Investigation of the role of medicinal leeches as potential reservoir hosts for Hepatitis B in transovarial transmission

Hirudotherapy, which involves the use of medicinal leeches (Hirudo verbana), is one of the oldest methods of traditional complementary medicine and is currently preferred as a supportive treatment in many clinical fields. However, despite its widespread use, the potential risks it carries in terms of blood-borne infections remain significant. In this study, it was investigated whether the Hepatitis B virus (HBV) can be transmitted vertically through leeches and whether it can spread to the environment through the leeches' biological waste or secretions. A total of 90 juvenile leeches from 52 HBV-exposed adult leeches fed with HBV-infected human blood, along with 15 environmental samples and 13 cocoon shells, were analyzed using the qPCR method. HBV was not detected in any of the samples. The findings indicate that HBV does not show vertical transmission in leeches and that the risk of environmental spread is low, thereby providing a scientific basis for sustainable and safe hirudotherapy practices.