Ultrastructural distribution of
6 h following nasal inoculation. Bacteria (black arrows) are present on the surface of the epithelium. Junctional complex (white arrow) between supporting cells (SC) remain intact (A). Bacteria may be located in the cytosol (arrows; B) or within vacuoles of supporting cells (arrowheads; inset in B). Highly vesiculated cells resembling macrophages are observed straddling the olfactory epithelium (OE) and lamina propria (LP; C). Bacteria are present in the vesicles of some macrophages in the lamina propria (arrows in inset of C) or more rarely in olfactory nerve bundles (arrows) that are comprised of large (L) and small (S) unmyelinated axons enveloped by cytoplasmic processes of olfactory ensheathing cells (D). Scale bar = 2 μm (A,B,C,D); 6 μm (inset in C).