[Sarcocystis cruzi (Protozoa: Apicomplexa: Sarcocystiidae) infection in european bison (Bison bonasus) from Białowieza Forest, Poland].

Samples of oesophagus, diaphragm and heart muscles were taken from one European bison from Białowieza Forest during seasonal European bison elimination in 2008. Five gram of each muscle was examined by staining small samples in 0.2% aqueous solution of methylene blue. After that they were placed between compressor glasses and examined under a dissecting microscope in order to detect Sarcocystis sp. infection. All sarcocysts observed were counted. The 5-g sample of the heart muscle yielded a total of 756 sarcocysts while that of the diaphragm contained 107 of them and that of the oesophagus--89. All of the sarcocysts were isolated from 1 g of each muscle by using preparation needles (probes). After that the sarcocysts were taken to 0.5% physiological solution and examined under light microscope. The special attention was paid to detection of their cyst wall, which was thin (1 microm up to 1.2 microm) and smooth in all cases. Sometimes villar protrusions were seen on the surface of the cysts. Differences between the size of sarcocysts isolated from different muscle samples were observed. The longest and the slenderest sarcocysts were found in the diaphragm. Slightly smaller in the oesophagus and the smallest ones in the heart muscle tissue. The average size of sarcocysts isolated from diaphragm was 957.6 microm x 112.7 microm. Sarcocysts found in the oesophagus measured 484.1 microm x 194.6 microm and those isolated from the heart muscle attained 305.4 microm x 103.9 microm. All of the sarcocysts isolated from heart, oesophagus and diaphragm muscles were identified Sarcocystis cruzi.