Introduction

Classification

Taxonomy

• Order: nidovirales.
• Family: coronaviridae.
• Sub-family: betacoronavirus 1.
• Species: bovine coronavirus (BCV).

Etymology

• Lt: corona-crown.

Active Forms

Clinical Effects

Epidemiology

Transmission

• BCV is shed in feces and nasal secretions.

Pathological effects

• The incubation time for BCV is approximately 20-24 hours in calves and 3-7 days in older cattle.
• Virus is excreted at very high titre for 3-4 days.
• BCV is characterized by fever, coughing, rhinitis, inappetence, bronchopneumonia, nasal discharge and sometime death, often with concurrent diarrhea. A dramatic reduction in milk production is observed with cases of winter dysentery Winter dysentery.
• Enteric BCV infections tend to be worse in calves.
• Respiratory BCV infections can be fatal if the animal is also exposed to stress factors (eg transportation, corticosteroids, infection with other viruses).
• BCV is believed to first replicate in the epithelial cells of the nasal mucosa from where it then spreads to the intestines via swallowing. Enteric infection begins in the small intestine from where it moves to the large intestine.
• BCV will damage enterocytes in the gut, resulting in malabsortive diarrhea.
• Severity of disease is influenced by a number of factors including dose, age of animal, type of husbandry.

Control

Control via animal

• Cleaning of the hindquarters of dams can help prevent fecal transmission to calves.
• Vaccination.
• Providing access to colostrum.

Control via chemotherapies

• Supportive fluid therapy Fluid therapy and astringents.

Control via environment

• Disinfection of cattle pens is important.
• Separate animals based on age groups.
• Avoid stress trigger factors such as:
  • Sudden changes in diet.
  • Cold temperatures.
  • Close confinement with other animals.

Vaccination

• Commercial vaccines are available but their efficacy is questionable.

Diagnosis

Further Reading

Publications

Refereed Papers

• Recent references from PubMed and VetMedResource.
• Saif L J (2010) Bovine Respiratory Coronavirus. Vet Clin North Am Food Anim Pract 26 (2), 349-364
• Ellis J A (2009) Update on viral pathogenesis in BRD. Anim Health Res Rev 10 (2), 149-53 PubMed.
•  Kapil S & Basaraba R J (1997) Infectious bovine rhinotracheitis, parainfluenza-3, and respiratory coronavirus. Vet Clin North Am Food Anim Pract 13 (3), 455-69 PubMed.
• Clark M A (1993) Bovine coronavirus. Br Vet J 149 (1), 51-70 PubMed.
• Saif L J (1990) A review of evidence implicating bovine coronavirus in the etiology of winter dysentery in cows: an enigma resolved? Cornell Vet 80 (4), 303-11 PubMed.