14 DAY TRIAL // For many people, they may represent some disgusting worms, but leeches (believed to come from an Old English word for "physician") were employed in therapies even 3,500 years ago by the ancient Egyptians.
And leech treatments were popular in Middle Ages Europe. Some of these treatments were legitimate, some weren't.
In 1758, Linnaeus gave the medicinal leech the name Hirudo medicinalis. But a new genetic research shows that the wild European medicinal leeches belong to at least three distinct species, not just to one, and the majority of the commercially available medicinal leeches employed around the world in biomedical research and postoperative care belong in fact to the newly found species Hirudo verbana, not Hirudo medicinalis. "This raises the tantalizing prospect of three times the number of anticoagulants, and three times as many biomedically important developments in areas like protease inhibitors," said lead researcher Mark Siddall of the American Museum of Natural History. "However, it will also require a better effort to conserve these much-maligned animals, in a way that takes into account their impressive diversity."
The problem is that, while Hirudo medicinalis received the approval of the U.S. Food and Drug Administration (FDA) in 2004, for medical uses (it helps restore blood flow following cosmetic and reconstructive surgery), Hirudo verbana did not and it is not protected. "This study is a great example of why the field of taxonomy [the science of classification of organisms] is so important," said Patrick Herendeen, program director in the National Science Foundation (NSF) Division of Environmental Biology.
"Taxonomists have been studying the diversity of life on Earth for hundreds of years. In this case, the discovery of previously unknown species diversity has very significant legal and commercial implications."
In 19th-century Europe, the demand for leeches was so high that some countries emitted some of the earliest laws of biological conservation.
Leeches are still offered protection by the World Conservation Union (IUCN) and are regulated by the Convention on International Trade in Endangered Species (CITES), the Berne Convention, and the European Union Habitat Directive.
The European medicinal leeches are still extensively employed in biomedical researchers investigating blood coagulation, developmental genetics and neurobiology. Their research led to the synthesis of anticoagulants and protease inhibitors, compounds with anti- cancer qualities. But most of the researches employed Hirudo verbana under the denomination of Hirudo medicinalis.
Siddall's team investigated mitochondrial and nuclear DNA of wild leeches from populations across their range in Europe, but also from commercial samples or university labs.