Lung alterations in guinea-pigs infected with influenza virus.
Guinea-pigs were infected intranasally with influenza A Hong Kong 68 (H3N2) virus. Infective particles were re-isolated from lung homogenates up to 3 days after inoculation and indicated local replication. The subsequent lung inflammatory stages were studied by light microscopy, scanning and transmission electron microscopy (TEM). Lung alterations appeared after 24 h and intensified up to 7 days after virus inoculation, progressively decreasing until 3 weeks thereafter. The damage was reversible and complete restoration of structure was obtained within 5 weeks. The lesions commenced with the infiltration of bronchiolar and alveolar walls by polymorphonuclear cells, histiocytes and macrophages. A purulent exudate was seen to occupy the bronchiolar lumen. Cilia disappeared from tracheal and bronchiolar epithelia. Tracheal epithelium desquamated in some animals. TEM examination showed deterioration in type I pneumocytes, an increase in type II pneumocytes and concomitant damage to alveolar capillaries. Alveolar oedema and fibrinous deposits were seen. The pleura presented slight modifications. These results show that infection of guinea-pigs with influenza virus is a useful model for the study of lung pathology associated with a non-lethal respiratory viral infection.
D000818:Animals; D001980:Bronchi / Q000648:ultrastructure; D002923:Cilia / Q000648:ultrastructure; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D008168:Lung / Q000473:pathology*; D008855:Microscopy, Electron, Scanning; D009976:Orthomyxoviridae Infections / Q000473:pathology*; D011650:Pulmonary Alveoli / Q000648:ultrastructure; D014132:Trachea / Q000648:ultrastructure