Viral antigen can be detected in ciliated epithelial cells of the nose and lungs, but not trachea [68], [69], [70], and induces an increase in IFNγ, IL-10, IL-6, MCP-1 and growth-regulated oncogene (GRO) (IL-8 homologue) mRNA in the lungs [71], and histopathological changes characterised by a desquamative, exudative rhinitis, and a mild proliferative bronchiolitis (Fig. 1I) [68], [72]. Here, IFNG is linked to bronchiolitis.