Leech on cutting edge of modern medicine | Sunday Observer

Leech on cutting edge of modern medicine

3 October, 2021

The leech is an aquatic or terrestrial annelid worm with suckers at both ends. Many species are bloodsucking parasites. This has given rise to the transferred sense of a person who extorts profit from or sponges on others. Leeches were traditionally used in medicine to draw off blood from patients. Its saliva contains an anticoagulant used after reconstructive surgery to reduce the congestion and swelling that may compromise the blood supply.

When Frederick Persson was helping to bring the Swedish cargo ship into the docks in Bristol, England, a rope coiled around his right hand disabling his fingers. As his condition was serious, he was rushed to Bristol’s Frenchay Hospital. In an operation lasting eight hours, surgeon Donald Sammut succeeded in reattaching the fingers that were nearly separated from the hand.

However, after two days, the fingers turned black. As he did not know any other remedy, he applied one of the oldest methods by fastening leeches to Persson’s fingers. They sucked the surplus blood and the patient’s blood circulation was restored. Although leeches were rather new to Western medicine, native physicians in Asian countries had used them regularly to suck bad blood from patients.

Leeches are found in many areas in Sri Lanka where the climate is cold and rain is regular. They cannot thrive on dry land. In those areas, leeches are a common sight and people are not afraid of them. However, those who are not used to them will have to wear boots when they walk along wet roads.

There are about 650 species of the leech ranging from half-inch-long slivers to 18-inch-long jumbos. They are found in many parts of the world. The annelids breathe through the skin and have two hearts. They can live without food for a few months. Some leeches have suckers at each end of the body.

Astonishing comeback

Although leeches are helpful, nobody seems to like them. Humphrey Bogart wading a stream in “The African Queen” said, “If there’s anything in the world I hate, it’s leeches.” Whether you like it or not, leeches have made an astonishing comeback in Western medicine.

The leech has been successfully used for medical purposes in recent years. You may be surprised to know that leeches have saved many people who had met with accidents around the world.

What we most fear is the leech’s bite into flesh with its sharp teeth. According to experts, a leech has about 300 sharp teeth. The bites inject a powerful anaesthetic and you feel no pain. If you do not forcefully remove the leech, it will start sucking your blood while secreting a cocktail of substances acting as an anticoagulant. This will ensure the blood’s purity and its free flow. The leech usually sucks for only 20 to 30 minutes, but bleeding will continue until the blockage is cleared.

The blood vessels of the ear are very small and sensitive. If an ear is damaged accidentally, it will not be an easy task to heal it. A five-year-old American boy’s ear was bitten off by a dog.

Surgeons successfully reattached the broken piece in a 12-hour long operation. However, after three days the ear turned dark blue and then purple. The medical team headed by Joseph Upton considered different mediations and finally decided to use leeches. He had successfully used leeches to heal soldiers wounded in the Vietnam War. Then he attached 12 leeches over six days to the injured ear. They dropped off one by one after sucking the blood. At the end of the leech treatment, the doctor found that the boy’s ear had healed and his blood circulation had returned to normal.

Cheap and effective

Even doctors have different opinions about the leech treatment. Some doctors think that they should not go back to the past in the treatment of patients.

However, surgeon Peter Mahaffey in Britain used leeches to treat patients. As a medical student, he had seen how patients with black eyes were cured using leeches. He used to keep many leeches in his laboratory. According to him, leech treatment is incredibly cheap and effective.

From where do doctors get leeches? When a patient is brought before them, they cannot go on collecting leeches.

In Britain and many other countries, there are leech-breeding farms. In fact, the leech-breeding farm in Britain was founded by Dr Roy Sawyer who came from South Wales. His company used to supply leeches to doctors and hospitals regularly. As a boy, he ran about in his native South Carolina where he found leeches for the first time. Even while swimming, he found leeches hanging on to his body. Unlike many of us, he did not hate them, but treated them as part of nature. When he proceeded to medical school, he saw how leeches were used in medicine.

Leeches were mostly used on patients having inflammatory conditions. He said leeches had been used for bleeding purposes for centuries.

Dr Sawyer did his postgraduate studies in Zoology at the University of Wales where he spent more than a decade to compile his three-volume “Leech Biology and Behaviour.” It is probably the most authoritative work on leeches. He had about 80,000 species kept in glass tanks. He fed them on cow’s blood obtained from a slaughterhouse.

Slimy parasite

In the 21st century, the leech is on the cutting edge of modern medicine. Doctors no longer think that the slimy parasite is a tool of the medieval quacks. In 1977, Dr Sawyer went on an expedition into the jungles of French Guiana looking for the giant Haementeria ghilianii, named after Vittore Ghiliani, a 19th century naturalist. He discovered the species in the Amazon forest.

Scientists have found that leech saliva contains a powerful enzyme capable of dissolving blood clots in patients. It is strange that a bloodsucking parasite of the third world could be used to treat patients suffering from cardiovascular diseases which remain the main killer in the West.

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