Pathological study and detection of Bovine parainfluenza 3 virus in pneumonic sheep lungs using direct immunofluorescence antibody technique

Bovine parainfluenza 3 virus is a common virus that causes respiratory tract infection in cattle, sheep, and goats worldwide. The objective of this study is to identify macroscopic and histopathological lung lesions in slaughtered sheep during the period from December 2018 to December 2019 and to determine the presence of Bovine parainfluenza 3 virus (BPI3V) in frozen sheep pneumonic lung using a direct immunofluorescence antibody technique (DFAT). The overall prevalence of lung affection was 11% (1440/13084). The gross lesions were acute bronchopneumonia (58.12%), interstitial pneumonia (07.15%), fibrinous bronchopneumonia (10.70%), suppurative bronchopneumonia (03.47%), verminous pneumonia (13.75%), and ovine pulmonary adenomatosis (06.81%). There was a significant difference in the rate of pulmonary lesions according to the seasons of the study. The lesions were more frequently observed in autumn and winter with a rate of 34.17% and 28.05%, respectively. The DFAT was carried out only on 107 pneumonic samples with interstitial pneumonia, fibrinous bronchopneumonia, and acute bronchopneumonia. The BPI3V antigens were detected in 12 samples (11.21%). This is the first study that revealed the presence of the BPI3V in pneumonic sheep lungs in Batna region using the direct immunofluorescence antibody technique. The latter may be used for definite diagnosis when histopathological modifications in pneumonic sheep caused by this virus are difficult to distinguish from those caused by other respiratory viruses.