Characteristically, by 5 days postinfection, there is diffuse necrosis of alveolar and ductal epithelium in the salivary and lacrimal glands, and polymorphonuclear leukocytes quickly infiltrate the necrotic debris and interstitium accompanied by interstitial edema. The ductal epithelium is rapidly repaired, becoming hyperplastic and squamous in appearance by 10 days postinfection. Complete restoration of normal glandular architecture requires about 30 days. Eye lesions include interstitial keratitis, corneal ulcerastion, keratoconus, synechia, hypopyon, hyphema, and conjunctivitis. Sequelae of infection include megaloglobulus with lenticular and retinal degeneration.
Thymic lesions are limited to focal areas of necrosis.
Focal necrosis and lymphoid hyperplasia occur in cervical lymph nodes. Presumptive diagnosis often can be based on characteristic histological changes in affected glandular tissue. The virus can be isolated by culture techniques using primary rat kidney cells or by intracerebral inoculation of neonatal mice. Control requires very strict adherence to preventative measures, including procurement only of SDAV-free rats and adherence to strict barrier housing procedures. Prompt elimination of infected populations is essential to prevent spread of infection to other rodents.