Alveococcus

Alveococcus is a larva of a parasitic worm (multi-chamber echinococcus) - causes a dangerous disease of alveococcosis, which is compared with cirrhosis and liver cancer in terms of the severity of the course, the complexity of treatment and the real threat of death.

For Ukraine, this type of helminthiasis is rare, but you can catch this parasite in Europe, and in America, and in Central Asia, which are endemic to it. So information about what alveococcus is, will not be superfluous.

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Structure of alveococcus

Alveococcus is a type of helminth that is widespread all over the world - echinococcus and belongs to the detachment of cyclones (cyclophyllide) of the class of cestodes (parasitic flatworms). The size of an adult, capable of breeding a female is no more than 3-3.2 mm in length. This cestode parasitizes the carnivorous animals in the small intestine, in particular, dogs (foxes, arctic foxes, wolves, jackals, dogs), and also wild mouse-like rodents.

The structure of the alveococcus, that is, the structure of its body in the sexually mature state includes the head (scolex), neck and several segments. The body (strobila) is covered with special cells that suck food from the intestines of the host. On the head are chitinous hooks, which are the organs of attachment. Next comes the cervix - the zone of growth of the worm, and after it the segments (proglottids). Chains have a hermaphroditic reproductive system, and it is present in every segment.

The last segment of alveococcus, performing the function of the genital organ, contains the uterus, which is filled with eggs. There is no outlet for the uterus, so laying eggs is as follows: the segment, together with the uterus, breaks away from the body, enters the animal's excrement and exits outwards. There, the segment breaks and scatteres the eggs. After this, the following separates the proglottide, since the body of the nematode can be restored by forming new segments.

In each egg there is a larva-embryo (oncosphere), also equipped with hooks. Elyos of alveococcus have increased resistance to unfavorable environmental conditions and are able to persist at any temperature.

It should be noted that alveococcus (multicameral echinococcus), like all invertebrates, has an orthogonal nervous system consisting of several pairs of longitudinal cords, tactile and receptor cells in the skin and a pair of ganglion (nerve node) that is located in the scolex.

The life cycle of alveococcus

The life cycle of alveococcus is a stage in the development of the organism of one individual, which changes its host, the intermediate and the primary. In the main (final) host - predatory mammals, including dogs - the adult parasite lives in the intestine. In the intermediate host (rodents, large and small cattle, humans) eggs of alveococcus enter (through the esophagus - with water or food). And here in the tissues of the body, cavities and organs begins a new stage of development - larval (stage larvocysts).

The entire life cycle of alveococcus flows clearly in accordance with the stages and has the following stages:

• the first stage: in the intestine of the final host, adult individuals live and multiply, forming eggs;
• the second stage: the eggs reach the necessary condition and are "laid off" by withdrawal outside the body of the main host;
• the third stage: in the eggs, embryos (oncospheres) are finally formed, which are completely ready for the second larval phase, which must take place in the new host - the intermediate one;
• the fourth stage: the eggs enter the organism of the intermediate host and turn into larvae.

As it happens when eggs of alveococcus enter the human body, let us consider in more detail. Once in the stomach and intestines, the embryo-larva emerges from the egg and, with the help of its hooks, penetrates the wall directly into the bloodstream and enters the bloodstream with any blood. Most often, the "place of dislocation" of the parasite becomes the liver, much less often - the lungs or other internal organs.

In the liver, the larva begins the main larval stage, during which a multi-chambered bubble is formed in the tissues of the human organ - the larvocyst. Within each small bubble, which constitutes the larvocyst, is the liquid and germinal head of the parasite, and in it the final maturation of the vesicular larva will take place and the structure of the alveococcus will form.

At the same time, the larvocysts behave quite aggressively: they germinate into the liver tissue and constantly grow due to the increase in the number of vesicles. Around them occurs necrosis of the hepatic parenchyma, the capillaries are damaged and cease to function. Intensive growth of the colony of alveococcus larvae can spread to nearby structures, leading to the formation of fibrous nodes with the inclusion of larval blisters.

All this can last for several years, resembling the metastasis of a cancerous tumor.