Role of the Leech in Veterinary Medicine
Leeches have an extremely wide range of applications in veterinary medicine. The most common patients are dogs, cats and horses, but even farm animals could also be treated with leeches. Hirudotherapy treatments should be performed by a skilled hirudotherapist. The animal-patients receive one to seven treatment sessions, depending on the disease condition being treated.
The number of leeches applied during one treatment session depends on the species of the patient, its size and its individual characteristics. Usually one leech is applied per 10 kg of body mass of an animal, while 5 to 15 leeches are used per animal in the case of horses. The therapist places the bloodsucking leaches on the affected sites, whereupon the leech pierces the skin of the host with its 3 sharp jaws, which leave a Y-shaped wound. As the leech saliva also contains an anesthetic which prevents the animal from feeling the bite, the animals appear to remain calm.
The leach must stay on the skin until it has reached satiety, which generally takes 30–60 minutes in dogs and cats and 40–120 minutes in horses. When the medicinal leech falls off, bleeding continues from the site of the leech bite, which is part of the therapy. Such bleeding should not be inhibited for a few hours, resulting in the loss of 50 ml of blood. After the cessation of bleeding, the hirudo-therapist treats the area with bandages.
The use of leeches in veterinary medicine has the same indications as in human medicine. The presence of venous congestion and blood clots especially after surgery, orthopedic trauma, limb amputation and castration of males, as well as cases of poorly healing wounds are the indications for the use of leeches in animals . The salvage of tissue flaps whose viability is threatened by venous congestion is the primary indication for leeching.
For the Dermatology surgeon, leech therapy can be useful in cases in which cutaneous flaps may be lost because of venous outflow obstruction. In animals, veterinary leech therapy (VLT) may be also used in dysplasia, inflammatory conditions or injuries of, inter alia, tendons, fascia or vertebrae. Hemophilia and blood clotting problems are absolute contraindications for hirudo-therapeutic intervention, as well as anaemia, acute infections, diseases that cause immunosuppression, pregnancy, bleeding disorders, cancer of the skin and fungal skin diseases.