Medicinal Leech

• utilidadIt was widely used in historical medicine for bloodletting, and is still used today in reconstructive surgery to encourage circulation in grafted tissue.
• Its saliva contains hirudin, an extremely powerful anticoagulant, along with anaesthetics and vasodilators, which is why the bite does not hurt and the wound goes on bleeding afterwards.
• Bloodletting with leeches was practised on a massive and largely unjustified scale during the nineteenth century, to the point that the species was overexploited and is today listed as Near Threatened.
• Its saliva is a complete pharmacological cocktail: it contains hirudin, the most potent natural anticoagulant known, along with anaesthetics, vasodilators and anti-inflammatories. That is how it manages to feed without the victim noticing and without the blood clotting.
• Hirudin was isolated in 1884, and recombinant versions are now produced and used as anticoagulants in medicine.
• Its medical use is not ancient folklore: in 2004 the FDA approved medicinal leeches as a medical device. They are employed in reconstructive surgery and in reattachments of fingers and ears, where they help drain pooled blood and restore circulation in the grafted tissue.
• It has three jaws with about a hundred teeth each, which leave a characteristic Y-shaped mark.
• It can ingest up to ten times its own weight in blood and then go months without feeding.
• Medical demand in the 19th century was devastating: millions of individuals were collected across Europe, and that is the main reason it is listed today as Near Threatened and protected in several countries.
• What is sold for medicine today is largely another species, Hirudo verbana, which prompted a taxonomic revision of the group.

Skeleton type

Invertebrate - no rigid skeleton (annelid)

Habitat and environment

Ponds, marshes and shallow lagoons with vegetation and amphibians

Sources consulted: Wikipedia (es): Hirudo medicinalis