(A-D) Colon sections of an asymptomatic dog naturally infected with L. infantum: (A and B) (A) Panoramic view of mucosal (lamina propria), muscularis mucosae and submucosal layers of caecum fragment showing an intense and diffuse cellular exudates, HE (Bar = 32 μm); (B) Higher magnification showing mononuclear cells represented by parasitized macrophages with Leishmania (white arrow) or not (black arrow), lymphocytes (white arrowheads) and plasma cells (black arrowheads) without ulcer or erosions of the epithelium (Bar = 16 μm); (C) Mucosa (Lamina propria) layer showing an increased number of cells. Macrophages with Leishmania can be noted (white arrows). Only a discrete atrophy (flatting) of the epithelial cells can be observed (black arrow), HE (Bar = 16 μm); (D) Same fragment of colon showing higher parasitism tissue load. Observe a hipertrophic macrophages with many intracellular forms of Leishmania (black arrow), Streptoavidin-peroxidase, (Bar = 16 μm). LP: Lamina Propria; MM: Muscularis mucosae; SM: Submucosal; GI: Glands of Intestine Mucosal and Hematoxilin-Eosin (HE).