Histological analysis of lungs and pulmonary lymph nodes in calves with respiratory disease

In order to identify pathomorphological changes, histological studies of the lungs of calves from two groups were performed. Calves of the first group had parainfluenza, and the second group included calves with an acute course of catarrhal purulent bronchopneumonia with clinical signs of chronic and acute pulmonary pathology. Clinical and histological methods of investigation were used in the work. Established pathomorphological changes in the lungs of calves of the first group in the form of chronic interstitial bronchopneumonia accompanied by compensatory chronic alveolar emphysema, formation of multinucleated symplast and multicellular syncytiae from the epithelium of alveoli, as well as mixed cytopathic forms of respiratory epithelium - symplasts-syncytiae are characteristic cytological signs of chronic parainfluenza infection. Detection of local thickening of bronchial walls due to proliferation of multilobular epithelium and infiltration of its submucosal base by lymphoid cells with narrowed lumen profiles also confirms parainfluenza etiology of the changes that occurred in the lungs. Marked manifestations of bronchopneumonia were manifested with maximum intensity in ventilated cardiac and diaphragmatic lungs of sick calves. Chronic inflammatory process in the lungs at parainfluenza was complicated by fibrinous pleurisy, as well as peri- and endocarditis, myocardiodystrophy with distorted structure of cardio-myocytes and atypical heart cells. In the pulmonary lymph nodes of parainfluenza-affected calves a moderately pronounced hyperplasia of lymphoid tissue cells with the presence of secondary lymph nodes, some of which had a pronounced structure of dark cellular periphery and a broad cell-rich germinative zone. In calves of the second group with an acute course of catarrhal purulent bronchopneumonia we could not detect the above cytopathic changes in the airways and the respiratory part of the lungs. Pathological changes in the lungs were predominantly exudative, represented by serous alveolitis, catarrhal purulent bronchopneumonia with involvement of anterior and cardiac lobes of the organ. Short course of the disease was accompanied by weak proliferation of lymphoid tissue cells in pulmonary lymph nodes.