Rare Leech Species Facing Extinction Being Bred at London Zoo

The medicinal leech, a rare species of sucking leech being farmed, is highly endangered due to habitat loss and medicinal use.

A rare species of medicinal leech

At London Zoo, rare blood-sucking leeches are being bred in a bid to be saved from extinction, with the species currently representing the UK's largest native leech species. They live in ponds and ditches in several places in England but also in Wales.

They mainly feed on amphibians and grazing animals. At the zoo, they are supplied with sheep's blood once a month, as Arran Harvey, aquarist at London Zoo, explains to the BBC. These leeches are the only ones to be officially authorized for hirudotherapy, which uses them to take, almost painlessly, human blood and inject an anticoagulant, hirudin, and a natural anesthetist.

London Zoo is breeding this species for the first time before reintroducing it into the wild in order to contribute to the preservation of freshwater ecosystems in Great Britain, explains the British media.

A more than threatened species

L'Hirudo medicalis, its Latin name, is one of the most endangered species of leeches. It was very widespread in the United Kingdom in the past, but its number of individuals has drastically decreased due to the loss of its habitat, which no longer represented a suitable living environment for their development with the pollution of fresh waters and pesticides.

Their use for medicinal purposes is also one of the causes of the low presence of this species protected by British law. Today, there are only four populations of medicinal leeches in the United Kingdom, which are recognizable by their brown color punctuated with yellow or red.

Leeches already used in the past

The medicinal leech is a very old species. Indeed, it was used, in the same way as its current use, as a remedy or medicinal practice. Dr Mike Jeffries, visiting researcher at Northumbria University reports that “Evidence for the use of leeches as a treatment dates back to 1500 BC. BC, they appear in the paintings of Egyptian tombs.

It was also widely used in the 19th century to treat most diseases, by reducing inflammation of the digestive tract thanks to the property of its saliva. It remains to be seen whether the zoo will succeed in increasing the number of individuals of this species, which will initially be placed in local ponds to observe their adaptation to a new ecosystem.

Source: BBC