Studies on the Prevention of Leucocytozoon Infection of the Chicken. : VI. The Observation of the Gametocytes of Leucocytozoon caulleryi in the Unstained Wet Blood Film.

Usually the diagnosis of the infected chickens with leucocytozoon disease has been made by finding gametocyte of Leucocytozoon caulleryi in the blood smear stained by Giemsa's or May-Grunwald's method. But, as the inner part of the gametocyte can be observed in the unstained wet film of blood, the feature of the gametocyte considerably differs from that of the fixed sample. Method: One drop of blood from an affected chicken is placed on a cover-glass. This is inverted on a slide and the preparation is rimmed with paraffin. Then it is examined with phase-contrast microscopy at 37℃. Results and considerations: In macrogametocyte, the nucleus is rather small, usually have a curved or twisted rod shape and is suspended in protoplasm. The protoplasm is rich and filled with the immense number of fine granules. But in an usual smear sample, the nucleus shrinks and is covered with the granules at the time of smearing, and yet the granules are stained in dark purple by Giemsa's method, and hence it is considered that the shape of the nucleus is obscured. In microgametocyte, the nucleus is globular or oval, rather large in size compared with the size of the gametocyte itself, and placed at the nearly central point of the cell. The granules of protoplasm are a little larger in size and less in number than that of the macrogametocyte, and as the most of the granules are attached around the nucleus, these look like a pearl necklace in an optical section. As the nucleus expands at the time of smearing, it extends on nearly the whole surface of gametocyte and the protoplasm is seen indistinctly around it. As the granules are attached to the nucleus, they scatter on the surface of the nucleus as it expands. Most of the macro- and microgametocyte are covered with the membrane of the host cell. These cell membranes contain semifluid thinner than the protoplasm of the parasite. Some of which contain the granules of various sizes and they present the vivid Brownian motion. But these granules cannot be stained with Giemsa's dye