Histopathological Changes in Mice Inoculated with Influenza Virus

Abstract

Intra-nasal instillation of the PR8 strain of influenza virus produced in mice an edematous pneumonic process which was fatal in about 4 days in 80-90% of the mice. The histological changes at various time intervals after inoculation are given in detail. The fully developed lesion showed edema, interstitial cellular exudation, and damage to the bronchial epithelium. Surviving mice sacrificed at intervals showed squamous metaplasia of the alveolar epithelium and persistence of the bronchial epithelial damage. The respiratory and olfactory epithelia of the nose showed no lesions. Slight lesions were present in the liver, spleen, thymus and kidney, with none in the adrenal, brain, thyroid, heart, pancreas or gastrointestinal tract.