[Pathomorphology of lung alterations in calves naturally infected with the virus of infectious rhinotracheitis].

In addition to diphtheroid rhinitis, and tracheitis, the infectious rhinotracheitis in calves has also been accompanied by a catarrhal-and-necrotic pneumonia. The mucous membrane of the bronchi, bronchioles, and alveoli in such cases is edematous with occasional necrotic areas. The necroses are focal and areactive. The peribronchial lymphoreticular system shows no signs of proliferation. The necrotic lesions in the bronchi and alveoli are considered as the porte d'entrée of the bacterial infection that aggravates the course of the disease and fairly often leads to death.