Balantidium coli is the only ciliated protozoon known to infect humans and is the largest protozoon infecting humans and nonhuman primates. Balantidiosis is a zoonotic disease and is acquired by humans via the fecal-oral route from the normal host, the pig, where it is asymptomatic. Water is the vehicle for most cases of balantidiosis. Medical Parasitology is the branch of biomedical sciences dealing with parasites which live temporarily or permanently, on or within the human body (host). It is