Maggots and leeches make a comeback
Aisha El-Awady
Bugs and parasites are making a comeback into modern medicine, and although
they have been used as a means of therapy for thousands of years, they lost
their popularity in the second half of the 20th century only to regain their
previous status as medical wonders during the 1980s. Two such parasites used
today are leeches and maggots. As gruesome as both are conceived, they have been
found to possess numerous advantages in the field of medicine.
The Practice of Leeching Throughout History
The
use of leeches in medicine dates as far back as 2,500 years ago when they were
used for bloodletting in ancient Egypt. All 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 unbalance 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 B.C. Bloodletting using leeches was one method used by physicians to
balance the humors and to rid the body of the plethora.
In medieval Europe, a number of superstitious ideas and religious
philosophies started to influence the practice of bloodletting. The practice
continued on up until the 19th century. In 1833, bloodletting became so popular
in Europe, that the commercial trade in leeches became a major industry. France,
suffering a deficiency, had to import 41.5 million leeches. The medicinal leech
almost became extinct in Europe due to the extremely high demand for them.
Leeches were collected in a particularly creepy way. Leech collectors would wade
in leech infested waters allowing the leeches to attach themselves to the
collector’s legs. In this way as many as 2,500 leeches could be gathered per
day. When the numbers became insufficient, the French and Germans started the
practice of leech farming. Elderly horses were used as leech feed where they
would be sent into the water and would later die of blood loss.
Leeches were thought to be able to cure everything from headaches to brain
congestion. They were used to cure obesity, hemorrhoids, nephritis, laryngitis,
eye disorders as well as mental illness. Their use continued on until the 1960s
when their use in medicine was discontinued.
Leeches in Modern Medicine
 The
use of leeches in medicine, otherwise known as Hirudotherapy, made its comeback
in the 1980s after years of decline, with the advent of microsurgery such as
plastic and reconstructive surgeries. In operations such as these, one of the
biggest problems that arises is venous congestion due to inefficient venous
drainage. This condition is known as venous insufficiency. If this congestion is
not cleared up quickly, the blood will clot and arteries that bring the tissues
their necessary nourishment will become plugged and the tissues will die. It is
here where the leeches come in handy. After being applied to the required site,
they suck the excess blood, reducing the swelling in the tissues and promoting
healing by allowing fresh, oxygenated blood to reach the area until normal
circulation can be restored. The leeches also secrete an anticoagulant (known as
hirudin) that prevents the clotting of the blood.
The leech’s saliva is truly extraordinary containing a number of chemical
compounds useful in medicine. These include a local anesthetic that the leech
uses to avoid detection by the host, the anti-coagulant hirudin that can help
prevent heart attacks and strokes, a vasodilator and a prostaglandin that help
reduce swelling. The leech’s gut harbors a bacterium known as Aeromonan
hydrophila. This bacterium aids in the digestion of ingested blood and
produces an antibiotic that kills other bacteria that may cause putrefaction.
Not only are leeches economically beneficial costing as little as $4.75 to
$6.50 apiece, but studies have shown that Hirudotherapy doubles the success rate
of transplanted tissue flaps. This is a much higher success rate than that
brought on by drugs or further surgery.
Hirudotherapy has proven to be useful for a number of other conditions
including cardiovascular disease, ophthalmology and dermatology. Hirudin is also
used in the treatment of inflammation of the middle ear. Osteoarthritis, which
is a painful condition of the knee, is also thought to benefit from leeching.
Studies performed by researchers from the Essen-Mitte Clinic in Germany have
shown that when leeches were applied to the knees of patients with
osteoarthritis, they helped to alleviate the inflammation and pain associated
with the condition.
The hazards associated with leech therapy include infection, excess blood
loss that may require blood transfusion, the loss of leeches in body orifices
and spaces, and allergic reactions. Some patients find the use of leeches
disgusting, which makes it necessary that they have basic information on the
benefit of leeches before the procedure. The secretion of a local anesthetic by
the leech makes the procedure painless except for the initial attachment phase.
They fall off promptly after they have completed feeding.
Scientists at the University of Wisconsin-Madison have developed a mechanical
leech as an alternative to real leeches. The synthetic leech mimics the action
of the leech allowing for fresh blood to flow through the wound, but unlike the
leech, it is insatiable and can continue to remove blood for as long as is
needed whereas the leech only feeds for about half an hour.
Maggots a Good Thing?
Maggots are now once again gaining respect in the medical field. Their use even
has a name, maggot debridement therapy or MDT. Maggots are efficient healers of
wounds. This was recognized centuries ago when wounded soldiers whose wounds
were infested with maggots healed better than those that were not infested. The
reason for this is that the maggots used for this purpose eat dead tissues and
leave the healthy, living tissues alone. They also excrete substances which
inhibit and may even kill bacteria. This is especially useful in areas with poor
blood supply that do not benefit much from antibiotics that cannot reach the
area in adequate concentration to do their job.
Maggots have been known for their healing ability since the 16th century.
Maggot therapy continued until the 1930s when their use in therapy was so common
that over 300 hospitals in the US alone were using them. In the 1940s antibiotic
therapy and surgical techniques replaced the use of maggots. Their superiority
in certain cases to antibiotics was realized in 1989 when they were recognized
to be more efficient cleaners of wounds than any other non-surgical treatment.
 Not
all maggots can be used in medicine; only those that do not burrow under the
patient’s skin and do not eat healthy tissues can be used. They do not
multiply in the wound as they must leave it to pupate or they will die. When the
maggots have completed their job, the doctor simply flushes them out of the
wound. The maggots range from 1 to 2 mm in length when they are one day old and
they reach a length of about 1 cm by their fourth day.
In order to ensure their sterility, scientists have developed techniques to
farm maggots for medical use. The cost of maggot therapy is typically half as
much as conventional therapy making it a very cost effective procedure. The only
disadvantage of this type of therapy other than the yuck factor is the tickling
sensation felt by some patients.
Article and images courtesy of http://www.islamonline.net
* Aisha El-Awady has a bachelor’s degree in medicine from Cairo University
and is currently working as instructor of Parasitology in the Faculty of
Medicine, while preparing her MA. She may be contacted at aawady@islam-online.net
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