Experimental amoebic liver abcess produced by oral administration of Entamoeba histolytica cysts.

To determine the possibility of amoebic invasion and liver-abscess formation Swiss albino mice were infected orally with E. histolytica cysts isolated from human stools. Parasitological and histopathological changes in mice colon and liver tissues were sequentially followed. Three weeks postinfection (p.i) 5% of immunocompetent and all cortisonized immunosuppressed mice passed the parasite in their stools. Only 70% of the latter group of mice sacrificed at that time developed invasive intestinal amoebiasis. At the end of the experiment (12 weeks p.i.) 100% of the remaining immunosuppressed animals developed the same intestinal pathology. Amoebic liver abscess was detected in 62.5% of them. Oral inoculation of E. histolytica cysts constitutes an easy highly reproducible procedure for inducing liver abscess in immunosuppressed mice.