Dicrocoelium Lanceatum (Trematoda, Dicrocoeliidae): the Study of the Neuro-Muscular System

Abstract

The work provides data on the presence and localization in the nervous system of the causative agent of dicroceliosis, Dicrocoelium lanceatum serotonergic and FMRFaminergic structures. Using the immunocytochemical method and confocal scanning laser microscopy, the test substances were found in the central and peripheral parts of the parasite's nervous system — in the head ganglia, the central nervous commissure, the longitudinal nerve trunks and the transverse commissures connecting them. The innervation of the nerve fibers of the attachment organs of trematodes by immunoreactive to serotonin and neuropeptide is shown.Trematode Dicrocoelium lanceatum (Stiles and Hassal, 1896) (Dicrocoeliidae) is the causative agent of Dicroceliosis, a widespread helminthiasis of domestic and wild animals. Dwelling in the bile ducts of the liver and in the gallbladder, dicroceliums cause irreversible pathological changes in the host organism, chronic inflammation of the bile ducts, cirrhosis of the liver, and metabolic processes in animals occur. As a result of the disease, animals are depleted, their productivity decreases, growth and development lag, and the nutritional and caloric value of meat decrease.In the cycle of development of the causative agent of dicroceliasis, the intermediate hosts are land mollusks, while the additional hosts are ants. The eggs of the parasite along with the bile enter the host intestine, and then with the feces into the external environment. Mollusks swallow eggs, miracidia come out from the eggs in the intestines of the mollusk, and penetrate the liver, where daughter sporocysts develop, in which cercariae form. Of the daughter sporocysts, cercariae are introduced into the respiratory cavity of the mollusk, where they are covered with sticky mucous substance. The formed mucous lumps are pushed by the respiratory movements of the mollusk into the external environment. Infection of ants occurs when eating these mucous balls. Once in the intestinal tract, cercariae enter the ant's abdominal cavity, where they turn into metacercariae. The definitive owners infect on pastures, swallowing invasive ants along with grass.