Investigation of bovine herpesvirus 1 and bovine parainfluenza virus 3 in bovine pneumonia using polymerase chain reaction, double immunohistochemistry, and double immunofluorescence

The aim of this study was to investigate the presence of bovine herpesvirus type 1 and bovine parainfluenza virus type 3 (PI-3) in cattle lungs exhibiting pneumonia symptoms observed during macroscopic examination. Polymerase chain reaction, double immunohistochemistry, and double immunofluorescence methods were used for viral detection. For this purpose, during the summer-autumn period of 2023, a total of 84 lung samples from cattle aged 1 year and older, exhibiting macroscopic signs of pneumonia, were collected in Kayseri province, Türkiye. Pneumonia lesions were recorded according to the anatomical locations. In virus detection, PI-3 was identified at a rate of 8.33% using double immunohistochemistry/immunofluorescence staining methods, while this rate was found to be 6.72% in polymerase chain reaction. Bovine herpesvirus type 1 was not detected by any of the three methods. In the cattle lungs, 44 lesions (52.38%) were detected in the apical lobe, while seven lesions (8.33%) were detected in the middle lobe, eight lesions (9.52%) in the accessory lobe, and 25 lesions (29.76%) in the basal lobe. The PI-3 immunopositivity was observed in alveolar epithelial cells, as well as mononuclear cells in the interstitial and peri-vascular regions. This study is the first to examine bovine herpesvirus type 1 and PI-3 presence in bovine lungs using three distinct validation techniques (polymerase chain reaction, double immunohistochemistry, and double immunofluorescence).