In general pulmonary lesions associated with influenza infection were roughly comparable at Days 1 and 2 and consisted of variable suppurative or necrosuppurative bronchiolitis and mixed cell alveolitis at minimal to moderate severity levels. By 1 DPI, there were some small foci of inflammation without much infiltration of the bronchi or bronchioles. There was an increased severity of inflammatory findings in lung lobes from infected ferrets on day 3. Specifically, more extensive infiltration of neutrophils can be seen within the bronchiolar lumen, along with necrosupprative bronchiolitis and mixed cell alveolitis. At Day 7, lesions observed in the lung lobes continued to exhibit an increased severity compared to the majority of lung lesions seen at 1 and 2 DPI. Bronchiolar epithelial hyperplasia and cytokaryomegaly were noted in addition to bronchiolitis.