Echinococcosis

EchinococcusEchinococcosis - helminthiasis associated with the penetration of Echinococcus and development in tissues and organs.
Etiology. Pathogens of human echinococcosis are heatedly Echinococcus (Echinococcus granulosus), calling gelatinous form, and alveolar hydatid cyst (Echinococcus alveolaris), calling alveolar form of echinococcosis (see Liviococcia). Mature stage Echinococcus - small cestode (ribbon worms) in length of 2,5-5,5 mm Cestode consists of solexa (head), armed double hooks, cervical and 3-4 segments. Recent Mature segment filled womb, full of eggs. Final owners of helminths are dogs, wolves, foxes, jackals, in whom he dwells in the small intestine in Mature stage. Larval form Echinococcus is a bubble. Outside it is surrounded layered shell. Internal embryonic layer it produces brood capsules with Kolaksai. Brood capsules - small bubble of education, scattered embryonic membrane and United with it in a thin leg. Each brood capsule contains attached to it koleksi. Koleksi are outside of capsules. The bladder is filled with a liquid, in which freely suspended away koleksi and brood capsule - the so-called heatedly sand. Often in the main bubble contains child bubbles. Meets and sterile form single chamber Echinococcus (Cefalonia), devoid brood capsules and scolokov. Larvae Echinococcus parasitize the intermediate hosts of sheep, cattle, pigs, various wild cloven-hoofed animals, man.
Epidemiology. Echinococcosis are widely spread around the globe. In the USSR his pockets registered mainly in the South, but are found in the Northern areas. In the area of tundra and taiga more common liviococcia.
Animals infected with Echinococcus, isolated from faeces Mature segments filled with eggs. Segments can also actively to crawl out of the anus, polluting coat. Human echinococcosis is transmitted through close contact with dogs that become infected if they fed raw meat waste or they have access to the corpses of cattle infected with Echinococcus. Echinococcus eggs can be on dog hair diffuse into the room to get to the vegetables in water, and so on, a Person can be infected while removing and cutting of skins of wild carnivores. From eggs, once in the body of man or other intermediate host that hatch into larvae, which penetrate into blood stream and is deposited in the liver, lungs, less often in other organs, where they transform into if Echinococcus bubbles. After 3 months. once infected, the bubble reaches 3-4 cm in diameter. As maturing in him develop brood capsules and koleksi. Further growth is slow and may take years. If the ultimate owner (for example, a dog will eat affected by Echinococcus authority intermediate host, it will develop in the future, many adults of cestodes, as each solexa grows self parasite. Because of this, animals are usually very intense invasion. The development of helminths in the gut of animals occurs within 2 to 3 months.
Pathogenesis and pathological anatomy. Development if Echinococcus bubbles causes pronounced mechanical effect, which leads to atrophy of the surrounding tissues, pinching vital organs. The absorption of substances prisoners in the cystic fluid leads to intoxication of the organism, development of allergies. As a consequence, in the event of a burst of the bubble can develop rapid anaphylactic reaction, leading to the death of the patient.

Echinococcosis is a human disease and some other mammals caused by the larvae of cestodes of the genus Echinococcus.
Pathogens of human echinococcosis are heatedly Echinococcus (Echinococcus granulosus Batsch, 1786), calling gelatinous form, and alveolar hydatid cyst (Echinococcus alveolaris, s. Echinococcus multilocularis Leuckart, 1863), calling alveolar form of echinococcosis.

Heatedly echinococcosis

The etiology and pathogenesis. Heatedly Echinococcus in the stage of puberty parasitizes in the small intestine of the dog, wolf, Fox, Jackal. The helminth (tapeworm) white color, with a length of 2.5-6 mm, width 0,25-0,3 mm; consists of solexa (head), neck, and 3-4 segments (Fig. 1). Scolex has 4 suction cups and proboscis, armed with two rows of hooks. Separated from the tapeworm Mature segment throws eggs, which, as the segment, with faeces owners are allocated to the outside. The dog and other animals, infested Mature-Echinococcus, pollute the helminth eggs released with excrement, pasture, barn, man. Mature segments are mobile and can sprawl on 5-25 cm from the place of their allocation. Eggs are very stable, and oncospheres remain in the water can survive up to 12 days, at a temperature of 0oC live for 116 days. Ecosfera when the soil temperature 48-50° under the action of sunlight dies within 1-2 days, and in the shadow at a temperature of 10 to 26 degrees. biological activity oncospheres lasts for one month. In water at a temperature of 50 degrees oncospheres die within one hour. Oncospheres Echinococcus when hit in the stomach of humans and other intermediate hosts (large and small cattle, and others) are exempt from shells and using the hooks are implemented in the mucous membrane of the gastrointestinal tract. Next, through the blood and lymph they are posted on the authorities, settling mostly in the liver; slightly less penetration of oncospheres into the lungs. Separate instances fall of light in the systemic circulation and may be entered in any organ or tissue. Deposited in the tissues of ecosfera turns into a larva, which by the end of the second week takes the form of a bubble.

Fig. 1. The structure of Echinococcus. Echinococcus granulosus (1); protocoles (2); the crown of hooks (3); Mature segments (4 and 5); ecosfera (6); the hooks (7).
Fig. 2. Child bubbles Galatenko Echinococcus.


After 5 months the size of the bubble is about 5 mm in diameter). Further growth of the parasite occurs very slowly, over the years, and bubble gradually reach large sizes. Described if Echinococcus cyst weight 12 kg of Around parasite is formed connective tissue capsule. Cavity bladder filled with colorless or slightly yellowish liquid. Shell bladder is composed of two layers: the outer tight - cuticle (chitin, of a thickness up to 5 mm, and inner - embryonic (its germinative, of a thickness 0,010-0,025 mm In the last thousands brood capsules in the form of bubbles up to 1.5 mm in diameter each, on the walls of which are developing embryo scolex (up to 100 in one capsule), barely visible to the naked eye of round shape. In the thick of individual sections of embryonic membranes are formed subsidiary bubbles (Fig. 2)that grow or to the outside (I.e. hydatidosus ехоgenes)or to the inside (that is, hydatidosus endogenes)that is more common.
In endogenous growth subsidiary bubbles float freely inside the mother of the bubble. In a cavity a child bubbles can be separated from them great bubbles. They both contain the brood capsules. When exogenous growth of child bubbles accumulate between cuticle shell maternal bladder and fibrous capsule. Part of Solakov, freed from the brood capsules, freely floating in the cavity of bubbles forming a so-called heatedly sand, 1 cm3 of which can contain up to 400 000 scolokov. In some cases bubbles contain no Solakov, nor brood capsules or grandchild bubbles (sterile bubbles, areality).
An animal that is suffering from echinococcosis, will be the prey of predators; when you slaughter a patient with echinococcosis of livestock inside, if Echinococcus containing bubbles often and throw them eat dog; thus, the parasite returns to its definitive host. In the intestines last koleksi become sexually Mature form of tape worms, and biotic parasite ends (Fig. 3).

Fig. 3. Development cycle-chamber Echinococcus. The main loop consists of a dog, animals and rights; at the bottom - natural foci of echinococcosis, where the cycle includes Dingo, kangaroo (Australia); moose and wolf (North America).

During the lifetime of the intermediate owner may rupture if Echinococcus cyst and the pouring out of its contents (for example, in the abdominal cavity). Maternal bubble with significant damage to walls usually perishes, but brood capsules remain viable. Fibrin that fell in aseptic peritoneal irritation, quick fixes them on the surface of the abdominal organs, where they are developing new bubbles. Seeding possible and at the break of cysts in the pleural cavity or into the soft tissues. With abundant or re-infestation swallowed oncospheres formed multiple bubbles in one or more organs simultaneously. In case of death of the parasite, which can sometimes occur even without visible injuries Usually occurs suppuration cyst due to the ingress of bacteria. Rarely is calcification of the dead parasite.
Epidemiology. Heatedly Echinococcus widespread in all countries of the world, but the degree of affected population varies widely. These differences depend on the intensity of development in the area of animal husbandry, especially sheep, and the associated herding dogs, from the research of the problem, correct accounting of morbidity, General and sanitary culture of the population, the method of economic management, implementation of preventive measures.
Echinococcosis affects all organs and tissues, without exception.
Pathological changes in tissues when echinococcosis is mainly due to the pressure of growing bubble on the surrounding tissue. The result is they atrophy. At the same time the absorption of waste products of the parasite, irritant action, causes chronic inflammation and intensive development of the connective tissue that forms fibrous wall parasitic cysts, which in the liver can reach thicknesses of 5 see the different layers of fibrous capsule there are pockets of small cell lung infiltration, mainly around blood vessels. Vascular walls were thickened. In some cases develop infiltrates, consisting mainly of eosinophils. When death and suppuration bubble autopsy picture changes dramatically due to acute purulent inflammation of the walls of the cysts. In other parts of the affected organ, is not subject to pressure (especially in the liver echinococcosis), there vicar hypertrophy.
General changes are beginning to allergization (sensitization if Echinococcus liquid)which may include periodic rash rash, sometimes clearly associated with a small trauma of the affected organ (microscopic tears bubble). When the bubble reaches a size join phenomena associated with its pressure on surrounding organs.