Inclusion Body Rhinitis

Inclusion body rhinitis

Inclusion body rhinitis (Image sourced from Bristol Biomed Image Archive with permission)

• Herpesviridae, porcine cytomegalovirus
• Disease of suckling piglets 1-5 wks of age
• Clinical signs: those associated with acute/subacute rhinitis (ie: serous nasal discharge, progressing to catarrhal or purulent discharge with time and secondary bacterial infections; sneezing; pyrexia), fever in young piglets (3-8wks old)
• May progress to sinusitis, otitis media or pneumonia
• Morbitity high, mortality low
• Gross pathology - catarrhal discharge becoming purulent (secondary infection)
• Histology:
  • Large basophilic intranuclear inclusion bodies in the surface and subepithelium of nasal and sinus glandular epithelium with lymphocytic infiltration of the mucosa
  • Bursting of nucleus with cell necrosis and sloughing of necrotic epithelium
• Can develop viraemic stage, with inclusions and focal necrotising lesions in other organs eg: renal tubular epithelium
  • Usually younger piglets, can die during this phase
• Usually resolves if uncomplicated but rhinitis may persist if secondary infection is present
• May persist in pulmonary macrophages