Studies on the host specificity of the medicinal blood leech Hirudo medicinalis L.

For the identification of host species of blood-sucking parasites, the suitability of disc-electrophoresis of the stomach contents was tested. Mammalian blood in the stomach of the medicinal blood leech Hirudo medicinalis gave satisfactory results. In the case of mixed blood samples from H. medicinalis, the identification of the host according to the electrophoretic patterns of the stomach contents failed as compared with an immunological method such as the Ouchterlony test. Medicinal blood leeches (H. medicinalis) collected in Istria Croatia, or bought in a pharmacy contained blood from cattle, horses, or frogs in their stomachs. Specimens of H. medicinalis from Lake Neusiedl or from the Seewinkel Austria, had sucked blood from mallards or frogs. Blood of cattle, mallards, and frogs was found in the stomachs of H. medicinalis coming from the National Park Kiskunsag Hungary. For the first time, horses were established as hosts for free-living specimens of H. medicinalis. A comparison of the weights of H. medicinalis bought in a pharmacy revealed that specimens containing frog blood in their stomachs weighed significantly less than those containing horse blood. These results confirmed the reports from Ssynewa (1944) concerning the breeding experiments. Probably, there is a change in hosts from the frog to warm-blooded animals during the life cycle of H. medicinalis. There were also significant differences in the weights of leeches as revealed by a comparison of the population from the Neusiedlersee with the leeches bought in the pharmacy.