Preparation materials for practical lessons ¹8
Leech Therapy
History of Leech Therapy
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. Which
were way too high, indeed!
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 became 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, and
as well, in non-invasive leech-therapy treatments outside of hospital
facilities.
In the Act of June 28, 2004, 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 Germany and
Russia. So it is little wonder that both countries achieved the highest level
in overall research on medicinal leeches and , Russia, became a biggest
producer of Hirudo Medicinalis in the World.
Leeches and their History
For over 4000 years, the leech has been a
familiar remedy, with Greek and Roman physicians praising the application of
this clever invertebrate.
In the 19th century leeches were enjoying a
golden age. Millions were raised for medical use as their fame as a cure-all
ensued. The mid 1800s saw their constant use for local bloodletting. Druggists
administered thousands of leeches to patients with anything from gumboils to
facial discolouration. Leeches were applied to the mouth and inside of the
throat using a leech-glass, although patients frequently swallowed them.
Patients were relieved only with a salty drink of water or perhaps the most
popular cure-all of the day, a couple of glasses of wine. Sometimes the leech
would not drink and then had to be encouraged by some blood or cream smeared at
the puncture site or bathed in a warm glass of beer until ready.
Once sucking, an average leech would drink
blood weighing as much as itself in about 15 minutes and consume between 2.5-
Apart from using the English and Scottish
leeches, huge numbers were imported from France, Hungary, the Ukraine, Turkey,
Rumania, Russia, Egypt and Algeria. In
Leeches are segmented worms that
belong to the phylum Annelida and comprise the subclass Hirudinea. Like other
oligochaetes, such as earthworms, leeches share a clitellum and are hermaphrodites.
Nevertheless, they differ from other oligochaetes in significant ways. For
example, leeches do not have bristles and the external segmentation of their
bodies does not correspond with the internal segmentation of their organs.
Their bodies are much more solid as the spaces in their coelom are dense with
connective tissues. They also have two suckers, one at each end.
The majority of leeches live in
freshwater environments, while some species can be found in terrestrial and
marine environments, as well. Most leeches are hematophagous, as they are
predominantly blood suckers that feed on blood from vertebrate and invertebrate
animals.Almost 700 species of leeches are currently recognized, of which some
100 are marine, 90 terrestrial and the remainder freshwater taxa.
Leeches, such as the Hirudo
medicinalis, have been historically used in medicine to remove blood from
patients. The practice of leeching can be traced to ancient India and Greece,
and continued well into the 18th and 19th centuries in both Europe and North
America. In modern times, the practice of leeching is much rarer and has been
replaced by other contemporary uses of leeches, such as the reattachment of
body parts and reconstructive and plastic surgeries and, in Germany, treating osteoarthritis.
Today leeches are bred in captivity in many
institutions including Bristol Zoo Gardens. Leeches have found new fame in
microsurgery, where doctors require the precision of the leech to drain
congested blood from wounded sites. Plastic surgeons are particularly grateful
for the contribution made by the leech, due to their use in the treatment of
difficult grafts and reconstructive surgery. The nervous system of the leech is
very similar to the human nervous system and is an enormous benefit to
researchers in their quest for the answers to human problems.
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.
Leeches are presumed to have
evolved from certain Oligochaeta, most of which feed on detritus. However, some
species in the Lumbriculidae are predatory and have similar adaptations as
found in leeches. As a consequence, the systematics and taxonomy of leeches is
in need of review. While leeches form a clade, the remaining oligochaetes are
not their sister taxon, but in a diverse paraphyletic group containing some
lineages that are closely related to leeches, and others that are far more
distant.
There is some dispute as to
whether Hirudinea should be a class itself, or a subclass of the Clitellata.
The resolution mainly depends on the eventual fate of the oligochaetes, which
as noted above, do not form a natural group as traditionally circumscribed.
Another possibility would be to include the leeches in the taxon Oligochaeta,
which would then be ranked as a class and contain most of the clitellates. The
Branchiobdellida are leechlike clitellates that were formerly included in the
Hirudinea, but are just really close relatives.
The more primitive
Acanthobdellidea are often included with the leeches, but some authors treat
them as a separate clitellate group. True leeches of the infraclass Euhirudinea
have both anterior and posterior suckers. They are divided into two groups:
Arhynchobdellida and Rhynchobdellida
Rhynchobdellida are
"jawless" leeches, armed with a muscular, straw-like proboscis
puncturing organ in a retractable sheath. The Rhynchobdellae consist of two
families:
Glossiphoniidae are flattened
leeches with poorly defined anterior suckers.
Piscicolida have cylindrical
bodies and usually well-marked, bell-shaped, anterior suckers. The
Glossiphoniidae live in freshwater habitats; the Pisciolidae are found in
seawater habitats.
Arhynchobdellida lack a proboscis
and may or may not have jaws armed with teeth. Arhynchobellids are divided into
two orders:
Gnathobdela: In this order of
"jawed" leeches, armed with teeth, is found the quintessential leech:
the European medical (bloodsucking) leech, Hirudo medicinalis. It has a
tripartite jaw filled with hundreds of tiny, sharp teeth. The incision mark
left on the skin by the European medical leech is an inverted Y inside a circle.
Its North American counterpart is Macrobdela decora, a much less efficient
medical leech. Within this order, the family Hirudidae is characterized by
aquatic leeches and the family Haemadipsidae by terrestrial leeches. In the
latter are Haemadipsa sylvestris, the Indian leech and Haemadipsa zeylanica
(yamabiru), the Japanese mountain or land leech.
Pharyngobdella: These so-called
worm-leeches consist of freshwater or amphibious leeches that have lost the
ability to penetrate a host's tissue and suck blood. They are carnivorous and
equipped with a relatively large, toothless mouth to ingest worms or insect
larvae, which are swallowed whole.
The Pharyngobdella have six to eight pairs of
eyes, as compared with five pairs in Gnathobdelliform leeches, and include
three related families. The Erpobdellidae are some species from freshwater
habitats.
Anatomy and physiology
The leech and its nervous system
The number and position of eyes are essential
for distinguishing the leech species.
Like other annelids, the leech is
a segmented animal. But unlike other annelids, there is no correspondence
between the external segmentation of a leech's body surface with the
segmentation of its internal organs. The body surface of the animal can be
divided into 102 annuli, whereas its internal structures are divided into 32
segments. Of the 32 segments within the body, the first four anterior segments
are designated as head segments, which include an anterior brain and sucker.
This is followed by 21 midbody segments, which include 21 neuronal ganglia, two
reproductive organs, and 9 pairs of testes. Finally, the last seven segments
are fused to form the animal's tail sucker, as well as its posterior brain. The
leech also has 32 brains because a brain segment is located in each
segmentation of the body.
Reproduction and development
Leeches are hermaphrodites,
meaning each has both female and male reproductive organs (ovaries and testes,
respectively). Leeches reproduce by reciprocal fertilization, and sperm
transfer occurs during copulation. Similar to the earthworms, leeches also use
a clitellum to hold their eggs and secrete the cocoon.
During reproduction, leeches use
hyperdermic injection of their sperm. They use a spermatophore, which is a
structure containing the sperm. Once next to each other, leeches will line up
with one's anterior side opposite the other's posterior. The leech then shoots
the spermatophore into the clitellur region of the opposing leech, where its
sperm will make its way to the female reproductive parts.
The embryonic development of the
la occurs as a series of stages. During stage 1, the first cleavage occurs,
which gives rise to an AB and a CD blastomere, and is in the interphase of this
cell division when a yolk-free cytoplasm called teloplasm is formed. The
teloplasm is known to be a determinant for the specification of the D cell fate.
In stage 3, during the second cleavage, an unequal division occurs in the CD
blastomere. As a consequence, it creates a large D cell on the left and a
smaller C cell to the right. This unequal division process is dependent on
actinomycin, and by the end of stage 3 the AB cell divides. On stage 4 of
development, the micromeres and teloblast stem cells are formed and
subsequently, the D quadrant divides to form the DM and the DNOPQ teloblast
precursor cells. By the end stage 6, the zygote contains a set of 25
micromeres, 3 macromeres (A, B and C) and 10 teloblasts derived from the D
quadrant.
The teloblasts are pairs of five
different types (M, N, O, P, and Q) of embryonic stem cells that form segmented
columns of cells (germinal band) in the surface of the embryo.The M-derived
cells make mesoderm and some small set of neurons, N results in neural tissues
and some ventral ectoderm, Q contributes to the dorsal ectoderm and O and P in
the leech are equipotent cells (same developmental potential) that produce
lateral ectoderm; however the difference between the two of them is that P
creates bigger batches of dorsolateral epidermis than O. The sludgeworm
Tubifex, unlike the leech, specifies the O and P lineages early in development
and therefore, these two cells are not equipotent. Each segment of the body of
the leech is generated from one M, O, P cell types and two N and two Q cells
types.
The ectoderm and mesoderm of the
body trunk are exclusively derived from the teloblast cells in a region called
the posterior progress zone.The head of the leech that comes from an
unsegmented region, is formed by the first set of micromeres derived from A, B,
C and D cells, keeping the bilateral symmetry between the AD and BC cells.
Mouthparts and sucker
In most blood-sucking leeches the
digestive system starts with the jaws, three blades set at an angle to each
other. In feeding they slice their way through the skin of the host, leaving a
Y-shaped incision. Behind the blades is the mouth, located ventrally at the
anterior end of the body. It leads successively into the pharynx, then the
esophagus, the crop, the gizzard, and the intestinum, which ends at the
posterior sucker. The crop is a distension of the alimentary canal that
functions as an expandable storage compartment. In the crop, some blood-sucking
species of leech can store up to five times the body mass of blood. The leech
produces an anticoagulant that prevents the stored blood from clotting, plus
other agents that inhibit microbial decay of the blood. These measures are so
effective that a mature medicinal leech does not need to feed more than twice a
year. Possibly as an adaptation, its digestive process is extremely slow.
The bodies of predatory leeches
are similar, though instead of jaws many have a protrusible proboscis, which
for most of the time they keep retracted into the mouth. Such leeches often are
ambush predators that lie in wait till they can strike prey with the
proboscises in a spear-like fashion. Some kinds that live on small
invertebrates or detritus have neither proboscis nor jaws, but simply engulf
their food with the mouth.
Bacteria in the gut were long
thought to carry on digestion for the leech, instead of endogenous enzymes that
are very low or absent in the intestine. As discovered relatively recently, all
leech species studied do produce endogenous intestinal exopeptidases, which can
unlink free terminal-end amino acids, one monomer at a time from a gradually
unwinding and degrading protein polymer. However, unzipping of the protein can
start from either the amino (tail) or carboxyl (head) terminal-end of the
protein molecule. The leech exopeptidases (arylamidases), possibly aided by
proteases from endosymbiotic bacteria in the intestine, starting from the tail
or amino end, slowly but progressively removing many hundreds of individual
terminal amino acids for resynthesis into proteins that constitute the leech.
Since leeches lack endopeptidases, the mechanism of protein digestion cannot
follow the same sequence as it would in all other animals in which
exopeptidases act sequentially on peptides produced by the action of
endopeptidases. Exopeptidases are especially prominent in the common North American
worm-leech Erpobdella punctata. This evolutionary choice of exopeptic digestion
in Hirudinea distinguishes these carnivorous clitellates from Oligochaeta.
Deficiency of digestive enzymes
(except exopeptidases), but, more importantly, deficiency of vitamins, B
complex for example, in leeches is compensated for by enzymes and vitamins
produced by endosymbiotic microflora. In Hirudo medicinalis, these
supplementary factors are produced by an obligatory symbiotic relationship with
two bacterial species, Aeromonas veronii and a still-uncharacterized Rikenella
species. Nonbloodsucking leeches, such as Erpobdella punctata, are host to
three bacterial symbionts, Pseudomonas, Aeromonas, and Klebsiella spp. (a slime
producer). The bacteria are passed from parent to offspring in the cocoon as it
is formed.
Behavior
Leech climbing a door by Lake Leake, Tasmania
Leeches are able to display a
variety of behaviors that allow them to explore their environments and feed on
their hosts. Exploratory behavior includes head movements and body waving.
Feeding
Leech attacking a slug
Most leech species do not feed on
human blood, but instead prey on small invertebrates, which they eat whole. To
feed on their hosts, leeches use their anterior suckers to connect to hosts for
feeding. Once attached, leeches use a combination of mucus and suction to stay
attached and secrete an anticoagulant enzyme, hirudin, into the hosts' blood
streams. Though certain species of leeches feed on blood, not all species can
bite; 90% of them feed solely on decomposing bodies and open wounds of
amphibians, reptiles, waterfowl, fish, and mammals (including humans). A leech
attaches itself when it bites, and it will stay attached until it becomes full,
at which point it falls off to digest. Due to the hirudin secreted, bites may
bleed more than a normal wound after the leech is removed.
Leech saliva are commonly
believed to contain anesthetic compounds to numb the bite area, but this has
never been proven. Although morphine-like substances have been found in
leeches, they have been found in the neural tissues, not the salivary tissues.
They are used by the leeches in modulating their own immunocytes and not for
anesthesizing bite areas on their hosts. Depending on the species and size,
leech bites can be barely noticeable or they can be fairly painful.
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, but only a few cases of leeches
transmitting pathogens to humans have been reported. A study found both HIV and
hepatitis B in African leeches from Cameroon.
Removal and treatment
A land leech can be removed by hand, since they
do not burrow into the skin or leave the head in the wound. A sore develops and
lasts for about a week. Grande Ronde River, Oregon (U.S.)
One recommended method of removal
is using a fingernail or other flat, blunt object to break the seal of the oral
sucker at the anterior end of the leech, repeating with the posterior end, then
flicking the leech away. As the fingernail is pushed along the person's skin
against the leech, the suction of the sucker's seal is broken, at which point
the leech will detach its jaws.
Common, but medically inadvisable, techniques
to remove a leech are to apply a flame, a lit cigarette, salt, soap, or a
chemical such as alcohol, vinegar, lemon juice, insect repellent, heat rub, or
certain carbonated drinks. These will cause the leech to quickly detach;
however, it will also regurgitate its stomach contents into the wound. The
vomit may carry disease, and thus increase the risk of infection.
An externally attached leech will
detach and fall off on its own when it is satiated on blood, which may be
anywhere from 20 minutes to two hours or more. After feeding, the leech will
detach and depart. Internal attachments, such as inside the nasal passage or
vaginal attachments, are more likely to require medical intervention.
After removal or detachment, the
wound should be cleaned with soap and water, and bandaged. Bleeding may
continue for some time, due to the leech's hirudin. Bleeding time will vary,
with location, from a few hours to three days. This is a function of the
hirudin and other compounds that reduce the surface tension of the blood.
Anticlotting medications also affect the bleeding time. Applying pressure can
reduce bleeding, although blood loss from a single bite is not dangerous. The
wound normally itches as it heals, but should not be scratched, as this may
complicate healing and introduce other infections. An antihistamine can reduce
itching, and applying a cold pack can reduce pain or swelling.
Some people suffer severe
allergic or anaphylactic reactions from leech bites and require urgent medical
care. Symptoms include red blotches or an itchy rash over the body, swelling
around the lips or eyes, feeling faint or dizzy, and difficulty breathing.
Medicinal use of leeches
Further information:
Hirudotherapy
The European medical leech Hirudo
medicinalis and some congeners, as well as some other species, have been used
for clinical bloodletting for thousands of years. The use of leeches in
medicine dates as far back as 2,500 years ago, when they were used for
bloodletting in ancient India. Leech therapy is explained in ancient Ayurvedic
texts. Many ancient civilizations practiced bloodletting, including Indian and
Greek civilizations. In ancient Greek history, bloodletting was practiced
according to the humoral theory, which proposed that, when the four humors,
blood, phlegm, black and yellow bile in the human body were in balance, good
health was guaranteed. An imbalance in the proportions of these humors was
believed to be the cause of ill health. Records of this theory were found in
the Greek philosopher Hippocrates' collection in the fifth century BC.
Bloodletting using leeches was one method used by physicians to balance the
humors and to rid the body of the plethora.
The use of leeches in modern
medicine made its comeback in the 1980s after years of decline, with the advent
of microsurgeries, such as plastic and reconstructive surgeries. In operations
such as these, problematic venous congestion can arise due to inefficient
venous drainage. Sometimes, because of the technical difficulties in forming an
anastomosis of a vein, no attempt is made to reattach a venous supply to a flap
at all. This condition is known as venous insufficiency. If this congestion is
not cleared up quickly, the blood will clot, arteries that bring the tissues
their necessary nourishment will become plugged, and the tissues will die. To
prevent this, leeches are applied to a congested flap, and a certain amount of
excess blood is consumed before the leech falls away. The wound will also
continue to bleed for a while due to the anticoagulant hirudin in the leeches'
saliva. The combined effect is to reduce the swelling in the tissues and to
promote healing by allowing fresh, oxygenated blood to reach the area.
The active anticoagulant
component of leech saliva is a small protein, hirudin. Discovery and isolation
of this protein led to a method of producing it by recombinant technology.
Recombinant hirudin is available to physicians as an intravenous anticoagulant
preparation for injection, particularly useful for patients who are allergic to
or cannot tolerate heparin.
The Benefits of Leech Therapy
and its Effects
Yes, leeches can be thought of
as slimy and unattractive creatures, but ugly or not, they do serve a lot of
medical purposes when it comes to us, humans.
Since ancient times, leeches
were used to treat many illnesses and disease through bloodletting, a method
where blood was drawn out in the hope that removing impure blood would heal the
body. Believe it or not, leech therapy is sometimes the best alternative in
treating illnesses, and even surpasses pharmacological treatments. Because of
its healing effects to the human body, this traditional method of curing
diseases is still thriving today.
Leeches shown during treatment of
varied conditions
The Benefits of Leech Therapy
There are more than 600
species of leeches that have been identified, but only 15 of the species are
used medically, so they are given a class of their own. They are classified as
Hirudo Medicinalis or medicinal leeches.
Leech therapy has been used
and is still in use for many diseases of the body. They are used to treat
arthritis and other inflammatory processes. It is perfect for those with
vascular (arterial and venous diseases), heart (ischemic diseases and
hypertension), and lung problems (bronchitis and bronchial asthma). The
medicinal leeches can also help in patients with pneumonia. The GI or
gastrointestinal tract can also benefit from leech therapy, especially those
who suffer from hepatitis, stomach ulcers, and pancreatitis, among others.
Likewise, individuals with problems in their genitourinary system and
gynecological disorders will also benefit greatly from leech therapy. Skin
diseases like psoriasis, herpes, and eczema can also be treated with leech
therapy. Other problems known to benefit from leech therapy are the eyes
(example is glaucoma) and the brain (for infantile cerebral palsy).
But how exactly do leeches
treat these many illnesses and diseases?
Leeches shown during treatment of
varied conditions
Anticoagulating Effects of
Leeches
The leech’s saliva contains
enzymes and compounds that act as an anticoagulation agent. The most prominent
of these anticoagulation agents is hirudin, which binds itself to thrombins,
thus, effectively inhibiting coagulation of the blood.
Another compound that prevents
coagulation is calin. This, on the other hand, works as an anticoagulant by
prohibiting the von Willebrand factor to bind itself to collagen, and it is
also an effective inhibitor of platelet aggregation caused by collagen.
The saliva of the leeches also
contains Factor Xa inhibitor which also blocks the action of the coagulation
factor Xa.
Clot Dissolving Effects of Leeches
The action of destabilase is
to break up any fibrins that have formed. It also has a thrombolytic effect,
which can also dissolve clots of blood that have formed.
Blood expelled after different treatments
Anti-inflammatory Effects of
Leeches
Bdellins is a compound in the
leech’s saliva that acts as an anti-inflammatory agent by inhibiting trypsin as
well as plasmin. It also inhibits the action of the acrosin. Another
anti-inflammatory agent is the eglins.
Vasodilating Effects of Leeches
There are three compounds in
the leeches’ saliva that act as a vasodilator agent, and they are the
histamine-like substances, the acetylcholine, and the carboxypeptidase A inhibitors. All these act to widen the vessels, thus,
causing inflow of blood to the site.
Bacteriostatic and Anesthetic
Effects of Leeches
The saliva of leeches also
contains anesthetic substances which deaden pain on the site and also
bacteria-inhibiting substances which inhibit the growth of bacteria.
Overall Effects to the Human
Body
Medicinal leech grown to 13cm
after
treatment
Once the leeches attach
themselves to the skin of the patient and start sucking blood, the saliva
enters the puncture site and along with it the enzymes and compounds
responsible for all these positive effects. Working together, they act to cure
the disease present in the individual. Because of anticoagulation agents, the
blood becomes thinner, allowing it to flow freely through the vessels. The
anti-clotting agents also dissolve clots found in the vessels, eliminating the
risk of them traveling to other parts of the body and blocking an artery or
vein. The vasodilating agents help widen the vessel walls by dilating them, and
this causes the blood to flow unimpeded, too.
Patients who suffer from pain
and inflammation will feel relief from the anti-inflammatory and anesthetic
effects of the leech's saliva.
In the long run, leech therapy
also helps to normalize the blood pressure of hypertensive individuals as well
as lessen their risk of suffering from stroke and heart attacks. Blood
circulation is also improved with leech therapy and it helps with the healing
process of wounds, as well as wounds and lesions caused by diabetes. There is
also a noticeable boost in the immune system's function due to bacteriostatic
agents.
Contraindication to Leech
Therapy
Leech therapy is contraindicated to patients with HIV and AIDS. It is
also not recommended to patients who are on immunosuppressive drugs. Leech
therapy puts these patients at risk for bacterial sepsis, thus, worsening their
conditions.
Leech therapy is the use of leeches in the treatment of medical conditions.
Leeches are carnivorous or bloodsucking aquatic or terrestrial worms typically
having two "suckers," one at each end. The back end suction cup helps
the leech to ambulate on dry surfaces, and to attach to its host; the 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, leeches can suck 5-15mL of blood, which is several times
its own body weight.
The first medical use of leeches
is thought to have taken place in ancient India in 1000 BC. The ancient Indians
used leeches to treat a wide range of conditions including headaches, ear
infections and hemorrhoids. In pre-scientific medicine, the medicinal leech was
used to remove blood from a patient as part of a process to "balance the
humors" that, according to Hippocrates, must be kept in balance in order
for the human body to function properly. The four humors of ancient medical
philosophy were blood, phlegm, black bile, and yellow bile. According to this
theory, any sickness that caused the subject's skin to become red (e.g. fever
and inflammation), must have arisen from too much blood in the body. Similarly,
any person whose behavior was strident and sanguine, meaning animated, was
thought to be suffering from an excess of blood. By the mid-1800s, the demand
for leeches in Europe was so large that the exporter in Germany shipped over 30
million leeches a year.
Leeches (Hirudo medicinalis)
historically used to remove "bad blood," are 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
biochemicals including vasodilators, anticoagulants, and anesthetics.
Perhaps the best-known advocate
of medical leeches today is Roy Sawyer, an American researcher. Several decades
ago, he noted the potential benefits of leech therapy and started one of the
world's first modern leech farms. Today, the company BioPharm, which is based
in Britain, provides tens of thousands of leeches every year to hospitals in
dozens of countries.
In 2001, the mechanical leech was
developed, in part by Nadine Connor, a University of Wisconsin at Madison
scientist. The device, which looks a little like a small bottle attached to a
suction cup, delivers an anti-clotting drug, similar to that in a leech's
saliva, to damaged tissue and then gently sucks out as much blood as needed.
Unlike real leeches, the mechanical version is insatiable and can remove as
much blood as doctors think is necessary.
Leech therapy is the use of
leeches in the treatment of medical conditions. Leeches are carnivorous or
bloodsucking aquatic or terrestrial worms typically having two
"suckers," one at each end. The back end suction cup helps the leech
to ambulate on dry surfaces, and to attach to its host; the 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, leeches can suck 5-15mL of blood, which is several times its own body
weight.
The first medical use of leeches
is thought to have taken place in ancient India in 1000 BC. The ancient Indians
used leeches to treat a wide range of conditions including headaches, ear
infections and hemorrhoids. In pre-scientific medicine, the medicinal leech was
used to remove blood from a patient as part of a process to "balance the
humors" that, according to Hippocrates, must be kept in balance in order
for the human body to function properly. The four humors of ancient medical
philosophy were blood, phlegm, black bile, and yellow bile. According to this
theory, any sickness that caused the subject's skin to become red (e.g. fever
and inflammation), must have arisen from too much blood in the body. Similarly,
any person whose behavior was strident and sanguine, meaning animated, was
thought to be suffering from an excess of blood. By the mid-1800s, the demand
for leeches in Europe was so large that the exporter in Germany shipped over 30
million leeches a year.
Leeches (Hirudo medicinalis)
historically used to remove "bad blood," are 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
biochemicals including vasodilators, anticoagulants, and anesthetics.
Perhaps the best-known advocate
of medical leeches today is Roy Sawyer, an American researcher. Several decades
ago, he noted the potential benefits of leech therapy and started one of the
world's first modern leech farms. Today, the company BioPharm, which is based
in Britain, provides tens of thousands of leeches every year to hospitals in
dozens of countries.
In 2001, the mechanical leech was
developed, in part by Nadine Connor, a University of Wisconsin at Madison
scientist. The device, which looks a little like a small bottle attached to a
suction cup, delivers an anti-clotting drug, similar to that in a leech's
saliva, to damaged tissue and then gently sucks out as much blood as needed.
Unlike real leeches, the mechanical version is insatiable and can remove as
much blood as doctors think is necessary.
Technique
The application of leeches to the
patient is relatively simple, but does require application by a qualified
healthcare professional. As few as one, or as many as six 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 by the healthcare provider to the
area of maximal venous congestion.
The patient's skin is typically
cleaned thoroughly with soap and water, and then rinsed with distilled,
non-chlorinated water. A gauze barrier around the area intended for the leech
is used to prevent the leech from wandering away from the site where its
attachment is desired.
Once the leech is attached, it
will likely remain safely in place until fully distended. The site should be
checked continuously to insure that the leech has not moved. The leech will let
go of the patient (host) when it is finished (usually within an hour).
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.
Theory/evidence
The benefits of leech therapy are
due, in large part, to the anticoagulant effects ("blood thinning"),
vasodilatory effects, and anesthetic effects of the biochemicals contained in
leech saliva, as well as the physical effects of blood letting (phlebotomy).
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 due to the
anticoagulant effect of hirudin. Many recently developed prescription drugs
used for similar conditions were designed based on the mechanism of action of
leeches.
Leeches are used to assist in the
reattachment of severed body parts such as fingers, hands, toes, legs, ears and
noses. Leeches are used to help with venous insufficiency when there is
sufficient arterial flow when reattaching severed body parts.
Today leeches are also used to
drain blood from swollen faces, limbs and digits (fingers and toes) after
reconstructive surgery. They are especially useful when reattaching small body
parts that have many small blood vessels. Leeches are used to prevent the
clotting of blood in these small veins. Leeches are gently placed in the area
needed by a qualified healthcare provider, and allowed to attach and engorge
for the next 6-12 hours, 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.
The leech will withdraw
approximately 5mL (one teaspoon) of blood. Further therapeutic benefit of leech
therapy comes after the leech is removed, during which up to 50mL of blood will
continue to ooze, for up to 48 hours. More leeches attached to the site will
result in the removal of more blood. 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 (removing blood).
Evidence: In 1998, Bapat et al.
investigated the use of medicinal leeches in the treatment of complicated
varicose veins and found that medicinal leeches aided ulcer healing and could
be used as an adjunct in the management of complicated varicose veins due to
their blood sucking ability. In a randomized controlled trial in 2003,
Michalsen et al. found that medicinal leech therapy was effective in relieving
symptoms in patients with osteoarthritis of the knee. Based on clinical use,
the leech may also be of value in those performing microsurgery who are faced
with the difficulties of reattaching minute veins.
Safety
Delayed infection, occurring a
few days after leech therapy has been reported and caution is advised.
Optimal care is recommended when
applying leeches because their use can be complicated by serious bacterial
infections.
Leech therapy may interact with
antibiotic therapy such as trimethoprim and sulfamethoxazole (Cotrim forte) and
may precipitate allergic reactions. In one case study, Beer et al. reported an
allergic reaction that developed after four days of leech therapy and
antibiotic use, which was reversed using systemic doses of glucocorticoids.
This case was not considered typical.
Once abundant in Europe from
Ireland to the Ural mountains (western Russia) and from southern Scandinavia to
the Mediterranean. It is still present in one or more localities in 24 European
countries although it is threatened in at least 12 of these. Its status is
uncertain in Portugal, Sicily and Turkey and it has been extinct in Ireland for
at least 100 years. It was imported into North America for medicinal purposes
but no recent records have shown its presence in the wild. Present in small
numbers in Britain particularly in rural areas such as New Forest, the Lake
District, South Wales, Anglesey and the west of Scotland. The largest
population in Britain is thought to be in Dungeness, Kent where a
mark-release-recapture experiment indicated a self-sustaining population of
6,000 - 12,000 leeches in 1985.
Ecological and Habitat Requirements
Hirudo medicinalis typical
habitats consist of shallow, eutrophic ponds or lakes with dense stands of
macrophytes and high summer temperatures. High temperature requirements have
important implications for the distribution of the medicinal leech, for
example, it cannot survive in many lakes and most of the tarns in the Lake
District due to the relatively low temperatures. The average temperatures for
10%, 50% and 90% activity in the medicinal leech are 11.9˚C, 19.0˚C
and 22.9˚C respectively. The minimum temperature threshold for swimming
activity is 5-9˚C. In a temperature gradient of 7-43˚C, studies have
shown that 21˚C is the preferred temperature. The optimum temperature
ranges for growth and breeding are 22-25˚C and 25.5-27.5˚C
respectively with the upper lethal range being 39-43.5˚C.
Food and Feeding
H. medicinalis is the only
species known to attack humans. Like other Gnathobdellid leeches, it has a
short muscular pharynx usually with toothed jaws. It feeds almost exclusively
on the blood of mammals but other hosts include amphibians and small fish. A
single leech can take two to five times its own weight of blood in a meal,
which is digested slowly over several months. For example, a leech weighing
128mg dry weight took 640mg dry weight of blood in one meal, took about 200
days to digest this meal and survived for a further 100 days without another
meal. Therefore, one meal can sustain a leech for a year. The bacterium
Aeromonas hydrophila is a normal symbiont in the gut of medicinal leeches which
produces enzymes necessary to digest the blood ingested by the leech. Although
it takes only about half an hour for a leech to become satiated on a mammalian
host, the host can move a considerable distance in this time and therefore it
is thought that in nature, leeches frequently detach from the host long before
they are satiated to ensure they do not become isolated from their habitat.
Life Cycle Summary
Leeches are protandrous
hermaphrodites and tend to cross fertilise by taking up a head-to-tail position
with another leech. H. medicinalis has an eversible penis, a single male and a
single female pore, a single pair of ovaries and between 10 and 100 pairs of
testes. Matings occur in summer and sperm can be stored so there can be a delay
of 1-9 months between copulation and cocoon deposition. Segments near the
middle of the body are modified in mature worms to form a clitellum that
secretes a cocoon for the eggs. Each sclerotized cocoon is about 10mm long,
either oval or spherical in shape with the wall consisting of an inner smooth
layer and an outer spongy layer and contains between 5 and 15 eggs. They are
laid in a damp place just above the water line on the shore or bank of lakes or
ponds. Cocoons are normally found in July and August and hatching time varies
from 4 to 10 weeks depending on temperature. In laboratory conditions, H.
medicinalis lay 1-7 cocoons in which 3-30 eggs develop and each individual can
produce 2 broods per year under optimum conditions. Newly hatched leeches weigh
approximately 0.12-0.18g live weight and this increases to 0.5-0.6g by end of
first year, about 1.4g in second year and 2.4g in third year. It is thought
that they take at least 2 years to reach sexual maturity in the field and
slow-growing leeches may not breed until 3 or 4 years of age.
Life Stages
Life Stage: Adult
Definitive Host: Mammals
(including humans), amphibians and fish.
Site Within Host: Ectoparasitic.
Host Habitat: Freshwater ponds
and lakes.
Free Living Environment:
Freshwater ponds and lakes (also comes onto the shore to lay cocoons containing
eggs).
Reproduction Capacity: Sexually
mature.
Morphology: Red-yellow
longitudinal stripes on the dorsal surface forming part of a fairly ornate
pattern, anus small and scarcely visible, each jaw is armed with a single row
of numerous sharp teeth capable of piercing human skin.
Economic Value
Raised commercially in ponds in
the 18th and 19th centuries especially in France, Hungary and Russia, they were
used occasionally as economic barometers but primarily for blood-letting
(phlebotomy), to drain haematomas and to enhance the success of tissue
transplants. Blood-letting was a common medical practice and an estimated 25
million leeches were used in France in 1846 and a further 7 million in London
hospitals in 1863. This large trade in medicinal leeches meant the indigenous
supply had to be supplemented by large importations. H. medicinalis is also a
popular subject for laboratory studies of morphology, physiology and behaviour
and is now in high demand for experimental biology (2000 are used in the US per
year), plastic surgery, the provision of pharmaceutical products and
neurobiology (thought to be a model organism for studies as they have
exceptionally large nerve cells and supporting glial cells). The saliva of H.
medicinalis contains hirudin, the most powerful anticoagulant known. Hirudin is
an acidic polypeptide with a molecular weight of about 7000. The collection of
hirudin led to the destruction of a large number of leeches but now as a result
of cloning and expression of a recombinant gene for hirudin in yeast and
bacteria, fewer animals are destroyed. Other important compounds in the saliva
are histamine (causes vasodilation of blood vessels in host), hyaluronidase
(breakdown of host tissues increases permeability) and bdellin & eglin
(basis of anti-inflammatory response in host).
Threats
In the past, over-collection of
H. medicinalis for blood-letting has been blamed for the rarity of these
leeches but in fact these leeches were frequently discarded into the nearest
ditch or pond after use and this practice may have helped the survival of the
species. However, more recent collections of H. medicinalis for experimental
biology, medical and pharmaceutical needs pose a more serious threat as these
leeches are destroyed. Today there is still a large trade in medicinal leeches
which are still exported from France, Italy, Portugal, Hungary, Romania,
Yugoslavia, Turkey and Greece (where they are supposed to be legally
protected). The change or loss of prime medicinal leech habitat has also helped
to hasten their decline. The alteration of many natural shallow ponds to deeper
fishponds more suitable for trout and the general loss of wetlands, especially
flushes and marshes, have not only reduced leech habitat but has also led to a
decline in amphibians, an important host for the medicinal leech. Change in
habitat, as well as their destruction, must be considered in conservation
management for both the leech and their potential host species. The rearing of
captive leeches is encouraged in order to reduce the number of individuals
removed from the wild and the establishment of a leech farm in Swansea in 1984
was a welcome development. Its aim was to meet the world demand for leeches for
use in research and medicine and today it provides the international market
with around 15,000 leeches per year.
Legal Protections
Although H. medicinalis has been
removed from the UK BAP list as it is not considered to meet the UK priority
species criteria, it is included in the 1996 International Union for the
Conservation of Nature (IUCN) invertebrate red data book as a low risk, near
threatened species, and also in the Finnish red data book. It was also added in
March 1988 to the list of species protected under the Wildlife and Countryside
Act (1981) making it an offence to kill, injure, take, posses or sell (alive or
dead) H. medicinalis from the wild or to damage, destroy or obstruct access to
their natural habitat.
Treat chest pain with leech
therapy
This type of pain is typically located around
the heart and may vary in length and intensity: pricking, aching, piercing,
sharp, momentary, lasting hours and even days (as though there is a stone lying
on your heart). The pain is usually felt in the left part of the chest and may
stretch as far as the left hand and back. Chest pains are often accompanied by
various symptoms including: a strong connection with pain of the spine around
the neck and chest level, diseases of the common bile duct, and hormonal imbalance.
Oftentimes, physical activity has no effect on the pain, and neither does
consumption of nitrates or other medications commonly used to prevent and
relieve chest pain.
Attachment Zones:
Zone 1
Top of the spine area
Points 1, 2, 3
Points 2 and 3 are 2 to
Zone 2
Area of the shoulders
Points 4, 5, 6, 7
Points 4, 5, 6, and 7 are located in the
middle of the left and right shoulders
Zone 3
Area of the heart
Points 16, 17, 18, 19, 20
Point 16 is underneath the third rib near the
sternum.
Points 17 and 18 are 1 to
Point 19 is on the edge of the chest right
below the fifth rib and Point 20 is on the middle bottom edge of the chest.
Zone 4
Area between the shoulder blades
Points 8, 9, 10, 11
Point 11 is on T5-6, the fifth or sixth
thoracic vertebrae. Points 9 and 10 are 1 to
Zone 5
Area of the lower back
Points 11, 12, 13, 14, 15
Point 15 is located at L2-3, second or third
lumbar vertebrae. Points 11, 12, 13, and 14 are spaced from the center point at
1 to
Zone 6
Area of the pelvis
Points 21-27
Points 21, 22, 23, 24, 25, 26, and 27 are
spread in a semi circle on the lower abdomen starting at the center over the
pubis (pubic bone).
Procedure Overview:
When there is nerve pain and pain in the
spine, use Zones 1, 2, 3 and
Quantity of attachments:
Use 3 to 4 per session. When including Zones 3
and 4, use 4 to 8 leeches per course.
Quantity of sessions:
First 3 to 4 sessions should be conducted
every other day using different zones, followed by additional 4 sessions 2
times a week. To solidify the effects of the entire course, follow-up with 2 to
3 sessions with a longer wait time in between. For aches and pains that have
continued for a long time, make sure to include 2 to 3 sessions concentrating
on Zone 3.
Combination healing:
While leech therapy can be the main treatment,
for additional healing benefits, drink infusions and teas, such as hawthorn,
intended for cardiovascular health.
Get the book to learn more...
Disclaimer: The purpose of this work is to
provide as accurate information as possible regarding the subject of leech
therapy. The actions and ideas put forth in this book are not intended to
replace a consultation with a physician or other medical specialists. The
author and/or publisher are not engaged in any professional medical services
and are not liable for any injury, loss, or other damages purportedly caused by
the use of the information found in this book. Do not attempt to apply any technique
described in this book on your own, without first receiving proper training
under the supervision of an expert.
Hirudotherapy
Hirudotherapy is a treatment with
using of medicinal leech. This kind of therapy is known from the time of
extreme antiquity and is still alive nowadays. This fact testifies to its
efficiency at the decision of various problems of health. The method of
hirudotherapy is approved by many countries.
Enormous experience of using of
medicinal leeches in the medical purpose is saved up during many centuries.
With the development of science the mechanism of action of a secret of salivary
glands of leeches was deciphered, biologically active substances which are
included in it were opened,their influence on the certain structures of an
alive organism is investigated. Some medical forms are created on a basis of
biologically active substances of salivary glands of leeches and work on
creation of new ones is conducting. Modern hirudotherapy differs from that of
an ancient one because now we use not wild leeches but grown at a special
biofactories where they are in severe quarantine. Besides, nowadays we use a
leech only once. This fact completely excludes infection of a patient.
Therapeutic properties of
hirudotherapy:
general reflexogenic
hypotensive
bloodletting
immunopotentiating
internal decongestion
bacteriostatic
anticoagulant
anti-inflammatory
protective antithrombotic
local anti-edematous
thrombolytic
analgesic
removal of microcirculation
disorders
antiatherosclerotic
anti-ischemic
removal of abnormal intersystem
interactions
Apothecary jar for Leeches which
have been used for clinical bloodletting for thousands of years. The use of
leeches in medicine dates as far back as 2,500 years ago, when they were used
for bloodletting in ancient India. Leech therapy is explained in ancient
Ayurvedic texts. Many ancient civilizations practiced bloodletting, including
Indian and Greek civilizations.