBCoV strains. Serologically, three MAbs directed to the HE glycoprotein of the WDBCoV strain BCQ.2590 recognized two serogroups amongst NCDBCoV strains by hemagglutination inhibition, whereas only one of the MAbs failed to react toward three of the four RBCoV isolates tested. Sequencing analysis of the S (S1 portion), HE, ORF4 and ORF5 genes of BCoV isolates associated with different clinical syndromes indicated that neither insertions or deletions could explain their distinct tropism. For the HE glycoprotein, a total of 15 amino acids (aa) substitutions were identified by comparing field isolates to the prototype Mebus strain. Two specific proline substitutions were identified for virulent strains being located in the signal peptides (aa 5) and aa position 367; one specific aa change was revealed at position 66 for RBCoV field isolates. Analysis of the S1 portion of the S glycoprotein revealed a total of eight aa changes specific to enteropathogenic (EBCoV) strains and eight aa changes specific to RBCoV strains. For all BCoV isolates studied, the region located between the S and M genes (ORF4) apparently encodes for two non-structural (ns) proteins of 4.9 and 4.8 kDa. A specific non-sense mutation was identified for the nucleotide at position 88 of the putative 4.9 kDa protein gene of RBCoV isolates resulting in 29 rather that 43 aa residues. The ORF5, which encodes a 12.7 ns protein and the 9.5 kDa E protein, was highly conserved amongst the BCoV field isolates.

Phylogenetic Studies of Bovine Coronaviruses Isolated in Japan

“…This study revealed that recent Japanese field isolates have distinctive genetic divergence from prototype enteric BCoV (EBCoV) strains (Mebus, Quebec, Kakegawa, F15 and LY138) and that they have diverged in 3 different aspects over this 8-year period. In addition, our study did not reveal the presence of certain genetic markers of pathogenicity and clinical symptoms in this polymorphic region, although some studies have suggested that several amino acids may contribute to each of the two disease types, that is, enteric (EBCoV) and respiratory (RBCoV) [2,4,6,13].…”

Respiratory Disease Associated with Bovine Coronavirus Infection in Cattle Herds in Southern Italy

“…The BCoV respiratory disease has been described in different areas worldwide, including the United States, 14,19,23 Canada, 8 Turkey, 13 Japan, 17 Finland, 1 and Sweden. 11 In the Finland study, 1 various microorganisms were detected in association with BCoV, including mycoplasmas (mainly Mycoplasma bovis and Mycoplasma dispar), Pasteurella multocida, Mannheimia haemolytica, and Arcanobacterium pyogenes, as well as other viral pathogens, specifically, BPIV3, BRSV, and bovine adenoviruses.…”

Epidemic of Equine Coronavirus at Obihiro Racecourse, Hokkaido, Japan in 2012

“…2). The p4.7 to p12.7 genes in ECoV, which corresponds to p4.9, p4.8 and p12.7 genes in BCoV [7], are between S and envelope genes in Betacoronavirus 1. In this region, CRCoVs have 3 (p4.9, p2.7 and p12.8) genes or 2 (p8.8 and p12.8) genes depending on virus strains [6,13].…”