European Medicinal Leech Fact File
The European medicinal leech has a cylindrical body which is divided in to narrow segments.
A sucker is present at either end of the body. One is used for holding on to items while the other contains the teeth and jaw. This is used to grab on to the prey and suck its blood.
Their body is colored green or brown with a darker color to the dorsal side and a light stripe running along the ventral stripe.
Located at the front of the head are five pairs of eyes.
Their diet is made up of blood. When the European medicinal leech grabs on to prey it will inject anticoagulants and anaesthetics which help to increase the time they can suck blood for.
In a single feeding the leech may eat up to 10 times its own body weight.
They may go as long as a year between feedings.
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European medicinal leeches are found across Europe and Asia. Here they can be found in Austria; Belarus; Croatia; Czechia; France; Germany; Hungary; Latvia; Lithuania; Netherlands; Norway; Poland; Russia; Slovenia; Sweden; Switzerland; Ukraine and the United Kingdom .
Unlike the majority of other blood sucking leeches capable of penetrating human skin which live in tropical environment the European medicinal leech can be found in temperate waters.
These animals are semi-aquatic and can move between land and water. They can only survive in fresh water.
Breeding for the European medicinal leech takes place from June through to August. Despite this they are fertile year round.
Mating will take place on the land. Like other leeches they are all hermaphroditic.
A cocoon will be formed around a thickening of the body ring which is known as the clitellum. This egg sac is then deposited in to damp soil. It may contain up to 50 eggs.
The eggs hatch from this sac after 14 days. At birth they look like a small version of the adult.
In water they move by contracting the body muscles. On land they will move by alternating between the anterior and posterior suckers.
They will rest under objects on the shoreline.
Predators and Threats
Populations of the European medicinal leech suffered heavy declines from over-exploitation during the 19th century. Populations are still yet to recover from this.
Leeches previously benefited from farming which would bring horses (a favored food source) to areas in large numbers along with the creation of water supplies for livestock. The transition to modern machinery and as such the reduction in horse use has removed this benefit.
Other losses come from habitat destruction and alteration.
The European medicinal leech is one of the 700 species of leech and is among the many which have been used in medicinal treatments.
European Medicinal leeches also produce a range of anticoagulants which have medical benefits.
Leech therapy is still used to this day. A Medicinal leech may be used to help stimulate circulation following a therapy.
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Robyn Jay, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons
Vijayakumarblathur, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
GlebK, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons
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iNaturalist. 2021. European Medicinal Leech (Hirudo medicinalis). [online] Available at: <https://www.inaturalist.org/taxa/357886-Hirudo-medicinalis> [Accessed 19 April 2021].
Utevsky, S., Zagmajster, M. & Trontelj, P. 2014. Hirudo medicinalis. The IUCN Red List of Threatened Species 2014: e.T10190A21415816. https://dx.doi.org/10.2305/IUCN.UK.2014-1.RLTS.T10190A21415816.en. Downloaded on 19 April 2021.
Silverstein, K. 2002. "Hirudo medicinalis" (On-line), Animal Diversity Web. Accessed April 19, 2021 at https://animaldiversity.org/accounts/Hirudo_medicinalis/