Pathogenicity of porcine respiratory coronavirus isolated in Québec.

Porcine respiratory coronavirus (PRCV) is present in many countries, including Canada, but controversy still exists concerning its pathogenicity. Eight-week-old piglets were inoculated intratracheally with a Quebec PRCV isolate (1Q90). Two contact piglets were kept with the inoculated animals. Three animals served as control. Polypnea and dyspnea were the main clinical signs observed. Diffuse bronchioloalveolar damage occurred 24 hours postinoculation. Changes compatible with bronchointerstitial pneumonia were present six days postinoculation. The inoculated virus was recovered from the respiratory tract and mesenteric lymph nodes, but not from the digestive tract, of the inoculated as well as the contact piglets. No virus was isolated from the control piglets. The development of clinical signs and histopathological changes in inoculated as well as in contact piglets and the reisolation of the inoculated virus demonstrated that PRCV can be an important respiratory pathogen.