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

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