Figure 3

Pathogenesis of EEEV in guinea pigs after aerosol exposure. (A) EEEV antigen was present in a segment of olfactory neuroepithelium, but not in the adjacent respiratory epithelium, of a guinea pig 48 hr after exposure. The junctions of olfactory mucosa and respiratory mucosa are demonstrated by the arrows. (B) EEEV antigen is present in the olfactory bulb of a guinea pig 72 hr after exposure. Note the disruption of the neuropil and the infiltration of the neuropil and meninx by inflammatory cells. (C) EEEV antigen was present in the cell bodies and neuritic processes of several neurons in the brain of a guinea pig 72 hr after exposure. (D) In the brain of the same guinea pig as in Figure 3C, there is abundant viral antigen throughout the pyriform cortex (*'s) and the deeper basal nucleus, as well as in the periventricular cells (arrow). (E) Abundant inflammatory cells thicken the meninx overlying the pyriform cortex (*), form cuffs around blood vessels in the basal nucleus (arrows) and also infiltrate the neuropil (arrowhead) of a guinea pig 96 hr after exposure. (F) In the brain of the same guinea pig as in Figure 2E, the wall of an inflamed blood vessel is disrupted, infiltrated by inflammatory cells and contains eosinophilic (fibrinoid) material (arrowheads). Also, note the perivascular hemorrhage (arrow). (G) Minimal viral antigen is present in the lung of a guinea pig 48 hr after exposure.