The virological safety of medicinal leeches has to be ensured prior to their use on patients. While leeches can be kept and bred under standardized conditions, feeding them horse blood adds a non-standardized component, which poses some risk of infection of the treated patients. Here, we investigated the speed at which blood-borne viruses are degraded by the microbial flora in the leech intestine, in order to define the safety of the product and the length of the necessary quarantine period prior to its administration to patients. Feeding blood was spiked with bovine viral diarrhea virus (BVDV), reovirus, and murine parvovirus (107 ID50 ml−1). The virus titer in the intestinal contents of the leeches was determined using permissive cell cultures and compared to that of the original virus titer at the following time points: immediately after feeding; after 3, 14, and 30 days; and monthly thereafter until the 7th month. The BVDV titer was below the detection limit of 101 TCID50 ml−1 after 3 months, while reovirus and murine parvovirus titers were undetectable after 4 months. No positive virus findings were obtained at later time points. Thus, when fed the blood of vertebrates, the finished product “Medicinal leech, Hirudo verbana” can be considered virologically safe if the animals are maintained at 20 °C, which corresponds to their natural habitat conditions and ensures a high metabolic rate. Therefore, after the last feeding, a quarantine period of 4–6 months and appropriate care at room temperature, which supports microbial degradation and digestive processes, are recommended.
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Al-Khleif A, Roth M, Menge C, Heuser J, Baljer G, Herbst W (2011) Tenacity of mammalian viruses in the gut of leeches fed with porcine blood. J Med Microbiol 60:787–792. doi:10.1099/jmm.0.027250-0
CEN 216 WI 002 16037 (2008). Chemical disinfectants and antiseptics. Quantitative nonporous surface test for the evaluation of virucidal activity of chemical disinfectants used in human medicine. Test method and requirements without mechanical action (phase 2/step 2).
DIN EN 14476 (2013) Chemical disinfectants and antiseptics. Quantitative suspension test for the evaluation of virucidal activity of chemical disinfectants used in human medicine. Test method and requirements without mechanical action (phase 2/step 1).
German Association for the Control of Virus Diseases (DVV) (2008) Guideline of the German Association for the Control of Virus Diseases and the Robert Koch Institute (RKI) for testing chemical disinfectants for efficacy against viruses in human medicine. Bundesgesundheitsbl Health Res Health 51:937–945
German Association for the Control of Virus Diseases (DVV) (2012) Guideline of the German Association for the Control of Virus Diseases. Quantitative examination of the virucidal efficacy of chemical disinfectants on non-porous surfaces (application in human medicine). Hyg Med 37:78–85
German Federal Institute for Drugs and Medical Devices (2009) Guideline of the BfArM to ensure quality and safety, communication on leeches in human medicine. Communication on the use of leeches in human medicine, guideline to ensure quality and safety: http://www.bfarm.de/SharedDocs/Downloads/DE/Arzneimittel/Pharmakovigilanz/Service/mitteil/mittl_blutegel.pdf?__blob=publicationFile&v=2
German Veterinary Medical Society (DVG) (2007–2012) Guideline for the testing of disinfection procedures and chemical disinfectants, 4th revised ed.
Kaehler Schweizer D, & Westendorff M (2013) Hirudotherapy: handbook of leech therapy. [GERMAN] Belisana
Keim A (1993) Studies on the host specificity of the medicinal blood leech Hirudo medicinalis L. Parasitol Res 79(3):251–5
Maaßen H-G (2013) Leech therapy not only on the joints. Podologie 64:18–20, In German
Medicines and Healthcare Products Regulatory Agency (MHRA) (2013) Executive agency of the Department of Health, United Kingdom, Guidance on legislation Borderlines between medical devices and medicinal products http://www.mhra.gov.uk/home/groups/dts-bs/documents/publication/con286964.pdf
Nehili M, Ilk C, Mehlhorn H, Ruhnau K, Dick W, Njayou M (1994) Experiments on the possible role of leeches as vectors of animal and human pathogens: a light and electron microscopy study. Parasitol Res 80(4):277–90
Trontelj P, Sotler M, Verovnik R (2004) Genetic differentiation between two species of the medicinal leech, Hirudo medicinalis and the neglected H. verbana, based on random-amplified polymorphic DNA. Parasitol Res 94(2):118–24
von Rheinbaben F, Wolff M H (2002) Handbook of virucidal disinfection. [GERMAN], Springer, Berlin
Working Group Virucidal (2004) Position of the Virucide Study Group of the Robert Koch Institute (RKI) and the Technical Committee "Virus disinfection" of the German Association for the Control of Virus Diseases (DVV) and the Disinfectant Commission of the German Society for Hygiene and Microbiology (DGHM): Evaluation and declaration of efficacy of disinfectants against viruses. Bundesgesundheitsbl - Gesundheitsforsch - Gesundheitsschutz 2004, 47:62–66 http://www.rki.de/DE/Content/Infekt/Krankenhaushygiene/Desinfektionsmittel/Viruzid.pdf
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von Rheinbaben, F., Riebe, O., Koehnlein, J. et al. Viral infection risks for patients using the finished product Hirudo verbana (medicinal leech). Parasitol Res 113, 4199–4205 (2014). https://doi.org/10.1007/s00436-014-4095-2
- Viral infection risk
- Hirudo verbana
- Medicinal leech
- Blood-borne viruses
- Transmission risk
- Patient safety