balantidiidae balantidiidae balantidiidae is a biological family of chromists in the phylum ciliophora. the family name comes from the type genus balantidium. balantidiidae balantidium coli trophozoite scientific classification domain: eukaryota clade: diaphoretickes clade: sar clade: alveolata phylum: ciliophora class: litostomatea order: vestibuliferida family: balantidiidaereichenow in doflein & reichenow, 1929 type genus balantidium distribution the balantidium coli species has a worldwide distribution, but is more frequent in subtropical and temperate climates. the medical condition balantidiasis is particularly prevalent where poor hygiene and undernourishment weaken a population coincide with living in close contact with pigs, the main reservoir for the species.