Etiology: Entamoeba sp. is a one celled, eukaryotic organism.
Incidence: Incidence of infection with Amoeba is common.
Transmission: Fecal-oral transmission via ingestion of infective cysts.
Distribution: Amoeba are distributed in the cecum and colon.
Clinical signs: There are no clinical signs. These protozoa may proliferate in diarrheic state, however, their role as contributors to disease is poorly understood.
Antemortem: Fecal floatation for cysts as well as PCR of feces can be used.
Postmortem: Wet mounts of intestinal contents may reveal cyst forms, or globular trophozoite amoebae with slow extension of pseudopods.
Diagnostic morphology: 15-24 µm round cyst with 1-8 nuclei (nucleus number increase from 1 to 8 with maturity) and vacuoles. Immature cysts tend to have larger and more vacuoles than mature forms. Globular amoeba trophozoites have a spherical nucleus. Nuclei of both amoeba and cyst forms have eccentric karyosomes.