First data on the Hirudinea fauna of lotic ecosystems of the Khanty-Mansi Autonomous Area (Russia)

Hirudinea, a small and ecologically important group of aquatic organisms, is poorly studied in northern Eurasia. In this study, we demyth the idea of the faunistic poverty of this region and present the first findings of rheophilic leeches from the Khanty-Mansi Autonomous Area, Russia. Investigation of 25 rivers (Severnaya Sosva, Ob, Konda-Irtysh, and Bolshoi Yugan river basins) resulted in finding 10 leech species with parasitic and non-parasitic life strategies. These species belong to two orders (Rhynchobdellida and Arhynchobdellida), three families (Glossiphoniidae, Piscicolidae, and Erpobdellidae) and six genera (Alboglossiphonia, Glossiphonia, Helobdella, Hemiclepsis, Piscicola, and Erpobdella). Five species, A.hyalina, G.verrucata, E.monostriata, E.vilnensis, and potentially new morphological species of piscine leeches Piscicola sp., have been discovered for the first time in Western Siberia. Data on species diversity of rheophilic leeches include the exact systematic position for all leech taxa. Each species from the list is supplemented with information about its geographical distribution.

Trypanosomatids (Protozoa: Kinetoplastida) in three species of Armored Catfish from Mogi-Guaçu river, Pirassununga, São Paulo, Brazil

Trypanosome infections have been reported in several species of fish, in majority of cases described on the basis of morphological characteristics. Trypanosomes in fish are heteroxenous and transmitted by hirudineans. This study aims to evaluate the prevalence and density of infections by Trypanosoma sp. in blood from three species of catfish, Hypostomus regani, H. strigaticeps, H. albopunctatus, from the Mogi Guaçu River, Pirassununga, São Paulo, Brazil. Further, this study intends to characterize the Trypanosoma specimens found in the blood of these fish by morphological and molecular techniques. The trypanosomes overall prevalence observed was 47.6% with a general average density of 0.75 parasites/µl of blood. Hypostomus regani and Hypostomus strigaticeps showed a significant difference in prevalence. The average densities of parasites were not significantly different among the three fish species. Similar findings were observed for the monthly variations in densities. The parasites found in the three species of catfish studied showed similar morphological characteristics. The morphological data and the statistical analyses used in this study didn't show the formation of groups. The analyses provided evidence of the presence of pleomorphisms in the trypanosomes found in the three studied fish.

The present state of the leech fauna (Annelida, Hirudinea) in the Upper Irtysh cascade of water reservoirs

Hirudinea is a small and ecologically important group of aquatic organisms. However, up to date, the leech fauna of Kazakhstan is poorly studied. The presence of large under-collected areas, such as the Upper Irtysh basin, makes biodiversity studies concerning these invertebrates from Kazakhstan relevant. In this paper, the latest information on species diversity of the freshwater hirudofauna of the Upper Irtysh cascade of water reservoirs, the Kazakhstan part of Irtysh River, is presented. It includes 10 free-living and parasitic species, of which 7 and 9 inhabit the Shulbinsk and the Bukhtarma reservoirs, respectively. These species belong to 2 orders, 3 families and 6 genera. The faunal list highlights four potentially new morphological species (Alboglossiphonia sp., Erpobdella sp., Piscicola sp. 1 and Piscicola sp. 2). Besides them, another three species Erpobdellavilnensis, Helobdellastagnalis and Theromyzontessulatum recorded for the first time in the area. The exact systematic position is stated for all leech taxa. Each species from the list accompanied with information on taxonomic synonymy, data on its geographic distribution, and brief summary of morphological and ecological characteristics.

Annotated checklist of the leech species diversity in the Maloe More Strait of Lake Baikal, Russia

In this paper, the very first checklist of the freshwater leeches of Maloe More Strait, a special part of Lake Baikal, is presented. It includes 14 free-living and parasitic species, of which four species belong to endemic Baikal genera - two species from Baicalobdella and one species each from Baicaloclepsis and Codonobdella. The checklist highlights six potentially new morphological species recorded for the first time in the area. The exact systematic position is stated for all leech species. Each species from the list is provided with information on taxonomic synonymy, data on its geographic distribution, and ecological characteristics. New species records are additionally provided with brief morphological characteristics and photos of their external morphology.

Genetic diversity of freshwater leeches in Lake Gusinoe (eastern Siberia, Russia)

The study of leeches from Lake Gusinoe and its adjacent area offered us the possibility to determine species diversity. As a result, an updated species list of the Gusinoe Hirudinea fauna (Annelida, Clitellata) has been compiled. There are two orders and three families of leeches in the Gusinoe area: order Rhynchobdellida (families Glossiphoniidae and Piscicolidae) and order Arhynchobdellida (family Erpobdellidae). In total, 6 leech species belonging to 6 genera have been identified. Of these, 3 taxa belonging to the family Glossiphoniidae (Alboglossiphonia heteroclita f. papillosa, Hemiclepsis marginata, and Helobdella stagnalis) and representatives of 3 unidentified species (Glossiphonia sp., Piscicola sp., and Erpobdella sp.) have been recorded. The checklist gives a contemporary overview of the species composition of leeches and information on their hosts or substrates. The validity of morphological identification of each taxon has been verified by phylogenetic approach with a molecular marker adopted for a DNA barcoding of most invertebrates.

Host specificity, pathogenicity, and mixed infections of trypanoplasms from freshwater fishes

This work summarizes the results of the 8-year study focused on Trypanoplasma sp. parasitizing freshwater fishes in the vicinity of Kyiv, Ukraine. Out of 570 fish specimens of 2 different species analyzed, 440 individuals were found to be infected. The prevalence of infection ranged from 24 % in Abramis brama Linnaeus (freshwater bream) to 100 % in Cobitis taenia Linnaeus (spined loach). The level of parasitemia also varied between moderate in freshwater bream and very high in spined loach. Interestingly, no clinical manifestations of trypanoplasmosis were observed even in extremely heavily infected C. taenia. We hypothesize that different species may differ in evolutionary timing allowing for reciprocal adaptation of the members of the "host-parasite" system. Molecular analysis of the 18S rRNA sequences revealed that several specimens were simultaneously infected with at least two different trypanoplasm species. To the best of our knowledge, this is the first report of the mixed infection with fish trypanoplasms.

Trypanosoma epinepheli n. sp. (Kinetoplastida) from a farmed marine fish in China, the brown-marbled grouper (Epinephelus fuscoguttatus)

An outbreak of trypanosomosis occurred in farmed Epinephelus fuscoguttatus in Xincun Bay, province of Hainan, South China Sea. The infected fish showed loss of appetite, lethargy, emaciation, severe anemia, and splenomegaly. Light and scanning electron microscopic examination of bloodstream trypomastigotes revealed morphological features typical for small-sized marine fish trypanosomes. The trypanosome possesses a short body length (mean 22.3 μm, range 17.6-25.9 μm) and narrow body width (mean1.7 μm, range 1.3-2.0 μm), a central nucleus, a narrow but distinct undulating membrane, and a relatively long free flagellum (mean 10.1 μm, range 7.4-13.3 μm). The kinetoplast is situated at approximately one quarter of body length from posterior extremity. The division process of this trypanosome was observed in the peripheral blood of the host, and occurred by transverse constriction at a point between the kinetoplasts. Comparison of the small subunit rDNA (SSU rDNA) sequences revealed that the trypanosome from E. fuscoguttatus showed 93.4-97.1% identity with the available sequences from Trypanosoma spp. from other piscine hosts. Phylogenetic analysis supported the existence of an aquatic clade, and the present trypanosome grouped with other marine fish trypanosomes, in a subclade together with Trypanosoma senegalense. Based on the differences in morphological characteristics, host species, and molecular data, the trypanosome infecting E. fuscoguttatus is considered to be a new species, for which we propose the name Trypanosoma epinepheli n. sp.

Experimental infection of yellow stingrays Urobatis jamaicensis with the marine leech Branchellion torpedinis

Infestations of elasmobranchs by the marine leech Branchellion torpedinis can be problematic in aquaria and negatively affect host health. To better characterize the extent and pathogenesis of disease, 12 yellow stingrays Urobatis jamaicensis were infected with 1 or 3 leeches for 14 d. Leeches were associated with anorexia, extensive cutaneous ulceration, decreased host packed cell volume (PCV) and serum total solids (TS), and mortality in 3 rays. Average decrease in host PCV positively correlated with ulcer size and parasite:host ratio. Average decrease in host serum TS positively correlated with parasite:host ratio. Blood chemistry and total white blood cell counts revealed no significant trends. Additional necropsy findings included gill and splenic pallor, pericardial edema, perirenal edema, and decreased hepatocellular lipid deposits. Microscopic evaluation of leeches demonstrated host erythrocytes and proteinaceous fluid within parasite intestines, confirming active blood feeding. Results indicate B. torpedinis has the potential to cause significant disease in elasmobranchs, including death in as few as 5 d, and identifies ulcer size and parasite:host ratio as risk factors for disease. Elucidation of this host-parasite interaction helps characterize host response to parasites and facilitate care of parasitized elasmobranchs in aquarium and wild settings.

Humoral response of captive zebra sharks Stegostoma fasciatum to salivary gland proteins of the leech Branchellion torpedinis

Parasitism by the marine leech Branchellion torpedinis is known to cause disease and mortality in captive elasmobranchs and is difficult to control when inadvertently introduced into public aquaria. Preliminary characterization of the salivary gland transcriptome of B. torpedinis has identified anticoagulants, proteases, and immunomodulators that may be secreted into host tissues to aid leech feeding. This retrospective study examined antigen-specific serum IgM responses in captive zebra sharks Stegostoma fasciatum to leech salivary gland extract. Antibody response was examined by ELISA and Western blot assays in 20 serum samples from six zebra sharks, with a 5 year history of leech infection, and 18 serum samples from 8 captive bred zebra sharks, with no history of leech exposure. ELISA demonstrated significantly higher serum IgM titers to salivary gland extract in exposed zebra sharks compared to the non-exposed population. No obvious trends in antibody titers were appreciated in exposed zebra sharks over a four-year period. One-dimensional and two-dimensional Western blot assays revealed IgM targeted specific salivary gland proteins within the 40, 55, 70 and 90 kD range. Antigenic proteins identified by liquid chromatography-tandem mass spectrometry and de novo peptide sequencing include a secreted disintegrin, metalloproteinase and thrombospondin motif containing protein (ADAMTS), tubulin, aldehyde dehydrogenase and two unknown proteins. Humoral immune responses to leech salivary gland proteins warrants further investigation as there may be options to exploit immune mechanisms to reduce parasite burdens in aquaria.

First record of Trypanosoma sp. (Protozoa: Kinetoplastida) in tuvira (Gymnotus aff. inaequilabiatus) in the Pantanal wetland, Mato Grosso do Sul State, Brazil

The blood infection by Trypanosoma sp. in tuvira (Gymnotus aff. inaequilabiatus) from the Pantanal wetland was reported in this study. Ten fish from the Paraguay River in the Pantanal were evaluated for the presence of hemoflagellates. Trypomastigotes of Trypanosoma sp. were observed in blood smears from three fish (30% prevalence) and some forms were seen to be undergoing division. Using the diagnostic methods of fresh examination and blood centrifugation in hematocrit capillary tubes, the prevalence rate was 80%. This is the first report of Trypanosoma sp. in tuvira in Brazil.