THE ROLE AND SIGNIFICANCE OF MORPHOLOGICAL CHANGES IN INTRAORGAN VESSELS IN ANIMALS DURING PATHOGENESIS OF BABESIOSIS

Abstract

The aim of this study is to investigate morphological changes in intraorgan vessels and their role in susceptible animals in the pathogenesis of babesiosis. The material of the study included the intraorgan vessels of domestic dogs with clinically and laboratory confirmed babesiosis and wild mouse-like rodents from latent foci of babesiosis in Volyn, Zhitomir, Kiev, Poltava, Sumy, Kharkov, Chernigov regions. For histological study, we used standard fixation in a 12% aqueous formalin solution in phosphate buffer (pH = 7.0-7.2). After the post-fixation and dehydration, the samples were placed into paraffin blocks; then a series of histological slices (5 μm) were prepared. The preparations were stained with hematoxylin and eosin, according to Van Gieson technique. All test animals, regardless of the species taxonomy, were divided into two groups. The control group included clinically healthy animals (∑ = 36). The group under clinical study consisted of animals with clinically and laboratory confirmed babesiosis (∑ = 91). Histological changes in intraorgan vessels in the control group corresponded to the anatomical and functional parameters in the health. The preparations taken from the group with basesiosis demonstrate that microvessels are branched, different in size, spasmodic; their walls have signs of delamination and through lesions. Delamination developed gradually, started with the detachment of a small horizontal fragment of the outer layer. Defects in the integrity of microvessels resulted in penetrations; there was an active diapedesis of erythrocytes into the periovascular space. The accumulation of erythrocytes directed to the areas of connective tissue, branching of blood vessels, and fatty fragments. Hemorrhages were local in nature, concentrated in the form of small blurred foci of irregular shape. In the pathogenesis of babesiosis, the defects in the walls of blood vessels with their further penetration and dissection, hemorrhages, microvesiculation of the endothelium, and its desquamation play a critical role. Other manifestations included the development of intravascular blood coagulation, thrombosis, stasis, microcirculation disorders followed by ischemia, destructive and degenerative changes in the walls of blood vessels.