Figure 1

Photomicrographs of liver sections from hamsters inoculated with E. histolytica or E. dispar trophozoites and sacrificed at 12 hs of infection. (a) Circumscribed nodular lesions (*) contained inflammatory infiltrate constituted predominantly by neutrophils, cellular debris and scarce E. histolytica trophozoites (arrow head). It is possible to observe the presence of leucocytes inside of the sinusoidal capillaries (arrow). (H) non-necrotic parenchyma. H&E; Bar = 100 μm. (b) Necrotic area (N) produced by E. dispar with intense capillary congestion, inflammatory infiltrate and trophozoite (arrow head). (H) non-necrotic parenchyma with presence of dilated sinusoidal capillaries. H&E; Bar = 20 μm. (c) Immunohistochemical reaction against E. histolytica trophozoites showing nodular necrosis with small central area of necrosis (N) and trophozoites (arrows). (H) non-necrotic parenchyma. Bar = 50 μm. (d) Immunohistochemical reaction against E. histolytica trophozoites showing extensive area of hepatic necrosis (N). Trophozoite (arrow) and antigens derived from the trophozoites (arrow heads) are also observed. (H) non-necrotic parenchyma. Bar = 50 μm. (e) Immunohistochemical reaction against E. dispar trophozoites (arrows) showing central area of necrosis (N). Bar = 20 μm. (f) Immunohistochemical reaction against E. dispar trophozoites showing nodular lesions (arrows) delimited by non-necrotic hepatic parenchyma (H). Granular dark brown material indicates positive staining for E. dispar antigens (arrow heads). Bar = 20 μm.