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Helminthoses — the diseases caused by helminths.
Helminthoses — eurysynusic parasitic diseases of the person. From 150 types of the helminths registered at the person, more than a half are localized mainly in digestive organs. In the world 900 million — ankilostomidam, 500 million — threadworms contain over 1 billion infested by ascarids. Incidence and mortality at helminthoses as a percentage to the infested persons is low. However, according to WHO data, total number of diseases and death from intestinal helminthoses is higher, than from bacterial, viral infections and other parasitic diseases, combined. The prevalence of the population of Russia intestinal helminthoses averages about 2%, in the southern regions of the country it reaches 7 — 10%. The prevalence an opisthorchosis in Western Siberia made 30 — 60% and more, in the Urals — 20 — 40%. It is significantly reflected on health of the population.
Etiology and pathogeny
Depending on biology of helminths and ways of transfer of an invasion distinguish geohelminthoses, biohelminthoses and contact (contagious) helminthoses. Eggs and larval forms of geohelminths (the majority of types of nematodes) develop in the soil at a certain temperature and humidity.
Biohelminths (cestodes, trematodes, some types of nematodes) before penetration into a human body in development replace one or two intermediate owners — mollusks, fishes, Crustacea, insects, etc. the Person can be also the intermediate owner — the carrier of larval forms of an Echinococcus (alveolar) or single-chamber (gidatidozny) alveolaris or larvae of a pork tapeworm — tsistitserok.
For infection with geohelminthoses matter contact with the soil contaminated by excrements of the person, non-compliance with hygienic rules. Infection with a strongyloidosis, necatoriasis (activators Strongyloides stercoralis, Necator americanus), is more rare a dochmiasis (Ancylostoma duodenalis), in addition to a peroral way, can occur at penetration of larvae of helminths through skin at circulation without footwear on the soil contaminated by excrements, at earthwork.
Infection with biohelminthoses occurs at the use in food of thermally not processed meat — the beef infected with Finns of a bull tapeworm (Taeniarhynchus saginatus), pork, struck with Finns of a pork tapeworm (Taenia solium), crude or light-salted fish with larvae of opistorkhis (Opisthorhis felineus), geterofios (Heterophyes heterophyes), metagonimus (Metagonimus jokogawai), a wide tape-worm (Diphyllobothrium latum). Larvae of activators of a fascioliasis (Fasciola hepatica), a fastsiolopsidoz (Fasciolopsis buski) after an exit from a body of mollusks can freely float in water or be attached to water plants. Infection comes at drink of the unboiled water containing larvae of helminths, washing by such water of vegetables, fruit, ware, the use in food of water plants.
The faces infested by pinworms (Enterobius vermicularis), a dwarfish tapeworm (Hymenolepis nana) excrete mature eggs therefore infection (and autoinfection) can occur at personal contact, use of the general linen, ware, toilet objects, at dust inhalation indoors where there are infested.
The majority of nematodes (an ascarid, an ankilostomida, a strongiloida) and cestodes (bull, pork, dwarfish tapeworms, a wide tape-worm) and some types of trematodes, a little widespread in Russia (metagonimus, geterofios) parasitize in a small bowel. In a large intestine pinworms and threadworms parasitize, in a wall of a large intestine trematode eggs — Munson's shistosoma are localized. In gepatobiliarny system trematodes — opistorkhisa, klonorkhisa, a fasciola parasitize. Cysts of an echinococcus are initially localized in a liver, at a rupture of a cyst and dissimination of affiliated bubbles — in a mesentery, visceral and parietal leaves of a peritoneum, in a spleen, etc. Tsistitserki (a larva of a pork tapeworm) get from a gut gleam into a blood channel and extend in a human body in the hematogenous way, settling in vessels of muscular tissue, a fatty tissue, in a brain, chambers of the eye.
Causative agents of helminthoses on a biological systematics belong to three classes: Nematoda — roundworms, Cestoidea — tape-worms and Trematoda — flukes. The most widespread diseases caused by roundworms are the ascaridosis, an enterobiosis, a trichuriasis, a strongyloidosis, ankilostomidoza (a dochmiasis, a necatoriasis). Also the diseases caused by tape-worms are eurysynusic: teniarinkhoz, teniosis, diphyllobotriasis, hymenolepiasis. The diseases caused by flukes are the general for the person and animals, house — a fascioliasis or mainly wild — an opisthorchosis and therefore are dated for cattle breeding areas (fascioliasis) or to the natural centers of an invasion (opisthorchosis).