On the morphological diagnostics and host specificity of the Sarcocystis species of some domesticated and wild bovini (cattle, banteng and bison).

Sarcocysts of Sarcocystis cruzi, S. hominis and S. hirsuta were described and compared by means of light (LM) and transmission electron microscopy (TEM) from cattle, bantengs (born in a zoo) and bisons (born in zoo). No morphological differences were observed in the three forms of sarcocysts from each of the three host species. The morphological criteria of the three species were discussed and, partly, newly defined. S. cruzi can easily be distinguished from the other two species. It shows 6-13 micron long hair-like villar protrusions in the freshly extracted sarcocyst, has large compartments often bump-like bulged out (by LM, in the fresh state), and a "thin cyst wall" ( < 1 micron; LM, histology). TEM investigation is not necessary in most cases. S. hominis and S. hirsuta: with a "thick, radially striated" and 2.5-9.0 micron high cyst wall (LM). S. hominis can be most reliably determined by means of TEM: the villar protrusions arise with a broad basis from the cyst surface, are finger-like in the outline and have microfilaments in the core. LM: the villar protrusions are broadly seated on the cyst surface, without optical interruption. Likewise, S. hirsuta can be determined most reliably by TEM (in some cases also in semithin sections): the villar protrusions are club- or bulb-shaped in the outline, with a stalklet at the base and with microfilaments and large osmiophilic granules in the interior. LM (best in the fresh state): the palisade of villar protrusions often shows a bright or dotted horizontal line in the middle and a basal line with dark dots, arranged like a string of pearls.