TREMATODOZY (trematodosis, the singular) — the helminthoses caused by flat worms — trematodes (flukes or flukes). At the person the following trematodoza are registered: a gastrodiscoidosis
(see), a heterophyasis (see), a dicrocoeliosis (see), a clonorchosis (see), a metagonimosis (see), nanofiyetoz (see), an opisthorchosis (see), a paragonimiasis (see), a fascioliasis (see), fastsiolopsidoz (see), shistoso-matoza (see), etc.
All T. are biohelminthoses (see Helminthoses). Life cycles of trematodes are various and quite often very difficult (fig.). Consecutive development of two or three generations of a parasite in an organism of two or three owners — the first intermediate, the second intermediate (additional) and final is characteristic of them (definitivny). The first intermediate owner of trematodes are always mollusks, the second intermediate owner — fishes, crabs, crayfish, final — the person and nek-ry vertebrate animals.
The helminths which are in an organism of the final owner allocate eggs, to-rye, getting to the environment, develop, and they leave miratsidiya — the larvae covered with a ciliary cover. At implementation in an organism of the first intermediate owner (mollusk) the ciliary cover is dumped (at trematodes of nek-ry types of miratsidiya leaves egg in intestines of a mollusk). In an organism of a mollusk develops maternal a sporocyst, then affiliated, in to-rykh the cercariae leaving a mollusk and living in water form. They have an oval body and the tail promoting free movement. At implementation the cercaria in an organism of the additional owner forms the based invasive stage — metacercarias. Encystment of cercariae in the environment (on water plants in standing or slowly current reservoirs) and their transformation in adoleskariyev is characteristic of a number of trematodes. Infection of the final owner happens or at consumption of fish, crabs, crayfish — additional owners (at an opisthorchosis, a clonorchosis, a paragonimiasis, etc.), or during the swallowing adoleskariyev to water or edible plants (salad, fennel, parsley, etc.), to-rye watered from open reservoirs (at a fascioliasis, a fastsio-lopsidoza, etc.). Cercariae shistoso-matid actively get through skin or mucous membranes of the final owner, and in his organism puberal helminths — marrites form. Puberal trematodes strike many bodies and fabrics: zhelchevydelitelny system (opistorkhisa, klonorkhisa, fasciola, dpkrotseliya), pancreat ducts (eurptrema, opistorkhisa, klonorkhisa), intestines (metarutting of an imusa, nanofiyetusa, fasciolopses, representatives of the Echinostomatidae family, etc.), easy (paragonima), venous system of an abdominal cavity (pshsto-catfishes).
Area of various T. it is not identical. It is defined by a complex of natural factors (climate, existence of reservoirs, populations of intermediate owners, their number, etc.) and social factors (features of life, a profession, a dignity. condition of settlements, level of the organization of health care etc.). In the most widespread T. shistosomatoza are.
Fig. Scheme of a life cycle of activators of trematodoz: 1 — egg of a trematode, you
divided with excrements or urine (at an urinogenital schistosomatosis) and got to an aqueous medium; 2 — miratsidiya, left egg in water; 3 — development of larvae in a mollusk (and — maternal a sporocyst — affiliated a sporocyst, in — cercariae); 4 — development of cercariae in fishes, crayfish, crabs — additional owners in whom the based invasive stage of metacercarias forms (.5); 6 — encystment of cercariae on water plants in standing or medlennotekushchy reservoirs and transformation of cercariae in adolescarias (7); 8 — cercariae shistosomatid,
getting through I mow.
Pathogeny and wedge, picture T. are defined by specific accessory of a parasite, a stage of his development, localization in an organism of the owner, intensity of an invasion, ways of migration of larval stages. Major factors of a pathogeny are a sensitization of an organism of the owner products of exchange and disintegration of parasites and mechanical impact of trematodes on it.
The diagnosis is based on kliniko-epidemiological and datas of laboratory (blood test for the purpose of detection of an eosinophilia, a research a calla, bile, a phlegm for detection of eggs of helminths). In diagnosis of a migratory stage particularly important become immunol. methods of a research (see. Helmintologic methods of a research).
Prevention of T. comes down to identification and treatment of the infested persons, and sometimes and animals, protection of reservoirs and soils from pollution by excrements (construction of a water supply system, the sewerage etc.), to destruction of mollusks — intermediate owners of trematodes. The dignity is of great importance. - a gleam, the work directed to instilling in the population a gigabyte. skills and on eradication of a habit to eat in the raw fish, crayfish, crabs — additional owners of trematodes, etc. In fight against a fascioliasis and fastsio-lopsidozy the leading role belongs vt. to service since domestic animals are the main sources of these invasions.
Bibliography: To and with with both r with to and y II. And.
, etc. Guide to tropical diseases, M.", 1974; The Multivolume guide to microbiology, clinic and epidemiology of infectious diseases, under the editorship of H. N. Shukova-Verezhnikova, t. At, page 387, M., 1968; Parasitic zoonoza, the Report of committee of WHO experts, It is gray. tekhn. dokl. L1 - 637, page 72, Geneva, WHO, 1980; Sh at l R. S. c and in about z-d e in E. V. Bases of the general helminthology, t. 1 — 2, M., 1970 — 1972;
Intestinal protozoan and belminthic infections, Teehn. rep. ser. L1 6G6, p. 86, Geneva, WHO, 1981; Mansoivs tropical diseases, ed. by Ch. Wilcocks a. P. Manson-Bahr, L., 1974.
M 11. Alekseeva.