ULTRASTRUCTURAL FINDINGS IN NATURAL CANINE HEPATOZOONOSIS

The ultrastructure of several stages of Hepatozoon canis found in dogs with clinically and histologically diagnosed infections was determine d using transmission electron microscopy. Merozoites, macro- and micro schizonts and gamonts were found in spleen, liver, kidneys and lungs. Macro- and micromeronts were characterized by their size and by the pr esence of intracytoplasmic amylopectin granules. Gamonts, which provid e the basis for clinical diagnosis of the disease, were observed withi n mononuclear cells (monocytes/macrophages); they were butterfly-shape d and exhibited varying electron densities. On the basis of the micros copic observations reported here, it is dear that the life cycle of H. canis is a complex one.