STUDIES ON THE NASAL HISTOLOGY OF EPIDEMIC INFLUENZA VIRUS INFECTION IN THE FERRET

Abstract

Because of the marked morphological abnormality of the nasal respiratory epithelium in ferrets recovering from epidemic influenza virus infection, attempts were made to determine whether the anatomical changes were associated with functional changes in the epithelial cells. It was found that on the 7th or 8th day after infection, at which time an immature transitional type of epithelium covers the respiratory area, the cells are resistant not only to reinfection with influenza virus but to a severe physicochemical stimulus supplied by iontophoresis or prolonged irrigation with zinc sulfate. Later, as the ciliated columnar cells return, susceptibility to physicochemical injury returns although resistance to influenza virus persists. The ciliated columnar cells are the ones which are damaged by the physicochemical agent while the deeper cells in the regenerating area remain unaffected. 5 weeks after infection the epithelium is anatomically normal but tissue resistance to zinc sulfate is still present to some degree as evidenced by foci of undamaged cells remaining after ionization.