Features of the microscopic structure of the intestinal wall in females of the ixodic tick of the genus Dermacentor during the feeding period

Abstract

Ixodic ticks of the genus Dermacentor are parasitomorphic ticks that are carriers of a number of dangerous zooanthropozonoses, have a wide distribution. The intestine of an adult contains several types of cells: digesting, secretory, reserve and yolk cells. Digestive cells of types 1 and 2 are involved in the process of intracellular digestion and are the main components of the wall of the middle intestine. After insemination, yolk cells begin to form in the intestine, regulating the development of oocytes. The research was carried out on the basis of the Department of Parasitology and Veterinary and Sanitary Examination, Anatomy and Pathanatomy named after Prof. S. N. Nikolsky and at the Scientific Diagnostic and Therapeutic Veterinary Center of the Stavropol State Agrarian University, as well as on the basis of veterinary clinics of IP Zaichenko "Veterinary Center named after Pirogova". The object of the study was ixode mites, the material for the study was the digestive system of females, in particular the middle part of the intestine. Macroscopic examination of the nourished females of the Dermacentor tick helped to reveal that the intestine is an unpaired tubular organ divided into three sections: the esophagus, the sac-like meatus and the small intestine. With the arrival of blood, the intestine expands, as a result of which reserve cells begin to grow and differentiate into primary digestive ones. By the time egg laying begins, digestive cells of type I degenerate and are replaced by digestive cells of type II, differentiated from reserve cells. In nourished females, with an active process of vitellogenesis, the presence of specialized yolk cells is noted. Thus, with the beginning of the feeding period in ixodic mites, an increase in the intestine occurs due to the asynchronous development of digestive cells of type I and II. During digestion, secretory cells are focally exfoliated into the intestinal cavity filled with the host's blood, which characterizes the acceleration of the process of erythrocyte hemolysis. In the final phase of digestion, and the beginning of the vitellogenesis process, yolk cells are formed that regulate the development of oocytes.