Experimental infection of adult axenic rats with Parker's rat coronavirus

The pathogenesis of Parker's Rat Coronavirus (PRCV) was studied in axenic CD rats. Three to four 9 to 10 week old rats were euthanized daily for eight days after intranasal inoculation. Rats remained free of clinical disease. Virus was recovered from the nasopharynx and trachea after twenty-four hours and from the lung by day three but was not detected in respiratory tract after seven days. Viral antigen was detected by indirect immunofluorescence in the mucosal epithelium of upper respiratory tract and in pulmonary alveolar septae from day two to six postinoculation. Acute rhinitis developed by day two and was associated with mild focal necrosis of respiratory mucosal epithelium. Mild nonsuppurative tracheitis and multifocal interstitial pneumonia appeared by day five and persisted through day eight. Dacryoadenitis did not occur, sialoadenitis was detected in only three rats and virus was recovered from only one submaxillary salivary gland. This experiment indicates that PRCV can be a primary pathogen for the respiratory system of adult rats. In contrast to sialodacryoadenitis (SDA) virus the tropism of PRCV for salivary and lacrimal glands is low.