Contribution to the problem of cyst-producing coccidians.

The problem of life cycles of cyst-producing coccidians, mainly those of the genus Sarcocystis, from carnivorous birds has been discussed. Oocysts of the "sarcocystic" type have been recovered from 9 species of birds of prey and owls from Czechoslovakia. The course of experimental infection in a group of birds consisting of the species Tyto alba, Asio otus, Strix aluco, Buteo buteo has been described. We inoculated these birds with cystic stages of the genus Sarcocystis obtained from white laboratory mice (Mus musculus) infected previously with oocysts from Tyto alba. The nomenclature of heteroxenous coccidians of the genus Sarcocystis has been discussed and suggestions have been made for the use of simple, one-word specific names. A description is given of a new species of the genus Sarcocystis--Sarcocystis dispersa sp. n. Its asexual development and cyst production in Mus musculus (intermediate host), and cyst production in Tyto alba and Asio otus (definitive hosts) have been studied.