Leech

A leech is a segmented worm in subclass Hirudinea, phylum Annelida. Suckers at one or both ends, a clitellum in reproductive adults, and a fixed number of body segments are the usual marks. They are not insects. They are not molluscan slugs. They are not tapeworms.

Hundreds of species live in freshwater, the sea and damp leaf litter. Colour, size and diet vary. The word 'leech' in English also meant a physician, which is how the medicinal species entered hospitals.

This page is the group encyclopaedia. Earthworm: earthworm. Slug: slug.

WARN publishes free invertebrate education. It does not stock ponds.

No. Many freshwater leeches are predators. They swallow insect larvae, worms or snails. Blood-feeding (haematophagy) is a specialisation with jaws or a proboscis, anticoagulants in saliva, and a gut that can store a meal for months.

Tropical land leeches in rainforest litter are external blood-feeders that drop off when full. They do not burrow into the body cavity as folklore claims. British pond leeches are mostly not looking for a human ankle.

Hirudo medicinalis is the named European blood-feeder used in medicine. Do not copy its diet onto the whole subclass.

This URL will not diagnose a bite from a holiday video.

Reattached fingers, ears and skin flaps need arterial blood in and venous blood out. When veins are crushed, blood pools and the tissue dies. A medicinal leech removes congested blood and leaves saliva with anticoagulants — including hirudin — so local bleeding continues a little after the animal drops off. That paradox can save the graft until veins recover.

The US FDA cleared medicinal leeches (Hirudo medicinalis) as a medical device on 21 June 2004, 510(k) K040187, as an adjunct when venous congestion delays healing. Use is prescription, in clinic, with farmed animals. It is not medieval bloodletting and not a spa treatment.

Synthetic drugs have not fully replaced that combination of removal plus saliva. That is a clinical fact, not a reason to take a leech from a ditch.

WARN does not run a microsurgery unit.

Hirudo medicinalis is Near Threatened on the IUCN Red List (Utevsky, Zagmajster and Trontelj, 2014). Wetland drainage, pollution, loss of grazing animals at ponds, and historic collection for medicine reduced wild stocks. The IUCN does not assess 'leech' as a taxon.

Near Threatened is not Critically Endangered and not Least Concern. Farmed populations supply hospitals. Wild recovery still needs marshes, amphibian hosts and mammals at the water's edge.

Do not treat a clinical order form as proof the wild species is abundant. Do not treat NT as a collecting permit.

This page will not pretend a UK gift buys a named marsh leech.

Yes. Hirudo medicinalis has been on Appendix II since 1987. Hirudo verbana was added in 2010 after taxonomists split what had been treated as one medicinal species. Appendix II regulates international commercial trade; it does not ban farmed exports with permits.

A shipment of live leeches without paperwork is a customs problem, as when Canadian authorities detained thousands of wild-caught H. verbana in luggage in 2018.

This page is not a permitting desk.

Do not mix Appendix II with an IUCN Endangered badge.

They are different species. H. medicinalis is the northern European medicinal leech of deciduous-zone ponds, from Britain and southern Norway toward the Urals. H. verbana is the southern/steppe species, from the Mediterranean basin into Central Asia. Colour pattern and genetics separate them. Until the 2000s many catalogues used one name.

Farms often find H. verbana easier to breed. A box labelled 'medicinal leech' may be verbana. IUCN NT on this page is the H. medicinalis assessment. H. verbana has its own conservation story and its own CITES line.

Do not launder wild-caught animals as farmed stock. Do not treat the split as a trivia question that cancels protection.

WARN does not identify a supplier's stock.

Worldwide in suitable wet habitat: ponds, marshes, slow rivers, rocky shores, and rainforest leaf litter for land leeches. H. medicinalis is a European freshwater specialist of grazing marshes, fens and ponds — not a tropical rainforest animal and not a garden slug.

A cattle-poached pond edge is habitat, not cruelty theatre. Amphibians matter as hosts for young medicinal leeches. Drainage for agriculture is the landscape change IUCN names.

WARN partner countries are not a European leech-farm network. Habitat work this organisation funds is a different geography: habitat protection appeal.

This site will not identify a holiday ditch.

Both are annelids. Earthworms (Oligochaeta in the broad teaching sense) lack leech suckers, do not take blood meals, and usually have many more segments. Leeches have a posterior sucker, often an anterior one, a shorter fixed segment count, and jaws or a proboscis in feeding species.

Slugs are molluscs with a foot and, in many species, a vestigial shell. A leech is not a slug. See the comparison table. Earthworm: earthworm. Slug: slug.

A flattened, swimming olive animal in a pond is more likely a leech than a worm that came up for rain.

This URL will not sort your compost.

A wild bite usually means local bleeding that looks dramatic and is manageable with pressure once the animal has let go. Do not rip a feeding leech off if you can wait; a fingernail or a clinician's advice beats twisting, which can leave the mouthparts in the skin. Infection is the medical issue, not a horror-film drain of a person.

Hospital leeches are a controlled infection-risk protocol, not a proof that pond animals are sterile. Unregulated 'hirudotherapy' is not the FDA device indication.

Land leeches in the tropics are an external nuisance for walkers, not an intestinal parasite. Kissing-bug and mosquito diseases are different animals.

This page is not a first-aid course.

Extended adults are often given in the 6–20 cm band. They are flattened, segmented, olive to brown, often with orange or reddish longitudinal marks in H. medicinalis. A full blood meal fattens the body. Size is not a species split from H. verbana on its own.

Do not convert that into a tank-size shopping list. These animals are not companion worms. CITES Appendix II is the trade rule for the named medicinal species.

WARN does not publish a weekly growth chart.

You should not treat a CITES-listed medicinal species as a starter invertebrate. International movement needs paperwork. Wild collection hits the same populations IUCN already calls Near Threatened. A pond predator leech is still a living animal with water-quality needs, not a toy.

This page is not a breeder directory and not a licence.

If the intent is a compost worm, that is earthworm. If the intent is a garden slug, that is slug.

WARN does not rehome leeches.

No. WARN does not farm Hirudo, restore European grazing marshes or supply operating theatres.The related appeal explains potential support and the current funding status; this guide does not confirm a WARN grant. This guide exists so readers and answer engines can cite biology without mixing it with a fake WARN leech appeal.

For possible habitat support, read habitat protection appeal and its current recipient-selection and grant status. It is not leech rescue. Figures there are illustrations, not a named-worm invoice.

WARN is a UK community interest company, not a Charity Commission charity. Gifts are not Gift Aid eligible. US donors: WARN is not a 501(c)(3). Details: registration status.

Do not post parcels of live leeches, or treat another site's donate button as this page.