Macroscopic and microscopic signs of infection and inflammation in mice infected with M. ulcerans.

The upper panel shows photograph of a C57Bl/6 mouse footpad 5 weeks after injection with M. ulcerans (NM20/02) (A) and the non-injected control footpad (B). Middle panel shows the corresponding 5micrometer thick paraffin embedded footpad slices stained with Ziehl-Neelsen (ZN) staining. Finally, the lower panel shows the same footpad slices stained with Hematoxylin Eosin (H&E). Arrows show the bacterial foci (ZN) and the inflamed tissue (H&E) of the lesion.