Inclusion body rhinitis
- 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