Leeching out Bad Blood
By Buddhika Samaraweera
All medical systems aim to restore those who are ill, and leech therapy is a proper example of a medical treatment valued in both complementary and conventional medicine. In Sri Lanka, Ayurevda medical treatment has particular strengths and much to offer to conventional medicine. It is also expected that it will find its way into integrated medical systems in the future.
In the Ayurveda medical system, bloodletting (Raktamokshana Karma) is considered as a regimental therapy. Leech therapy, a para-surgical procedure in the Ayurveda surgical stream has been used for many diseases.
Leeches suck only impure blood, and leech therapy is therefore considered as a blood purification therapy. The therapeutic application of leeches is practiced in other indigenous medical systems such as Unani and Siddha as well. Leeches have been used in medical practice since ancient times to treat many diseases. It is a method in which localised impure blood is let out to heal the tissue. Due to its therapeutic effects, it has brought progressive results.
Records of using leeches for therapy can be found in old literature which describes the nature of leeches, their habitats, methods of application, diseases indicated like Herpes and skin diseases in detail. Though there are hundreds of leech species, only 15 out of them are used for therapy. Leeches are used to relieve venous congestion and improve blood circulation.
According to Dr. Tharindu Upeka Silva, Ayurveda medicine is believed to be the oldest medical system in which leech therapy was adopted for treating specific disease conditions of patients. Some of the indications in which leeches were used were in treating for tumors, hemorrhoids, abscesses and boils, skin disorders, ulcers, gout, diseases of the eye, headache, herpes zoster, thrombosis, and wounds.
The saliva of the leech consists of anaesthetic agents, anticoagulant, antiplatelet aggregation factors, antibiotic, anti-inflammatory substances, and gelatinous substances. Leeches suck the excess blood, reduce the swelling in the tissues, and promote healing by allowing fresh oxygenated blood to reach the area until normal circulation can be restored.
Also, clinical studies have been conducted in different parts of the world to observe the scientific background of leech therapy. Studies with leeches have been carried out to observe the healing of complicated varicose veins, pain reduction in osteoarthritis, and other disorders.
According to field biologist of the University of Sri Jayewardenepura, Chathuranga Dharmarathne who works with different animal taxonomic groups in Sri Lanka, leeches are segmented parasitic worms that belong to the phylum Annelida and comprise the subclass Hirudinea. A majority of leeches live in freshwater habitats, while some species can be found in terrestrial and marine environments.
The best-known species, such as the medicinal leech, Hirudomedicinalis, attach themselves to a host with a sucker and feed on blood, having first secreted the peptide ‘hirudin’ to prevent the blood from clotting. The jaws used to pierce the skin in other species are replaced by a proboscis which is pushed into the skin. These leeches are dark in colour and marked with six longitudinal stripes. Their bodies are two to three inches long, convex and wrinkled transversely, tapering at each end.
A minority of leech species are predatory, mostly preying on small invertebrates. Leeches have been used in medical treatments from ancient times until the 19th century to draw blood from patients. The leech is a freshwater animal, living in eutrophic water bodies. The temperature suitable for survival of leeches ranges between 0 to 30 degrees Celsius and like other water beings leeches are also sensitive to rapid changes in temperature.
In modern times, leeches are used in treatments for joint diseases such as epicondylitis and osteoarthritis, vein diseases, and in microsurgery, while hirudin is used as an anticoagulant drug to treat blood-clotting disorders. Leeches were named Hirudomedicinalis in 1758 by Linnaeus and these leeches are found in high quantity in fresh water bodies. The treatment with medicinal leeches is also known as “Hirudotherapy”.
Dr. Silva also mentioned that in modern medical science, leech therapy began in the 1960s, because of the practical results in plastic and reconstructive surgery for postoperative venous congestion and graft rejections treatment. The bio-active substances found in leeches’ saliva are commonly known as ‘Hirudo substances’ and are also called salivary glands secretion. They contain more than 120 bio-active substances with potent anticoagulant, vasodilator anaesthetic, bacteriostatic, anti-inflammatory, and analgesic properties.
Ayurvedic texts describe the use of leeches for bloodletting in ancient India. In ancient Greece, bloodletting was practised according to the theory of humours found in the Hippocratic Corpus of the 5th century BCE, which stated that health depended on a balance of four humours: blood, phlegm, black bile and yellow bile.
Bloodletting using leeches enabled physicians to restore balance if they considered blood was present in excess. Sucking causes pain and itching over the bite because initially, leeches suck the impure blood and then the pure.
According to Dr. Silva, in Ayurveda medicine, leech therapy is usually applicable in disorders, abscesses, inflammatory skin disorders, inflammatory condition of the abdomen and skin diseases.
Leech therapy is widely used in modern medicine for treating a variety of challenging medical and surgical conditions such as plastic surgery, arthritis (osteoarthritis and rheumatoid arthritis), venous congestion, vascular diseases and thrombophlebitis. It is further believed that they can also be used in treatments for varicose veins, acne, non-healing ulcers, diabetic wounds, thrombosis, sciatica, dermatitis, psoriasis, alopecia and many other diseases.
He also mentioned that, leech therapy is contraindicated in anemic patients, generalised edema, individuals suffering from gastrointestinal tract disorders, cachexia patients and pregnant women. Leech therapy is contraindicated in Human Immunodeficiency Virus (HIV) infected patients or those who take immunosuppressive drugs, hemorrhagic diseases, hypotension, hypotonia, absolute hemophilia, pregnancies, severe anemia (<5g/dL) and allergy to leeches. Leeches should not be applied directly over large, prominent veins or to the eyelids, breasts, or genital organs.
Care should be taken in using leeches with children, as bleeding can be severe (intense) or prolonged. Applying leeches at midday or during the evening or night is also inadvisable, as this can lead to complications such as hemorrhage.
Leech therapy is seen as becoming increasingly popular among practitioners of complementary and alternative medicine. Many studies are currently underway to evaluate its effects, mainly in the treatment for pain. In Europe and the United States, thousands of patients have been healed using leech therapy. Many traditional medical systems, for example, the Greek, Arab, and Russian, are also encouraging the use of leech therapy.
Dharmarathne also mentioned leeches to be used for treatments are best to be collected during the rainy season. According to him, they should be kept in fresh water, in a big jar, and fed on algae and powdered dried meat of aquatic animals. Placing straw and aquatic plants in these jars helps create an appropriate environment for them to survive. Water should be changed and food residue should be cleaned once in a period of three days. Transferring the leeches to another jar, at least once a week, also appears beneficial.
Explaining the way in which the leech therapy is generally carried out, Dr. Silva said the area to which a leech is to be applied should be cleaned thoroughly with sterile water. Disinfectant or soap should be avoided, as this can irritate the leech and prevent it from attaching. The leech should be taken out of the jar and its mouth should be placed precisely over the spot where the blood is to be removed. The leech’s tail should be held until it begins to draw blood, at which time it can be gently released.
The leech should be lightly covered with moist cotton (cotton material or cotton wool) while it works. This should be kept wet until the end of the process by applying a few drops of water, as needed. Leeches normally absorb about 5 ml of blood and leeches should only be allowed to suck impure blood. Symptoms such as pricking pain and itching at the site of the bite may occur when leeches start sucking pure blood. If such symptoms appear, the leech should be removed gently by sprinkling powdered rock salt or turmeric around its mouth.
These mild substances are disliked by leeches, causing them to stop sucking in a comfortable way. These substances are chosen because they are non irritant to the host and do not stimulate the leeches. They are also antiseptic and antitoxic.The maximum amount of blood to be removed from an individual patient depends on the strength of the patient and the nature of the disease.
Dharmarathne also said that leeches act by secreting biologically active substances in their saliva. This saliva, which contains a hundred or so different substances, includes antiplatelet aggregation factor, anaesthetic, anti-inflammatory and antibiotic agents. Leech saliva also contains an anticoagulant, hirudin, which stops blood clotting and dissolves thrombin, clearing partial and complete blockages in distal arteries.
When leeches bite, chemicals in their saliva dilate hosts’ blood vessels and thin their blood. By ingesting excess blood, leeches reduce tissue swelling and promote healing. These microcirculatory actions enable fresh oxygenated blood to reach hosts’ affected areas prior to the restoration of the normal circulation.
According to Dharmarathne, about three quarters of leech species are parasites that feed on the blood of a host, while the remaining are predators. Leeches normally carry parasites in their digestive tracts, which cannot survive in humans and do not pose a threat; however, bacteria, viruses, and parasites from previous blood sources can survive within a leech for months. Nevertheless, only a few cases of leeches transmitting pathogens to humans have been reported.
Leech therapy or Hirudino therapy has its roots back in ancient civilisation. It was a prevalent form of therapy in various ailments. It is claimed to have been the supreme therapy because of its high efficiency in curing blood related disorders. According to Ayurvedic classics it is a safer and less complicated natural process and it is therefore recommended even for the king, rich, old, fearful, weak, women, and people of tender nature. It is expected to be of paramount importance due to the ease of leech application and minimum side-effects. Leech therapy has Ayurvedic origin, but it is acknowledged by modern medicine due to its effectiveness in healing various kinds of diseases.