Experimental infection of rhesus monkeys with Entamoeba histolytica mimics human infection.

Experimental infection of Entamoeba histolytica was successfully established in rhesus monkeys (Macaca mulatta). Parasites of proven pathogenicity maintained through liver passage in hamsters were used in this study. Laparotomized monkeys were inoculated intracecally/intrahepatically with trophozoites, or by oral administration of cysts (2000 cysts/ml). The cysts were isolated from an infected human stool sample. Formation of typical amebic lesions in the inoculated tissues along with alterations in hematologic indices were studied in the infected monkeys. All the experimentally inoculated monkeys showed leukocytosis and mild neutrophilia, while the hemoglobin content and levels of blood sugar and blood urea remained unaltered during the post-infection period. Specific antiamebic antibodies were readily detectable in post-infected sera.