Saturday, September 27, 2008

Leech..... An Overview

Leeches are annelids comprising the subclass Hirudinea. There are fresh water, terrestrial, and marine leeches. Like their near relatives, the Oligochaeta, they share the presence of a clitellum. Like earthworms, leeches are hermaphrodites. There are 650 known species of leeches.


Medicinal leeches are any of a group of several species of leeches but most commonly Hirudo medicinalis or the European Medical Leech. Other species sometimes referred to as Medical Leeches include (but are not limited to): Hirudo verbana, Macrobdella decora (North American Medical Leech), Hirudo troctina, Hirudo orientalis and Hirudinaria manillensis (Asian Medicinal Leech).


Today, doctors use leeches for treating abscesses, painful joints, glaucoma, myasthenia, and to heal venous diseases and thrombosis. Medical leeches are used in plastic surgery, for improving blood circulation and for curing infertility.

The general indications for hirudotherapy are:

Inflammatory Reactions, Heart Diseases, Rheumatic Diseases, Tendovaginitis and Tendinitis, Venous Disease and Varicose Veins, Arthrosis, Arthritis, Muscle Tension, Antidyscratic therapy (blood purification and regeneration) of toxicoses and mental illnesses, Thrombosis and embolism, Passive congestions and spastic conditions, Vertebrogenic Pain Syndromes, Transudates and exudates.

A simple principle lies at the heart of all hirudo-miracles. During the process of feeding, leeches secrete a complex mixture of different biologically and pharmacologically active substances into the wound. Hirudin is the best known component of leech saliva. Hirudin is sometimes used to describe all active substance in leech saliva. In reality, Hirudin refers only to one specific active substance in leech saliva.


The job of the leeches in veterinary medicine is spread since ancient time but it seems that the lack of material on the definite job of the annelidas is partly at the origin of their weak use in this domain. However the applications of the leech could be similar to those of human medicine.

The majority of the applications of the leech in human medicine are also valid in veterinary medicine. So they are similarly pointed out in the treatment of thromboses, phlebitis, furuncles, haemorrhoids, haematomata, enemata, tendinitis they can also be used in surgery in cases of tissulaires transplants.


There are lots of bioactive substances in Medicinal Leeches and Leech Powder. These bioactive substances are used in Cosmetics and Pharmacies. Bioactive substances of the Medicinal Leeches:

1. Hirudin
2. Hyaluronidase
3. Pseudohirudin
4. Destabilase
5. Apyrase
6. Bdellines
7. Eglines
8. Kininases
9. Histamine-like substances
10. Collagenase
11. Leech prostanoids
12. Inhibitor of kallikrein of the blood plasma
13. Proteases
14. Lipolytic enzymes
15. Intibitor of Xa factor of the blood coagulation
16. Triglyceridase
17. Cholesterol esterase
18. Lipase

Although medicinal leeches have been successfully bred in laboratories for some time, we know little about their requirements for breeding, particularly for egg-laying in the wild. The medicinal leech leaves the water to lay its eggs, which are coated in a spongy protective cocoon. Cocoons must be deposited in a place where they will not dry out nor become waterlogged, and from where the young can easily reach the water after hatching.

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