EN
Blood parasites of birds in Wrocław and its environment were investigated during the two complete annual cycles of 1957-1959. In all 362 birds belonging to 36 species were examined. The blood parasites were found in 128 cases; i. e. 35,5 per cent of the total amount of the examined birds. Ot these Protozoa were recognized in 72 cases and microfilariae of the family Filariidae in 56 cases. The Protozoa were represented by the genera: Leucocytozoon, Haemoproteus, Plasmodium and Atoxoplasma. Leucocytozoon was found in 46 birds belonging to 12 species; or 36 per cent of the total amount of the infected birds. The mature gametocytes had a round shape only and their dimensions varied from 11 to 12,4μ for the macrogametocytes, and from 10 o 12μ for the microgameocytes. Haemoproteus was recognised in 21 cases or 18 per cent of the infected birds. Two species were represented: H. danilewskii and H. fringillae, differing in shape, the extent of surrounding of the host cell nucleus, and the amount of the pigment grains. Plasmodium relictum was found in 31 birds or 24,2 per cent of the infected birds. In the circulating blood schizonts containing from 10 to 20 merozoites and gametocytes were found. Both of them had round shape and shifted the nucleus of the host cell;, the schizonts shifted it towards one of the two poles and the gametocytes in the side – direction. Atoxoplasma was recognised in 9 cases (7 per cent of the total amount of the infected birds). The mature parasites had oval or round shape and were, on the average, 6μ long and 3,8μ wide. Mixed invasions were found in 33 birds; in 32 cases they were double invasions and in one case a triple invasion.