Hirudo medicinalis: is parasitic and the adults feed on the blood of mammals. It attaches to the host by means of its two suckers and bites through the skin of its victim. Simultaneously, the leech injects an anaesthetic so that its presence is not detected, and an anticoagulant in order for the incision to remain open during the meal. It has three jaws, which work back and forth during the feeding process, which ususally lasts about 20 to 40 minutes and leaves a tripartite star-shaped scar on the host. After a full meal of 10ml to 15 ml of blood, the medicinal leech may increase 8 to 11 times its initial body size. Leeches only feed about once every six months, this is about how long the blood meal takes to be fully digested. Certain bacteria keep the blood from decaying during the long digestion period. H. medicinalis may even go longer than six months without food by digesting its own tissues.
Hirudin: is the active principle in the salivary secretion of leeches. The name hirudin is from Hirudo medicinalis, the name of the medicinal leech..
In 1884 John Haycraft in Strasbourg found that leeches contained a substance with anticoagulant properties. This anticoagulant in leech saliva was isolated in the 1950s and found to be an antithrombin. The primary chemical structure of hirudin was determined in 1976.
The anticoagulant drugs desirudin and lepirudin (brand name: Refludan) are genetically engineered forms of hirudin.
Leeches are not field expedient medicine. Leeches are used post reconstruction to relieve pressure and increase venous circulation in tissue grafts. There is often constriction and or seepage in smaller blood vessels. Leeches will pull pooled blood out of the effected area, Hirudin will cause the blood flow to increase, this fosters tissue growth and helps prevent infection.
I have seen Leeches used to great effect on appendage reattachment and large tissue flap reconstruction such as burns and post-cancer reconstruction.
case studies:
http://www.leechesusa.com/LEECHESUSA/case1.asp
http://www.leechesusa.com/LEECHESUSA/case1.asp
Hybrid Mode
