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The Eurasian lynx (Lynx) is a medium-sized wild cat species distributed throughout Eurasia. There has been no report on Taenia species (Cestoda: Cyclophyllidea) infecting this felid in China. In this study, 24 tapeworms were found in two Eurasian lynxes (#1 and #2) in Xinjiang Uygur Autonomous Region (XUAR), northwestern China. Based on the number, measurements and the shape of rostellar hooks, these tapeworms belong to two Taenia species. According to the number (n = 32) and length (185–194 μm) of small hooks, the first Taenia species (n = 1, found in #2 lynx) was identified as Taenia laticollis. Phylogenetically, this species was clustered with T. laticollis genotype C (JX860623) based on its cytochrome c oxidase subunit 1 (cox1) and 16S rDNA sequences. The second Taenia species (n = 23, provisionally named as “Taenia sp.“) may represent a potentially novel tapeworm species, because of its obvious differences in the shape and lengths (174–182 μm, 98–113 μm) of large and small rostellar hooks in comparison with ten taxonomically related species. Molecular and phylogenetic analyses of the cox1 gene revealed that “Taenia sp.” has the highest rate of sequence identity (92.93%, 368/396 bp) with Taenia hydatigena reported from sheep (Ovis aries) in Slovakia. To sum up, a potentially novel tapeworm species, “Taenia sp.“, is found in Eurasian lynx. In addition, T. laticollis was found for the first time in China.

In this study, 263 tapeworms were collected from eight road-killed red foxes in Xinjiang Uygur Autonomous Region (XUAR, northwestern China). The tapeworms were analyzed based on morphological characters and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequences. Eighty-three Taenia and 180 Mesocestoides tapeworms were identified according to the presence or absence of rostellum, and the number, the length and the shape of the large rostellar hooks. The morphological and molecular analyses revealed that i) 180 Mesocestoides tapeworms, here named as Mesocestoides sp. (Vulpes vulpes), showed 99.21% (378/381 bp) identity to Mesocestoides sp. reported from red fox in Mongolia; and ii) 83 Taenia tapeworms belonged to three species. The first Taenia species [n = 16, named as Taenia sp. (Vulpes vulpes)], based on the length of large rostellar hooks (337–342 μm) and its cox1 sequence, was identified as a potentially novel species, which is phylogenetically close to Taenia laticollis. The second species [n = 54, named as Taenia sp. (Vulpes vulpes & Rhombomys opimus)], was morphologically similar to Taenia endothoracicus according to the number (n = 52), the length (319–332 μm) and the shape of the large rostellar hooks. This species, infecting three red foxes, shared 100% cox1 sequence identity with Taenia sp. (Rhombomys opimus) genotype C found previously in great gerbils (Rhombomys opimus) in the same region. The third species (n = 13, named as Taenia polyacantha-like), had shorter large rostellar hooks (178–180 μm) and showed 96.27% (361/375 bp) sequence identity to Taenia polyacantha reported from red fox in Italy. The “great gerbil-red fox” life cycle of Taenia sp. (Vulpes vulpes & Rhombomys opimus), belonging to the mitochondrial lineage of T. endothoracicus, is confirmed. The T. polyacantha-like species was firstly found in red fox in China. Taenia sp. (Vulpes vulpes) is a potentially novel species, which is close to T. laticollis based on its phylogenetic properties.

The Baltimore-Bullock's Oriole hybrid zone is one of the best-studied avian hybrid zones in North America, yet our understanding of the causes of selection against hybrids remains poor. We examine if endohelminth parasites may cause selection against hybrid orioles but found no evidence for this hypothesis. Of the 139 male orioles we examined, 43 individuals contained endohelminth parasites from at least 1 of these groups: Cestoda, Acanthocephala, or Nematoda. Across the hybrid zone, Baltimore Orioles (Icterus galbula) and Bullock's Orioles (I. bullockii) differed in their parasite communities, such that Baltimore Orioles frequently contained both Acanthocephala and Cestoda parasites whereas Bullock's Orioles primarily contained Cestoda parasites. Despite these differences in parasite communities between parental species, the frequency of hybrid orioles with parasites was similar to parentals, suggesting that hybrids were as susceptible to endohelminth parasites as parentals. Using a subset of 99 adult male orioles, we explored how parasites may be associated with the expression of orange carotenoid-based plumage in hybrids and parentals. Associations between carotenoid-based plumage color and parasites were most strongly expressed in Bullock's Orioles, but patterns were subtle and counterintuitive because individuals with parasites often had more enhanced color measures compared to individuals without parasites. Taken together, these data suggest that endohelminth parasites impose little fitness costs to male orioles on the breeding grounds and likely do not cause selection against hybrids. [ABSTRACT FROM AUTHOR]

Parasitic helminths with complex life cycles require multiple hosts in a particular order to complete their life cycles. Although almost all helminths infect invertebrates at some point in their life cycle, we know very little about which species of invertebrates harbor parasites compared with what is known for vertebrates. In New Zealand, <1% of marine invertebrates that may be expected to host parasites have records of parasite infections. This is a strong indication that our knowledge of invertebrate parasites within marine ecosystems is highly limited. Here, we provide the first comprehensive parasite–host checklist including data from the literature and newly discovered infections of parasitic helminths infecting marine invertebrates in New Zealand. Including both pre‐existing and newly found data from our survey, we present data on 73 parasite taxa (five acanthocephalans, 13 cestodes, nine nematodes, and 46 trematodes) infecting 62 marine invertebrate species in New Zealand. In addition, we compile existing and new genetic data for many of these parasites, as a useful tool for future studies of parasite biodiversity and phylogenetics. [ABSTRACT FROM AUTHOR]

We analyzed the diet and helminthological fauna of the frog Boana pulchella from the extreme south of Brazil. A total of 100 males were collected from two wetland areas in the state of Rio Grande do Sul: Ilha dos Marinheiros (n = 50) in the Rio Grande municipality, and the UFPel/ Embrapa (n = 50) in the Capão do Leão municipality. Boana pulchella food items and helminths found in different organs were identified and quantified. We analyzed the relationship between helminth assemblage and host diet, body size, and sampling sites. Boana pulchella presented a generalist diet, composed mainly of terrestrial insects, with diet richness higher at Ilha dos Marinheiros. Helminth fauna was composed of Nematoda, Cestoda, Digenea, and Acanthocephala, with no difference in helminth richness and abundance between sampling sites. However, the abundance of helminths presented a significant correlation with the volume of items found in the gastrointestinal contents of the anurans from UFPel/Embrapa-CL. Although for some helminth taxa there were significant differences in prevalence and mean intensity of infection among host size classes, the GLM (generalized linear model) between helminth abundance and anuran SVL (snout-vent length) was not significant. Oxyascaris oxyascaris, Cosmocercinae gen. spp., Ochoterenella sp., Diplostomidae gen. spp., Pseudoacanthocephalus sp., and Centrorhynchus sp. were the main taxa constituting the helminth assemblage associated to B. pulchella males at the sampling sites. The occurrence of helminths at larval and adult stages suggests that B. pulchella may occupy different trophic levels in the biological cycles of those helminths. This helminth parasitic fauna associated with B. pulchella is mainly composed of taxa with heteroxenous cycles involving several intermediate and paratenic hosts, which agrees with the observations of a typical generalist anuran diet in this species. [ABSTRACT FROM AUTHOR]

Parasitic worms (helminths) with complex life cycles divide growth and development between successive hosts. Using data from 597 species of acanthocephalans, cestodes, and nematodes with two‐host life cycles, we found that helminths with larger intermediate hosts were more likely to infect larger, endothermic definitive hosts, although some evolutionary shifts in definitive host mass occurred without changes in intermediate host mass. Life‐history theory predicts parasites to shift growth to hosts in which they can grow rapidly and/or safely. Accordingly, helminth species grew relatively less as larvae and more as adults if they infected smaller intermediate hosts and/or larger, endothermic definitive hosts. Growing larger than expected in one host, relative to host mass/endothermy, was not associated with growing less in the other host, implying a lack of cross‐host trade‐offs. Rather, some helminth orders had both large larvae and large adults. Within these taxa, however, size at maturity in the definitive host was unaffected by changes to larval growth, as predicted by optimality models. Parasite life‐history strategies were mostly (though not entirely) consistent with theoretical expectations, suggesting that helminths adaptively divide growth and development between the multiple hosts in their complex life cycles. [ABSTRACT FROM AUTHOR]

Introduction: Branchiopodataenia bazaletica sp. n. (Cestoda, Cyclophyllidea) is described from the black tern, Chlidonias niger L., after re-examination of material deposited in the helminthological collection of the Institute of Zoology, Ilia State University, Institute of Zoology in Tbilisi, Georgia. Methods: The cestodes were collected from Bazaleti Lake in Georgia and originally identified as Wardium cirrosa, as labeled on the slides. Cestodes were examined using light microscopy. Results: Detailed examination of the morphology of these specimens showed that they belong to the genus Branchiopodataenia and are described as a new species. The presence of 10 aploparaksoid hooks with an elongate handle, three testes, and chitinoid latch-like structure in the copulative part of the vagina support the assignment of the new species to Branchiopodataenia. The new species has rostellar hooks 48–52 in length, a long, armed cirrus, and long copulative part of the vagina. Branchiopodataenia bazaletica sp. n. differs from its congeners by the size of rostellar hooks and by the shape of the cirrus and vagina. [ABSTRACT FROM AUTHOR]

The Lecanicephalidea represents one of 11 currently recognized elasmobranch-hosted tapeworm lineages. It is quite speciose, with nearly 100 validly recognized species to date. Yet spermatozoon features have been fully characterized for only a single species; spermatozoon characters for a second species were previously included in a data matrix used to infer phylogenetic relationships among cestode orders, but data are limited and no images were provided. Specimens of Tetragonocephalum sp. were collected from the whipray, Urogymnus asperrimus 1, from the Solomon Sea off the Solomon Islands. The mature spermatozoa of Tetragonocephalum sp. are distinctly different from the other lecanicephalidean species for which spermatozoon ultrastructure has been thoroughly investigated. Tetragonocephalum sp. spermatozoa represent the Type IV (sensu Levron, 2010) morphology possessing a single axoneme, crested bodies, cortical microtubules running parallel to the axoneme, and nucleus, which is helical to the axoneme. Although spermatozoa for both lecanicephalideans examined to date are of the Type IV spermatozoon morphology, they differ in the number of crested bodies and cortical microtubules, the relative size of the spermatozoon—specifically as it relates to the nuclear region—and the presence or absence of the anterior spiral structure. Significant spermatozoon character variation is present across these 2 representatives of 2 lecanicephalidean families, indicating that additional studies of representatives of the other families in the order are needed to better understand the extent of character variation present in the Lecanicephalidea. Overall, spermatozoon ultrastructure is understudied in elasmobranch-hosted tapeworm lineages compared to other vertebrate-hosted tapeworm orders at both the species and family levels. [ABSTRACT FROM AUTHOR]

Metacestode infestation of Semibalanus balanoides (L., 1767) and Balanus crenatus Bruguiеre, 1789, collected in the Barents and White Seas and in the northern part of the Sea of Okhotsk in 2020 and 2021, respectively, was studied. A total of 313 S. balanoides from Mogilnaya Bay of Kildin Island (Barents Sea) and isolated mature wrinkled barnacles B. crenatus, two and four specimens from the Pechora Sea and Kandalaksha Bay of the White Sea, respectively, were examined in 2020. Metacestodes Fimbriarioides intermedia (Fuhrmann, 1913) (Cyclophyllidea, Hymenolepididae) were found in 1.0 ± 0.6% of S. balanoides in the Barents Sea with an invasion intensity (I. I.) of 2-5 specimens, and in one of two B. crenatus from the Pechora Sea (I. I. 15 specimens). For the first time, in both B. crenatus from the Pechora Sea, taken from the valves of the mussel Mytilus edulis, metacestodes Microsomacanthus sp. I (I. I. 13 and 20 specimens) with proboscis hooks 38-41 (39.4 ± 0.1) µm long and blades of 9.5-11 (10.7 ± 0.1) µm were obtained. One of four B. crenatus from the Kandalaksha Bay was infected with another Microsomacanthus sp. II (I. I. 19 specimens) with proboscis hooks 44.0-49.5 (45.7 ± 0.5) µm long and blades 14.0-16.0 (14.8 ± 0.07) µm long. A total of 362 S. balanoides were collected and dissected in Gizhiginskaya Bay of the northern part of the Sea of Okhotsk in 2021, of which 8.0 ± 1.4% were infected with F. intermedia metacestodes (I. I. 1-19 specimens). Study results of the infestation of S. balanoides on the Koni-Pyagin coast of the Sea of Okhotsk (according to the collections of 2006-2007) were supplemented and clarified. Description of metacestodes and the taxonomic affiliation of cysticercoids Microsomacanthus spp. are given., (© 2024. Pleiades Publishing, Ltd.)

The dominant helminths infecting spiny mice ( Acomys dimidiatus ) in the montane wadis of the Sinai Peninsula of Egypt are spirurid nematodes, notably Protospirura muricola and Mastophorus muris . Both are relatively large robust stomach worms that accumulate in hosts resulting in high worm burdens. To ascertain whether the presence of spirurid worms or their burdens alters the host's likelihood of infection with other helminth species, we analysed a database containing quantitative data on helminth parasites of these mice ( n = 431). This comprised of worm burdens recorded during 4 surveys, conducted at 4-year intervals, in 4 wadis, during late summer of each year. The presence of spirurid worms did not significantly alter species richness with other helminth species nor the likelihood of mice carrying other nematode species. However, there was a significant association, particularly of P. muricola , with the presence of intestinal stages of cestodes, and with the acanthocephalan Moniliformis acomysi . After controlling for intrinsic and extrinsic factors, mice harbouring spirurid worms had greater worm burdens of other helminths compared with mice without spirurids. Moreover, spirurid worm burdens showed a significant positive covariation with similarly adjusted species richness of other helminths, non-spirurid helminths, non-spirurid nematodes, oxyuroid nematodes and intestinal stage cestode worm burdens. We interpret these results as an indication that the key driver for co-occurrence of spirurids with other helminths is likely to be transmission via common arthropod hosts (for cestodes and acanthocephalans), but also that mice carrying the heavier spirurid worm burdens become more susceptible to directly transmitted nematodes such as the Oxyuroidea.

A total of 508 fish specimens belonging to 19 species collected in the coast of Şile region of the Black sea were examined to detect the presence of endohelminths. Of this, 357 (70.27%) were found to be infected with parasites. 15 distinct helminths species were recovered including four species of nematodes, seven digenean species, one species of cestodes and three species of acanthocephalans. It was also determined that the species of nematode Hysterothylacium aduncum was the most common parasite and the most diverse endohelminth fauna was found in Gobius niger and Solea vulgaris, with five species. Furthermore, it should be noted that Capillaria gracilis is reported for the first time from the Turkish coasts. The infection rates, hosts, and parasites are listed in this paper.

ABSTRACT The southern lapwing, Vanellus chilensis, is a bird frequently seen in most of Brazil. Although it is widely distributed in other Brazilian biomes, including some parts of the Brazilian Amazon, it has only been recorded in the western Amazonian state of Acre since 2000. We report the presence of intestinal parasites in individuals of V. chilensis from the Cazumbá-Iracema Extractive Reserve in Acre through a coproparasitological analysis. Seven of the nine sampled individuals were parasitized. We observed larvae of Strongyloides sp. (28.5% of the samples), and eggs of Ascaridia sp. (28.5%), Ancylostoma sp. (14.2%), and Choanotaenia sp. (42.8%). These parasites are reported for the first time parasitizing V. chilensis in Brazil. The parasitized birds may act as reservoirs and were recorded in a peridomicile area, which may facilitate their contact with domestic birds.

Recent advances have increased our understanding of the molecular machinery in the cytoskeleton of mammalian cells, in contrast to the case of tapeworm parasites, where cytoskeleton remains poorly characterized. The pertinence of a better knowledge of the tapeworm cytoskeleton is linked to the medical importance of these parasitic diseases in humans and animal stock. Moreover, its study could offer new possibilities for the development of more effective anti-parasitic drugs, as well as better strategies for their surveillance, prevention, and control. In the present review, we compile the results of recent experiments on the cytoskeleton of these parasites and analyze how these novel findings might trigger the development of new drugs or the redesign of those currently used in addition to supporting their use as biomarkers in cutting-edge diagnostic tests.

In the year 2012 a total of seven individuals (one bull and six cows) of European bison (Bison bonasus) were introduced to a fenced 200 ha area in a forest district (Almindingen, Island Bornholm, Denmark) in the Baltic Sea. In 2017 the herd was supplemented by introduction of another bull. The animals all originated from a population in the Polish Bialowieza forest. Faecal samples were recovered with intervals and subjected to a copro-parasitological investigation (applying egg flotation, sedimentation and Baermann technique). In addition, parasites were sampled during necropsy of animals euthanized or found dead three years after introduction. The animals carried a range of parasite types including trematodes (liver fluke Fasciola and rumen fluke), cestodes (Moniezia), nematodes (Dictyocaulus viviparus, trichurids , and other gastrointestinal nematodes (GIN) including Trichostrongylus axei and Haemonchus contortus). Egg and larval morphology also suggested presence of GIN genera Nematodirus, Ostertagia and Cooperia. The trematodes did not establish a life cycle in the recipient area, as judged by examination of calves born in the new area, but the cestode and several nematode species occurred in these animals. Especially Dictyocaulus viviparus was successfully spread and occurred together with GIN at moderate to high infection intensities at most sampling points. The reproduction among bison in the herd was high during the first few years. The exact birth rate is unknown but up to 24 calves are believed to be born during the ten year study period. Mortality among adults and calves occurred and in early June 2022 the total number of live animals was 11 (seven males, three females, one calf). The possible impact of the parasite infections on the bison health and future wildlife infection status is discussed. [Display omitted] • European bison used for translocation projects may carry parasites. • Translocated parasites species may establish in recipient regions. • Lungworm Dictyocaulus viviparus is persistent in European bison herds. • Gastrointestinal nematodes are spread with translocated bison. • Mortality in bison herds may be associated with high parasite burdens. [ABSTRACT FROM AUTHOR]

Phylogenetically or taxonomically related hosts may harbour similar parasite communities due to phylogenetic conservatism. In addition, host attributes may favour their exposure to parasites. This study aimed to characterize the helminth fauna of sigmodontine rodents in an Atlantic Forest area in northeastern Brazil and determine the pattern of the helminth metacommunity structure. The influence of host attributes and host taxonomy on the metacommunity structure was also investigated. The most abundant helminth species were Raillietina sp. and Hassalstrongylus lauroi. Euryoryzomys russatus was the most infected host species for helminth parasites, as approximately 81% (35/43) of the animals were infected by at least one helminth species. The helminth metacommunity structure was coherent at both the infracommunity and the component community scales, indicating that species responded to the same environmental gradient. A quasi-Clementsian pattern was observed for the infracommunities, indicating the occurrence of compartments of parasite species that were substituted along the environmental gradient, which was formed by host individuals. A quasi-Gleasonian pattern was found at the component community scale, showing random boundary clumping, which is consistent with the individualistic responses of parasite species to each host species. These patterns corroborated the high values of beta-diversity observed, indicating high species turnover among communities at both scales. Host taxonomic distance was the most important variable explaining the patterns of the helminth metacommunity structure. [Display omitted] • This is the first report of the helminth fauna of two sigmodontine rodents. • Rodent hosts had low levels of helminth species sharing among them. • Helminth species responded to the same environmental gradient in the metacommunity. • Helminths formed clusters that were replaced along their hosts at infracommunity scale. • Species showed random responses to one another at component community scale. [ABSTRACT FROM AUTHOR]

Three hymenolepidid species (Cyclophyllidea, Hymenolepididae) from anseriform birds are reported for the first time in Bulgaria (new geographical records). These are Diorchis asiatica Spasskii, 1963 from Tadorna ferruginea (Pallas) (new host record), Echinocotyle minutissima Singh, 1952 from Spatula querquedula (L.), and Fimbriarioides tadornae Maksimova, 1976 from Tadorna tadorna (L.). The species are redescribed and figured on the basis of newly-collected and voucher specimens from Bulgaria. The taxonomic status and the synonymy of D. asiatica are discussed. The authorship of Diorchis diorchis Burt & McLaughlin, 1975 is clarified and its position as a junior synonym of D. asiatica is justified. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this work was the morphological study of the onchoproteocephalidean cestodes from two shark species of the Persian Gulf. Methods: Several specimens of Rhizoprionodon oligolinx, as well as of Carcharhinus dussumieri, were collected from the Persian Gulf, and the isolated cestodes from them were studied morphologically by light and scanning electron microscopy. Results: Phoreiobothrium sarahae n. sp. and Phoreiobothrium iraniense n. sp. were isolated, respectively, from Rhizoprionodon oligolinx Springer and Carcharhinus dussumieri (Müller & Henle). Both species are quite distinct from their congeners, except for P. sorrahcola Masoumi Ganjgah & Haseli, 2020, in the distribution of the vitelline follicles (i.e., having more than two columns of vitelline follicles in each lateral band in the proglottids) and are distinguished from each other based on measurement, e.g., by the length of the cephalic peduncle, the width of the scolex at the level of hooks, and some measures related to the hooks. Phoreiobothrium iraniense n. sp. most closely resembles P. sorrahcola, earlier described from C. sorrah (Müller & Henle) from the Persian Gulf, with which it has an extensive overlap in the ranges of measurements and morphology. Nonetheless, it differs from P. sorrahcola in the length of the cephalic peduncle and possessing, rather than lacking, the gladiate spinitriches on the proximal bothridial surfaces. Conclusion: Along with the description of the two new species increasing the number of members of the genus in the Iranian coastal waters from three to five, for the first time a variation in distribution of the vitelline follicles is reported for Phoreiobothrium in this paper. [ABSTRACT FROM AUTHOR]

During the evolution of the Earth, the increase in the atmospheric concentration of oxygen gave rise to the development of organisms with aerobic metabolism, which utilized this molecule as the ultimate electron acceptor, whereas other organisms maintained an anaerobic metabolism. Platyhelminthes exhibit both aerobic and anaerobic metabolism depending on the availability of oxygen in their environment and/or due to differential oxygen tensions during certain stages of their life cycle. As these organisms do not have a circulatory system, gas exchange occurs by the passive diffusion through their body wall. Consequently, the flatworms developed several adaptations related to the oxygen gradient that is established between the aerobic tegument and the cellular parenchyma that is mostly anaerobic. Because of the aerobic metabolism, hydrogen peroxide (H2O2) is produced in abundance. Catalase usually scavenges H2O2 in mammals; however, this enzyme is absent in parasitic platyhelminths. Thus, the architecture of the antioxidant systems is different, depending primarily on the superoxide dismutase, glutathione peroxidase, and peroxiredoxin enzymes represented mainly in the tegument. Here, we discuss the adaptations that parasitic flatworms have developed to be able to transit from the different metabolic conditions to those they are exposed to during their life cycle. [ABSTRACT FROM AUTHOR]

Three subspecies of the ringed seal (Pusa hispida) are found in northeastern Europe: P. h. botnica in the Baltic Sea, P. h saimensis in Lake Saimaa in Finland, and P. h. ladogensis in Lake Ladoga in Russia. We investigated the poorly-known cestode helminth communities of these closely related but ecologically divergent subspecies using COI barcode data. Our results show that, while cestodes from the Baltic Sea represent Schistocephalus solidus, all worms from the two lakes are identified as Ligula intestinalis, a species that has previously not been reported from seals. The observed shift in cestode communities appears to be driven by differential availability of intermediate fish host species in marine vs. freshwater environments. Both observed cestode species normally infect fish-eating birds, so further work is required to elucidate the health and conservation implications of cestode infections in European ringed seals, whether L. intestinalis occurs also in marine ringed seals, and whether the species is able to reproduce in seal hosts. In addition, a deep barcode divergence found within S. solidus suggests the presence of cryptic diversity under this species name.

The production of environmentally friendly livestock products is currently receiving much attention, especially in the European Union. The problem of monitoring the quality and safety of meat and milk in modern conditions is relevant not only for Ukraine but also for the world community. The scientific substantiation of the methods of research on meat for sale subject to invasive diseases is especially important, as the product may pose risks to the consumer. One of the criteria for assessing the welfare of a herd is the prevalence of helminthiases in cattle. Ruminant parasitoses in Ukraine have always been and remain a separate, often significant, problem for veterinary specialists. Helminths have evolved to use a wide range of ecological niches. In this study, we tried to quantify the prevalence of helminthiases among ruminants (cattle, sheep and goats) in Ukraine. The relevant studies were searched for in the online databases. The meta-analysis included 15 publications from January 2015 to December 2020 which reported the spread of parasites in Ukraine. The research results show that the infestation of ruminants with gastrointestinal helminths on the territory of Ukraine is 56.7%. Egger’s regression test revealed no significant publication bias. During the period of pastured farming, stable parasitocenoses are formed in the body of ruminants. The parasitoses are caused by helminths (gastrointestinal strongyles, liver flukes, paramphistomas, dicrocelia). They are recorded in monoinvasions or mixed invasions. Ruminants, according to helminthological examination in different climatic zones, are constantly infested with trematodes. In Ukraine, the presence of three species of flukes has been confirmed in ruminants: Fasciola hepatica, Dicrocoelium dendriticum and Paramphistomum cervi. Parasitization by those species negatively affects the profitability of dairy farming. Trematodes cause significant economic losses: reduced milk productivity of cows, reduced live weight gain of young animals, negative impact on reproduction. At the same time, fascioliasis is socially significant and dangerous to humans. According to the analyzed literature sources, two types of cestodes have been registered in Ukraine: Moniezia benedeni and M. expansa. The epizootic situation regarding nematodes is just as fraught. That is the most numerous group of helminths, their fauna is represented by the following species: Strongyloides papillosus, Nematodirus spathiger, Bunostomum spp., Oesophagostomum radiatum, Haemonchus contortus, Toxocara vitulorum, Trichuris skrjabini, T. ovis and T. globulosa. It is proven that in cattle parasitocenoses are recorded more often than monoinvasions. The highest rates of prevalence of infection were observed when polyinvasion included gastrointestinal strongyles, namely from the order Strongylida. Strongyloides papillosus is the most common taxonomic representative, while Fasciola hepatica has the lowest prevalence of infection, especially in sheep. Updated data on helminthiasis will expand the screening strategy to maintain the health of farm ruminants and reduce economic losses.

Abstract As social insects, ants represent extremely interaction-rich biological systems shaped by tightly integrated social structures and constant mutual exchange with a multitude of internal and external environmental factors. Due to this high level of ecological interconnection, ant colonies can harbour a diverse array of parasites and pathogens, many of which are known to interfere with the delicate processes of ontogeny and caste differentiation and induce phenotypic changes in their hosts. Despite their often striking nature, parasite-induced changes to host development and morphology have hitherto been largely overlooked in the context of ecological evolutionary developmental biology (EcoEvoDevo). Parasitogenic morphologies in ants can, however, serve as “natural experiments” that may shed light on mechanisms and pathways relevant to host development, plasticity or robustness under environmental perturbations, colony-level effects and caste evolution. By assessing case studies of parasites causing morphological changes in their ant hosts, from the eighteenth century to current research, this review article presents a first overview of relevant host and parasite taxa. Hypotheses about the underlying developmental and evolutionary mechanisms, and open questions for further research are discussed. This will contribute towards highlighting the importance of parasites of social insects for both biological theory and empirical research and facilitate future interdisciplinary work at the interface of myrmecology, parasitology, and the EcoEvoDevo framework.

Ophiotaenia is the most diverse genus among proteocephalids, composed of species commonly found parasitizing snakes worldwide. However, the diversity of Ophiotaenia in the Neotropical region is still underestimated. This study describes Ophiotaenia karipuna n. sp. found parasitizing Erythrolamprus miliaris in the State of Amapá, Brazil. Additionally, we redescribe Ophiotaenia arandasi based on a re-examination of type series and newly collected material from Erythrolamprus taeniogaster in the State of Pará, Brazil. The new species differs from its congeners in the following characteristics: scolex width, number of testes, relative length of the cirrus–sac, absence of a vaginal sphincter, presence of a vestigial apical organ resembling a sucker, and relative size of the ovary in relation to the surface of the proglottid. Furthermore, we provide taxonomic information for Ophiotaenia arandasi not reported in the original description, including morphology of embryophore, uterine development, and the absence of the vaginal sphincter in the species. Ophiotaenia karipuna n. sp. represents the 21st- species described in snakes -from the Neotropical region and the first formally described in the Brazilian Amazon. Additionally, we provide the first ultrastructural analysis, a new host, and locality records for O. arandasi. [Display omitted] • New species of Ophiotaenia parasite of Amazonian snake. • Ophiotaenia karipuna is the -21st species described in snakes from Neotropics. • The first species described from the Amazon Region. • Redescription of Ophiotaenia arandasi. [ABSTRACT FROM AUTHOR]

Background: A central question in parasitology is why parasites mature and reproduce in some host species but not in others. Yet, a better understanding of the inability of parasites to complete their life cycles in less suitable hosts may hold clues for their control. To shed light on the molecular basis of parasite (non-)maturation, we analyzed transcriptomes of thorny-headed worms (Acanthocephala: Pomphorhynchus laevis), and compared developmentally arrested worms excised from European eel (Anguilla anguilla) to developmentally unrestricted worms from barbel (Barbus barbus). Results: Based on 20 RNA-Seq datasets, we demonstrate that transcriptomic profiles are more similar between P. laevis males and females from eel than between their counterparts from barbel. Impairment of sexual phenotype development was reflected in gene ontology enrichment analyses of genes having differential transcript abundances. Genes having reproduction- and energy-related annotations were found to be affected by parasitizing either eel or barbel. According to this, the molecular machinery of male and female acanthocephalans from the eel is less tailored to reproduction and more to coping with the less suitable environment provided by this host. The pattern was reversed in their counterparts from the definitive host, barbel. Conclusions: Comparative analysis of transcriptomes of developmentally arrested and reproducing parasites elucidates the challenges parasites encounter in hosts which are unsuitable for maturation and reproduction. By studying a gonochoric species, we were also able to highlight sex-specific traits. In fact, transcriptomic evidence for energy shortage in female acanthocephalans associates with their larger body size. Thus, energy metabolism and glycolysis should be promising targets for the treatment of acanthocephaliasis. Although inherently enabling a higher resolution in heterosexuals, the comparison of parasites from definitive hosts and less suitable hosts, in which the parasites merely survive, should be applicable to hermaphroditic helminths. This may open new perspectives in the control of other helminth pathogens of humans and livestock. [ABSTRACT FROM AUTHOR]

Echinococcosis is a zoonotic helminthiasis of humans and animals, caused by Echinococcus granulosus tapeworms. Treatment of echinococcosis is often expensive and complex and may require extensive surgery or long-term drug therapy. In addition, echinococcosis causes serious damage to livestock every year. At any given time in the world, more than 1 million people are affected by echinococcosis. Kazakhstan is among the countries unfavorable for echinococcosis. The purpose of this study is to establish the infection of sheep with cystic echinococcosis in the most endemic regions in the south and west of the country. In addition, to analyze statistical data on the incidence of human echinococcosis in the Republic of Kazakhstan for 2020-2021 to assess the current situation on echinococcosis. The situation with echinococcosis currently remains difficult. Echinococcosis is found in all regions of the republic, but the most endemic region is the south of Kazakhstan, which is a large livestock center. The highest rates of infection in sheep were found in the West Kazakhstan region and Almaty region - 16.7% and 12.52%. In terms of the incidence of people in the republic for a year and a half, 557 cases of larval echinococcosis have been identified. The highest rates are observed in Turkestan, Zhambyl, Almaty regions and in Shymkent. Echinococcosis is least common in Pavlodar, Kostanay regions and in the city of Nur-Sultan. The existing system of registration of patients with echinococcosis and statistical data do not fully reflect the real number of people infected with echinococcosis, since only surgical cases are taken into account. Monitoring of natural foci of echinococcosis is necessary, especially in the south, for coordinated disease control measures. [ABSTRACT FROM AUTHOR]

Helminths of 12 fish species collected near the South Orkney Islands, West Antarctica were studied. In the whole sample of 115 fish specimens, we identified one species of Monogenea, 5 species of Trematoda, 4 species of Cestoda, 5 species of Nematoda, and 7 species of Acanthocephala. All cestode species, 3 species of nematodes, and 5 species of acanthocephalans were represented only by larval stages; fish are definitive hosts for the remaining 10 helminth species. Details of composition and structure of helminth communities were studied in 3 fish species: Chaenocephalus aceratus (Lönnberg, 1906), Champsocephalus gunnari Lönnberg, 1905, and Pseudochaenichthys georgianus Norman, 1937, each represented by more than 20 specimens in a sample. In these hosts, 19, 8, and 16 helminth species were found, correspondingly. In the helminth communities of C. aceratus and P. georgianus, the highest values of the infection prevalence and abundance were recorded for larval cestodes (Diphyllobothrium sp., Tetrabothriidea), nematodes (Pseudoterranova sp., Contracaecum sp.), acanthocephalans (Corynosoma spp.), as well as adults of the trematode Neolebouria georgiensis Gibson, 1976. The same trematode species and larval cestodes predominated in the helminth community of C. gunnari. All recorded species of parasites are generalists, each known from a range of fish hosts in Antarctica. [ABSTRACT FROM AUTHOR]

A study of cestode specimens that were collected during survey work on elasmobranchs collected from Taiwan and Northern Territory, Australia, revealed the presence of 1 new combination into the genus Stillabothrium (Rhinebothriidea: Escherbothriidae) and 2 new species of the genus. Phyllobothrium biacetabulatum, collected from Rhinobatos schlegelii, is transferred to Stillabothrium and its description is emended, as is the diagnosis for the genus Stillabothrium and the family Escherbothriidae. Stillabothrium biacetabulatum n. comb. differs from existing species of the genus in that the face of its bothridia is laced with a network of longitudinal and horizontal muscle fibers that do not contribute to the formation of septa. Stillabothrium lunae n. sp. is described from Himantura leoparda and differs from existing species of the genus in that its bothridium possesses an anterior field of 7–8 loculi that are wider than long. Stillabothrium mariae n. sp. is described from Maculabatis astra. This species differs from all species of Stillabothrium except Stillabothrium campbelli in possessing 10–12 horizontally oriented bothridial loculi. Stillabothrium mariae n. sp. differs from S. campbelli in having longer bothridia and from all other species of Stillabothrium in that it lacks, rather than possesses, conspicuous septa and loculi that are longer than wide in the posterior region of its bothridia. Bayesian and parsimony-bootstrap analysis of 28S rDNA revealed S. biacetabulatum n. comb., S. lunae n. sp., and S. mariae n. sp. to be part of Clade 1 of Stillabothrium, with S. biacetabulatum n. comb. being the sister species to S. mariae n. sp. Stillabothrium lunae n. sp. was found to be the sister species to Stillabothrium borneoense. [ABSTRACT FROM AUTHOR]

Abstract: The presence of parasites in marine fish is a serious problem for the fishing industry in many countries. Some species of parasites can present a risk to consumers. Human health can be compromised by allergic reactions to parasitic antigens (hypersensitivity). The aim of the present study was to report the occurrence of parasite larvae in samples of frozen Alaskan fish fillets. A total of 108 samples of frozen Alaska pollock fish fillet were purchased from commercial establishments in the state of São Paulo - Brazil, from July 2017 to November 2019. The parasite search was carried out using the method dissection under transmitted light (candling table) according to AOAC (2005), method 985.12. Only 18 samples (17%), from four different brands, did not present any parasitic form, the others (90 samples) had at least one parasitic form, with the presence of cestodes of the order Trypanorhyncha (found in 73 samples) and nematodes of the Anisakidae family prevailing (found in 57 samples). It was also observed that more than half of the studied samples (76 samples) presented up to 5 parasitic forms in the kilogram rate. The results demonstrate the need for more data regarding the incidence of parasites in fish and their impact on human health, in order to alert the population and health authorities about its dangers, so that preventive and corrective measures are taken in the inspection process of these products, aiming to reduce any possibility of the occurrence of illnesses.

This is the first reported case of Bertiella mucronata infection in a black-and-gold howler monkey (Alouatta caraya) in Brazil. The present study confirms the widespread of B. mucronata in South America and suggest that black-and-gold howler monkeys may serve as viable reservoirs for B. mucronata., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Rodentolepis (sensu lato) asymmetrica (Janicki, 1904) is redescribed on the basis of materials from Microtus agrestis, Microtus arvalis and Myodes glareolus from Eastern Europe (Belarus, Lithuania, Latvia, Estonia, Ukraine and the north-eastern part of Russia). A new genus, Kontrimavichusia n. g., is proposed for it based on morphological and molecular evidence. The unique morphological diagnostic characters of this currently monotypic genus include the presence of an armature on the suckers, ventral osmoregulatory canals connected with irregularly spaced transverse anastomoses, an internal seminal vesicle with circular musculature and uterus with numerous diverticula, situated dorsally to the genital ducts, extending bilaterally beyond the longitudinal osmoregulatory canals. In addition, the new genus differs from morphologically related genera of the Rodentolepis clade by the structure of its vagina. The copulatory part of the vagina in specimens of Kontrimavichusia n. g. is surrounded by circular musculature and covered externally by a dense layer of intensely-stained cells; the conductive part of the vagina is clearly distinguishable from the seminal receptacle. Molecular analysis of the partial 28S rRNA gene fully supports the erection of Kontrimavichusia n. g. as a distinct lineage. [ABSTRACT FROM AUTHOR]

Plerocerci of the trypanorhynch cestode Progrillotia dasyatidis Beveridge, Neifar & Euzet, 2004 (Progrillotiidae) were isolated from the gallbladder of the three-spined stickleback Gasterosteus aculeatus from a small freshwater marsh in the Lake Atanasovsko Wetlands, a coastal area adjacent to the Black Sea coast, Bulgaria. The parasite was recorded in five out of 134 fish individuals studied (prevalence 3.73%, intensity 1–7, mean intensity 2.40 ± 1.17 and mean abundance 0.09 ± 0.06). A description of the plerocerci is presented, expanding data on intraspecific variation. The present report is the first record of P. dasyatidis from G. aculeatus (new host record) and from Bulgaria (new geographical record). Recording only plerocerci with evaginated scoleces in the sticklebacks is consistent with the hypothesis that teleosts are paratenic hosts and not intermediate hosts of P. dasyatidis. [ABSTRACT FROM AUTHOR]

The cestode Hymenolepis nana is a common parasite of humans and mice. Fecal shedding in the absence of clinical disease has previously been reported in ring-tailed lemurs (Lemur catta). This report describes fatal, disseminated H. nana cestodiasis infection in an aged ring-tailed lemur in a zoological collection. The parasites were associated with severe multifocal to coalescing and regionally extensive pyogranulomatous hepatitis and moderate multifocal pneumonia. The morphology of the parasites was highly unusual. Profiles were variably sized, ellipsoid to irregularly serpiginous, lined by a thin tegument, and filled with lightly eosinophilic fibrillar stroma and numerous, round basophilic cells. Polymerase chain reaction targeting a portion of the 18S rRNA gene and DNA sequencing of the amplicon showed 100% homology with H. nana. [ABSTRACT FROM AUTHOR]

In this study, 263 tapeworms were collected from eight road-killed red foxes in Xinjiang Uygur Autonomous Region (XUAR, northwestern China). The tapeworms were analyzed based on morphological characters and mitochondrial cytochrome c oxidase subunit 1 (cox1) gene sequences. Eighty-three Taenia and 180 Mesocestoides tapeworms were identified according to the presence or absence of rostellum, and the number, the length and the shape of the large rostellar hooks. The morphological and molecular analyses revealed that i) 180 Mesocestoides tapeworms, here named as Mesocestoides sp. (Vulpes vulpes), showed 99.21% (378/381 bp) identity to Mesocestoides sp. reported from red fox in Mongolia; and ii) 83 Taenia tapeworms belonged to three species. The first Taenia species [n = 16, named as Taenia sp. (Vulpes vulpes)], based on the length of large rostellar hooks (337–342 μm) and its cox1 sequence, was identified as a potentially novel species, which is phylogenetically close to Taenia laticollis. The second species [n = 54, named as Taenia sp. (Vulpes vulpes & Rhombomys opimus)], was morphologically similar to Taenia endothoracicus according to the number (n = 52), the length (319–332 μm) and the shape of the large rostellar hooks. This species, infecting three red foxes, shared 100% cox1 sequence identity with Taenia sp. (Rhombomys opimus) genotype C found previously in great gerbils (Rhombomys opimus) in the same region. The third species (n = 13, named as Taenia polyacantha -like), had shorter large rostellar hooks (178–180 μm) and showed 96.27% (361/375 bp) sequence identity to Taenia polyacantha reported from red fox in Italy. The "great gerbil-red fox" life cycle of Taenia sp. (Vulpes vulpes & Rhombomys opimus), belonging to the mitochondrial lineage of T. endothoracicus , is confirmed. The T. polyacantha -like species was firstly found in red fox in China. Taenia sp. (Vulpes vulpes) is a potentially novel species, which is close to T. laticollis based on its phylogenetic properties. [Display omitted] • The life cycle of Taenia sp. (Vulpes vulpes & Rhombomys opimus) is confirmed. • The Taenia polyacantha -like species was firstly found in China. • Taenia sp. (Vulpes vulpes) is a potentially novel species in China. [ABSTRACT FROM AUTHOR]

The Eurasian lynx (Lynx) is a medium-sized wild cat species distributed throughout Eurasia. There has been no report on Taenia species (Cestoda: Cyclophyllidea) infecting this felid in China. In this study, 24 tapeworms were found in two Eurasian lynxes (#1 and #2) in Xinjiang Uygur Autonomous Region (XUAR), northwestern China. Based on the number, measurements and the shape of rostellar hooks, these tapeworms belong to two Taenia species. According to the number (n = 32) and length (185–194 μm) of small hooks, the first Taenia species (n = 1, found in #2 lynx) was identified as Taenia laticollis. Phylogenetically, this species was clustered with T. laticollis genotype C (JX860623) based on its cytochrome c oxidase subunit 1 (cox1) and 16S r DNA sequences. The second Taenia species (n = 23, provisionally named as " Taenia sp.") may represent a potentially novel tapeworm species, because of its obvious differences in the shape and lengths (174–182 μm, 98–113 μm) of large and small rostellar hooks in comparison with ten taxonomically related species. Molecular and phylogenetic analyses of the cox1 gene revealed that " Taenia sp." has the highest rate of sequence identity (92.93%, 368/396 bp) with Taenia hydatigena reported from sheep (Ovis aries) in Slovakia. To sum up, a potentially novel tapeworm species, " Taenia sp.", is found in Eurasian lynx. In addition, T. laticollis was found for the first time in China. [Display omitted] • Taenia. laticollis was found for the first time in China. • " Taenia sp." is a potential novel tapeworm species found in Eurasian lynx. • Pairwise comparisons of the shape of the large rostellar hooks in Taenia sp. and the related species. [ABSTRACT FROM AUTHOR]

Purpose: The Antarctic dragonfish, Parachaenichthys charcoti is a notothenioid teleost fish endemic to the Southern Ocean surrounding Antarctica. It is a relatively rare fish species; therefore, published data on the parasite communities of P. charcoti are limited. The present study was performed on the Ukrainian Antarctic Station "Akademik Vernadsky", Argentine Islands, West Antarctica and the purpose was to examine the species diversity of the parasites of P. charcoti and to identify the parameters of helminth infection and helminth component community. Methods: Fifteen specimens of P. charcoti were caught at a depth of 10–30 m and examined using standard parasitological techniques. All helminths (6251 specimens) were collected manually, fixed in 70% ethanol and identified based on their morphology. Results: All examined specimens of P. charcoti were found to be infected with helminths; each fish harboured 10–20 helminth species (mean 13.2; median 13) and 237–804 helminth specimens (mean 417; median 401). Twenty-seven helminth species were found, including nine species of trematodes, 4 of cestodes, 4 of nematodes and 10 of acanthocephalans. P. charcoti is the definitive host for 11 out of 27 helminth species recorded. In the helminth component community, the diversity indices were 2.03 (Shannon's index) and 0.79 (Simpson's index); Pielou evenness index was 0.61, and Berger–Parker dominance index was 0.38. Conclusions: Our results indicate a high species diversity and complex structure of the helminth community in Antarctic dragonfish P. charcoti in the Argentine Islands. [ABSTRACT FROM AUTHOR]

Purpose: Endo-parasites of the bathypelagic king of herrings Regalecus glesne and oarfish Regalecus russelii are only known from few specimens opportunistically examined. As a consequence, there are few records of parasites from either Regalecus species. We report plerocercoid larvae of phyllobothriidean cestodes parasitizing an adult R. glesne stranded in Bahía de La Paz, Baja California Sur, Mexico. Methods: Sixty-three plerocercoids were obtained from the intestine of R. glesne and characterized using morphological and molecular methods (nuclear 28S rDNA and mitochondrial cytochrome c oxidase I gene sequences). Results: Following the morphological diagnostic criteria of scolex and muscle bands in the strobila, plerocercoids specimens were preliminary assigned to the genus Clistobothrium. Mitochondrial and nuclear DNA sequences indicate these plerocercoids correspond to Clistobothrium montaukensis Ruhnke, 1993. Conclusion: Regalecus glesne is a new host known for C. montaukensis and this report is a new geographical record of C. montaukensis parasitizing species of the genus Regalecus previously known only from California and Florida, USA. [ABSTRACT FROM AUTHOR]

Purpose: Studies of proteins expressed in the morphological structures of the parasite are necessary for elucidating the biological functions of unknown proteins and understanding the molecular basis of parasitism. The research aim was to investigate the spatial distribution of major proteins in scolex, immature and gravid proglottids of Triaenophorus nodulosus and Triaenophorus crassus. Methods: Protein extracts of worm body parts were analyzed using two-dimensional difference gel electrophoresis (DIGE) and mass spectrometry. Results: Comparison of the protein repertoire of the adult worm and the encysted plerocercoid revealed differences between the worm body parts, life stages and parasite species. The content of proteins associated with the cytoskeleton and musculature (actin, myosin regulatory light chain, and tropomyosin 2) decreased with distance from the scolex. Mature proglottids were rich in transforming growth factor-beta-induced protein, propionyl-CoA carboxylase, glutamate dehydrogenase and beta-tubulin. Interspecific variation in T. nodulosus and T. crassus was found in the content of the myosin, paramyosin, the major vault protein and an uncharacterized secreted protein TRINITY_DN24645. Differential expression of TRINITY_DN24645, paramyosin and tropomyosin 2 was found between plerocercoids and adult worms. Conclusion: The present study provides the first characteristics of the spatial distribution of the major proteins of T. crassus and T. nodulosus. Comparison of the protein composition of plerocercoids and adult parasites indicates a significant similarity in the proteomic organization of Triaenophorus sp. in the second intermediate and final hosts. The gradual change in the morphological organization of tapeworms in the longitudinal direction coincided with the expression of some structural and metabolic proteins. [ABSTRACT FROM AUTHOR]

Abstract Amphipods are often key species in aquatic food webs due to their functional roles in the ecosystem and as intermediate hosts for trophically transmitted parasites. Amphipods can also host many parasite species, yet few studies address the entire parasite community of a gammarid population, precluding a more dynamic understanding of the food web. We set out to identify and quantify the parasite community of Gammarus lacustris to understand the contributions of the amphipod and its parasites to the Takvatn food web. We identified seven parasite taxa: a direct life cycle gregarine, Rotundula sp., and larval stages of two digenean trematode genera, two cestodes, one nematode, and one acanthocephalan. The larval parasites use either birds or fishes as final hosts. Bird parasites predominated, with trematode Plagiorchis sp. having the highest prevalence (69%) and mean abundance (2.7). Fish parasites were also common, including trematodes Crepidostomum spp., nematode Cystidicola farionis, and cestode Cyathocephalus truncatus (prevalences 13, 6, and 3%, respectively). Five parasites depend entirely on G. lacustris to complete their life cycle. At least 11.4% of the overall parasite diversity in the lake was dependent on G. lacustris, and 16% of the helminth diversity required or used the amphipod in their life cycles. These dependencies reveal that in addition to being a key prey item in subarctic lakes, G. lacustris is also an important host for maintaining parasite diversity in such ecosystems.

The mature spermatozoon of Khawia armeniaca, a monozoic caryophyllidean parasite of templar fish Capoeta capoeta sevangi (De Filippi, 1865) from the Lake Sevan, Armenia, has been studied using transmission electron microscopy and cytochemical technique of Thiéry (1967) for the first time. The mature spermatozoon of K. armeniaca consists of a single axoneme with the 9+‘1’ trepaxonematan structure, cortical microtubules and nucleus which are situated parallel to the longitudinal axis of the spermatozoon, and a moderately electrondense cytoplasm with glycogen particles. The cortical microtubules are arranged in one continuous semicircle beneath the plasma membrane in Region II and anterior part of Region III of the mature spermatozoon. The two opposite rows of cortical microtubules are observed in the remaining nuclear and at the beginning of the postnuclear part (Regions III, IV) of the male gamete The number of cortical microtubules is remarkably variable in the spermatozoa of various Khawia species. K. armeniaca exhibits the highest number of cortical microtubules in comparison with K. sinensis and K. rossittensis. Glycogen was detected in the cytoplasm of prenuclear (II), nuclear (III) and postnuclear (IV) regions with different ultrastructural organization of the mature spermatozoon of K. armeniaca. Variations of sperm ultrastructural characters within caryophyllideans and other cestodes are discussed.

The study was conducted in 2016–2017 on three sites in the Belogorye State Nature Reserve (Russia) located in the forest-steppe zone. These sites are 1) «Les na Vorskle», upland oak (Quercus robur) forest; 2) «Ostrasyevy Yary», ravine oak forest, grass-meadow steppe; 3) «Yamskaya Step'», Sury valley, shrublands and forb meadow steppe, Eremkin Log valley, upland oak forest, forb meadow steppe. The small mammals investigated in this present parasitological study were caught using snap traps. These traps were established in lines of 50 or 100 traps per line. In addition, single traps and cone-shape pitfall traps (average length of 30 m) were used. The caught rodents (118 specimens) concern five species: Myodes glareolus, Microtus arvalis, Sylvaemus flavicollis, Sylvaemus uralensis, and Apodemus agrarius. The total prevalence by helminthes was 72%. About 91% of the Muridae animals were infected, while the prevalence of infestation was 55.6% among the Cricetidae specimens. We registered 20 helminth taxa belonging to three classes, six orders, and 12 families. Among the trematodes only eurixenous species were found. Among the cestodes, eurixenous species predominated. Among the nematodes, eurixenous and stenoxenous species were present in almost equal proportion. Dominant species are characterised by maximal values of prevalence of infestation. There were Hymenolepis sp. (17%) among Plathelminthes, species of Syphacia (35.6%) and Heligmosomoides (27.1%) among Nematoda, including Syphacia stroma (17%) and Heligmosomoides polygyrus (14.4%). The other helminth species registered in the present study were either small in number (with prevalence of invasion from 2% to 14%) or rare (with prevalence of invasion less than 2%). Platynosomum muris (Trematoda, Dicrocoeliidae) and Pterothominx sadovskoi (Nematoda, Capillariidae) were reported for the first time in the Central Chernozem Region of Russia.

Abstract Background The flatworms (Lophotrochozoa: Platyhelminthes) are one of the major phyla of invertebrates but their interrelationships are still not well understood including unravelling the most closely related taxon of the Neodermata, which includes exclusively obligate parasites of all main groups of vertebrates with some 60,000 estimated species. Recent phylogenomic studies indicate that the freshwater ‘microturbellarian’ Bothrioplana semperi may be the closest ancestor to the Neodermata, but this hypothesis receives little morphological support. Therefore, additional morphological and ultrastructural characters that might help understand interrelations within the Neodermata are needed. Methods Ultrastructure of the excretory ducts of representatives of the most basal parasitic flatworms (Neodermata), namely monocotylid (Monopisthocotylea) and chimaericolid (Polyopisthocotylea) monogeneans, aspidogastreans (Trematoda), as well as gyrocotylidean and amphilinidean tapeworms (Cestoda), were studied using transmission electron microscopy (TEM). Results The present study revealed the same pattern of the cytoarchitecture of excretory ducts in all studied species of the basal neodermatans. This pattern is characterised by the presence of septate junctions between the adjacent epithelial cells and lateral ciliary flames along different levels of the excretory ducts. Additionally, a new character was observed in the protonephridial terminal cell of Gyrocotyle urna, namely a septate junction between terminal and adjacent duct cells at the level of the distal extremity of the flame tuft. In Amphilina foliacea, a new type of protonephridial cell with multiple flame bulbs and unique character of its weir, which consists of a single row of the ribs, is described. A remarkable difference has been observed between the structure of the luminal surface of the excretory ducts of the studied basal neodermatan groups and B. semperi. Conclusions The present study does not provide ultrastructural support for a close relationship between the Neodermata and B. semperi.

In Brazil, when prevalence data were examined using simple summary statistics, there is a negative association between prevalence of Taenia spp. infection and Schistosoma mansoni or soil-transmitted helminths (STH) irrespective to routes of infection. That does not occur in African data. However, they vary considerably when plotted. So, in data collected on Brazilian area, it to show in ordered (smallest first) scores prevalence of STH infections both long lag phase in prevalence of STH infecting by oral route (Ascaris and Trichuris), and into STH infecting by skin route (hookworm and Strongyloides). To the other side, African study it show smaller lag phase in prevalence of STH infecting by oral route or into STH infecting by skin route. Darwinian, it was suggested Taenia spp. and STH, inhabiting a non-human environment which became so suitable for them according to their biological needs, their develop by means of natural selection.

Stable isotope analysis offers a unique tool for comparing trophic interactions and food web architecture in ecosystems based on analysis of stable isotope ratios of carbon (13C/12C) and nitrogen (15N/14N) in organisms. Clarias gariepinus were collected from six sites along the Vaal River, South Africa and were assessed for ectoparasites and endoparasites. Lamproglena clariae (Copepoda), Tetracampos ciliotheca and Proteocephalus glanduligerus (Cestoda), and larval Contracaecum sp. (Nematoda) were collected from the gills, intestine and mesenteries, respectively. Signatures of δ13C and δ15N were analysed in host muscle tissue and parasites using bulk stable isotope analysis. Variable stable isotope enrichment between parasites and host were observed; L. clariae and the host shared similar δ15N signatures and endoparasites being depleted in δ13C and δ15N relative to the host. Differences in stable isotope enrichment between parasites could be related to the feeding strategy of each parasite species collected. Geographic and spatial differences in enrichment of stable isotopes observed in hosts were mirrored by parasites. As parasites rely on a single host for meeting their nutritional demands, stable isotope variability in parasites relates to the dietary differences of host organisms and therefore variations in baseline stable isotope signatures of food items consumed by hosts.

The offspring of skate Bathyraja sp., caught in the environs of the Simushir Island (Greater Kuril Chain), were studied for infections and stomach contentment. Three species of cestodes: Onchobothrium sp., Pseudanthobothrium purtoni, and Phyllobothrium georgiense were found. Eight taxa of invertebrates were found in the stomach: seven amphipods Acanthostepheia behringiensis, Ampelisca eschrichtii, Eusirus cuspidatus, Gammaridea fam. gen. sp., Lysianassidae gen. sp., Oedicerotidae gen. sp., Stenothoidae gen. sp., and one isopod Arcturus crenulatus. The explosive increase in the number of cestodes infecting Bathyraja sp., has been caused by a change in the food spectrum, characterized by the appearance of bony fish. It is the first time that these three species of cestodes have been recorded in the Bathyraja (inhabiting the Northwestern Pacific). The obtained data expands knowledge on the feeding of skates, the fauna of cestodes of the North Pacific Ocean, and their final hosts, as well as coastal communities of the middle Kuril Islands that are poorly studied.

Abstract Background Few reports of Echinococcus spp. have been described in the USA; however, the geographical distribution of Echinococcus spp. in wild hosts is increasing consequent to human activities. In the early 2000’s, 253 elk (Cervus canadensis) originating from Alberta, Canada were released into the Great Smoky Mountains National Park and North Cumberland Wildlife Management Area in an effort to re-establish their historical range. Methods We investigated the prevalence of Echinococcus spp. in re-established elk populations in the North Cumberland Wildlife Management Area and the Great Smoky Mountains National Park via a retrospective analysis of banked elk tissues and helminth examinations on intestinal contents from coyotes (Canis latrans) from the North Cumberland Wildlife Management Area. Results Four elk were PCR and sequence positive for E. canadensis. Each sequence had 98% or greater coverage and identity to multiple E. canadensis genotypes on GenBank. Adult Echinococcus spp. were not detected in any of the coyotes examined in this study. Conclusions Continued surveillance of this disease in susceptible species in these areas is warranted, and these data further underscore the risk of zoonotic pathogen introduction secondary to wildlife translocation.

Abstract Background Parasites may mediate the success of biological invasions through their effect on host fitness and thus, on host population growth and stability. However, a release from the pressure of parasites is strongly related to the genetic differentiation of the host. In invasive host populations, the number of available genetic variants, allowing them to ‘fight’ the infection, are likely to be influenced by founder events and genetic drift. The level standing genetic variation of invasive populations may be crucial in successfully adapting to new environments and resisting diseases. We studied invasive populations of raccoon that experienced a random reduction in genetic diversity during the establishment and evaluated the relationship between host immune genetic diversity and intestinal parasites infection. Results We distinguished two different genetic clusters that are characterized by different sets of functionally relevant MHC-DRB alleles. Both clusters were characterized by considerably different allele-parasite associations and different levels of parasite infection. The specific resistance MHC-DRB alleles explained the lower prevalence of Digenea parasites. An increased infection intensity was related to the presence of two MHC-DRB alleles. One of these alleles significantly decreased in frequency over time, causing a decrease of Digenea abundance in raccoons in consecutive years. Conclusions Our findings suggest that intestinal parasites can exert selective pressure on an invasive host with lowered levels of immune genetic diversity and contribute to promoting local adaptation over time. The random genetic drift that created the two different genetic clusters in the invasive raccoon range imposed completely different MHC-parasite associations, strongly associated with the infection status of populations. Our findings underline the role of standing genetic variation in shaping host-parasite relationships and provide empirical support that functional genetic variation may be, at least partly, responsible for differences in the success of invasive populations.

Helminths of 12 fish species collected near South Orkney Islands, West Antarctica were studied. In the whole sample of 115 fish specimens, we identified one species of Monogenea, 5 species of Trematoda, 4 species of Cestoda, 5 species of Nematoda, and 7 species of Acanthocephala. All cestode species, 3 species of nematodes, and 5 species of acanthocephalans were represented only by larval stages; fish are definitive hosts for the remaining 10 helminth species. Details of composition and structure of helminth communities were studied in 3 fish species: Chaenocephalus aceratus (Lönnberg, 1906), Champsocephalus gunnari Lönnberg, 1905, and Pseudochaenichthys georgianus Norman, 1937, each represented by more than 20 specimens in a sample. In these hosts, 19, 8, and 16 helminth species were found, correspondingly. In the helminth communities of C. aceratus and P. georgianus, the highest values of the infection prevalence and abundance were recorded for larval cestodes (Diphyllobothrium sp., Tetrabothriidea), nematodes (Pseudoterranova sp., Contracaecum sp.), acanthocephalans (Corynosoma spp.), as well as adults of the trematode Neolebouria georgiensis Gibson, 1976. The same trematode species and larval cestodes predominated in the helminth community of C. gunnari. All recorded species of parasites are generalists, each known from a range of fish hosts in Antarctica.

The phylogenetic relationships within Neodermata were examined based on putative orthologous groups of proteins (OGPs) from 11 species of Monogenea, Trematoda, and Cestoda. The dataset included OGPs from BUSCO and OMA. Additionally, peptidases were identified and evaluated as phylogenetic markers. Phylogenies were inferred using the maximum likelihood method. A network analysis and a hierarchical grouping analysis of the principal components (HCPC) of orthologous groups of peptidases were performed. The phylogenetic analyses showed the monopisthocotylean monogeneans as the sister-group of cestodes, and the polyopisthocotylean monogeneans as the sister-group of trematodes. However, the sister-group relationship between Monopisthocotylea and Cestoda was not statistically well supported. The network analysis and HCPC also showed a cluster formed by polyopisthocotyleans and trematodes. The present study supports the non-monophyly of Monogenea. An analysis of mutation rates indicated that secreted peptidases and inhibitors, and those with multiple copies, are under positive selection pressure, which could explain the expansion of some families such as C01, C19, I02, and S01. Whilst not definitive, our study presents another point of view in the discussion of the evolution of Neodermata, and we hope that our data drive further discussion and debate on this intriguing topic.

The broad fish tapeworm, Dibothriocephalus latus (Diphyllobothriidea), is the most frequent causative agent of diphyllobothriosis, a fish-borne zoonosis, in Europe. Diphyllobothriosis is characterized by the transmission of D. latus larvae to humans via the consumption of raw, marinated, smoked or inadequately cooked fish products. The most important European foci of diphyllobothriosis have been Fennoscandia, the Baltic region, the Alpine lakes region, the Danube River region, and several endemic regions in Russia. This review provides basic data on the biology, life cycle, host specificity, methods of identification of D. latus, and a detailed summary of its occurrence in intermediate and definitive hosts in Fennoscandia and the Baltic, Alpine, and Danube regions during the last 120 years (1900-2020). Deeper insight into the unique pattern of distribution of D. latus in endemic regions is provided. The numbers of records are associated with several milestones of particular time periods. The first milestone (historical), which influenced studies on D. latus in Europe, was the period during and after World War II (1941-1950). The second milestone (epidemiological) was the decade 1981-1990, when previous massive health campaigns led to a marked decline of diphyllobothriosis in Europe and less published data on D. latus. Based on recent data, the broad fish tapeworm is either absent or present at very low prevalences in Fennoscandia and the Baltic and Danube regions, but the Alpine lakes region represents a continuous ongoing circulation of the parasite in the natural environment and humans. [ABSTRACT FROM AUTHOR]