Leech class (Hirudinea). Medical leech (Hirudo medicinalis)Engl. Medicinal leech Leeches are used as food

External structure

The body of leeches is noticeably flattened in the dosoventral direction. At the anterior end there is a muscular anterior sucker, in the center, which accommodates mouth opening. At the posterior end there is a second, very strongly developed posterior sucker, above which the anal opening opens on the dorsal side.

Leeches do not have any appendages or parapodia. The bristles are preserved only in a primitive species - the bristle leech. It has four pairs of setae on its five anterior segments.

Leeches very mobile, crawling and swimming animals . Having attached itself with a posterior oral sucker, the leech pulls its body forward, then attaches itself with an oral sucker, while the posterior sucker is pulled away from the substrate and the body is pulled towards the head end, bending into a loop. Then the leech is sucked again by the rear sucker, etc. In this way, the leeches make “walking” movements. Leeches swim, producing wave-like movements with their whole body, during which their body bends in the dorsoventral direction.

The external ringing of leeches is false, secondary, it does not coincide with the true internal segmentation. Each true segment in various leeches corresponds to 3 to 5 outer rings. The external ringing of leeches is an adaptive feature that provides body flexibility with powerful development skin-muscle bag.

The body of leeches is formed by 33 segments (with the exception of the bristle leech, which has 30 segments), of which the weakly separated head lobe - prostomium - and four head segments are part of the anterior sucker. The trunk section is represented by 22 segments. The posterior sucker is formed by the fusion of the last seven segments.

Skin-muscle bag

The skin-muscular sac of leeches is formed by a single-layer epithelium, secreting a dense layered cuticle, and powerfully developed muscles. The skin of leeches is rich in glandular cells that secrete mucus and is penetrated by a network of lacunar capillaries. Under the epithelium there are numerous pigment cells, which determine the peculiar pattern of leeches.

Leeches are characterized by the presence of three continuous layers of musculature of the skin-muscular sac, like in flatworms: outer annular, diagonal, most powerful longitudinal. The dorsoventral muscles, which are not part of the skin-muscle sac, are also highly developed.

Body cavity and circulatory system

In almost all leeches, the entire space between the organs is filled with parenchyma, like in flatworms. Only in leeches does the parenchyma fill secondary cavity body, whereas in flatworms it is primary.

In another order - proboscis leeches (Rhynchobdellida) - a stronger proliferation of parenchyma is observed. This leads to a partial reduction of the coelom. However, the coelomic cavity is preserved as a whole system of lacunae. Four main coelomic lacunae run along the entire body: two on the sides, one above the intestine, surrounding the dorsal blood vessel, and another below the intestine, housing the abdominal blood vessel and the abdominal nerve cord. These lacunae communicate with each other, forming a network of smaller lacunae. Thus, proboscis leeches have both a circulatory system and a lacunar system, which is a modified coelom.

In the third order - the higher jawed leeches (Gnathobdellida), which includes the medicinal leech and many other freshwater leeches - the process of parenchyma development goes as far as in proboscis leeches. The blood vessels lying inside the coelomic lacunae in proboscis leeches are reduced in jaw leeches. The function of the circulatory system is performed by the lacunar system, which originates from the coelom. This process of functional replacement of one organ with another, different in origin, is called substitution or organ replacement.

Excretory system

The excretory organs of leeches are represented by segmental organs of metanephridial origin. However, the number of pairs of pephrndia does not correspond to the number of segments. The medical leech has only 17 pairs of them. In connection with the transformation of the coelom into a system of lacunae, the structure of the metanephridia of leeches also changed. The metanephridial funnels open into the abdominal lacuna (coelom), but not directly into the nephridial canal. They are separated from the nephridial canal by a septum, so secreted substances penetrate from the funnel into the nephridium diffusely.

This structure of the metanephridia of leeches (separation of the funnel from the nephridial canal) is explained by the functional transformation of the lacunae into the main circulatory system, replacing the circulatory system. Metanephridia of leeches are characterized by the presence of a special expansion - the bladder.

Digestive system

The mouth is placed at the bottom of the front sucker. It leads to the anterior section digestive system, lined with ectoderm and consisting of an oral cavity and a muscular pharynx. The structure of the oral cavity and pharynx is different in proboscis and jaw leeches.

In proboscis leeches, the oral cavity, growing backwards, seems to surround the pharynx in the form of a vagina. The very muscular pharynx turns into a proboscis, protruding and retracting with the help of special muscles. The proboscis can penetrate the thin coverings of various animals (for example, mollusks), and thus the leech sucks out blood.

In jawed leeches (medicinal leech, etc.), in the oral cavity there are three longitudinal muscular ridges that form jaws, with their ridges directed towards each other. The muscle ridges are covered with chitin, jagged along the edge. With these jaws, leeches cut the skin of an animal or person. In the throat of blood-sucking jawed leeches, glands open that secrete a special substance - hirudin, which prevents blood clotting.

Next, food enters the midgut, which consists of the stomach and the posterior midgut. The stomach forms paired lateral projections, of which the last pair is usually especially developed, extending to the posterior end of the body. The stomach serves as a reservoir for long-term storage of blood. The blood that filled his pockets did not clot for weeks and months.

The posterior section of the midgut is represented by a relatively short straight tube in which final digestion and absorption of food occurs. It passes into a short, often dilated posterior ectodermic gut, opening with the anus above the posterior sucker.

Nervous system and sensory organs

Nervous system leech consists of a paired suprapharyngeal ganglion connected by peripharyngeal connectives with the subpharyngeal ganglion mass. The latter is formed by the fusion of the first four pairs of ganglia of the ventral nerve chain. This is followed by 21 ganglia of the ventral nerve cord and a ganglionic mass (of eight pairs of ganglia) innervating the posterior sucker.

The sense organs of leeches are represented by sensitive kidneys, or goblet organs. Each such organ consists of a bundle of spindle cells located under the epithelium. The outer end of the sensory cells forms a sensory hair. Nerves from the ventral nerve cord approach the inner ends of these cells.

Some of the goblet organs perform the functions of chemical sense organs, others - tactile ones. The eyes of leeches have a similar structure to the goblet organs described above. There may be several pairs of them. The eye consists of vesicle-shaped light-sensitive cells with a large vacuole inside, to which the nerves that make up the axial part of the eye approach. The eye is surrounded by dark pigment.

Reproductive system, reproduction and development

In terms of the structure of the genital organs and method of reproduction, leeches have much in common with oligochaete ringlets. They are hermaphrodites, and their genitals are concentrated mainly in the area of ​​the 10th and 12th body segments. Leeches have a girdle section, which, unlike oligochaetes, coincides in position with the genitals. The girdle becomes noticeable only during the breeding season.

The male reproductive apparatus consists of several pairs (4-12 or more) of testes. The medicinal leech has 9 pairs of testes located inside the seminal sacs. Short vas deferens extend from them, opening into longitudinal paired vas deferens. The latter in the area of ​​the 10th segment form dense balls - appendages of the testes, in which sperm accumulates. Next, they pass into the ejaculatory (paired) canals, which open in the copulatory organ, which can protrude forward through the unpaired male genital opening on the 10th segment. Not everyone has a copulatory organ. In many leeches, sperm are enclosed in spermatophores. Spermatophores are either introduced into the female genital opening or stuck into the skin, and sperm penetrate the leech's body and make their way to the female genital tract.

The female reproductive apparatus consists of a pair of ovaries located in egg sacs. They pass into short and wide uteri, which connect with each other and form an unpaired oviduct, which flows into a wide vagina, which opens on the 11th segment with the female genital opening.

Fertilized eggs are laid in a cocoon secreted by the girdle. The cocoon is either attached to aquatic plants or located at the bottom of the reservoir. Some leeches lay single eggs.

Development in leeches is not direct, since larvae emerge from the eggs, remaining, however, in a cocoon. Larvae have cilia and protonephridia. The transformation of larvae occurs in the cocoon, and already formed leeches emerge from the cocoon into the water. Laying eggs in relatively strong cocoons that well protect eggs and larvae results in a small number of eggs. It is measured in various leeches in units, at most in tens.

Classification

The class of leeches is divided into three orders: 1. Bristle-bearing leeches (Acanthobdellida); 2. Proboscis (Rhynchobdellida); 3. Jawfish (Gnathobdellida).

Order Bristle-bearing leeches (Acanthobdellida)

A very primitive relict form, bearing four pairs of sharp curved setae on the five anterior segments. The anterior sucker is absent, only the posterior one is present. The parenchyma is poorly developed, there is a coelomic cavity and a circulatory system.

Order Proboscis leeches (Rhynchobdellida)

Proboscis leeches are remarkable for breeding and caring for offspring. The leech lays eggs that remain attached to the ventral side of its body. At this time, the leech is little mobile: it sits, attached with suction cups, on some plant and makes oscillatory movements with its body. When the eggs hatch, the leech does not change its position and the young leeches remain attached to the ventral side of the mother with their suckers, usually for several days, and then spread out and begin to lead an independent existence.

Order Jaw leeches (Gnathobdellida)

Most jawed leeches have the jaw apparatus described above in the oral cavity.

In addition to the medicinal leech (Hirudo medicinalis), common in the southern part of Russia, this order includes the ubiquitous false horse leech (Haemopis sanguisuga). This is a large, dark-colored leech, has weak jaws and is not able to bite through the skin of humans and mammals. It feeds on worms, mollusks and other invertebrates. The false-cone leech buries its cocoons in the coastal strip, above the water level.

Some jawed leeches (especially those found in southern latitudes) can be parasites of humans, for example from the genus Limnatis. One of them - L. turkestanica - is found in Central Asia. When drinking raw water from a reservoir, it can enter the human nasopharynx, where it settles and sucks blood. In addition to severe irritation, it causes bleeding. In the jungles of Sri Lanka, India, and Indonesia live land animals of the genus Haemadipsa. They hide in damp places, in grass and under leaves and attack animals and humans, causing very sensitive bites.

In Latin hirūdō show the same suffix as in testūdō“turtle”, but the etymologization of the root is difficult. Named as possible relatives hīra"small intestine" and haruspex"haruspex".

Structure

The body length of different representatives varies from several millimeters to tens of centimeters. Most major representative - Haementeria ghilianii(up to 45 cm).

The anterior and posterior ends of the body of leeches bear suckers. At the bottom of the anterior there is an oral opening leading to the pharynx. In proboscis leeches (order Rhynchobdelida) the pharynx is able to move outward. In jawed leeches (for example, the medicinal leech), the oral cavity is armed with three movable chitinous jaws that serve to cut through the skin.

Nutrition

Biology of the organism

The body is elongated or oval, more or less flattened in the dorso-ventral direction, clearly divided into small rings, which, 3-5 in number, correspond to one body segment; there are numerous glands in the skin that secrete mucus; at the posterior end of the body there is usually a large sucker; often at the anterior end there is a well-developed sucker, in the center of which the mouth is placed; more often the mouth is used for suction. At the anterior end of the body there are 1-5 pairs of eyes, located in an arc or in pairs one behind the other. Powder on the dorsal side above the posterior sucker. The nervous system consists of a two-lobed suprapharyngeal ganglion, or brain, connected to it by short commissures of the subpharyngeal node (derived from several fused nodes of the abdominal chain) and the abdominal chain itself, located in the abdominal blood sinus and having about 20 nodes. The head node innervates the sensory organs and pharynx, and from each node of the abdominal chain 2 pairs of nerves depart, innervating the corresponding body segments; the lower wall of the intestine is equipped with a special longitudinal nerve that gives branches to the blind sacs of the intestine. The digestive organs begin with a mouth, armed either with three chitinous toothed plates (jawed P. - Gnathobdellidae), which serve to cut through the skin when sucking blood in animals, or capable of protruding with a proboscis (in proboscis P. - Rhynchobdellidae); Numerous openings into the oral cavity salivary glands, sometimes secreting a poisonous secretion; the pharynx, which plays the role of a pump during sucking, is followed by an extensive, highly extensible stomach, equipped with lateral sacs (up to 11 pairs), of which the posterior ones are the longest; the hindgut is thin and short. The circulatory system consists partly of real, pulsating vessels, partly of cavities - sinuses, which represent the remainder of the cavity (secondary) of the body and are connected to each other by ring canals; The blood of proboscideans is colorless, while that of jawed animals is red due to hemoglobin dissolved in the lymph. Only the river has special respiratory organs. Branchellion, shaped like leaf-like appendages on the sides of the body. The excretory organs are arranged according to the type of metanephridia, or segmental organs of annelids, and most P. have a pair of them in each of the middle segments of the body. P. - hermaphrodites: the majority of male genital organs consist of vesicles (testes), a pair in 6-12 middle segments of the body, connected on each side of the body by a common excretory duct; these ducts open outward with one opening lying on the ventral side of one of the anterior rings of the body; The female genital opening lies one segment behind the male and leads into two separate oviducts with sac-like ovaries. Two individuals copulate, each simultaneously playing the role of a female and a male. During the laying of eggs, P. secretes, through the glands located in the genital area, thick mucus that surrounds the middle part of P.'s body in the form of a sheath; eggs are laid in this case, after which P. crawls out of it, and the edges of its holes come together, stick together and thus form a capsule with eggs inside, usually attached to the lower surface of the algae sheet; The embryos, leaving the facial membrane, sometimes (Clepsine) remain for some time on the underside of the mother’s body. All P. are predators, feeding on the blood of mostly warm-blooded animals or mollusks, worms, etc.; They live mainly in fresh water or in damp grass, but there are also marine forms (Pontobdella), just like terrestrial forms (in Ceylon). Hirudo medicinalis - medical P. up to 10 cm long and 2 cm wide, black-brown, black-green, with a longitudinal patterned reddish pattern on the back; the belly is light gray, with 5 pairs of eyes on the 3rd, 5th and 8th rings and strong jaws; distributed in the swamps of the South. Europe, South Russia and the Caucasus. In Mexico, Haementaria officinalis is used medicinally; another species, N. mexicana, is poisonous; V tropical Asia Hirudo ceylonica and other related species living in damp forests and grass are common and cause painful bleeding bites to humans and animals. Aulostomum gul o - horse P., black-green in color, with a lighter underside, has weaker mouth armament and is therefore unsuitable for therapeutic purposes; most common appearance all in. And Central Russia. Nephelis vulgaris is a small P. with a thin narrow body, gray in color, sometimes with a brown pattern on the back; equipped with 8 eyes located in an arc at the head end of the body; related to it is the original Archaeobdella Esmonti, Pink colour, without rear sucker; lives on the silt bottom in the Caspian and Seas of Azov. Clepsine tessel ata - Tatar P., with a broad oval body, greenish-brown color, with several rows of warts on the back and 6 pairs of triangular eyes located one after the other; lives in the Caucasus and Crimea, where it is used by the Tatars for medicinal purposes; Acanthobdella peledina, found in Lake Onega, occupies a transitional place to the order of chaetopoda Oligochaeta worms.

History of medical use

Medical leech ( Hirudo officinalis) - found in the north of Russia, especially in the south, in the Caucasus and Transcaucasia, in Poti, Lankaran. Leeches were a profitable export item in the 19th century: Greeks, Turks, Italians and others came to the Caucasus for them. In addition, leeches were artificially propagated in special pools or parks according to the Sale system in Moscow, St. Petersburg, Pyatigorsk and Nizhny Tagil. Based on current laws, fishing for leeches during their breeding season - in May, June and July - is prohibited; when fishing, only those suitable for medical use should be selected, that is, at least 1 1/2 inches in length; leeches that are small or too thick should be thrown back into the water when caught. To supervise compliance with these rules, provincial medical departments are entrusted with the responsibility of verifying the stocks of leeches among barbers and other traders who trade in them. Since medicine drove leeches out of use, the leech industry has fallen completely.

Notes

Sources

• Ruppert E. E., Fox R. S., Barnes R. D. Zoology of invertebrates. T. 2: Lower coelomic animals. M., "Academy", 2008.

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See what “Leeches” are in other dictionaries:

- (Hirudinea), class of annelids. Dl. from several mm up to 15 cm, rarely more. Originated from oligochaete worms. The body is usually flattened, rarely cylindrical, with two suckers (perioral and posterior); consists of a head blade, 33 rings... ... Biological encyclopedic dictionary

LEECHES, class of worms. Length 0.5-20 cm. The body is usually flattened, with 2 suckers. About 400 species live in fresh and marine waters. Most leeches are bloodsuckers, the salivary glands of which secrete the protein substance hirudin, which prevents... Modern encyclopedia

Class of annelids. Length 0.5-20 cm. They have front and rear suction cups. 400 species. In fresh and marine waters. Most leeches are bloodsuckers whose salivary glands secrete hirudin, which prevents blood clotting. Medical leech… … Big encyclopedic Dictionary

- (Hirudinei) order of the annelid class. The body is elongated or oval, more or less flattened in the dorso-ventral direction, clearly divided into small rings, which, among 3 to 5, correspond to one body segment; There are numerous glands in the skin... Encyclopedia of Brockhaus and Efron

– the mention of it causes unpleasant associations for many. And it's true appearance among leeches it is unattractive, one might even say repulsive. But this creation brings great benefits to humans, helping to get rid of many diseases.

Types of leeches

Medical leeches belong to the type of annelids, class belt worms, subclass of leeches, order of proboscis, family Hirudinidae (jawed leeches). Its name in Latin is Hirudo medicinalis. The medical form is successfully used in the treatment of patients in Europe, Russia, and Ukraine. Asia, Africa, America use other types of leeches.

IN wildlife There are up to 500 varieties of leeches. With such a variety of bloodsuckers, only three main types are used in treatment:

Other types of leeches not only do not bring benefits, but can also cause harm to humans and animals.

Horse (Limnatis nilotica). Also known as Egyptian or Nile. Habitat: Transcaucasia, Central Asia, Mediterranean. This species cannot bite through the skin, so they stick to the mucous membranes. Can penetrate into the oral cavity. The animal, increasing in size while sucking blood, can cause suffocation in humans and lead to death.

Surveyor leech (Piscicola geometra). It has a large rear sucker, although it itself measures no more than 5 cm in length. Feeds on the blood of fish. Having smelled a fish, it begins to move towards it and firmly attaches itself to it. Fish sometimes die due to loss of blood. Can cause harm to fisheries if leeches multiply in large numbers.

Common or false cone (Haemopis sanguisuga). This is a predatory species, reaching 10 cm in length. Lives in rivers, ditches, ponds, crawls ashore. It can swallow the victim whole, or bite off pieces. It attacks those animals that it can easily handle. Doesn't suck blood. Habitat: Ukraine, Russia, Moldova, Belarus.

Eight-eyed (Herpobdella octoculata). Flat, about 6 cm long. Lives in reservoirs with stagnant water, survives even in very dirty environments. It feeds on both living and dead larvae of insects and small animals.

Pond (Helobdella stagnalis). The smallest representative. Grows no more than 1 cm. Distributed in almost all bodies of water. The main color is brown, but green is also found. Attaches to worms, larvae, snails.

Habitat

The wild animal is very common in Europe, but its numbers are constantly declining due to constant fishing. And also the decline of the species is facilitated by the drainage of swamps and the unfavorable ecological state of the water. Widely distributed in the north, all the way to Scandinavia, and in the south it is also found near Algeria.

Medical species most often live in Transcaucasia and Azerbaijan. But the distribution area of ​​pharmacies is Stavropol and Krasnodar Territory.

Animals can live perfectly well both in water and on land. They can only live in fresh water. Salty bodies of water are unsuitable for them. When moving from one habitat to another, they can cover quite long distances on hard surfaces.

They settle in ponds and reservoirs where the bottom is silted and reeds grow. However, the water must be clean. Gets along well with frogs. The favorite habitat of leeches is stones and driftwood. She hides under them, sometimes not fully protruding from the water.

What does it look like

Medical leech body round shape , slightly flattened, divided into 33 annular segments. In turn, each of the segments is divided into 3 or 5 parts. Each segment has a central ring in which the sensory papillae are located. They perform the function of a sensor. There are suction cups on the back and front. The front sucker functions as a mouth. The bloodsucker has 270 teeth. Rear sucker much bigger size, since with its help the leech is attached to the surface.

The medical appearance is dark brown, almost black. The back is darker, with distinct stripes along it. The body is without setae and covered with cuticle. The bloodsucker sheds it periodically as the animal grows. As a rule, this happens once every 2–3 days.

The animal moves without any problems and quite quickly. Able to move both through water and on hard surfaces. The leech uses suction cups as a means of movement on the ground, and also helps itself by contracting its body. Once in the water, the animal makes oscillatory movements and swims in waves. She is so strong that with one end of her body she can stick to the surface and lift her body into a vertical position. This way she can search for what she needs.

How a leech works

The choice of the location of the bite remains with the leech. Having decided on the attachment site, it makes a bite no more than 2 mm deep and is saturated with blood. The total volume of blood sucked at one time does not exceed 15 ml. After the bloodsucker detaches, the wound will bleed for 4 to 20 hours. Everything will depend on the individual characteristics of the organism, as well as on how much enzyme the leech releases. It's called hirudin and prevents blood from clotting. There is no need to stop the blood, as this achieves a therapeutic effect.

From the moment the medicinal leech’s saliva penetrates the skin and enters the human blood, the therapeutic effect begins. Beneficial components are carried throughout the body through the bloodstream within 15–20 minutes.

A person does not feel how a leech sucks blood. A slight unpleasant feeling may occur when the skin is bitten. After this, the blood flows by gravity into the mouth, and then into the stomach of the bloodsucker. It doesn't curl up there. As the animal becomes saturated, it increases in size. When the limit of filling her stomach comes, it falls off on its own.

While waiting for food, leeches attach to the surface with two suckers. As soon as they sense that a potential victim is approaching, they begin to move towards it. Having reached the target, the leech attaches itself to the body with its rear end, and with its front end it looks for the most suitable place to bite. This will either be a plot with thin skin, or where the vessels are located closest to the surface.

Having attached itself, the leech does not let go of the victim until it is completely satiated. The animal may not eat for a long time. Therefore, the amount of blood drunk will depend on how long the bloodsucker was fasting. For example, if a leech has not received food for about six months, then it can take up to 1.5 hours to become saturated.

Leeches reproduce in nature once a year, when the animals reach sexual maturity. It occurs at the age of four. To breed offspring, leeches choose summer period. The mating process in leeches is called copulation. Mating occurs by entwining one individual with another, as if they are glued. Once fertilization has occurred, the female lays cocoons after mating. Usually their number does not exceed 5 pieces.

Leech embryos feed on the protein mass located inside the cocoon. The cocoon itself is covered on top with a dense protective shell. After about two weeks, small leeches hatch and can already drink blood. The number of babies ranges from 20 to 40 pieces.

Benefits of leeches

Medical leeches are successfully used in the treatment of many diseases. They can, if not completely cure, then significantly improve the patient’s condition. The use of leeches in complex treatment speeds up the patient’s recovery.

Treatment with medicinal leech is called hirudotherapy. The highest effect is achieved thanks to several actions of hirudotherapy:

• hirudin– a hormone that prevents blood clotting and thrombus formation;
• eglins – substances that prevent joint damage and cure existing diseases;
• hyaluronidase – an enzyme that promotes the fertilization process is used in the treatment of infertility.

Salivary secretion contains analgesic and antibacterial substances.

The main diseases for which the use of medicinal leech is indicated are.

For hirudotherapy, medical leeches grown artificially should be used. It is strictly forbidden to use leeches caught in open waters for treatment. Wild animals are carriers of dangerous diseases; diseases accumulate on their jaws when bitten by infected animals.

Contraindications to hirudotherapy

Despite the enormous benefits and positive result when treating diseases with medicinal leeches, There are a number of contraindications:

• poor blood clotting;
• oncology;
• hemolysis;
• individual intolerance to enzymes;
• allergic reactions;
• anemia;
• tuberculosis of various forms.

Treatment with a medicinal leech will undoubtedly bring great benefits. However, hirudotherapy must be carried out by a qualified specialist so as not to harm the human body.

• Kingdom: Animalia, Zoobiota = Animals
• Class: Clitellata = Belted
• Subclass: Hirudinea Lamarck, 1818 = Leeches
• Subfamily: Hirudinariinae Whitman, 1886 = Leeches
• Genus: Hirudo Linnaeus, 1758 = Leeches

Family: Hirudinidae Whitman, 1886 = Leeches

Leeches (Hirudinei) are a detachment of the class of annelids. The body is elongated or oval, slightly flattened in the dorsal-abdominal direction, clearly divided into small rings, which, 3-5 in number, correspond to one body segment. The skin contains numerous glands that secrete mucus. At the posterior end of the body there is a large sucker, and often at the anterior end there is a well-developed sucker, in the center of which the mouth is located. At the head end of the body, from 1 to 5 pairs of eyes are located in an arc or in pairs one after another.

The digestive organs begin with a mouth armed with three chitinous toothed plates (maxillary - Gnathobdellidae), which serve to cut through the skin when sucking blood in animals, or capable of protruding with a proboscis (in Rhynchobdellidae).

Numerous salivary glands open in the oral cavity, sometimes secreting a poisonous secretion. The pharynx, which plays the role of a pump, is followed by an extensive, highly extensible stomach, equipped with lateral sacs (up to 11 pairs), of which the posterior ones are the longest. The hindgut is thin and short.

The circulatory system consists partly of real, pulsating vessels, partly of sinus cavities. The blood of proboscis leeches is colorless, while that of jawed leeches is red, due to hemoglobin dissolved in the lymph. Only the river has special respiratory organs. Branchellion, shaped like leaf-like appendages on the sides of the body.

Leeches are hermaphrodites. Most male genital organs consist of vesicles (testes), a pair in 6 to 12 middle segments of the body, connected on each side of the body by a common excretory duct. These ducts open outward with one opening lying on the ventral side of one of the anterior rings of the body. The female genital opening lies one segment behind the male and leads into two separate oviducts with sac-like ovaries. Two individuals copulate, each simultaneously playing the role of a female and a male. When laying eggs, a leech secretes thick mucus that surrounds the middle part of the body in the form of a sheath. Eggs are laid in this case. After which the leech crawls out of it, the edges of its holes stick together and thus form a capsule with eggs inside, usually attached to the lower surface of the algae sheet. The embryos, leaving the egg shell, remain for some time on the underside of the mother’s body.

All leeches are predators, feeding on the blood of most warm-blooded animals, or mollusks, worms, etc.

Hirudinei live mainly in fresh waters or in wet grass, but there are also marine forms, for example Pontobdella.

Land surveying leech Piscicola geometra. 1-5 cm in length. Thin round body with a very large rear sucker. Swims in water (fresh and brackish) or stays on plants, lying in wait for fish, whose blood it feeds on. After mating, which occurs on the host fish, both leeches (hermaphrodites) lay on aquatic plants up to 90 cocoons.

Aulostomum gulo - horse leech. Black-green in color, with a lighter underside. Distributed in swamps and rivers of Europe.

Common leech, or false horse leech, Haemopis sanguisuga. About 10 cm in length, maximum 15 cm. Greenish or brownish-black. Common in ponds, rivers and ditches; goes ashore. Predator. It attacks any animal that it can overcome, such as earthworms. Cocoons are laid in moist soil on the shore.

Medical leech - Hirudo medicinalis up to 15 cm in length and 2 cm in width, black-brown or black-green, with a patterned longitudinal reddish pattern on the back. The belly is light gray, with 5 pairs of eyes on the 3rd, 5th and 8th rings and strong jaws. Found in lakes, ponds and swamps in Europe. Young leeches feed on larvae and worms, while adults suck the blood of vertebrates (especially mammals) and can, having pumped to the limit, go without food for more than a year. Cocoons are laid in damp coastal soil. Leeches, like oligochaetes, are hermaphrodites and are similar to them in their reproductive features (they lay cocoons through the girdle); however, their ability to regenerate is much lower and they reproduce only sexually.

Eight-eyed leech - Herpobdella octoculata. Up to 6 cm in length, rather flat. It is common in stagnant or slow-flowing bodies of water, and can tolerate even severe pollution. Attacks various (living and dead) insect larvae, mainly bell-bellied mosquitoes, and other small animals. It lays its brown cocoons on stones, plants, etc.

Clepsiue tesselata - with a broad oval body, greenish-brown color, with several rows of warts on the back and 6 pairs of triangular eyes located one after the other. Lives in southern Russia and Ukraine.

Flattened leech - Glossiphonia complanata. 1-3 cm in length. Transparent; The color may be different, but the dorsal side is greenish or brownish. Lives in standing and flowing bodies of water; on plants and stones. It attaches mainly to lung snails, but also attacks worms and insect larvae. Shows care for the offspring, carrying a cocoon and young leeches.

Bordered leech - Hemiclepsis marginata. Up to 5 cm in length. Widely distributed in standing and flowing water bodies. Sucks mainly the blood of fish and amphibians. The cocoon sticks to plants or stones. Shows care for the offspring by creating a current of fresh water near the cocoon.

Pond leech - Helobdella stagnalis. Up to 1 cm in length. Easily recognized by the dark round plate on the back between the 12th and 13th segments. It is found everywhere: on plants and stones, in standing and flowing bodies of water. Sucks out small animals (worms, isopods, molluscs and insect larvae, such as mosquito larvae).

Treatment with leeches dates back to ancient times. For example, drawings depicting the use of leeches are found on the walls of ancient Greek tombs. Treatment with leeches was described in their writings by ancient Greek and Roman healers, such as: Hippocrates And Galen. The use of leeches for medical purposes was also mentioned in his writings by the great Arab physician Avicenna.

History of hirudotherapy

Hirudotherapy literally translated from Latin language means “treatment with a leech”, since “hiruda” is translated as a leech, and “therapy” means treatment.

Treatment with leeches is most widespread in Europe. And although hirudas were used for medicinal purposes in Europe for hundreds of years, their peak occurred in the 17th and 18th centuries. This is due, first of all, to the fact that it was at this time in Europe that a rather interesting concept of the so-called “bad blood” appeared in medical circles. In general, in Europe they really liked to let blood. And there were two methods of bloodletting - vein And hirudny. The latter was popular for bleeding from hard-to-reach places and so-called “tender” places (for example, gums).

Sometimes doctors could simultaneously apply up to 40 leeches to a patient! Leeches at this time were very hot commodity. In London at the time, with a population of approximately 3 million people, approximately 7 million leeches were used annually. And you need to take into account that not everyone could call a doctor, since treatment was expensive. Russia supplied Europe with up to 70 million leeches per year. It was a very profitable export item at that time.

However, after the second half of the 19th century, the concept of “bad blood” left Europe. The bloodletting has ceased. At the same time, research began on the substance contained in the saliva of the hiruda. The enzyme was discovered in 1884 by John Haycraft hirudin, contained in leech saliva. This discovery gave a strong impetus to further study and use of leeches in medicine on a scientific basis. In 1902, the first drugs based on hirudin were obtained.

Currently, hirudotherapy is experiencing a rebirth. This is due to several factors. In the 20th century, a real revolution took place in traditional medicine: fundamental discoveries were made, many diseases were defeated, many were invented and put into mass production. medications. But by the end of the 20th century, discoveries in medicine began to occur less and less often. The influence of many has been studied medicines on the human body and it turned out that they are not always beneficial features overpowered the negative impact. The global fascination with hirudotherapy in Asia, especially China and Japan, also played a role. These countries are characterized by a philosophy of harmony with environment, and alternative medicine has a strong position in them. All this together gave impetus to the revival of hirudotherapy.

A little about leeches

Leeches feed on blood. Blood is digested in the leech’s intestines for an extremely long time, so one feeding is enough for the leech to remain without food for a very long time. Leeches are hermaphrodites. They move with the help of special suction cups, which are located at both ends of their worm-like body.

Stages of treatment

1. Bite

The biting process occurs as follows: the leech is attached to the desired area on the patient’s body using suction cups. After the leech feels that it is securely attached, it bites through the skin. Its depth is usually 1.5 - 2 millimeters. After biting, the leech injects its saliva into the resulting wound, which, as is already known, contains hirudin, which prevents blood clotting.

2. Feeding

The leech usually remains on the patient's body for 20 to 60 minutes, depending on the disease. During this time, one leech can “drink” from 5 to 15 milliliters of blood.

3. Stopping blood sucking

In most cases, the leech should move away on its own after it is saturated. However, it is often necessary to remove leeches from the patient’s body prematurely. For this, a swab moistened with alcohol or iodine is usually used. As a rule, the leech immediately disappears after such use. Also practice
using tobacco smoke on a leech, sprinkling salt or snuff on the leech, pouring wine on the leech, or lemon juice, sometimes with vinegar.

If all these methods do not make the leech “lag behind” the patient, then take a scalpel. It is important to remember that a specialist will never cut a leech in half, as this will not stop it and the process will continue. Use a scalpel to separate the anterior sucker, letting air under it. When using the surgical method, the leech will definitely “fall off” from the patient.

After the bite, a wound will remain that will secrete blood and lymph for 6 to 16 hours. This is normal, since the wound contains hirudin. Normally, blood loss from one wound can range from 50 to 300 milliliters of blood.

Therapeutic effect:

• the blood undergoes renewal as dosed bleeding occurs (the same effect is present during the blood donation procedure);
• the action of biologically active substances contained in leech saliva is triggered;
• a set of body responses occurs to blood loss, the bite itself, and active biological substances that get into the wound with the leech’s saliva.

Active biological substances contained in leech saliva have the following properties:

• anti-inflammatory;
• pain reliever;
• fibrinolytic.

In this regard, with the help of hirudotherapy it is possible to
reduce the risk of thrombosis, fight thrombophlebitis, relieve swelling from affected areas of the body (for example, with venous stagnation), improve blood circulation of internal tissues in osteochondrosis, relieve pain, remove toxic substances from the body.

Leeches are actively used in microsurgery to save transplanted skin areas. They are also widely used in complex therapy. varicose veins veins, are used to relieve muscle spasms and help in the treatment of arthrosis.

Warnings and contraindications

In hirudotherapy, there is a risk of transmitting infection with leech saliva from the pathogenic environment of its stomach. The risk is minimal if more than 4 months have passed since the last feeding of the hiruda, since by this time only a small amount of “drunk” blood remains in its stomach, and the growth of pathogenic bacteria is suppressed by the symbiont bacterium produced by the leech itself. Reliable protection is considered to be the use of so-called “sterile” leeches, that is, leeches grown in an artificial environment, where, by definition, there cannot be pathogenic flora.

There are the following contraindications to treatment with hiruda:

• low blood clotting (use of leeches can be fatal);
• diseases that are accompanied by bleeding due to poor blood clotting (hirudin will increase bleeding);
• anemia (anemia);
• hemolysis (destruction of red blood cells with the release of hemoglobin into the environment);
• low blood pressure;
• extreme weakening or exhaustion of the body (for example, against the background of a long or serious illness);
• weakened immunity (possible infection through leech titer);
• individual allergic reaction of the body to leech enzymes;
• pregnancy period;
• lactation period;
• childhood.

Only a specialist can prescribe treatment with leeches. It is he who should determine the risk of using hirudotherapy in each specific case.

Remember, the benefits should always outweigh the possible harmful effects!