Histological evolution of caecal lesions in experimental amoebiasis.

Histopathological studies in guinea-pigs infected intracaecally with Entamoeba histolytica were carried out longitudinally on days 3, 7, 11, 15, 20 and 35 after infection. Three characteristic modes of development of caecal lesions were observed. These in order of their prevalence were the classical inflammatory cellular infiltration, lymphoid hypertrophy and necrotizing colitis. Occasional amoeboma formation was observed in progesterone-treated animals. This is the first time that histological lesions which mimic the human intestinal amoebiasis have been described in the experimental animal.