Three groups of Hirudo verbana were used to study the leech microbiota: farmed leeches fasting for a long time, farmed leeches recently fed with bovine blood, and wild specimens fed with amphibian blood. The microbiota of the leeches’ mouth, pharynx, crop, and intestine was analyzed. Metasequencing analyses were performed using amplification of the 16S rRNA V3-V4 region on a NovaSeq Illumina platform. The relative abundance of bacterial microbiota included environmental bacteria from the families Rhizobiaceae, Comamonadaceae, Sphingobacteriaceae, Phreatobacteraceae, Myxococcaceae, Chitinophagaceae, Rhodospirillaceae, and Bdellovibrionaceae, as well as symbiotic/probiotic bacteria such as Mucinivorans, Aeromonas, Vagococcus, Lactobacillales, and Morganella. Significant differences were found in the different regions of the digestive system among the three groups of leeches, and environmental bacteria were present in all groups to varying degrees. A negative correlation was found between the dominant environmental and the symbiotic/probiotic bacteria. In contrast, a positive correlation was found between environmental and symbiotic/probiotic bacteria, indicating their association with host factors. Microbiota diversity, abundance, and bacterial correlations may be influenced by factors such as the leech’s fasting state, blood meal source, and environmental conditions. The identified opportunistic pathogens, such as Rickettsia, Anaplasma, and Treponema, identified for the first time in H. verbana, should be taken into consideration when using this leech in hirudotherapy. Our results show that extensive screening for opportunistic and pathogenic agents should be performed on leeches intended for medical use. Long-fasting leeches and leeches cultured in specialized farms are recommended for hirudotherapy (Karasartova et al. 2025).

We report a case of a 29-year-old male patient with a history of cerebral palsy (CP), requiring assistance with basic activities of daily living, and treated with valproic acid. He was unable to speak but communicates with sound. The patient was admitted to the hospital due to four days of epigastric pain accompanied with diarrhea, hemoptysis, and epistaxis. A fiber optic laryngoscopy examination revealed an unidentified mass in the nasopharynx. Due to this mass, a computed tomographic (CT) scan was performed which revealed a polypoid finding extending from the posterior wall of the hypopharynx. Due to these findings the patient was taken into the operating room and under general anesthesia, a 6-7 cm long leech was removed which was later was identified as Limnatis nilotica (Machloof et al. 2024).

In our laboratory, we maintain leeches of the species Hirudo medicinalis, Hirudo verbana, and Hirudo orientalis. The leeches are examined for the presence of Aeromonas bacteria, and tests are conducted to determine the antibiotic susceptibility or resistance of these Aeromonas strains, thereby assisting physicians in selecting appropriate prophylactic treatment during hirudotherapy. Since 2002, more than 200 patients have been treated with leeches in the plastic surgery and orthopedic departments of virtually all major hospitals in Israel. To the best of our knowledge, in the majority of cases the treated fingers and flaps were successfully salvaged (Mumcuoglu et al., 2007, 2021; Gileva & Mumcuoglu, 2013; Mumcuoglu, 2014; Mumcuoglu & Taylan-Özkan, 2025; unpublished data).