Hemorrhagic lesions in the olfactory epithelium of CHIKV infected IRF3/7^-/- mice.

<p>(A, C, E) H&E of the head of IRF3/7^-/- mouse day 5 post CHIKV infection and (B, D, F) H&E of the head of a control uninfected IRF3/7^-/- mouse; T—turbinate bones, arrows—red blood cells, NC—nasal cavity. (A) Low magnification image showing extensive red blood cells and mucous exudates (pink staining material) in the nasal cavities. (*—large foci of vacuolization in the olfactory bulb). (B) The same region and magnification as in A for an uninfected mouse. (C) Medium magnification image showing breaches in the olfactory epithelium (dotted white circles). (D) The same region and magnification as in C for an uninfected mouse. (E) High magnification image of a lesion in the olfactory epithelium showing pyknotic nuclei (white arrow heads) and some neutrophils (black arrow head). (F) The same region and magnification as in E for an uninfected mouse.