Leech Species Research Articles

Insights into the distribution of Freshwater Leeches (Annelida, Clitellata, Hirudinea) in Southwestern Tunisia

The study aims to highlight the diversity of leech species living in southwesternTunisia. Our study highlights the prevalence of Limnatis nilotica, whichrepresents 63.01% of the leech population, while the less frequently observedspecies include Erpobdella johanssni (25.31%) and Batracobdella argila(10.75%). These species thrive in watersheds, rivers, water sources andswamps. Interestingly, This study reveals a poverty of leech diversity in thesouth-west of Tunisia compared to the north, which favors conditions conduciveto the development of leeches

Predation of anurans in southern England by Batracobdella algira, a leech previously unknown in the UK

Leech predation of amphibians is known to occur in Europe. Observation of severe leech infestation affecting a common toad Bufo bufo in southern England in summer 2020, with leeches covering the toad’s eyes, throat and axillae, initiated a collaborative investigation to learn more about the occurrence of such leech predation of anurans in the UK. Soliciting reports from the general public identified leech predation of common toads and common frogs Rana temporaria in Devon, Greater London, Hampshire, the Isle of Wight and Somerset in southern England. Through morphological and/or molecular investigation of samples, Batracobdella algira, a leech species not previously reported in the UK, was identified in the majority of cases. The known native Placobdella costata was also identified, with the observed feeding behaviour on anuran hosts being indistinguishable from that of B. algira. Whether the latter is a previously unrecorded or an introduced species has not yet been established. However, sequence data from multiple gene loci were identical to B. algira found in Tunisia, suggesting it more likely to be a non-native species to the UK. Further work is required to elucidate the potential origin and distribution of B. algira in the UK and whether it has any impact on amphibian populations. Keywords: amphibians, Bufo bufo, Glossiphoniidae, Hirudinea, Rana temporaria

Transgenesis enables mapping of segmental ganglia in the leech Helobdella austinensis.

The analysis of how neural circuits function in individuals and change during evolution is simplified by the existence of neurons identified as homologous within and across species. Invertebrates, including leeches, have been used for these purposes in part because their nervous systems comprise a high proportion of identified neurons, but technical limitations make it challenging to assess the full extent to which assumptions of stereotypy hold true. Here, we introduce Minos plasmid-mediated transgenesis as a tool for introducing transgenes into the embryos of the leech Helobdella austinensis (Spiralia; Lophotrochozoa; Annelida; Clitellata; Hirudinida; Glossiphoniidae). We identified an enhancer driving pan-neuronal expression of markers, including histone2B:mCherry, which allowed us to enumerate neurons in segmental ganglia. Unexpectedly, we found that the segmental ganglia of adult transgenic H. austinensis contain fewer and more variable numbers of neurons than in previously examined leech species.

Molecular based identification and phylogenetic relationship of the leech Hirudinaria manillensis from India by using mitochondrial cytochrome c oxidase subunit I gene.

A molecular approach for the identification of unknown species by the using mitochondrial cox1 gene is an effective and reliable as compared with morphological-based identification. Hirudinaria manillensis referred to as Asian Buffalo Leech, is found in South Asia and traditionally used as medicine owing to its medicinal properties. The study aimed to isolate and identify the leech species using cox1 gene sequencing and their phylogenetic relationships. The nucleotide sequences of cytochrome c oxidase subunit I (cox1) mitochondrial genes were analyzed for species identification and the phylogenetic relationship of crucial therapeutic leech Hirudinaria manillensis. The isolated DNA from the leech sample was amplified with cox1 gene-specific primers. BLAST results with the H. manillensis sequence showed 89.24% homology with H. manillensis and phylogenetic tree analysis revealed the genetic relationship with other GenBank submitted sequences. The present study concluded that the cox1 gene could be an effective way to identify the leech H. manillensis and provided sufficient phylogenetic information to distinguish H. manillensis indicating a significant mtDNA-based approach to species identification.

Occurrence of parasitism promoted by Myzobdella lugubris Leidy, 1851 (Annelida: Piscicolidae) in Callinectes bocourti (Crustacea: Portunidae): A report of invasive leech in Brazilian Amazon province

This study reports the presence of high parasitic load by Myzobdella lugubris Leidy, 1851 in the swimming crab Callinectes bocourti A. Milne-Edwards, 1879 from Amazon mangrove. We sampled the swimming crabs using a baited trap, between January and June 2023, in Santa Maria River, located in the municipality of Curuçá, state of Pará, Brazil (geographical coordinates 0°40′3.705”S, 047°54′43.405”W). After sampling, each swimming crab was individually placed in plastic containers for the count of leeches per individual. In the laboratory, the specimens were sexed, measured (parasite and host) and fixed in 70% alcohol. For the leech species identification, macroscopic techniques were combined with light microscopy (LM) and scanning electron microscopy (SEM). We examined 86 specimens of C. bocourti (75 males and 11 females) in a ratio of 1 M:0.14 F, all infested with leeches. In total, 186 leech specimens were collected, ranging from 1 to 21 leeches per host. Leeches oviposited the cocoons in greater quantities in ventral area of swimming crab carapace (32%), followed by dorsal area of carapace (29.09%), chelipeds (24.34%) and ambulatory legs (14.57%). The presence of M. lugubris is a risk to the health of the host, once it may transmit a range of diseases to aquatic organisms, and subsequently risk to human health.

Not that many leech species after all: Myzobdella lugubris and Myzobdella patzcuarensis (Annelida: Hirudinida) are the same species

The genus Myzobdella groups five species of leeches parasites of fishes mainly of freshwater but with tolerance to brackish waters. Native distribution of these species includes the New World from North to South America. Myzobdella lugubris Leidy, 1851, the type species of the genus, was briefly described based on specimens from the USA, but subsequently their morphology, known distribution and host range were expanded; however, less is known about the other four species of the genus. As part of a survey focusing on characterizing the diversity of leeches from Mexico, specimens of Myzobdella patzcuarensis (Caballero, 1940), from the type locality of the species were included for the first time in a phylogenetic study. In addition, specimens assigned to Myzobdella from the southeast of Mexico as well as from Nicaragua, were also included. In the resulting phylogenetic tree, our newly generated sequences were found nested in the same clade that M. lugubris; with unresolved relationships and relatively low genetic divergence, suggesting conspecificity. In addition, the internal morphology of the specimens of Myzobdella from Mexico is consistent with the description of M. lugubris. Our morphological examination reveals high degrees of variability in the external pigmentation of the specimens. Based on our results we formally synonymize M. patzcuarensis under M. lugubris.

New marine leech species of Branchellion Savigny, 1822 (Hirudinida: Piscicolidae) and new host record of Pontobdella muricata in the Gulf of Tunis

New marine leech species of Branchellion Savigny, 1822 (Hirudinida: Piscicolidae) and new host record of Pontobdella muricata in the Gulf of Tunis

A new checklist of Slovenian leeches (Hirudinea: Euhirudinea): In memory of Boris Sket (1936–2023)

The new (as of 2023) checklist of Slovenian leeches (Euhirudinea) contains 33 species, which represents a 44% increase since the last published inventory in 2003. Notable new entries include Placobdella costata found parasitizing on European pond turtles, the marine fish leech Trachelobdella lubrica from the Slovenian Adriatic coast, the semi-terrestrial Haemopis elegans, the terrestrial Xerobdella praealpina – making Slovenia possibly the only country with confirmed occurrence of all three European land leeches – and a new, still undescribed highly troglomorphic cave leech from a deep Dinaric cave. The number of freshwater fish leeches is underwhelmingly low: two. This, and several unresolved taxonomic questions in erpobdellids suggest that more faunistic and taxonomic work is needed and that the list of Slovenian leech species is far from concluded. The authors dedicate this contribution to their teacher, Prof. Boris Sket (1936–2023), a leading figure in biodiversity research in the Dinaric Karst, including leeches and cave life.

IMPLICATION OF LEECH THERAPY AND ASBAB-E-SITTA ZAROORIYAH IN THE PREVENTION AND TREATMENT OF VARICOSE VEINS: A COMPREHENSIVE REVIEW

Varicose veins are characterized by abnormally twisted, dilated superficial vessels that are caused by the inefficient or defective valves within the vein. It is currently a prevalent disease with the incidence varying globally between 10% and 60%. The Unani Medicine (also called Greco-Arab medicine) is the ancient system of medicine practiced all around the world. According to the Unani classical text, Leech therapy (Irsal-e-Alaq) is one of the most important regimenal therapy for the successful treatment and management of varicose vein and a unique combination of Asbab-e-Sitta Zarooriyah (Six essential factors) is involved in the prevention of this disease. The research studies have proved that medicinal leech therapy displays anticoagulant, antimicrobial, anti-inflammatory and analgesic effects. Leech saliva contains medicinally useful bioactive molecules like hirudin, histamine, etc. that shows anti-coagulant effect and hence improve microcirculation in diseases like varicose vein. Leech therapy is reliable, well tolerated, cost effective treatment that has the potential of preventing varicose vein complications. This review seeks to describe medicinal leech therapy, present therapeutic leech species, and highlight the processes by which leech saliva affects wound healing. Additionally, the review paper highlights the role of Asbab-e-Sitta Zarooriyah in prevention and control of varicose veins. Irregularity in diet and lifestyle may cause disturbance in normal body functioning, which may lead to lifestyle disorder that is a major risk factor thought to influence the susceptibility of varicose vein. The Unani System exerts a major influence on preventing the development of varicose vein by making modification in Asbab-e-Sitta Zarooriyah.

Loop-Mediated Isothermal Amplification for On-Site Visual Identification of Leech Species

Loop-Mediated Isothermal Amplification for On-Site Visual Identification of Leech Species

Treatment of Cutaneous Leishmaniasis lesion caused by Leishmania major Using Leech Therapy in BALB/c Mice.

Amphotericin B, Allopurinol, Glucantime and Beta-Glucan are the main drugs currently used for the treatment of cutaneous leishmaniasis. In present study, we evaluated the effect of medical leeches on BALB/c mice models infected with Leishmania parasites. To create animal models of leishmaniasis, BALB/c mice were inoculated with the standard Leishmania major strain MRHO / IR / 75 / ER. Treatment was performed through blood sampling with leeches. We used medical leech (Hirudo medicinalis) species. This leech is a European medicinal leech, one of several species known used as medicinal leech. 22 mice infected with Leishmania major were used for the tests .The studied mice were divided into two groups which were named with the letters L and D. The duration of blood sampling was 25 min for initial treatment, 20 min for the 2nd blood sampling and 15 min for the third times and onwards. Meglumine antimoniate (Glucantime) is a pentavalent antimony (SbV) that recommended by the World Health Organization as a golden standard treatment for all kind of leishmaniasis, but many side effects are still reported. Criteria for anti-leshmania assessment of Leech were including: Leech saliva has an anti-leishmania effect by acting on the purin pathway. Leech saliva prevents the growth and multiplication of Leishmania by a mechanism of action similar to Glucantim (breaking ATP). The duration of leech treatment in BALB/c mice infected with L.major parasites was about 6-8 weeks. Out of the 22 leishmaniasis mice models that underwent treatment, 13 survived until the end of the treatment duration. The recovery rate was about 56%; lesions improved in five out of the 13 surviving mice models. Paired t-test showed a significant difference between the mean wound size at the beginning of treatment and the 8th week of treatment (PV <0.0001). Considering the fact that the standard drugs for the treatment of leishmaniasis have many side effects, alternative therapies such as leech therapy can be effectively used to treat these chronic wounds. There are about 20 active substances in leech saliva. These substances include antistasin, eglins, guamerin, hirudin, saratin, bdellins, complement, and carboxypeptidase inhibitors. Leech saliva is an anticoagulant, anti-inflammation and prevents the platelet. Leech therapy was effective in treating leishmaniasis wounds in BALB/c mice. In this study, there was complete wound healing in 56% of the mice models.

Leeches (Annelida, Hirudinea) Fauna of Nakhchivan Autonomous Republic

The fauna of the leeches of Nakhchivan Autonomous Republic is represented by 10 species belonging to 9 genera, 5 families, 2 orders and one class. According to zoogeographical affiliation, leech species belong to 4 faunistic complexes. In the benthic infauna of various types of water bodies, glossyphonides predominate in the frequency of occurrence and abundance of individuals. An extremely rare medical leech (Hirudo medicinalis) is the only practically useful representative of the girudofauna. Functional significance of other species in biocenoses is low. The article also presents data on morphology, body sizes, objects of finding and biotopes of leeches of fauna of Nakhchivan.

An Investigation into the Diversity of Leeches (Hirudinida) in the Baltic States

The Baltic states—Estonia, Latvia, and Lithuania—are situated on the eastern coast of the Baltic Sea between Russia and the Scandinavian countries. This region is characterized by diverse landscapes and numerous bodies of water, including lakes, peat bogs, and marshes, which serve as natural habitats for aquatic invertebrates, including leeches. Despite the rare and uncertain taxonomic status of leech species in the area, research in the Baltic region has been inadequate. Therefore, this study aims to examine the composition of leech species in the Baltic countries, drawing on both past and current research. The study also seeks to assess the status of Hirudo medicinalis in the Baltic region and discuss the rare, questionable, and potentially present leech species in the Baltic states. A scoping review method was employed, surveying published references, books, and databases. In total, the study found records of 21 leech species in Estonia, 15 in Latvia, and 26 in Lithuania, belonging to the families Glossiphoniidae, Erpobdellidae, Hirudinidae, Haemopidae, and Piscicolidae. Hirudo medicinalis L. is distributed throughout all Baltic countries, but the most recent records on their location are only available for Estonia. The data on a few Piscicolidae species is questionable and requires verification, but further research on Piscicolid leeches can potentially lead to the discovery of rare species.

НОВЫЕ НАХОДКИ МЕДИЦИНСКОЙ ПИЯВКИ HIRUDO VERBANA (CARENA, 1820) В ВОДНЫХ ЭКОСИСТЕМАХ КАБАРДИНО-БАЛКАРИИ

Background. Medicinal leeches are a traditional aquatic biological resource in Russia, officially used in practical medicine, pharmacology and cosmetology. However, in recent decades, the distribution range and abundance of these valuable aquatic organisms on the Russian territiry have decreased considerably. Relevance. The study of the present geographical range of this exploitable leech species is of practical importance, since the modern technology of their controlled breeding at biological production facilities requires constant replenishment of the broodstock and procurement of mature individuals from natural populations. This work is aimed at the identification of the current habitats of medicinal leeches in the aquatic ecosystems of the Kabardino-Balkarian Republic. Methods. This research was carried out in the last ten days of August 2021 in the daytime, in the littoral part of the water bodies of the plain and foothill zones of Kabardino-Balkaria. Leeches were caught with a handheld net, as well as collected manually from the objects in the immediate surroundings. The species of the caught leeches were determined using taxonomic keys in accordance with the modern classification. Results. New data on the distribution of the exploitable species of medicinal leeches Hirudo verbana (Carena, 1820) in the aquatic ecosystems of Kabardino-Balkaria are presented. Habitats of natural populations of this leech species were found in the Trek Lake and Deya River. Conclusion. The presence of the medicinal leech H. verbana in the investigated water bodies indicates their good ecological state. The results of this study make it possible to expand our understanding of the present distribution range of this exploitable species of aquatic organisms.

Effect of Sulfotyrosine and Negatively Charged Amino Acid of Leech-Derived Peptides on Binding and Inhibitory Activity Against Thrombin.

Hirudins, natural sulfo(glyco)proteins, are clinical anticoagulants that directly inhibit thrombin, a key coagulation factor. Their potent thrombin inhibition primarily results from antagonistic interactions with both the catalytic and non-catalytic sites of thrombin. Hirudins often feature sulfate moieties on Tyr residues in their anionic C-terminus region, enabling strong interactions with thrombin exosite-I and effectively blocking its engagement with fibrinogen. Although sulfotyrosines have been identified in various hirudin variants, the precise relationship between sulfotyrosine and the number of negatively charged amino acids within the anionic-rich C-terminus peptide domain for the binding of thrombin has remained elusive. By using Fmoc-SPPS, hirudin dodecapeptides homologous to the C-terminus of hirudin variants from various leech species were successfully synthesized, and the effect of sulfotyrosine and the number of negatively charged amino acids on hirudin-thrombin interactions was investigated. Our findings did not reveal any synergistic effect between an increasing number of sulfotyrosines or negatively charged amino acids and their inhibitory activity on thrombin or fibrinolysis in the assays, despite a higher binding level toward thrombin in the sulfated dodecapeptide Hnip_Hirudin was observed in SPR analysis.

Abundance and composition of invertebrate-feeding leeches in relation to fish status in ponds

Leeches feeding on invertebrates are an important component of freshwater communities, including those dominated by fish, but the effects of fish on their abundance and distribution are not well explored. The relative densities and assemblage structure of two leech families, Erpobdellidae and Glossiphoniidae, were studied from May to August 2014 in ponds stocked with low biomass densities of young common carp Cyprinus carpio, too small to prey on leeches (low-fish ponds), and in ponds containing high biomass densities of large (one- or two-year-old) carp (high-fish ponds), using two types of activity traps (placed either on the bottom or near the water surface). The most common and numerous species were Erpobdella octoculata, Helobdella stagnalis, and Erpobdella nigricollis. The traps near the water surface captured relatively small numbers of leeches, yet the catches showed that in summer some of the leeches moved to the upper layers of the water column, which was free of macrophytes. No differences in leech species richness or diversity were found with respect to fish status of ponds; however, bottom erpobdellids were more abundant in high-fish ponds. Redundancy analysis identified the fish status of the ponds and total nitrogen concentration in water as the only significant variables explaining the distribution of leeches among ponds. Species distribution was nested, but the nestedness pattern was not affected by the fish status of the pond. While fish are generally believed to adversely affect macroinvertebrate diversity and abundance, our study shows that some predatory leech species can persist in the presence of fish and possibly indirectly benefit from it.

First description study on molecular characterization of Hemiclepsis khankiana (Hirudinea: Glossiphoniidae) in China

BackgroundLeeches are an integral component of aquatic biocenosis and can be found in a wide range of ecosystems such as freshwater, saltwater, flowing, and still-water ecosystems. It especially plays an important role in the freshwater benthic community and is an important part of the food web. In this study, a leech species was found in the mantle cavity of wild freshwater mussels in Zigong City, Sichuan Province, China, and its identity was determined through morphological analysis and molecular biological analysis.ResultsThe leech is Hemiclepsis khankiana, a new species of Hemiclepsis that has been discovered in Russia in recent years. Through morphological analysis, the current survey observed that the morphological characteristics of Hemiclepsis khankiana eyespots were significantly different from the first reported description. The first pair of eyespots on the leech were separated and clear, while it had been reduced to unclear shadows in the previous report. The phylogenetic tree based on the COI gene showed that the COI gene sequence obtained in this study was in the same evolutionary branch as Hemiclepsis khankiana (MN295420, MN295421). Genetically, it was most closely related to Hemiclepsis kasmiana (mean COI p-distance = 3.98%).ConclusionsThe current study reported on the new distribution range of Hemiclepsis khankiana, which was initially discovered in China. This study indicates that the distribution range of the leech species has expanded, laying a foundation for further studies in China.

Revisiting the Asian Buffalo Leech (Hirudinaria manillensis) Genome: Focus on Antithrombotic Genes and Their Corresponding Proteins.

Leeches are well-known annelids due to their obligate blood-feeding habits. Some leech species secrete various biologically active substances which have important medical and pharmaceutical value in antithrombotic treatments. In this study, we provided a high-quality genome of the Asian buffalo leech (Hirudinaria manillensis), based on which we performed a systematic identification of potential antithrombotic genes and their corresponding proteins. Combining automatic and manual prediction, we identified 21 antithrombotic gene families including fourteen coagulation inhibitors, three platelet aggregation inhibitors, three fibrinolysis enhancers, and one tissue penetration enhancer. A total of 72 antithrombotic genes, including two pseudogenes, were identified, including most of their corresponding proteins forming three or more disulfide bonds. Three protein families (LDTI, antistasin, and granulin) had internal tandem repeats containing 6, 10, and 12 conserved cysteines, respectively. We also measured the anticoagulant activities of the five identified hirudins (hirudin_Hman1 ~ hirudin_Hman5). The results showed that three (hirudin_Hman1, hirudin_Hman2, and hirudin_Hman5), but not the remaining two, exhibited anticoagulant activities. Our study provides the most comprehensive collection of antithrombotic biomacromolecules from a leech to date. These results will greatly facilitate the research and application of leech derivatives for medical and pharmaceutical purposes in the treatment of thrombotic diseases.

Blood recovery of wild Mekong snail-eating turtles (Malayemys subtrijuga Schlegel and Müller, 1845) in captivity from leech infestation

Blood cell counts are valuable diagnostic tools for assessing the health status of chelonians, however, reference standards for healthy blood parameters in various turtle species are lacking. In this study, forty wild female Malayemys subtrijuga were captured from ponds in Kasetsart University, and transported to laboratory for recuperating in captivity. All turtles were infected with a single leech species, Placobdelloides siamensis, with a mean of 513.7 ± 164.9 individuals per turtle, and exhibited penetrating and lesion wounds from leech infestations on both their skin and shell. Subsequently, they were cleaned and treated to eliminate ecto- and endoparasites before the recuperation period began. The turtles did not exhibit significantly differences in weight, carapace length (CL), red blood cell count (RCC), and white blood cell count (WCC) with a mean of 654.2 ± 199.9 g, 15.0 ± 2.5 cm, 327,080 ± 70,156 cells/mm3, and 73,340 ± 15,859 cells/mm3, respectively, during the initial records (week 0). However, after being maintained for 17 weeks, their health significantly improved in term of their blood parameters (RCC and WCC) and weight, except CL which remained unchanged, with a mean of 491,470 ± 16,169 cells/mm3, 18,790 ± 1496 cells/mm3, and 738.9 ± 191.5 g, respectively. Therefore, the health status obtained in this study can be used as a reference for blood parameters, weight, and recuperation period for the treatment of ill wild M. subtrijuga in captivity or as part of conservation management programs for turtles.

On the taxonomic status of Dina ratschaensis Kobakhidze, 1958 with a description of two new species – Dina imeretiensis sp. nov. and D. samegreloensis sp. nov. (Annelida, Hirudinida: Erpobdellidae)

Two species of leeches were described from Georgia in the past, Dina ratschaensis Kobakhidze, 1958 from the Racha-Lechkhumi and Kvemo Svaneti region and Trocheta ariescornuta Grosser, Barjadze &amp; Maghradze, 2021 from the Samegrelo-Zemo Svaneti region. Both species were the only known typical representatives of cave leeches in Georgia. Recently, two more species of the genus Dina R. Blanchard, 1894 have been found in karst caves in this country. These leeches are morphologically similar to D. ratschaensis, from which they differ in the shape of the reproductive system, primarily the shape of the cornua of the genital atrium and the shape and extension of the vasa deferentia and ovisacs, justifying the description of two new species, Dina imeretiensis Grosser, Barjadze &amp; Maghradze sp. nov. from the Imereti region and Dina samegreloensis Grosser, Barjadze &amp; Shavadze sp. nov. from the Samegrelo-Zemo Svaneti region. Data on the cave dwelling invertebrate communities in the studied caves are provided. Molecular data are provided, and a phylogenetic tree based on Cox1 sequences of Dina spp. and related genera is provided and discussed.