Balantidiasis is a zoonotic disease and is acquired by humans via the fecal-oral route from the normal host, the pig, where it is asymptomatic.

[4] It is its size at this stage that allows Balantidium coli to be characterized as the largest protozoan parasite of humans.

[4] Unlike the trophozoite, whose surface is covered only with cilia, the cyst form has a tough wall made of one or more layers.

Some specific safeguards include the following:[citation needed] Balantidiasis can be treated with tetracycline, metronidazole or iodoquinol.

[8] However, this experiment was not successful in creating an infection and it was unclear whether Balantidium coli was the actual parasite used.

[12] In a Japanese study that analyzed the fecal samples in 56 mammalian species, Balantidium coli was found to be present not just in all the wild boars tested (with wild boars and pigs being considered the same species), it was also found in five species of non-human primate: Chimpanzee (Pan troglodytes), White-handed gibbon (Hylobates lar), Squirrel monkey (Saimiri sciurea), Sacred baboon (Comopithecus hamadryas), and Japanese macaque (Macaca fuscata).