Sequential histopathology of cavitary liver abscess formation induced by axenically grown Entamoeba histolytica.

Animal models of amebic hepatic abscess should parallel the human disease. Experimental amebic hepatic abscess in the hamster results in granulomatous lesions during the early period (six days) following inoculation. Hamster inoculated intrahepatically with axenically grown, non-liver passaged strains of Entamoeba histolytica revealed no evidence of lesions when sacrificed at later times. However, hamsters similarly inoculated with multiply liver passaged substrains were found to have large fluid-filled hepatic abscesses four to six weeks following inoculation. The histopathologic appearance of these lesions closely resembled that most often described in human amebic hepatic abscess. Production of amebic hepatic abscess in the hamster may provide a valuable animal model of this potentially fatal human disease and provide new information concerning both the pathogenesis and host response.