The role of birds as definitive hosts and intermediate hosts of heteroxenous coccidians.

Sarcocystis-like oocysts-sporocysts were found in four species of owls (Asio otus, Bubo bubo, Strix aluco, and Tyto alba) and in five species of predatory birds (Accipiter gentilis, Accipiter nisus, Buteo buteo, Circus aeruginosus, Falco tinnunculus). In addition, the muscles of 15 of 41 (36.5%) pheasants (Phasianus colchicus) and one of two jays (Garrulus glandarius) were found to harbor three types of Sarcocystis. Three of 15 (20%) infected pheasants had type I cystozoites (6-8 X 2 microns) in muscle homogenates, but sarcocysts were not seen whereas the other 12 infected pheasants had type II cystozoites (16 X 2-3 microns) and sarcocysts (90 X 600 microns) in their muscles. The one infected jay had type III cystozoites (8-10.5 X 2.5-3 microns) and sarcocysts (35-40 X greater than 770 microns) in its muscles.