Hirudotherapy in Veterinary Medicine
Hirudotherapy, also known as medicinal leech therapy (MLT) or leeching, is a complementary and integrative treatment that uses blood-sucking leeches to treat a variety of conditions.
Medicinal leech therapy or Hirudino therapy have roots back in ancient civilization. It was a prevalent form of therapy in various ailments. The novel Ayurveda text Sushruta Samhita devoted a complete chapter on hirudino therapy. In the early 20th century this therapy had a major setback due to origin and evolution of antibiotics. There was a discontinuity in the flow of knowledge about this therapy. Then, resumed and revived after few recent decades, due to its contribution in reconstructive surgeries. During this period, the research work on various aspects have been conducted.
Hirudotherapy is the use of leeches in a medically controlled environment to treat medical and surgical problems. Within the veterinary world, Hirudotherapy is less commonly used than in human medicine, yet has been shown to aid a variety of cases. This is something I have never personally seen or worked with, but as someone who likes a fair few too many gory movies, something I’d love to have the chance to.
Leeches are used to reduce swelling and inflammation of a desired area, therefore treatment for haematomas and seromas. This can also include orthopaedic swellings around pins/plates, especially at fracture sites. In some patients with hip and elbow dysplasia, owners reported increased mobility and decreased painful symptoms after treatment with leeches, proving its effectiveness. Horses with laminitis have been found more comfortable after the treatment, as the joint and hoof swelling is reduced.
In the present scenario many life intimidating and contagious diseases have been wiped out by innovative efforts in modern medicine. If we see, in developed countries, the average life expectancy of humans has increased from 40 years to about 70 years today. However, in modern medicine therapeutic interventions have some concomitant side effects in both human and animal patients. At the present time addendum in medication errors, expenditure in health care and the rummage for more successful approaches to health and healing have contributed to increased use of complementary and alternative medicine. Hirudotherapy or leech therapy is one of the oldest complementary therapies employed by various clinicians for treating various ailments. Historically, leeches were used to treat ailments, like gout and nosebleeds in Egypt as early as 1500 BC. Modern hirudotherapy differs from the ancient therapy, by using the leeches for a single treatment, which are developed in farms and which have undergone strict quarantine. Nowadays, wild leeches are not employed anymore. In this non invasive methodology, medicinal leeches (Hirudo medicinalis) are used. Talking about their biology, leeches are hermaphroditic, segmented, blood-sucking worms which are permanent or temporary external parasites of numerous animals such as amphibians, fishes, birds, and mammals, including humans. Around 650 species of leeches have been described in the world and only 15 are classified as medicinal leeches. Leeches are gifted by the nature with a capacity to ingest an amount of blood approaching 10 times their own weight and may not require feeding for up to 1 year after their last meal. The saliva of medicinal leeches is commonly used in hirudotherapy that contains more than 100 bioactive substances like hirudin, hyaluronidase, calin, destabilase, eglin and bdellin with various beneficial properties like therapeutic, anticoagulant, vasodilatory, thrombolytic, anti-inflammatory and anaesthetic. The most important therapeutic substance produced by the leeches is hirudin, well-known for its antithrombotic properties. In addition, leeches are rewarded by the nature with anti-cancerous properties and some important neurotransmitters like dopamine, serotonin, acetylcholine, and enkephalin are produced by leeches, which lend a hand in the reduction of the perception of pain by the patients along with a relaxation effect. In veterinary medicine, hirudotherapy in being practiced to treat number of diseases in animals, especially dogs, cats and horses. These days, Pharmaceutical corporations are in quest to expand their repertoire of leech salivary components as anticoagulants. As far as the maintenance and care of leeches is concerned, it is imperative that leeches going to be used in human and animal medicine should originate from specialized leech breeding farms. Natural environment is strictly forbidden for collection of leeches because of contamination with bacteria, viruses, fungi, and parasites. Hirudotherapy engages an initial bite, which is usually painless due to anesthetic effect, and an attachment period lasting 20 to 45 minutes, during which the leech sucks about 5 and 15 ml of blood. Its main therapeutic benefits are derived from the anticoagulant and vasodilator restricted in the saliva of leech. These properties permit the wound to ooze up to 50 ml of blood for up to 48 hours. Leech bites usually lose blood for an average of six hours. The procedure in leech therapy involves the exposure of an area followed by cleaning with sterile distilled water. Then leeches are placed on the desired area. Both human and animal patients are regularly monitored during the therapy for various clinical parameters and infections or allergic reactions. After auto-detachment, the leeches are detached. Even after the detachment of the leech, blood continues to ooze from the attachment site of the leech for hours. About 1 to 5 leeches are used for each session of treatment, depending on the clinical case and purpose of the treatment. The bite area is cleaned every 3-4 hours with a physiological saline soaked gauge, to remove any locally forming clots, and with heparin soaked gauze, to increase the time of blood oozing. Finally, the detached leech is killed in 70% ethyl alcohol and is disposed of in bags as biological waste. As we know every creation of God is for the benefit of mankind so this tiny creature serves a lot with wonderful benefits both in human and veterinary medicine. In case of humans the indications cited by medical practitioners of hirudotherapy are numerous like inflammatory reactions, passive congestions and spastic conditions, plastic and reconstructive surgery, cardiovascular diseases, hypertension, varicose veins, haemorrhoids, arthrosis, osteoarthritis, periarthritis, rheumatoid arthritis, thrombophlebitis, thrombosis, embolism, haematomas, external ear and chronic ear inections, eye diseases like cataracts, traumatic injuries and inflammations, dental problems like gingivitis and gingival edema, chronic skin diseases (scabies, psoriasis, eczematous dermatitis and chronic ulcers), respiratory disorders like asthma, acute rhinopharyngitis, spasmodic coryza and some gynaecological disorders like male and female sterility, endometriosis, parametritis etc. The most important indications for veterinary hirudotherapy are postoperative wound, spinal osteoarthritis, discopathies, cauda equine syndrome, hip and elbow dysplasia, neuritis, eczema of the ear, poor wound healing, post-surgical scars, tendinitis, mastitis, tenosynovitis, inflammation of the knee, laminitis, mud fever in horses, ataxias, myositis, and arthritis in shoulder joints. Hirudotherapist must keep in mind about the health status of patients first before the therapy because leech therapy cannot be employed in all patients. There are some conditions in which hirudotherapy are contraindicated like haemophilia, anemia, leukemia, hypotonia and pregnancy. Regarding the complications of hirudotherapy, the most important is the infection due to the presence of Aeromonas hydrophila (bacteria) in leech’s digestive system. Infections can result in abscesses and cellulitis, which can progress in some cases to sepsis. The risk of infection may be diminished by dipping leeches in 0.02% chlorhexidine hydrochloride solution for 10 to 15 seconds before application to the wound, or by applying prophylactic parenteral antibiotics to the patients before leech application. Due to the tangible benefits of hirudotherapy, it outweighs the risks associated with infection of wounds. It is a remedy that is economical, safe and sound and repeatedly turns out to be the best way out when conventional treatment fails. Hirudotherapy can be learned quickly and also with an edge of reducing hitches arising from the excessive use of synthetic drugs. So, efforts should be made in optimizing the success of hirudotherapy in clinical as well as private practice.
The History of the Leech in Medicine
Medicinal leeches are as old as the Pyramids. Literally. Records indicate that Egyptians used leech therapy over 3,500 years ago and leeches (often mistakenly credited as cobras) are included in the hieroglyphics painted on the walls. Leech therapy was used to treat a wide range of conditions, from headaches to hemorrhoids.
Bloodletting is one of the oldest medical practices, having been practiced since ancient times, including the Mesopotamians, the Greeks, the Mayans, and the Aztecs. In Greece, bloodletting was standard practice around the time of Hippocrates and Herophilos.
Herophilos (335-280 BC) was a Greek physician who was the first scientist to systematically perform scientific dissections of human cadavers and is deemed to be the first anatomist. Hippocrates of Cos (460BC-370BC) was also a Greek physician and is referred to as the “father of medicine”. He was the first physician to reject superstitions, legends and beliefs that credited supernatural or divine forces causing illness.
Both physicians used medicinal leeches, amongst other methods, for blood letting to remove blood from a patient to “balance the humours”. The four humours of ancient medical philosophy were blood, phlegm, black bile and yellow bile. The belief at the time was that these four humours must be kept in balance in order for the human body to function properly. Any disease or illness was thought to be a result of an imbalance of these humours. The dominant humour was believed to be blood.
However it was Aelius Galenus (AD 129 – 200), a prominent physician and philosopher and the most accomplished medical researcher of the Roman era who practiced blood letting extensively and introduced blood letting to Rome. His theories dominated and influenced Western medical science for well over a millennium. Of the four humours, Galen believed that blood was the dominant humour and the one in most need of control. Romans were the first to use the HIRUDO name for leeches.
Leech therapy or HIRUDOTHERAPY survived the fall of the Western Roman Empire and remained popular throughout the Middle Ages. Over the centuries it remained an integral part of treating disease and illnesses all around the world. Bloodletting in its various forms was especially popular in the young United States of America. Benjamin Rush (a signatory of the Declaration of Independence) saw the state of the arteries as the key to disease, recommending higher than ever levels of bloodletting. Although, the levels of bloodletting applied were way to high!
As a lecturer at the Royal College of Physicians would state in 1840, “blood-letting is a remedy which, when judiciously employed, is hardly possible to estimate too highly”
Indeed, by the mid 1800’s the demand for leeches was so high that the French imported about forty million leeches a year for medical purposes, and in the next decade, England imported six million leeches a year from France alone, since the leech production from their own farm near Oxford were insufficient. And it wasn’t just Europe – there was an explosion in the use of leeches in Asia and the Middle East.
Many abandoned leeches with the advent of antibiotics in the 1930’s. However bloodletting still persisted and was even recommended by Sir William Osler in the 1923 edition of his textbook The Principles and Practice of Medicine. In the second half of the 20th century leeches refound an important role in medical practice and leeches are now used extensively by reconstructive surgeon’s needing to remove stagnant blood from a flap or reattached limb.
In the Act of June 28, 2005, the Food and Drug administration (FDA) cleared for the first time the commercial marketing of Medicinal Leeches for medicinal purposes and determined that leeches are medical devices because they meet the definition of a medical device.
Medical research and the use of leeches never stopped in some parts of the world, especially in Russia. So it is little wonder that Russia achieved the highest level in overall research on medicinal leeches and became a biggest producer of Hirudo Medicinalis in the World.
Today the rest of the world is catching on as leeches are on the cusp of not only enjoying a revival for known health benefits, but there are constant new discoveries based on thorough medical research about positive effects of the substances produced by medicinal leeches, that are later induced by leeches into human body (and/or animals as well!) during the hirudotherapy treatments.
NATURAL HISTORY OF LEECHES
The medicinal leech (Hirudo medicinalis) is a segmented worm (Phylum: Annelida). This phylum includes the Polychaetes, the Oligochaetes (earthworms) and the Hirudinea (leeches). Leeches have two “suckers,” one at each end. The caudal (back end) suction cup helps the leech to ambulate on dry surfaces, and to attach to its host; the rostral (front end) suction cup also contains the mouth with three sharp jaws that leave a Y-shaped bite. The medicinal leech lives in clean waters. Leeches swim free in the water, with an undulating motion. When attached to its host for feeding, the leech remains in place for 30 minutes to 6 hours or more, as it fills with blood. During feeding, H. medicinalis can suck 5 – 15 ml of blood — several times its own body weight. Leech saliva contains several bioactive substances, including anti-coagulants, vaso-dilators, and anesthetics. Hirudin, a potent anticoagulant in leech saliva, inhibits the conversion of fibrinogen to fibrin, preventing blood from clotting. Indeed, a wound may continue to bleed for many hours after the leech has already detached. The benefits of leech therapy are due, in large part, to the anti-coagulant effects, vasodilatory effects, and anesthetic effects of these biochemicals, as well as the physical effects of blood letting (phlebotomy). Like a snake, the leech periodically must shed its skin. The leech is hermaphroditic, having both male and female elements. Fertilization and egg-laying usually occur during the spring, summer, and winter months. Young leeches feed on the blood of small water animals (frogs, toads or fish). Leeches may not be ready for medical application until they are several years old.
CLINICAL PRACTICE OF LEECH THERAPY
The application of leech therapy is simple: leeches are gently placed in the area needed, and allowed to attach and engorge (usually within 1 hour), after which they will release. The entire course of treatment may require one to 6 treatments or more, depending upon the goals and rate of response. For more details about the specific application procedures, readers are referred to the manufacturer’s directions. A list of manufacturers can be found elsewhere on this site. Leeches (Hirudo Medicinalis) have been used medically for more than 1500 years. Originally used to remove “bad blood,” the leech is now used extensively by reconstructive surgeons needing to remove stagnant blood from a flap or reattached limb. When the venous blood does not return to the heart, it pools in the wounded area, increasing pressure and preventing fresh arterial blood from entering the area with oxygen and nutrients. The venous blood must be removed and the pressure must be reduced in order to save the flap or limb. The leech is able to do this exceptionally well, because its saliva contains important biochemicals, including vasodilators, anticoagulants, and anesthetics. The leech will withdraw approximately 5 ml (one teaspoon) of blood. Further therapeutic benefit of leech therapy comes after the leech is removed, during which up to 50 mls of blood will continue to ooze, for up to 48 hours. More leeches attached to the site mean more blood will be removed. After 3-7 days, the veins have usually reconnected themselves such that the blood is no longer pooling in the limb. Normal color and pressure should return to the area, as arterial blood circulates easily in the damaged zone. By that time, the wound will be able to heal, without further phlebotomy (leech therapy). The application of leeches to the patient is relatively simple, but does require care. As few as one, or as many as 6 or more leeches may be required for a wound, depending upon its size and its clinical response. The greatest number of leeches should be applied to the area of maximal venous congestion. The patient’s skin must be cleaned thoroughly with soap and water, and then rinsed with distilled, non-chlorinated water. A gauze barrier around the area intended for the leech will help prevent the leech from wandering away from the site where it’s attachment is desired. It can be carried to the site by hand, or it can be placed within a 5 cc plastic syringe (plunger removed) and then applied to the wound site, containing the leech until it is attached. If the leech is reluctant to bite, it might be necessary to entice it with a tiny droplet of blood, drawn from the wound site with a needle prick. Once the leech is attached, it will likely remain safely in place until fully distended. The gauze square can be removed and used elsewhere without disturbing the animal;however, it is important that the site be checked continuously to insure that the leech hasn’t moved. The leech will let go of the patient (host) when it is finished (usually within an hour).
Compiled & Edited by Team LITD
