Enteric disease in postweaned beef calves associated with Bovine coronavirus clade 2

Abstract

Bovine coronavirus (BoCV; Betacoronavirus 1) infections are associated with varied clinical presentations including neonatal diarrhea, winter dysentery in dairy cattle, and respiratory disease in various ages of cattle. The current report presents information on BoCV infections associated with enteric disease of postweaned beef cattle in Oklahoma. In 3 separate accessions from a single herd, 1 in 2012 and 2 in 2013, calves were observed with bloody diarrhea. One calf in 2012 died and was necropsied, and 2 calves from this herd died in 2013 and were necropsied. A third calf from another herd died and was necropsied. The gross and histologic diagnosis was acute, hemorrhagic colitis in all 4 cattle. Colonic tissues from all 4 animals were positive by fluorescent antibody testing and/or immunohistochemical staining for BoCV antigen. Bovine coronavirus was isolated in human rectal tumor cells from swabs of colon surfaces of all animals. The genomic information from a region of the S envelope region revealed BoCV clade 2. Detection of BoCV clade 2 in beef cattle in Oklahoma is consistent with recovery of BoCV clade 2 from the respiratory tract of postweaned beef calves that had respiratory disease signs or were healthy. Further investigations on the ecology of BoCV in cattle are important, as BoCV may be an emerging disease beyond the initial descriptions. Challenge studies are needed to determine pathogenicity of these strains, and to determine if current BoCV vaccines are efficacious against the BoCV clade 2 strains.

Bovine coronavirus in Uruguay: genetic diversity, risk factors and transboundary introductions from neighboring countries

“…Although only one serotype of BCoV has been identified, there is increasing evidence of divergence of recent isolates from the historical reference strain used for most vaccine formulations (Mebus strain) [18,42,43]. In this regard, the strains detected in this study are divergent from the Mebus strain, as observed in the phylogenetic analysis, and nine amino acid differences were observed between the Uruguayan strains and Mebus.…”

Detection of Bovine Coronavirus in Healthy and Diarrheic Dairy Calves

“…38 Similar results have been reported in Europe and Asia . In 2012, the BCoV clade 2 strain was recovered from postweaned calves (6–7 months) suffering of severe enteritis with bloody diarrhea; the authors of that study suggested that this clinical syndrome caused by BCoV clade 2 should be added to the already known syndromes caused by BCoV . The results of these studies suggest that current BCoV strains circulating in worldwide are diverging from the prototype BCoV isolated in earlier studies and used in vaccines .…”

“…The results of these studies suggest that current BCoV strains circulating in worldwide are diverging from the prototype BCoV isolated in earlier studies and used in vaccines . This can result in the emergency of new clinical syndromes, outbreaks of enteric diseases with higher morbidity and case fatality (similar to the one described in this study), increased detection rates of BCoV in nasal and fecal samples of healthy and ill calves, and the lack of efficacy vaccination protocols . Future studies should focus on investigating the biological, antigenical, and genomical characteristic of BCoV circulating in Canada.…”

Brazilian strain of bovine respiratory coronavirus is derived from dual enteric and respiratory tropism

“…The same phenomenon might occur with certain strains of other countries such as Brazil. However, challenge studies in validated animal models are required to ascertain the correlation between strain-specific antigenic distances and efficiency of vaccine protection in cattle infected with the current Brazilian field strains of BCoV (Fulton et al, 2015).…”