Bovine tapeworm life cycle

Bovine tapeworm, or in Latin terminology Taeniarhynchus saginatus, is a tape-like flatworm parasite, which can live in the human body for some time and harm it in the process of its life activity. Being in the intestines of the host, the tapeworm can reach impressive sizes - up to 10 m in length. The disease associated with the presence of such a parasite in the body is called teniarinhoz, respectively. "Bovine" tapeworm is called because it is able to live not only in the body of people, but also in cattle.

Distinctive features of tapeworms

Tape parasites, or cestodes, are a class of flatworms. They need a foreign organism (that is, they lead a parasitic lifestyle) precisely because they do not have their own digestive system.

In addition, tapeworms, including bovine tapeworm, are characterized by a number of features:

1. In addition to the digestive system, such animals have an undeveloped nervous system and sense organs, since the survival of these parasites does not depend on their response to external stimuli.
2. The most developed system in cestodes is the reproductive system, since reproduction plays an important role in the spread of parasites. These worms self-fertilize. These individuals are hermaphrodites, with a double set of genitals present in each segment of the body.
3. The "tape" worms owe their name to the specific structure of the body, which is a long tape (it can grow up to 10 m, such a length is reached, in particular, by the bovine tapeworm). The tape is composed of a sequence of segments (proglottids), which is collectively called "strobila".
4. Between the head and the body of the cestodes, there is a short cervical region, from which all new segments bud. Here the worm has a growth zone.
5. The head of a tapeworm is called a "scolex". This is a small part (in comparison with the rest of the body) on which the fixation device is located. In particular, in the bovine ("unarmed") tapeworm, these are suckers, with which it is attached to the wall of the small intestine of the host. Also in the head is a paired nerve ganglion, from which nerve cords depart, forming 2 trunks in the body.
6. From above, the body of the worm is covered with tegument (neodermis), on the surface of which there are microfibers involved in the absorption of nutrients.
7. Muscular elements in cestodes are represented by annular, longitudinal and dorsoventral bundles.

Attention! All of these features are also characteristic of the bovine tapeworm as a representative of tapeworms.

How the bovine tapeworm works

The chain, like other tapeworms or cestodes, has a body of a special structure - a strobilus. Such a structure presupposes the presence of numerous constituent parts - metameres or proglottids. Together with them, the head end of the worm - the scolex, on which the suction apparatus is located, with which the parasite fixes itself to the intestinal wall, also enters the strobila. In connection with the structure of the scolex, the bovine tapeworm is also called "unarmed" (since in another type of tapeworm - a pig or armed sucker, two rows of hooks are added).

Internal structural features of the chain

The internal structural features of the bovine tapeworm are summarized in the table:

Table 1. The internal structure of the helminth

System	Structural features
Respiratory	Absent. Organic substances in the body of the helminth are split in an oxygen-free environment
Excretory	The worm secretes water, carbon dioxide and fatty acids through a system of tubules, which in the form of 2 tubules have an outlet on the end segment of the body opposite to the head
Nervous	The bovine tapeworm has no sense organs. There is a head nerve node, from which 2 trunks and nerves depart
Sexual	Most advanced system. Each segment contains a double set of genitals, fertilization is usually carried out between segments

How bull tapeworms breed

Reproduction in the bovine tapeworm is carried out sexually. What are the features of such reproduction in cestodes:

• self-fertilization occurs in worms, since both ovaries and testes (hermaphrodite worms) are present in proglottids;
• fertilized eggs ripen in the uterus (it is also in each segment along with the testes);
• eggs after fertilization are excreted in the same way as their waste products, that is, together with the feces of the host, in whose body the parasite is currently residing. Each year, the worm sheds about 600 million fertilized eggs;
• after getting into the external environment in this way, the fragments of the worm are eaten by other animals.

In particular, bovine tapeworm enters the body of cattle and lives there its larval stage.

Development of the worm in the body of the intermediate host

A segment (segment) with a fertilized egg enters the ground along with human feces. Each such egg contains a larva (the so-called "oncosphere"). Mostly, the isolated eggs are on the grass, so they are often eaten by herbivores. So the egg is inside the organism of the intermediate host.

Important! Chains are biohelminths. This means that their larval stage takes place, not as, for example, in ascaris ("geohelminths") - in the ground, but in the organism of intermediate hosts. In a bovine tapeworm, such intermediate carriers are cattle.

Once in the intestine, the larva leaves the egg, and then, with blood and lymph, is transferred to the tissues. Here the larva forms a specific bubble with liquid - the Finnu, in which it is encapsulated. The Finn already contains the head of the parasite - the scolex, the structure of which is exactly the same as that of an adult. It is at this stage that the intermediate host can become a source of infection, for example, if a person eats the thermally poorly processed meat of a chain-affected cow.

Human infection with bovine tapeworm

In the body of cows and other artiodactyls (for example, deer), the Finns can stay for several years, after which they die. But if during this time the Finn's parasite passes into the body of its main host, it will turn into an adult, and then the cycle will resume.

How a person can get infected:

• eat raw or just poorly cooked or cooked meat from an infected animal;
• butcher the infected meat, and then, without washing or poorly washing the knife, start cutting the "clean" meat. Then the larvae can be transferred to uninfected foods;
• there is also a small chance of flea transport of larvae from animals.

By the way! You can contaminate previously clean food and surfaces with larvae of parasites not only with an unwashed knife, but also with other kitchen utensils - towels, cutting boards, etc. Therefore, in order to avoid contamination, it is recommended to use different tools for raw and finished products.

What is the danger of a bovine tapeworm for humans?

In general, it is extremely unprofitable for the parasite itself to worsen the health of the host. However, when the worm is in the intestine, some negative changes still occur:

1. Inflammatory process in the intestinal wall. The worm is fixed to the wall and sucks out nutrients. From this, local inflammation is possible at the place of fixation.
2. Intestinal dysfunction. Since the parasite, living in the intestine for a long time, reaches a rather considerable length, it can interfere with the normal functioning of the intestine (the passage of food mass through it) and even obturate it clearance.
3. Based on the above mentioned point, when infected with such large worms, constipation and abdominal pain may occur.
4. As absorption of nutrients is impaired, a person may begin to lose weight and feel weak.
5. Due to poor bowel function and impaired absorption of nutrients and vitamins, immunity decreases, so an infected person begins to get sick more often.
6. At the same time, allergic reactions (to the waste products of the parasite itself) are aggravated.
7. In connection with allergies and immunosuppression, the condition of the skin changes for the worse.

Attention! As you can see from the above list, the worm that lives in the intestines is not at all harmless. If you notice such symptoms, you should go to a specialist who, through blood tests, feces and X-ray studies, will detect the parasite and carry out appropriate treatment.

The life cycle of the bovine tapeworm tapeworm is fertilization in the human body, the release of a fertilized egg along with with feces into the external environment, the subsequent ingestion of cattle (intermediate host) into the body with the passage of larval stages. If during this period the animal is eaten by a person (or some other way is realized infection), then the parasite in the body of the final host will develop into an adult, and the cycle will start over.

Video - Bull tapeworm

Video - How to make the correct diagnosis and how to get rid of the parasite