CIRCULATING LEUKOCYTES AFTER B.C.G. AND EXPERIMENTAL BABESIA EQUI INFECTION IN DONKEYS

A group of 6 donkeys were used to evaluate the effect of B.C.G. injection on the activation of non-specific cell mediated immunity against the experimental infection of Babesia equi.
The experimental donkeys were previously treated against internal parasites until proved its freedom from infestation. The animals were proved to be free from tuberculosis using tuberculin test. The experimental animals were injected by B.C.G. intradermally. After one month they were challenged experimentally by B.equi infected blood (98% parasitaemia) intravenously.
· Out of the experimental group three donkeys were splenectomized to induce relapses.
All animals were clinically observed, blood samples and bone marrow smears were routinly examined for estimation of leukocytic picture.
The study revealed that the injection of B.C.G. had protected donkeys from acute babesiasis, however it failed to protect splenec tomized animals from acute relapses and severe p < /strong>arasitaemia was observed, and all splenectomized animals were died.
The observations of leukograms revealed a highly significant leukocy taemia to reach maximum (19.2 + 3.4 X 10 /ul) two weeks post B.C.G. injection, and one week post experimental babesial infection.
The relative count revealed a highly significant neutrophilia and eosinophilia post B.C.G. up to one month post infection with the increase of the relative number of non sigmented cells, however, monocytes achieved non significant increase in the peripheral blood.
Leukograms of splenectonized animals revealed a highly leuocyttosis (47x10°/ul) in two of them, however, the 3rd one showed severe leukopenia (2.7X10 ul). The relative values of segmented and non sigmented neutrophils achieved a highly significant increase (neutrophilia), while the relative number of lymphocytes was dec resed, however, the relative values of eosinophils and monocytes were significantly increased.
It was observed that the phagocytic processes were highly activated post experimental infection. Neutrophils were able to engulf more than one parasitic cell in the peripheral blood, however monocytes were able to phagocyte a lot of parasitic cells and others could
engulf more than one of the infected erythrocytes (erythrophagocy tosis) especially in bone marrow smears.