[Growth of Balantidium coli populations under in vivo and in vitro conditions]

Trophozoites of Balantidium coli were isolated from the pig's caecum and cultivated in vitro. Pigs were divided into two groups: one with the acute balantidiosis and the second--with the asymptomatic balantidiosis. In the first case the biotic potential of protozoans turned out to be higher (the most intensive divisions occurred 24 hours after the second passage). Protozoans isolated from pigs with the asymptomatic balantidiosis had lower biotic potential (the most intensive divisions occurred 24 hours after the third passage). This fact indicates the differentiation of the investigated populations of B. coli.