Table of contents:
- Echinococcus parasitic worm
- Types of echinococci
- The life cycle of echinococcus in the human body
- The hosts of the parasite
- Clinical manifestations of infection
Video: The Parasitic Worm Echinococcus
Echinococcus parasitic worm
Echinococcus is a tape parasitic worm belonging to the order cyclophyllid. Being in the larval stage, these parasites pose a danger to humans, as they can provoke the development of a disease such as echinococcosis.
Echinococcus is a tape parasitic worm belonging to the order cyclophyllid.
Echinococci, like other parasitic organisms, have a simple structure, although their life cycle is extremely complex, so only a few individuals become sexually mature and get the opportunity to reproduce.
Types of echinococci
In nature, there are 9 varieties of echinococci. The most common is Echinococcus granulosus, which is found all over the world and is a common cause of infection in humans. A species such as Echinococcus felidis is found only in limited areas of Africa. It is rare. Its intermediate hosts have not yet been established, but adults are detected in lions.
A variety of Echinococcus Echinococcus multilocularis is found exclusively in the northern hemisphere.
Parasites belonging to the species Echinococcus shiquicus are found mainly in South and Central Asia. In intermediate hosts (the parasite of this species is carried by sheep, cows and other herbivores), they form cystic blisters, but whether they are capable of infecting humans is unknown, since they were previously detected only in animals.
Echinococcus, belonging to the species Echinococcus equinus, is found throughout the world. It has not yet been established whether cysts caused by this parasite can form in humans.
The parasite of the species Echinococcus oligarthra is found throughout South America and most of the Northern continent. Parasites rarely infect humans. Another species, Echinococcus vogeli, is found in this area. Like the previous type, this parasite rarely infects humans.
Another type of echinococcus - Echinococcus ortleppi - is found all over the world.
Another type of echinococcus - Echinococcus ortleppi - is found all over the world. This type of parasite rarely causes the development of echinococcosis in humans.
The Echinococcus Canadensis species is subdivided into several subspecies. Some of them are found all over the world, while others are found only in the Northern Arctic.
The life cycle of echinococcus in the human body
The cycle of development of the parasite in the human body is a dead end for echinococcus. In this case, the parasite will not be able to release eggs into the external environment. A person becomes infected by contact with animals that are carriers of this parasite. The most often affected by echinococcosis are people engaged in agriculture or hunting for fur-bearing animals, and in addition, those who perform work on the processing of skins.
People who hunt fur-bearing animals most often suffer from echinococcosis.
Once in the human body, eggs pass through the stomach. In the intestine, larvae emerge, which penetrate through its wall into the circulatory system of the portal vein, and then move to the liver, lungs, bones, muscles and even the brain. After such a movement, the larva transforms into a cystic Finn, which gradually increases in size. Thus, echinococcosis of the lungs, liver and other organs develops.
The hosts of the parasite
During its life cycle, echinococcus must change its owner several times. Only in this case will it be transformed into an adult, capable of dwelling in the intestines and producing eggs, which will subsequently be excreted along with feces.
Echinococcus eggs, like other worms, including cestodes, fall into the soil. Being in their shell, they are reliably protected from the influence of adverse environmental factors. Herbivores and rodents act as an intermediate host for these parasites, including:
- moose, etc.
The role of an intermediate host in the development of the echinococcus worm can be a cow.
Horses can act as an intermediate host for echinococcus.
Mice are carriers of echinococcus eggs.
After passing through the stomach, larvae hatch from the eggs, which enter the bloodstream, which allows them to move to internal organs.
They need this to start the next phase of their lives.
In the internal organs of the intermediate host, they begin to form a primary cyst, on the walls of which secondary formations appear.
Many scolexes are formed on such bubbles. Each scolex head has 4 suction cups.
Infection of the final hosts occurs by eating rodents and ungulates, which have formed Finns.
Thus, the frequent final hosts are:
- wild felines.
Echinococcus adults are found mainly in dogs.
On the territory of Russia and the CIS countries, sick dogs and foxes can most often be found. Living in the intestines of the main host, echinococci produce eggs.
The morphological structure includes several main body elements. The size of an adult echinococcus reaches from 2 to 11 mm. On the head there is a proboscis with hooks, suction cups, necessary for attachment to the intestinal wall. This part of the body is attached to the immature segment. The next element is the hermaphroditic proglottid. At the end of the echinococcus body, there are several segments with eggs.
The larval form has the ability to reproduce by budding. The parasite bubble, which forms in the tissues of the organs of the intermediate organ by the larva of the echinococcus, is a dense ball filled with liquid. In such formations, scolexes are present, ready to penetrate into the body of the final host and attach to the intestinal wall.
Clinical manifestations of infection
For a long time, the Finns of echinococcus that form in the human body do not manifest themselves with burned out symptoms. In the future, the following signs of parasitic invasion may be observed:
- pain in the area of cyst formation;
- itchy skin;
Itching can be a sign of the development of the echinococcus worm.
Pain in the area of cyst formation can be observed with echinococcus.
Diarrhea is a sign of parasitic infestation.
In severe cases, peritonitis, pleurisy, ascites, aspiration pneumonia, abscess and other disorders may occur.