Leeches make a comeback

Two leeches suck the blood  of a patient in a therapy  session at a clinic in Moscow.
Two leeches suck the blood of a patient in a therapy session at a clinic in Moscow. / Viktor Korotayev / Reuters
  • They're like "mobile pharmacies" due to their therapeutic properties. Medicine is rediscovering a treatment that was popular during Napoleon's time

Leeches? Surgeon Mario Mateos is used to some of his patients wincing when he tells them about the treatment they are to be given. He works in the maxillofacial surgery department of the Joan XXIII hospital in Tarragona, which has been a pioneer in reintroducing leeches into Spanish medicine.

"About 20 years ago we discovered that French plastic surgeons were using leeches successfully in skin grafts and we decided to try them as well," explains Dr Mateos. Although at first his team faced misgivings from the management and some of their colleagues, the excellent test results cleared the way and laid the groundwork for hirudotherapy (from hirudo', the scientific name of the animal) to be used at the hospital.

The leeches, which are also called annelids because of the rings that shape them, have shown themselves to be especially suitable in guaranteeing the success of implants or skin grafts.

When the doctors detect that there is a risk of an implant not taking because of vascular congestion, they place a few leeches on the affected area so they suck the blood through the skin. Not only does the leeches' biting alleviate the congestion, it also provides a very effective natural drainage thanks to a powerful anticoagulant - hirudin - in their saliva. What they actually do is activate the irrigation of the blood vessels of the grafted areas. Dr Mateos calculates that the therapy solves problems which arise with the transplanted sections of skin in up to 80 per cent of cases.

"The leeches are really like mobile pharmacies because they have more than 100 substances with therapeutic properties in their organism," says Elena Bogoslovskaya, the president of the Spanish Hirudotherapy Association. She was born and trained in Russia, where annelids are used to treat a wide range of conditions.

"Clinical research into hirudotherapy began in Moscow in 1936 and since then leeches have gradually been incorporated into treatments at clinics and hospitals as a regular curative measure," she explains.

The use of annelids for medicinal purposes is also widespread in other countries. Hospitals and doctors in the UK, France, USA and especially Germany use leeches for a range of therapies and these are increasing as clinical tests reveal new therapeutic properties.

Some treatments are covered by public health systems, although it is within the alternative health sector that they are most often used.

The leeches come from four farms which are subject to strict biosanitary protocols. One of these, the only one in France, is called Ricarimpex and is based in Bordeaux. The company began in 1845, at a time when leeches were enjoying great popularity. Elena Bogoslovskaya says that the golden age of hirudotherapy was after Napoleon's surgeon, François Brousais, made them fashionable.

"Napoleon's life is said to have been saved thanks to the leeches," she explains. "He suffered a shoulder wound on the battlefield and it became so badly infected that they feared for his life. Brousais applied some leeches, and he underwent a remarkable improvement."

France at that time was the hegemonic power in science and culture, so it didn't take long for interest in leeches to spread all over the world. The demand was so great that within a few decades the 'hirudo medicinalis' was on the point of extinction. The annelids were used for any disorder and with no scientific criteria, so the results left quite a lot to be desired.

In the mid-19th century the use of leeches was so common that it was said that a French person was easily recognisable from the numerous small marks on their skin from leech bites.

Bred in Toledo

Spain at that time was one of the main suppliers of leeches from the continent. Elena Bogoslovskaya says that the principal breeding farm in Europe was located in Toledo. Wetlands such as Doñana and the Ebro Delta also provided plentiful captures.

The reduction in the leech population through over-exploitation and the discovery of new therapies meant that hirudotherapy fell into disuse. The arrival of penicillin and new generations of medication relegated the leeches to the condition of a remedy from the past, although they continued to be useful tools for a small group of doctors until well into the 20th century.

Ricarimpex, the farm which is based in Bordeaux, is partly responsible for the resurfacing of hirudotherapy in recent years. In 2004 the French authorities obtained permission from the rigorous Food and Drug Administration (FDA) to introduce the leeches into the USA for therapeutic purposes. It wasn't an easy process, but it aroused great interest among the medical profession.

"The fact that an institution as demanding as the FDA had given the go-ahead meant that many doctors started looking at hirudotherapy again," says Brigitte Latrille, the owner of Ricarimpex.

The USA is now the French company's main market. It exports about 70 percent of its production, which is about 100,000 leeches a year. Business is booming, because each leech costs about 10 euros on average, although the definitive price depends on variables such as the amount required and the urgency of delivery.

The company only sells to hospitals and professionals, which means that the animals will only be used in accordance with medical protocol, which requires them to be sacrificed immediately after being used to prevent them transmitting health problems from one patient to another.

The French company's leeches are bred in the wetlands of Las Landas, close to Arcachon. They are extraordinarily sensitive to environmental conditions and any sign of water contamination can kill them. They used to be bred in ponds into which sick horses were led, so they could feed on their blood, and were collected by people who entered the water with bare legs, so they would latch on to the skin. These days they are fed on chicken blood and collected in big sieves.

They are then classified according to size; those which are big enough to be sold are kept in special containers and are not given any food. The leeches have an extraordinary metabolism which enables them to live for up to two years without eating. The ones which are sold to doctors and hospitals have normally not eaten for about six months; this ensures that when they are placed on the patient's skin they immediately look for their blood.

Carmelo Betrán, who is 60 and comes from Zaragoza, says treatment with leeches saved the toes on one of his feet. "They operated on my knee and I had a thrombosis which went down to the foot and formed microthrombi in the toes. They treated me with medication, but the arteries were so narrow that toes soon became necrotic and the doctors told me they would have to amputate them," he says.

Carmelo looked into alternative treatments, and then heard about leeches. "For two months I went to see Elena Bogoslovskaya three times a week. She put two or three leeches on me;the anticoagulant in their saliva dissolved all the microthrombi and ended the necrosis. I can say that the leeches saved my toes," he says.

The treatment, he adds, is simple. The animals are placed on the affected area so they start to suck the blood. "You don't really feel anything, maybe just a very slight cramp, and in half an hour or less the leeches fall off by themselves because they are sated," he explains.