Medical leech (Hirudo medicinalis)Engl. Medical leech

With the exception of two ancient species, all leeches are divided into two large groups: some have a muscular trunk in front of the digestive tube, others are equipped with jaws seated with teeth. With the help of these "tools", blood-sucking species damage the skin or mucous membranes of their victims.

In the inflicted wound, leeches introduce a special protein substance - hirudin, which prevents blood clotting. If hirudin had not been released, damaged vessels would quickly clog with blood clots, which prevents blood from being sucked out.

Thanks to hirudin and other substances secreted by the salivary glands, the blood can remain in the stomach of a leech in a liquid state for months without being putrefied.

The most ancient species in origin - Acanthobdella peledina - occupies an intermediate position between oligochaete worms and leeches. Traveling in Siberia in 1842-1845, the outstanding Russian naturalist Alexander Fedorovich Middendorf discovered these then unknown worms on peled. Having fixed them in a special solution, he sent them to his colleague, a great specialist in annelids, the Swiss zoologist E. Grube. The scientist described them and assigned them to the new genus Asapthobdella.

Later it turned out that this leech attacks salmon fish and graylings. It lives in freshwater bodies of northern Europe and Asia, from Norway to Kolyma, and its southernmost location is Lake Onega.

On fish, these leeches appear in late spring or early summer, when they weigh only 5-10 milligrams, but by the beginning of winter, when the worms reach sexual maturity and their weight is more than 200 milligrams, they leave the prey. Further fate them is unknown. Most likely, worms breed and develop in small places overgrown with plants. But no one has yet caught these leeches in a free state and observed how they reproduce and develop, although for some time it was possible to keep them in aquariums.

Well-known are common in almost all water bodies of Moldova, Ukraine, the Caucasus and Central Asia(except Turkmenistan) medicinal leeches (Hirudo medicinalis). AT vivo they usually attack frogs and mammals that come to drink. In an aquarium, hungry medicinal leeches can attack any animal that can be bled; it is natural that the fish die after such bloodletting.

It looks like a large false-horse leech (Haemopis sanguisuga), widespread in the water bodies of Russia, Ukraine, Belarus, Moldova, and the Caucasus. But, unlike the medical one, it is painted in gray-black tones and does not have orange-red spots. This leech is not a bloodsucker - it either swallows its prey whole or tears off pieces from it. If you set out to fatten the false horse leech, then you can grow a specimen up to 40 centimeters long. A strong voracious predator eats worms (including other leeches), molluscs, aquatic insect larvae, tadpoles, and sometimes small fish.

Representatives of the Fish Leech family (Ichthyobdellidae, or Piscicolidae) are much smaller than the species described above. It is very easy to distinguish them from other leeches: their anterior sucker is sharply separated from the rest of the body and is usually disc-shaped or cup-shaped, which helps it to attach securely to the fish. In most species, the anterior sucker has two pairs of eyes, while the posterior one often has eye-like points.

Piscicola lives only in water that is sufficiently saturated with oxygen. In stagnant ponds and especially swamps, it is extremely rare.

During breeding, the leech lays eggs enclosed in cocoons 1.5 mm long, which it attaches to aquatic plants and other substrates. Depending on the temperature of the water, after 1-3 months, young leeches emerge from the cocoons, which are immediately able to attack the fish.

The leech Cystobranchus fasciatus lives in the Dnieper, Volga, Ural, Kura, which is dangerous for fish. Its elongated body reaches a length of 75 millimeters and a width of 8. The posterior sucker is very large, the eye-like spots on it, like in the common fish leech, are located between the radial pigment stripes. The body color is gray with a purple tint; wide dark gray transverse stripes with blurry edges stand out against this background.

In the reservoirs of the Leningrad region, the leech C. respirans lives, which is also very undesirable in the aquarium. Her body is relatively short (up to 40 millimeters with a width of 10), grayish-yellow in color, completely dotted with small brown pigment spots.

In the water bodies of Russia, with the exception of the European northeast and Western Siberia, the flat leech Hemiclepsis marginata is widespread. The length of her body is 30 millimeters with a width of 7. In calmly sitting leeches, the body is flat and short, while in elongated ones it becomes very long, and in this position they can be mistaken for an ordinary fish leech. The dorsal side of the body is convex, the ventral side is slightly concave. The coloration is variegated, greenish-brown, in young it is greenish-blue. Seven longitudinal rows of yellow spots run along the dorsal side of the body; there are also yellow spots on the posterior sucker. These leeches suck blood not only from fish, but also from amphibians (newts, frogs).

Like all flat leeches, N. marginata takes care of its offspring. The mother leech covers with her body the thin-walled shapeless cocoons laid by her, in which many eggs are enclosed. After hatching, the juveniles attach themselves to the mother's belly and move with her. In case of danger, the leech stops moving, protecting the offspring with its body. Growing up, juveniles move to an independent life - at first temporarily, and later permanently.

Another representative of flat leeches - the snail leech (Glossiphonia complanata) - is not an enemy of fish, but also damages the aquarium economy. Its victims, as the name implies, are molluscs, so aquarists who collect, in addition to fish, and various snails, should know her well “by sight”, especially since she gets into the aquarium (with plants, soil, etc.) more often other of their relatives and goes unnoticed longer.

The body length of the snail leech rarely exceeds 20 millimeters, the color is greenish-brown. Due to the fact that her body is translucent, it is easy to see the internal organs and the entire process of bearing offspring.

The snail leech cannot swim and crawls. She is extremely lazy and lies motionless for a long time, clinging to underwater objects or plants. It is not easy to tear it off the substrate, and if it succeeds, it curls up like a hedgehog.

For an inquisitive naturalist, leeches can be an interesting object of observation. But, of course, they should be kept in a separate vessel. So that they do not get into the aquarium, you must carefully examine everything that enters it from a natural reservoir (sexually mature leeches are visible to the naked eye) or pre-treat according to special methods. If young leeches still go unnoticed and in the future you will find them on the inhabitants of the aquarium, it is necessary to treat your pets. For fish, these are short-term salt baths: 25 grams of salt are dissolved in 1 liter of water and treated for 10 minutes.

Bibliography

S. Sharaburin "Leechs."

The body is flattened in the dorsal-abdominal direction, bears two suckers. The anterior or oral sucker is formed as a result of the fusion of four segments; at its bottom there is a mouth opening. The posterior sucker is formed by the fusion of seven segments. The total number of body segments is 30-33, including segments that form suckers. Parapodia are absent. True leeches lack bristles, bristle-bearing ones have. Leeches living in water swim, bending their body in waves, land leeches "walk" on the ground or leaves, alternately sticking to the substrate with either the front or the back suction cup.

rice. one. Diagram of the structure of the front
end of the body of a medical leech:
1 - ganglion, 2 - longitudinal muscles,
3 - pharynx, 4 - muscles of the pharynx,
5 - jaws, 6 - wall
front sucker.

The composition of the skin-muscle sac includes a dense cuticle, a single-layer epithelium, annular and longitudinal muscles. The epithelium contains pigment and glandular cells. The cuticle is divided into small rings; the outer segmentation does not correspond to the larger inner segmentation.

In general, in bristle-bearing leeches it is preserved, in real leeches it is reduced to one degree or another. In most species of true leeches, the secondary cavity is filled with parenchyma, and longitudinal lacunar canals remain from the coelom.

rice. 2. Structure diagram
medicinal leech:
1 - head ganglia,
2 - oral sucker,
3 - pockets of the stomach,
4 - midgut,
5 - hindgut,
6 - anus,
7 - rear suction cup,
8 - abdominal nervous
chain, 9 - metanephridia,
10 - testes, 11 - egg
bag, 12 - vagina,
13 - copulatory organ.

real circulatory system closed type, similar to that of oligochaetes or polychaetes, is present only in some species of leeches (bristle-bearing leeches). In jawed leeches, the circulatory system is reduced, and its role is played by lacunae of coelomic origin: dorsal, ventral, and two lateral.

Gas exchange occurs through the integument of the body, some sea leeches have gills.

Excretory organs - metanephridia.

The nervous system is represented by the ventral nerve chain, which is characterized by a partial fusion of the ganglia. The subpharyngeal ganglion consists of four pairs of merged ganglia, the last ganglion of seven pairs. The sense organs of leeches are goblet organs and eyes. Goblet organs - chemoreception organs - are located in transverse rows on each segment, with their help, leeches learn about the approach of the victim, identify each other. The eyes are transformed goblet organs of the anterior segments, they have only a photosensitive value. The number of eyes different types- from one to five pairs.

Leeches are hermaphrodites. Fertilization is usually internal. The eggs are laid in cocoons. Postembryonic development is direct.

The Leech class is subdivided into subclasses: 1) Ancient, or Bristle-bearing leeches (Archihirudinea), 2) True leeches (Euhiridinea). The subclass Real leeches is divided into two orders: 1) Proboscis (Rhynchobdellea), 2) Proboscis (Arhynchobdellea).

rice. 3. Appearance
medicinal leech

Detachment Beskhobotnye (Arhynchobdellea)

Medical leech (Hirudo medicinalis)(Fig. 3) is bred in the laboratory for medical purposes. The body length is on average 120 mm, width 10 mm, the maximum values ​​can be much higher. Each of the three jaws has 70-100 sharp "teeth". After a leech bite, a trace in the form of an equilateral triangle remains on the skin.

Under laboratory conditions, they reach sexual maturity in 12-18 months and breed at any time of the year. The reproductive system consists of nine pairs of testes and one pair of ovaries enclosed in egg sacs. The vas deferens merge into the ejaculatory canal, which ends with the copulatory organ. The oviducts leave the ovaries, which flow into the convoluted uterus, which opens into the vagina. Fertilization is internal. Cocoons are oval in shape and reddish-gray in color, average length 20 mm, width 16 mm. In one cocoon from 15 to 20 eggs. The egg diameter is about 100 microns. After 30-45 days, small leeches, 7-8 mm long, emerge from the cocoons. In laboratory conditions, they are fed on blood clots of mammals.

Adult leeches are used for hypertension, strokes, for resorption of subcutaneous hemorrhages. Hirudin, contained in the saliva of leeches, prevents the development of blood clots that clog blood vessels.

In nature, medicinal leeches live in small fresh water bodies and feed on mammals and amphibians.

rice. four. Big
false horse leech

Large false horse leech (Haemopis sanguisuga)(Fig. 4) lives in fresh water bodies. It leads a predatory lifestyle, feeds on invertebrates and small vertebrates, swallowing them whole or in part. The mouth and pharynx can be greatly stretched. The number of blunt "teeth" on each jaw is 7-18. Stomach - with one pair of pockets.

The false horse leech is often confused with the medical one, although they are quite easily distinguished by the color of the dorsal side of the body. The dorsal surface of the body of the false horse leech is black, uniform, sometimes with randomly scattered dark spots. On the dorsal side of the body of a medical leech there is a characteristic pattern in the form of longitudinal stripes. False horse leeches should not be kept together with medical ones, as they eat them.

Medical leeches (Hirudo medicinalis) feed on blood. As soon as we take them out of the cocoons, we immediately begin the first feeding. After we withstand a certain period and temperature and feed again, up to a size of 1.5 -1.7 gr. (weight of an average leech), before it goes into the market, it fasts for more than 3 months. In a hungry state, she can live up to 6 months. During this time, she digests the blood in her stomachs. No need to feed her with honey, sugar or anything like that.

In total, about 650 species of leeches are known, contrary to popular belief, not all leeches are bloodsuckers. In fact, many of them are predators and feed on various invertebrates, insects (midges, mosquitoes, larvae, water bugs), oligochaetes (aquatic, earthworms), amphipods, and many different types of molluscs, including pond snails and freshwater molluscs. These predatory leeches either swallow their prey whole or they are equipped with a proboscis that resembles hypodermic needles.

Leeches, especially some of their species, are sensitive to weather changes. The abilities of the "weather forecaster" are especially pronounced in the predatory large false-horse leech. By the behavior of leeches, you can understand whether it will rain, hail or sunny weather. Leeches, it turns out, feel the differences atmospheric pressure. Having settled leeches in an aquarium or glass jar with water and observing their behavior, with the help of such a kind of barometer, you can determine the weather. If the weather is clear, the leeches are in the water and are amazingly active. When atmospheric pressure decreases, they try to get out on land, or at least stay closer to the surface of the water. As a rule, this indicates an imminent rain or snowfall.

leeches(lat. Hirudinea) - a subclass of annelids from the class of belt worms (Clitellata). Most representatives live in fresh water. Some species have mastered terrestrial and marine biotopes. About 500 species of leeches are known, 62 species are found in Russia. Russian word"leech" goes back to the Proto-Slavic *pjavka (cf. Czech. pijavka, Polish. pijawka), formed from the verb *pjati, a multiple form verb from *piti "drink".

general information

Leeches can move both in water and on land using the contraction of the muscles of the body. In water, it swims, making wave-like movements, on land it moves with the help of suction cups and crawling, like other worms. Both suction cups are used to move along the substrate and attach to it. Due to the strong muscular body, active leeches can, freely held by the posterior sucker, lift the body and make prowl searching movements with the anterior end of the body. During the rest, it prefers to climb under stones, snags and lie, partially leaning out of the water.

Leeches are able to respond to light, as well as to temperature, humidity and water fluctuations. They have a reflex reaction to the shadow, which may indicate the approach of potential food. The sensitivity of leeches decreases sharply during sucking and mating, to the point that when the posterior end of the body is cut off, the leech does not show a reaction and continues its behavior.

Food

On average, a hungry leech weighing 1.5–2 g is capable of sucking up to 15 ml of blood at a time, while increasing by 7–9 times in mass.

AT natural conditions hungry leeches wait for their prey, attaching to plants or other substrate with both suckers. When signs of an approaching victim appear (ripples, shadows, water vibrations), they unhook and swim in a straight line towards the source of vibrations. Having found an object, the leech fixes on it with its back sucker, while the front one makes prowl movements in search of a suitable bite site. Usually this is the place with the thinnest skin and superficial vessels.

The duration of bloodsucking varies depending on the activity of the leech, the properties of the blood of the animal and other conditions. On average, a leech that has been starving for 6 months is saturated in 40 minutes - 1.5 hours.

Reproduction and development

Wild leeches reach puberty in 3–4 years, feeding up to this age only 5–6 times. In captivity, maturation occurs faster, in 1–2 years.

Reproduction occurs once a year during the summer period from June to August. Copulation takes place on land, two leeches wrap around each other and stick together. Despite the fact that leeches are hermaphrodites, and cross-fertilization is possible, each individual, as a rule, acts in only one capacity. Fertilization is internal, immediately after it, leeches look for a place on the shore near coastline for laying a cocoon.

Leech cocoon

One leech can lay up to 4-5 cocoons, they are oval in shape and covered with a spongy shell on the outside. Inside the cocoon there is a protein mass for feeding embryos, the number of which can be up to 20-30, their development to hatching takes 2-4 weeks. The hatched little leeches are miniature copies of adults and are ready to feed on blood. They feed mainly on frogs, as they cannot yet bite through the skin of mammals.

The history of the use of leeches in medicine

Hirudotherapy(lat. hirūdō - "leech", other Greek. θεραπεία - "treatment") - method alternative medicine, one of the directions of naturopathy, treatment various diseases person using a medical leech. Leech therapy was previously used in conventional medicine, but fell into disuse in the 20th century due to the advent of synthetic anticoagulants, including hirudin.

Hiruda, a medicinal leech native to Europe, has been used for bloodletting for hundreds of years. Hippocrates, Galen, Avicenna wrote about the treatment with leeches. On the walls of Egyptian tombs, drawings of the use of leeches were found. Medicinal properties Medicinal leeches have been known to people for thousands of years. A description of the methods of treating various diseases with the help of a leech can be found in the medical collections of most ancient civilizations: ancient egypt, India, Greece. The use of leeches was described by Hippocrates (4th-5th centuries BC) and Avicenna (Ibn Sina, 980-1037).

Most wide application Medicinal leeches were obtained in the 17th-18th centuries in Europe for bloodletting in connection with the concept of "bad blood", which then dominated medicine. In order to release bad blood, doctors sometimes put up to 40 leeches at the same time to one patient. Preference over vein bloodletting was given to them in case of need for bloodletting from hard-to-reach or tender places (for example, gums). In the period from 1829 to 1836, 33 million leeches per year were used in France for the treatment, in London - up to 7 million with a population of 2.3 million inhabitants. Russia supplied Europe with about 70 million leeches a year. After a paradigm shift in the middle of the 19th century, bloodletting was abandoned, and the use of leeches in Europe practically ceased.

Scientific studies of the mechanisms of action of leeches on humans began in the late 19th and early 20th centuries with the work of John Haycraft, who discovered the anticoagulant effect of leech extract. In 1884, he discovered an enzyme from the saliva of a leech - hirudin, and in 1902 preparations were obtained from hirudin. These studies marked the beginning of the scientific use of leeches in medicine. In our time, treatment with the help of medicinal leeches is experiencing a rebirth.

Features of the therapeutic effect

Live leeches are attached directly to the human body according to specially designed schemes. The choice of the place of attachment is determined by many factors: the disease, the severity of the process, the condition of the patient. The sucking process lasts from 10–15 minutes to an hour, after which the leeches are removed with alcohol, iodine, or, if fed to the full, they are released on their own. Well-fed leeches must be destroyed by placing them in a solution of chloramine, their reuse is not allowed. The therapeutic effect of exposure to live leeches is due to several factors:

• Dosed bloodletting (from 5 to 15 ml of blood for each leech, depending on the mass of the leech and the duration of the attachment). It is used to treat arterial hypertension, glaucoma, congestion in the liver, general intoxication of the body.
• The action of biologically active substances in leech saliva, the main of which is the anticoagulant hirudin, which reduces blood clotting. Used to treat angina and myocardial infarction, thrombophlebitis, vein thrombosis, hemorrhoids.
• A complex of body responses to a bite, biologically active substances of leech saliva and subsequent blood loss.

A reliable guarantee of protection against the transfer of infectious agents by a leech is the use of animals grown under artificial conditions and starving for a sufficient time, in the intestines of which there is no pathogenic flora. The use of leeches in therapy was revived in the 1970s: in microsurgery, they are used to stimulate blood circulation in order to save grafted skin and other tissues from postoperative venous stasis.

Other clinical uses for medicinal leeches include the treatment of varicose veins, muscle spasms, thrombophlebitis, and arthrosis. The therapeutic effect comes not only from the flow of blood through the tissues while feeding on leeches, but from further and steady bleeding from the wound left after the detachment of the leeches. The saliva of leeches has analgesic, anti-inflammatory and vasodilating properties.

What leeches can treat?

Of several dozen types of medicinal, there are only three:

• pharmacy;
• medical;
• eastern.

We hasten to upset lovers of self-treatment with leeches. Caught in a local reservoir, at best they will be useless, at worst they will bring irreparable harm, rewarding a person with a number of unpleasant diseases that they can carry. Leeches intended for hirudotherapy are grown in the complete sterility of special laboratories and are used only once.

Indications for use

There are a number of diseases in which treatment with leeches significantly improves the patient's condition:

• Problems with blood vessels, blood formation, tendency to form blood clots, blood stasis.
• Diseases of connective tissues and joints.
• Violation of the functions of the genitourinary system.
• Diseases of a neurological nature.
• Violations menstrual cycle, inflammation of the genital organs, ovarian dysfunction, endometriosis.
• Neurosis, epilepsy, migraine, sleep disorders.
• diseases associated with disorders of the thyroid gland.

The benefits of leeches in the treatment of blood vessels and blood

With varicose veins, treatment with leeches stimulates blood formation, helps to strengthen the walls of blood vessels. Hirudin, secreted by a leech with saliva, is a natural biologically active substance that improves metabolism and prevents the formation of blood clots. On the early stages diseases can be completely cured or stopped its development with the help of hirudotherapy.

Treatment for arthrosis and osteochondrosis

Non-inflammatory lesions of the joints and cartilaginous tissues, caused by circulatory or metabolic disorders, large or improperly distributed loads, injuries, are successfully treated with leeches. Treatment is aimed at reducing pain, increasing the motor work of the joints and stopping the progression. The secret secreted by leeches when bitten contains a natural analgesic enzyme that improves the patient's condition. No wonder a couple of centuries ago, military doctors put soldiers of these bloodsuckers in the wound area to prevent pain shock.

Treatment of diseases of the spine

Hirudotherapy plays an important role in the complex treatment of spinal ailments. It contributes to the restoration of normal physiological processes occurring in the deep tissues surrounding the spinal column. As effective remedy, supplementing the main one, is the treatment with leeches for a hernia of the spine. In the absence of the desired result from conservative treatment, one has to resort to surgical intervention. During the period of postoperative rehabilitation, leeches can bring a lot of benefits to the patient. Their use helps to prevent postoperative complications. Thanks to hirudotherapy sessions, cicatricial adhesions in ligaments and tendons are reduced, the likelihood of new hernias is reduced due to the redistribution of loads, congestion in the vertebral veins disappears.

Treatment with leeches is also effective in osteochondrosis. The cause of this pathology is degeneration of the intervertebral discs, ligaments that lose water, become thinner, covered with microcracks. As a result, the distance between the vertebrae decreases, there is pressure on the nerve roots, causing them to be pinched, spasms and inflammation in the paravertebral muscles.

The benefits of leeches for weight loss

Medical leeches are actively used in aesthetic medicine for weight loss and cellulite treatment. This effect occurs due to the influence of substances in the saliva of annelids on metabolism and blood circulation. Biologically active substances of leeches have a lipolytic effect - they burn fat. In addition, the process of microcirculation is being established and the provision of cells with oxygen is enhanced, the stagnation of lymphatic fluid in adipose tissue is eliminated. All this contributes to the reverse development of pathological changes in cellulite and a decrease in body volume.

The effect after using leeches for weight loss will be even more noticeable if you combine hirudotherapy with a balanced diet and regular exercise.

Acne treatment with leeches

Acne treatment with medicinal leeches is very effective. Already after several sessions of putting leeches on the face, the rash is significantly reduced, and after the entire course it completely disappears. The result of such treatment lies in the amazing and varied properties of these animals on the skin.

Firstly, saliva of leeches has a powerful bacteriological and antiseptic effect. It destroys all pathological pyogenic microorganisms, which cause the formation of acne. Secondly, substances that leeches transmit with a bite have a pronounced anti-inflammatory effect, due to which the inflamed areas heal quickly. Thirdly, due to the mechanical and biological action of animals, the blood supply to the skin increases, which plays an important role in the normal functioning of the sebaceous glands.

As you can see, hirudotherapy in cosmetology has a wide range of applications. Do not refuse such treatment just because you are disgusted with leeches. You just have to be patient a little and, perhaps, you will get rid of the cosmetic problem that has tormented you for many years forever.

Contraindications

Contraindications are:

• diseases accompanied by bleeding due to reduced blood clotting;
• hemolysis;
• anemia (anemia);
• weakening or exhaustion of the body;
• intolerance to the body of leech enzymes (allergic reactions);
• tuberculosis of various localizations;
• oncological diseases.

Harm of leeches

Due to its specific structure and diet, the use of leeches for medicinal purposes may be associated with the following risks:

• The digestive tract of the medical leech constantly contains the bacterium Aeromonas hydrophila, which protects it from infections when feeding on the blood of sick animals and promotes proper absorption nutrients. In humans, it can cause gastrointestinal disorders, poisoning, and even diseases of the mucous membranes. Although hirudotherapists deny the possibility of bacteria getting into the jaws of leeches, this hypothesis has not been definitively refuted.
• With the blood of infected animals, pathogens of various dangerous diseases enter the body of a leech. Settling on the jaws, they can be transmitted by bite to other people and animals. The use of leeches grown in artificial conditions made it possible to get rid of this problem.
• Leech saliva contains substances that thin the blood, and after removing it, the wound may bleed for a long time. In addition, in some cases, these substances can severely irritate the skin.

The process of breeding leeches is simple and accessible to anyone. In order to organize a leech farm, you need to find a room with several rooms, since leeches at various stages of their growth: cocoon, fry, adult, should be kept separately. As an option, you can adapt one room by dividing it into sectors. The main condition for breeding leeches is to maintain a favorable microclimate for them: the air temperature is from 25 to 27º C.

Although wild leeches in natural environment live in colder waters, the reproduction and development of their medical relatives in the heat is much better. The temperature of the water in which the leeches are located should be at room temperature, that is, the same 25-27º C. The air humidity in the room should be at least 80%.

Containers for leeches are the usual 3 liter cans filled with purified water through special filters. Aquariums can also work, but it will be much more expensive. It is necessary to carefully monitor all stages of the growth of leeches and “transfer” animals to other premises (sectors) in time when they reach the next “age”.

By the way, all work on feeding leeches, purifying water in containers, transplanting leeches, etc., is carried out only manually. Even on large leech farms. Leeches feed on blood, which can be obtained from livestock farms, from private farmers, at a slaughterhouse, having concluded appropriate agreements with them.

Breeding leeches on an industrial scale is carried out by special biofactories. Currently, there are only four such factories in Russia: two in the Moscow region, one in St. Petersburg and one in Balakovo Saratov region. In total, they grow 5-5.5 million leeches per year, which makes Russia the world leader in the production of leeches in the world: only 0.5 million per year are grown in France and the United States.

A leech is a worm that has a kind of "brain". Nietzsche's Zarathustra tried to assert that he was familiar with the mental, or rather mental, activity of the leeches of these interesting worms. The researchers, of course, have not yet found the “brain” of leeches, but it can be argued that the leech has a fairly branched nervous system, consisting of a peripheral section and a sympathetic autonomic system.

There is an opinion that a leech "loves" a person. Researchers of this "crawling world" have long wondered if any senses are possible in leeches or any other worms. Well, animals, of course, cannot love like people. But some species of mammals are characterized by certain emotional experiences associated with devotion, friendliness, affection.

Sources

https://ru.wikipedia.org/wiki/Leechs http://www.pijavki.com/o_pijavkah.html http://polzovred.ru/zdorovie/piyavki.html#i-2 http://pomogispine.com /lechenie/girudoterapiya.html http://www.aif.ru/health/life/1188201

Previously, the medicinal leech lived in almost every corner of Europe, but now its numbers have declined sharply. This happened because active commercial trapping in the past, as well as the drainage of swamps, significantly reduced the population.

The body of a medical leech is flattened, rounded, having two suckers that grow at the anterior and posterior ends. The anterior sucker is crowned with a mouth opening.

In natural habitat, the leech is attached to various underwater plants, where it waits for the victim. The leech is very voracious, with a weight of about 2 g, it can easily suck out up to 15 ml of blood at one time, while the body weight increases by almost 10 times.

The blood that the leech sucked from the victim does not clot and can remain in a liquid state for up to several months. The period that she can live from the first meal to the next is about 2 years.

To digest the blood and keep it in its original liquid form, special bacteria called Aeromonas hydrophila are found in the intestines of the leech. Leeches have a symbiotic relationship with these microorganisms. This means that both participants in the tandem benefit for themselves. In addition, if unwanted bacteria are found in the leech's stomach, the symbiont destroys them, purifying the blood contained in the worm.

The use of leeches in domestic medicine is directed against diseases such as varicose veins, bleeding (hemorrhage), ulcers. In the West and in Europe, with the help of these worms, they are struggling with venous congestion, which is formed during tissue transplantation. Some medicines contain leech extract. Today, technological progress allows you to make attempts to create an artificial leech.

Distribution area of ​​medicinal leeches

They live in large numbers in the north to the border with Scandinavia, in the south - to Algeria and Transcaucasia. There is an assumption that within the boundaries of their habitat, they live in isolated populations, avoiding contact with groups of other leeches. The form of leeches used in medicine lives mainly in Azerbaijan and Transcaucasia. Another form, pharmacy, lives in Krasnodar Territory, Stavropol.

Typical habitat for leeches

Leeches are adapted to aquatic and air habitats. To pump from one reservoir to another, they are able to overcome a long distance by land. Live only in fresh waters. Salt water sources are intolerant. The usual place where they live is lakes or ponds, the bottom of which is lined with silt. Prefer clean water where frogs live and reeds grow thickly.

The International Union for Conservation of Nature (IUCN) classifies medicinal leeches as an animal of vulnerable quantitative composition. Some habitats that have long been familiar to leeches are no longer areas of their distribution. The reason for the decline in numbers is a massive outflow for medical purposes. To date, the intensity of the impoverishment of the population has decreased, due to the fact that the technique of bloodletting has become irrelevant.

Also, biofactories are being created on which leeches are artificially grown, however, this does little to restore the population. Also a clear factor that leads to death a large number of these animals, is a reduction in the number of frogs. They are the main source of nutrition for small leeches that are not able to suck on larger animals.

Features of the body structure of leeches

As mentioned earlier, the medical leech has an elastic body, elongated, with well-developed muscles. It is divided into 33 segments. It has two suction cups, the back is larger than the front, its function is to gain a foothold on the substrate. Each segment is divided into a certain number of segments (3 or 5), sensory papillae are located in the central ring of each segment.

The abdomen and back differ in color, the back is dark, with brown stripes. Outside, the body has a cuticle, it is repeatedly shed during growth. By the intensity with which the animal sheds, you can find out the state of health of the leech.

The leech has four layers of muscles. The first consists of circular fibers responsible for swallowing blood, followed by a layer of diagonal and deep longitudinal fibers, they provide contraction of the body, the last layer is the dorsal-abdominal muscles, they serve to make the body flat. Connective tissue is very elastic, dense, it covers both muscle fibers and organs.

The nervous system consists of ganglia and segmental nerves extending from them. At the anterior and posterior ends of the body, the ganglia unite and form a pair of synganglia, one pharyngeal and one anal.

The receptors that are located on each segment are divided into three types according to the type of sensitivity: baroreceptors, thermoreceptors and chemoreceptors. All of them serve to search for food and orientation in space. On top of that, on the first five segments there are five pairs of eyes, including special pigment cells, with the help of which the leech can distinguish light from darkness.

The digestive system includes: a mouth, in the central part of the anterior sucker, jaws - one upper and two lower, each with 100 chitin teeth, they can damage the skin of the organism to which it sticks. A special secret also enters the mouth opening, which prevents blood from clotting at the time of absorption. The stomach is presented in the form of an elastic tube, which has 11 paired pockets. The muscular sphincter separates the stomach from the intestines. In the latter, fecal masses accumulate, during the removal of which the water turns into dark color.

Urine, which is formed in the body of a leech, is excreted through the nephropores. According to the type of hermaphrodite reproduction, she cannot fertilize herself alone, she still needs a pair.

Nutrition and breeding of leeches

It feeds mainly on the blood of warm-blooded animals, but sometimes it can attack frogs and fish. The duration of blood absorption always varies from the state of the leech.

A starving individual can take blood for 2 hours.

It breeds once a year, in summer. The copulation process takes place on land, the leeches wrap around each other and stick, after fertilization, the leech lays 5 cocoons, of which babies will be born in 2 weeks.

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