Protazoa.- Transmission: Cysts in water

Amebiasis – 1-4 weeks of bloody diarrhea (dysentery), liver abscess ("anchovy paste" exudate), usually a single liver abscess in the right lobe, RUQ pain.

Diagnosis: Serology, antigen testing, and/or trophozoites (with engulfed RBCs in the cytoplasm) or cysts with up to 4 nuclei in stool.- Histology of colon biopsy shows flash-shaped ulcers.

Treatment: Metronidazole; paromomycin or iodoquinol for asymptomatic cyst passers.