INVESTIGATION OF THE PRESENCE OF PARAINFLUENZA-3 INFECTION IN PNEUMONIA-INFECTED BOVINE LUNG TISSUES

10. INTERNATIONAL CONGRESS ON CONTEMPORARY SCIENTIFIC RESEARCH, Madrid, İspanya, 18 - 25 Nisan 2026, cilt.1, ss.1750-1758, (Tam Metin Bildiri)

Parainfluenza type-3 (PI-3) virus is one of the major viral agents involved in bovine respiratory system

diseases. This enveloped, single-stranded RNA virus belongs to the family Paramyxoviridae and the genus

Respirovirus, and is particularly effective in young animals and those with weakened immune systems. PI-3

infections generally present with mild clinical signs or remain subclinical; however, when combined with

bacterial and other viral agents, they contribute to the development of more severe respiratory diseases known

as Bovine Respiratory Disease Complex (BRDC). The aim of this study was to investigate the presence of PI-

3 virus in pneumonic cattle and to determine the types of pneumonia. For this purpose, 50 pneumonic bovine

lung tissue samples were collected, fixed in buffered formalin, and examined using macroscopic and

histopathological methods. Subsequently, all samples were evaluated for the presence of PI-3 by

immunohistochemical methods. Macroscopic examination revealed increased lung volume, a mottled marblelike

appearance, bloody or purulent exudate, and, in some cases, pleural thickening. Histopathological findings

included fibrin accumulation, hepatization areas, and intense neutrophil infiltration in fibrinous

bronchopneumonia; mononuclear cell infiltration and edema in interstitial pneumonia; abundant exudate in

catarrhal bronchopneumonia; and necrotic areas in suppurative-necrotic bronchopneumonia.

Immunohistochemical analysis demonstrated the presence of PI-3 antigen in 14 out of 50 samples. Viral

antigens were localized in the cytoplasm of bronchial, bronchiolar, and alveolar epithelial cells. In conclusion,

PI-3 virus was found to have a certain prevalence in pneumonic cattle and may play a role in the etiology of

respiratory diseases. This finding indicates that PI-3 infections should be taken into consideration in the control

of respiratory diseases in regional livestock production.