<prompt> Common host of Balantidium coli isCattleDogGoatPig  <response>: Ans: d PigRef: C K Jayaram Panickers Textbook of Medical Parasitology, 6th ed. Pg. 111-112Balantidium coli Only ciliate protozoan parasite of humans Largest protozoan parasite in humans It is a zoonosis, the principal reservoir being pigs, monkeys and rats. It occurs in 2 stages -- trophozoite and cyst form. Trophozoite lives in the large intestine Infective form is the cyst in food and water. Clinically resembles amoebiasis -- diarrhoea or dysentery, abdominal colic, nausea, vomiting Treatment is with tetracycline metronidazole is also useful. 