Papers by Gergana Vasileva
<i>Citrilolepis</i> n. g. <i>Diagnosis</i> Cyclophyllidea, Hymenolepidida... more <i>Citrilolepis</i> n. g. <i>Diagnosis</i> Cyclophyllidea, Hymenolepididae. Body mediumsized. Scolex oval, covered by distinct microtriches. Rostellar apparatus musculo-glandular. Suckers round, muscular. Rostellum retractile, ovoid. Rostellar sheath oval, thick-walled, not reaching level of posterior margin of suckers. Rostellar hooks diorchoid, more than 10 in number, in single row. Neck long. Strobila with gradual maturation. Proglottides craspedote, much wider than long. Inner longitudinal muscle bundles numerous. Ventral osmoregulatory canals often with distinct irregular transverse anastomoses. Genital pores unilateral, sinistral. Genital ducts dorsal to osmoregulatory canals. Testes oval, usually three, rarely four or five per proglottis, arranged in transverse line, rarely in triangle; situated usually in two groups separated by female glands. Cirrus-sac elongate, thin-walled, situated near anterior proglottis margin, not reaching midline of proglottis. Cirrus cylindrical, armed. Female glands median. Ovary multilobate, median. Vitellarium median, with irregular shape, consisting of 3–4 compact, oval lobes, posterior to ovary. Seminal receptacle voluminous, convoluted. Vagina with thick-walled copulatory part, surrounded by thick cellular sleeve; ventral or posteroventral to cirrus-sac; lumen of copulatory part covered by hair-like microtriches. Young uterus narrow, tubular, transversely-elongated; with further development becoming labyrinthine, with numerous sacculations. Fully-developed uterus sacciform, thick-walled, occupying entire median field, not crossing lateral osmoregulatory canals. Eggs oval or elliptical, with thick embryophore. In Fringillidae (Passeriformes). <i>Type-species</i>: <i>Citrilolepis citrili</i> n. g., n. sp. <i>Etymology:</i> The name of the new genus is derived from the common English name (''citril'') of the typehost; '' <i>lepis</i> '' (Latin) - scale, a frequently used ending for names of cyclophyllidean cestode genera.
Systematic Parasitology, 2022
The type-species of the genus Diorchis Clerc, 1903, D. acuminata (Clerc, 1902) Clerc, 1903, is re... more The type-species of the genus Diorchis Clerc, 1903, D. acuminata (Clerc, 1902) Clerc, 1903, is re-described and illustrated on the basis of the type-material from Fulica atra L. from the Middle Ural, Russia, and new specimens from the same host species from Bulgaria. Since the type-series consists of specimens of two species, a syntype is designated as lectotype. The main differentiating characters of D. acuminata are the diorchoid rostellar hooks, 36-39 µm long, with a foliate epiphyseal thickening of the guard; cirrus-sac of variable length, usually reaching and often crossing the midline of proglottis, occasionally reaching antiporal osmoregulatory canals; evaginated cirrus with cylindrical basal part, bulbous middle part and pipette-like distal part; compact vitellarium situated dorsally to the ovary; copulatory part of vagina with muscular poral and middle portions and an antiporal sac-like reservoir; elongate eggs with polar filaments on their envelopes. The type-specimens of D. ransomi Johri, 1939 and D. longibursa Steelman, 1939 from Fulica americana Gmelin from USA are also re-examined and illustrated. Based on the present results, D. ransomi and D. longibursa are recognised as synonyms of D. acuminata. The previous records of the species are discussed. Diorchis acuminata is recognised as a specific parasite of Rallidae (mainly species of the genera Fulica and Gallinula) in the Holarctic.
... Page 124. 116 BB Georgiev, GP Vasit. eva, NH Chipev and ZM DimiTrova Strobila. Available long... more ... Page 124. 116 BB Georgiev, GP Vasit. eva, NH Chipev and ZM DimiTrova Strobila. Available longest strobila terminating with male proglottides; minute, delicate, 2.0-2.7 mm (2.3 mm, n= 7) long and 0.201-0.308 mm (0.263 mm. ... eva, NH Chipev and ZM DimiTrova Figs. 11-14. ...
Water, 2021
Further biogeographical studies of parasites are vital to improve our understanding of biodiversi... more Further biogeographical studies of parasites are vital to improve our understanding of biodiversity distribution and predict the impacts of global change. Hypersaline lakes are good laboratories to investigate the avian cestode abundance and species diversity given the abundance of hosts (waterbirds and Artemia) and their broad latitudinal distribution. We analysed cestode infection in brine shrimp Artemia franciscana in northern (Atacama) and central Chile and compared them to results from A. persimilis in southern Chile (Patagonia). Thus, we covered a broad latitudinal gradient from 23° to 53° S. Five cestode taxa including two species of the genus Flamingolepis, Gynandrotaenia stammeri, Eurycestus avoceti, and Fuhrmannolepis averini were recorded from A. franciscana in Atacama lagoons (prevalence = 4.1%). In contrast, no cestode infection was detected in central Chile, likely because they are temporary wetlands. Parasites of flamingos and shorebirds were associated with Atacama l...
from brine shrimps at the Mediterranean coasts of Spain and France, with a key to cestodes from A... more from brine shrimps at the Mediterranean coasts of Spain and France, with a key to cestodes from Artemia spp.
Systematic Parasitology, 2021
Neoskrjabinolepis (Neoskrjabinolepis) yanchevi n. sp. is described from common shrews Sorex arane... more Neoskrjabinolepis (Neoskrjabinolepis) yanchevi n. sp. is described from common shrews Sorex araneus L. (Eulipotyphla: Soricidae) from Pirin Mts., Bulgaria (type-locality) and Russia (Arkhangelskaya Oblast'). The new species is characterised by ten rostellar hooks 37-40 μm long and possessing claw-like blades with crooked middle parts and well-developed epiphyseal thickenings of handles; a whip-shaped cirrus, 80-100 μm long, consisting of basal region with numerous small, rosethorn-shaped spines, and middle and distal regions armed with fine, needle-shaped spines; vagina provided with sphincter close to its orifice, with copulatory and conductive part not clearly distinct from one another; 40-50 eggs per gravid uterus. The species is differentiated from the remaining 4 species of the nominotypical subgenus of the genus Neoskrjabinolepis, which are parasites of the Palaearctic shrews of the genus Sorex.
Journal of Science Natural Science, 2020
The study aimed to evaluate the role of transmitting flatworms (Cestoidea and Trematodea) of wild... more The study aimed to evaluate the role of transmitting flatworms (Cestoidea and Trematodea) of wild bird populations in three national parks of Vietnam: Xuan Son in the Northwest mountainous region, Tam Dao in the Northeast mountainous region, and Cat Ba in the Hong River Delta region. Twenty-two wild avian species of 10 families were found to contain parasitic flatworms. According to the number of avian species containing parasitic flatworms, bird families are ranking: Timaliidae recorded with 7 species > Leiothrichidae and Nectariniidae both with 3 species > Pycononotidae and Muscicapidae both with 2 species > Vireonidae, Sylvidae, Picidae, Cisticolidae and Cettiidae with 1 species. According to sex, avian populations containing parasitic flatworms decrease in the order: females accounting for 43.94% of the total individuals > males for 39.40% > juveniles for 16.66%. Three bird species containing flatworms A. pallidus, M. gularis and C. bayumas were found in two of th...
Parasitology Research, 2020
The hypersaline lagoons located in evaporation basins or salars (salt flats) in the Atacama Deser... more The hypersaline lagoons located in evaporation basins or salars (salt flats) in the Atacama Desert are extreme environments harbouring a specialised biota able to survive harsh conditions for life. The knowledge of the parasitic biodiversity of these extreme habitats is still scarce despite their functional importance in regulating relevant non-economic services like habitats of waterbirds. The present study is the first report on the cestode infection of Artemia franciscana Kellogg in Salar de Atacama lagoons in northern Chile. A total of 23 parasite larvae were isolated and identified as belonging to five cestode taxa of the order Cyclophyllidea: two species of the family Hymenolepididae, i.e. Flamingolepis sp. 1 and Flamingolepis sp. 2 (adults parasitic in flamingos); two species of Dilepididae, i.e. Fuhrmannolepis averini (adults parasitic in phalaropes) and Eurycestus avoceti (adult parasitic in charadriforms birds); and one species of Progynotaeniidae, i.e. Gynandrotaenia (?) stammeri (adult parasitic in flamingos). The cysticercoids of each species are described and figured. The study represents the first geographical record of the genera Eurycestus, Gynandrotaenia and Fuhrmannolepis in South America and the first report of Gynandrotaenia and Flamingolepis in A. franciscana in its native range. This survey also contributes to the knowledge of cestodes of Phoenicopteriformes and Charadriiformes and their life cycles in the Neotropical Region. A review of cestodes recorded in brine shrimps of the genus Artemia in the world is provided. Further studies on cestode fauna of aquatic birds and their intermediate hosts in hypersaline habitats of the Neotropical Region are needed to understand their functional role in such extreme and unique ecosystems.
PeerJ, 2019
The brine shrimp genus Artemia Leach (Crustacea, Branchiopoda), a keystone group in hipersaline w... more The brine shrimp genus Artemia Leach (Crustacea, Branchiopoda), a keystone group in hipersaline wetlands all over the world, offers an excellent model to study species interactions (parasitism) and to explore “hidden fauna” (avian endoparasites). The present study is the first report on the parasite infection of the South American species Artemia persimilis from the Southern Chilean Patagonia (50°S–53°S). Samples were collected in Los Cisnes and Amarga lagoons, the two most austral populations of this crustacean described to date, during two seasons (spring and autumn). A total of 98 larvae of cestodes of the family Hymenolepididae (Cestoda, Cyclophyllidea) were found and identified as belonging to the following taxa: Confluaria podicipina (adult parasitic in grebes), Flamingolepis sp. (a cestode parasite of flamingos), Fimbriarioides (?) sp. (adults of the species of this genus infect waterfowl and shorebirds) and Wardium sp. (definitive host unknown, most probably charadriiform bi...
Systematic Parasitology, 2019
Two new cestode species of the family Hymenolepididae Perrier, 1897 are described from birds of t... more Two new cestode species of the family Hymenolepididae Perrier, 1897 are described from birds of the order Passeriformes at Wondo Genet, Ethiopia. Passerilepis zimbebel n. sp., a parasite of Terpsiphone viridis (Müller) (Monarchidae), is distinguished from its most similar congeners by its diorchoid rostellar hooks with length 37-38 lm, its median ovary consisting of three compact lobes, its compact vitellarium and the variable position of the terminal genital ducts passing mostly dorsally to the poral osmoregulatory canals. Citrilolepis n. g. is erected as monotypic for C. citrili n. sp., a parasite of Crithagra citrinelloides (Rüpell) (Fringillidae). The new genus is distinguished from the remaining avian and mammalian genera of the family Hymenolepididae by the presence of numerous (18) rostellar hooks, unilateral sinistral genital pores, ventral osmoregulatory canals with transverse anastomoses, 3 (rarely 4, in c.10% of proglottides) testes in number with variable positions in the proglottis and the sac-like uterus not extending beyond the osmoregulatory canals. This article was registered in the Official Register of Zoological Nomenclature (ZooBank) as 51AF63BB-9A07-4C4C-B0E5-DB7D6C6726C2. This article was published as an Online First article on the online publication date shown on this page. The article should be cited by using the doi number. This is the Version of Record. This article is part of the Topical Collection Cestoda.
Parasitology Research, 2018
The aims of the study are to enrich the partial 28S rDNA dataset for hymenolepidids by adding new... more The aims of the study are to enrich the partial 28S rDNA dataset for hymenolepidids by adding new sequences for species parasitic in the genera Sorex, Neomys and Crocidura (Soricidae) and to propose a new hypothesis for the relationships among mammalian hymenolepidids. New sequences were obtained for Coronacanthus integrus, C. magnihamatus, C. omissus, C. vassilevi, Ditestolepis diaphana, Lineolepis scutigera, Spasskylepis ovaluteri, Staphylocystis tiara, S. furcata, S. uncinata, Vaucherilepis trichophorus and Neoskrjabinolepis sp. The phylogenetic analysis (based on 56 taxa) confirmed the major clades identified by Haukisalmi et al. (Zool Scr 39:631-641, 2010) based on analysis of 31 species: Ditestolepis clade, Hymenolepis clade, Rodentolepis clade and Arostrilepis clade; however, the support was weak for the early divergent lineages of the tree and for the Arostrilepis clade. Novelties revealed include the molecular evidence for the monophyly of Coronacanthus, the nonmonophyletic status of Staphylocystis and the polyphyly of Staphylocystoides. The analysis has confirmed the monophyly of Hymenolepis, the monophyly of hymenolepidids from glirids, the position of Pararodentolepis and Nomadolepis as sister taxa, the polyphyly of Rodentolepis, the position of Neoskrjabinolepis and Lineolepis as sister taxa, and the close relationship among the genera with the entire reduction of rostellar apparatus. Resolved monophyletic groups are supported by the structure of the rostellar apparatus. The diversification of the Ditestolepis clade is associated with soricids. The composition of the other major clades suggests multiple evolutionary events of host switching, including between different host orders. The life cycles of Coronacanthus and Vaucherilepis are recognised as secondarily aquatic as these taxa are nested in terrestrial groups.
Revue suisse de zoologie., 1998
Aquatic Invasions, 2015
The American brine shrimp Artemia franciscana Kellogg, 1906 is invasive in the Mediterranean regi... more The American brine shrimp Artemia franciscana Kellogg, 1906 is invasive in the Mediterranean region where it has displaced native populations of sexual A. salina and clonal A. parthenogenetica from many hypersaline wetlands. Brine shrimps are intermediate hosts of several cyclophyllidean avian cestodes, whose effects have been studied in native Artemia. However, determinants of these infections in the alien invader remain unknown. We present the most detailed study to date of parasitism of A. franciscana by cestodes in its invasive range, conducted in the Ebro Delta salterns (NE Spain) over a 33 month period, when a total of 9,293 A. franciscana adults and 8,902 juveniles were studied. We examined for first time whether host age and sex influence infection rates. Ten cestode species were recorded, with a total prevalence of 11.1% in adults and 2.7% in juveniles. The most abundant cestodes were Eurycestus avoceti (in adults) and Flamingolepis flamingo (in juveniles). Prevalence, abundance and intensity of infection were significantly higher in adults for four cestode species (Flamingolepis liguloides, Wardium stellorae, E. avoceti and Anomotaenia microphallos), and significantly higher in juveniles for F. flamingo. Mean cestode species richness was four times higher in adults. One cestode species (F. liguloides), was significantly more abundant in adult females than in adult males. Host age influences infection patterns which seem to be strongly related to the feeding behaviour of avian final hosts (filtering versus picking), suggesting complex ecological interactions among predators, prey and their parasites, with important implications for native biodiversity and ecosystem stability.
Systematic Parasitology, 2015
Diorchis thracica n. sp. (Cestoda, Cyclophyllidea, Hymenolepididae) is described from the ruddy s... more Diorchis thracica n. sp. (Cestoda, Cyclophyllidea, Hymenolepididae) is described from the ruddy shelduck Tadorna ferruginea (Pallas) (Aves, Anseriformes, Anatidae), collected in the vicinities of Radnevo, Stara Zagora Region, Bulgaria. The new species is differentiated from other members of Diorchis Clerc, 1903 by possessing rostellar hooks with length of 36 lm, a thick-walled cirrus-sac with strong longitudinal muscular fibres in its middle part and a copulatory vagina with two sphincters. Main morphological criteria for distinguishing species of the genus Diorchis are discussed.
Folia parasitologica, Jan 2, 2015
The present study is the first survey on the role of Artemia franciscana Kellogg as intermediate ... more The present study is the first survey on the role of Artemia franciscana Kellogg as intermediate host of helminth parasites in its native geographical range in North America (previous studies have recorded nine cestode and one nematode species from this host in its invasive habitats in the Western Mediterranean). Samples of Artemia franciscana were collected from four sites in the Great Salt Lake (GSL), Utah, across several months (June-September 2009). A. franciscana serves as intermediate host of five helminth species in this lake. Four of them are cestodes: three hymenolepidids, i.e. Confluaria podicipina (Szymanski, 1905) (adults parasitic in grebes), Hymenolepis (sensu lato) californicus Young, 1950 (adults parasitic in gulls), Wardium sp. (definitive host unknown, probably charadriiform birds), and one dilepidid, Fuhrmannolepis averini Spassky et Yurpalova, 1967 (adults parasitic in phalaropes). In addition, an unidentified nematode of the family Acuariidae was recorded. Confl...
Parasite, 1999
Cestode communities in Podiceps cristatus, P. grisegena, P. nigricollis and Tachybaptus ruficolli... more Cestode communities in Podiceps cristatus, P. grisegena, P. nigricollis and Tachybaptus ruficollis during their migrations and overwintering are studied at the Bulgarian Black Sea coast. The infracommunities exhibit high richness, abundance and dominance, and low diversity and similarity. The component communities have a similar taxonomic structure at the levels higher than species, a small number of core species and a high portion of grebe specialists in the richness and abundance. The comparison with cestode communities in grebes from Canada (Stock & Holmes, 1987) reveals several differences and similarities. The higher richness and abundance of the infracommunities in Canada are explained by the constant conditions of breeding habitats enhancing higher transmission rates. At the component community level, there is a significant difference between the two species lists. The degree of parasite exchange among the grebe species in Bulgaria is lower. Several characters of cestode component communities in grebes do not depend on either historical factors or different habitats. These are the similar patterns of the taxonomic structure at the levels higher than species, almost the same list of generalists, the participation of specialists of anatids, and the leading role of grebe specialists in the structure.
A survey of cestodes (Platyhelminthes: Cestoda) recorded from the waterfowl (Aves: Anseriformes) ... more A survey of cestodes (Platyhelminthes: Cestoda) recorded from the waterfowl (Aves: Anseriformes) in Bulgaria is presented. Up to now, 52 cestode species of the order Cyclophyllidea, belonging to the families Dilepididae (3 species) and Hymenolepididae (49 species), have been recorded from various localities in the country. As hosts of cestodes, 16 wild waterfowl species were recorded. The most species-rich cestode assemblages have been recorded in Anas platyrhynchos (26 species), A. querquedula (20) and A. crecca (14); 18 and 9 cestode species were recorded in domestic ducks and geese, respectively.
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Papers by Gergana Vasileva