Observations on Haematoxenus separatus Uilenberg & Andreasen 1974 in the erythrocytes of Kenyan sheep.

Two Kenyan sheep were splenectomised; on examination of Giemsa stained blood smears large numbers of piroplasms identical in morphology to Theileria ovis and Haematoxenus separatus (with a veil in the infected erythrocyte) were detected. Uncoagulated infected blood was examined under phase-contrast and it was found that the vast majority of the infected erythrocytes had veils. The veils were more resistant to lysis than the erythrocyte itself and in lysed preparations the veils were seen floating in the plasma. The origin, function and taxonomic importance of the veils has yet to be established.