Experimental infections with some pneumotropic viruses in the mouse. Note I. Virological and pathomorphological aspects of the associated infections with influenza virus, adenovirus and respiratory syncytial virus.

In white mice, the associated infections with the influenza virus type A(H3N2), the adenovirus type 3 and the long strain of the respiratory syncytial virus, detected by the appearance of homologous serum antibodies and by positive I.F. reactions in pulmonary tissue, induce histological, histochemical and histo-enzymatic lesions, the severity of which exceeds that of the lesions in animals infected with only one of the mentioned viruses. In comparison with the morphological picture in animals inoculated with a single virus, expressed by inflammatory, infiltrative, lymphohistiocytic pulmonary (infiltrative, interstitial, diffuse, sometimes "cuffing", peribronchial and perivascular broncho-pneumonias), hepatic and renal processes, in the case of associate infections pathomorphological changes appear on wider surfaces and with a high frequency, manifested also by hyalinosis of the vascular media in the lung and the spleen, vacuolization of the cytoplasm of hepatocytes, hypertrophy of the lymphoid follicles in the spleen and the lymph nodes (in associated infection due to the influenza virus+adenovirus and vice versa) or, on the contrary, hypotrophy of the lymphoid follicles in the spleen and lymph nodes (in the associated infection due to the influenza virus+respiratory syncytial virus and vice versa).