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[Display omitted] • Strong mitonuclear discordance in phylogeny and evolutionary rates were found in Neodermata. • Polyopisthocotylea may have the fastest-evolving mtDNA sequences in Bilateria. • Polyopisthocotylea exhibits a long stem branch in the mtDNA, but not in the nDNA topology. • We found weak evidence of mitonuclear co-evolution and none for compensatory evolution. • A large (≈6.3 kb) numt in Diplorchis sp. exhibits signs of ncRNA expression. The genomic evolution of Polyopisthocotylea remains poorly understood in comparison to the remaining three classes of Neodermata: Monopisthocotylea, Cestoda, and Trematoda. Moreover, the evolutionary sequence of major events in the phylogeny of Neodermata remains unresolved. Herein we sequenced the mitogenome and transcriptome of the polyopisthocotylean Diplorchis sp., and conducted comparative evolutionary analyses using nuclear (nDNA) and mitochondrial (mtDNA) genomic datasets of Neodermata. We found strong mitonuclear discordance in the phylogeny of Neodermata. Polyopisthocotylea exhibited striking mitonuclear discordance in relative evolutionary rates: the fastest-evolving mtDNA in Neodermata and a comparatively slowly-evolving nDNA genome. This was largely attributable to its very long stem branch in mtDNA topologies, not exhibited by the nDNA data. We found indications that the fast evolution of mitochondrial genomes of Polyopisthocotylea may be driven both by relaxed purifying selection pressures and elevated levels of directional selection. We identified mitochondria-associated genes encoded in the nuclear genome: they exhibited unique evolutionary rates, but not correlated with the evolutionary rate of mtDNA, and there is no evidence for compensatory evolution (they evolved slower than the rest of the genome). Finally, there appears to exist an exceptionally large (≈6.3 kb) nuclear mitochondrial DNA segment (numt) in the nuclear genome of newly sequenced Diplorchis sp. A 3′-end segment of the 16S rRNA gene encoded by the numt was expressed, suggesting that this gene acquired novel, regulatory functions after the transposition to the nuclear genome. In conclusion, Polyopisthocotylea appears to be the lineage with the fastest-evolving mtDNA sequences among all of Bilateria, but most of the substitutions were accumulated deep in the evolutionary history of this lineage. As the nuclear genome does not exhibit a similar pattern, the circumstances underpinning this evolutionary phenomenon remain a mystery. [ABSTRACT FROM AUTHOR]

Ivanovcestus yakiae gen. et sp. nov. was collected from specimens of the batoid Sympterygia bonapartii from waters off Río Negro and Buenos Aires Provinces, in the Argentine Sea. Ivanovcestus gen. nov. is assigned to the Rhinebothriidea for their possession of facially loculated bothridia borne on stalks and a cirrus covered by spinitriches. The new genus is unique in the arrangement of loculi and septa on the distal bothridial surface. The molecular analysis based on 18S and 28S rDNA of two specimens of the new species identified Ivanovcestus gen. nov. as a member of the family Escherbothriidae, with our study representing the first record of this family in the Argentine Sea. The proposed new genus requires a new amended diagnosis for the Escherbothriidae, to include a new pattern of loculi and septa for the distal bothridial surface, as well as a new host. In addition, the present study proposes to transfer two species of Rhinebothrium , originally described parasitizing the skate Sympterygia lima in the Chilean Sea (i.e., Rhinebothrium chilensis and Rhinebothrium leiblei), to Ivanovcestus gen. nov. Examination of the original descriptions and type material revealed several morphological characters that justify the relocation of both species to the new genus. [ABSTRACT FROM AUTHOR]

[Display omitted] • MicroRNA, miR-71, knockdown was achieved in whole cestode worms. • miR-71 in Mesocestoides vogae larvae controls strobilation. • miR-71 is important for parasitic infection establishment in the experimental host. • miR-71 target genes showed upregulation after miR-71 knockdown. Parasites belonging to the class Cestoda include zoonotic species such as Echinococcus spp. and Taenia spp. that cause morbidity and mortality in endemic areas, mainly affecting pastoral and rural communities in low income countries but also upper middle income countries. Cestodes show remarkable developmental plasticity, implying tight regulation of gene expression throughout their complex life cycles. Despite the recent availability of genomic data for cestodes, little progress was made on postgenomic functional studies. MicroRNAs (miRNAs) are key components of gene regulatory systems that guide diverse developmental processes in multicellular organisms. miR-71 is a highly expressed miRNA in cestodes, which is absent in vertebrates and targets essential parasite genes, representing a potential key player in understanding the role of miRNAs in cestodes biology. Here we used transfection with antisense oligonucleotides to perform whole worm miRNA knockdown in tetrathyridia of Mesocestoides vogae (syn. Mesocestoides corti) , a laboratory model of cestodes. We believe this is the first report of miRNA knockdown at the organism level in these parasites. Our results showed that M. vogae miR-71 is involved in the control of strobilation in vitro and in the establishment of murine infection. In addition, we identified miR-71 targets in M. vogae , several of them being de-repressed upon miR-71 knockdown. This study provides new knowledge on gene expression regulation in cestodes and suggests that miRNAs could be evaluated as new selective therapeutic targets for treating Neglected Tropical Diseases prioritised by the World Health Organization. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mitochondrial and morphometric data were used to delimit Transversotrema species. • Almost all species of Transversotrema are shown to be morphologically cryptic. • Molecular data proved the only reliable basis for Transversotrema identification. • Ten new species are described for fishes of the tropical Indo-west Pacific. • Transversotrema is the richest trematode genus infecting Australian marine fishes. Species of Transversotrema Witenberg, 1944 (Transversotrematidae) occupy a unique ecological niche for the Trematoda, living externally under the scales of their teleost hosts. Previous studies of the genus have been impeded partly by limited variation in ribosomal DNA sequence data between closely related species and partly by a lack of morphometrically informative characters. Here, we assess richness of the tropical Indo-west Pacific species through parallel phylogenetic and morphometric analyses, generating cytochrome c oxidase subunit 1 mitochondrial sequence data and morphometric data for hologenophore specimens from Australia, French Polynesia, Japan and Palau. These analyses demonstrate that molecular data provide the only reliable basis for species identification; host distribution, and to a lesser extent morphology, are useful for identifying just a few species of Transversotrema. We infer that a combination of morphological simplicity and infection site constraint has led to the group displaying exceptionally low morphological diversification. Phylogenetic analyses of the mitochondrial data broadly support previous systematic interpretations based on ribosomal data, but also demonstrate the presence of several morphologically and ecologically cryptic species. Ten new species are described, eight from the Great Barrier Reef, Australia (Transversotrema chrysallis n. sp., Transversotrema daphnidis n. sp., Transversotrema enceladi n. sp., Transversotrema hyperionis n. sp., Transversotrema iapeti n. sp., Transversotrema rheae n. sp., Transversotrema tethyos n. sp., and Transversotrema titanis n. sp.) and two from off Japan (Transversotrema methones n. sp. and Transversotrema panos n. sp.). There are now 26 Transversotrema species known from Australian marine fishes, making it the richest trematode genus for the fauna. [ABSTRACT FROM AUTHOR]

Alveolar echinococcosis (AE) is a life-threatening zoonotic infection caused by Echinococcus multilocularis , an intestinal cestode of carnivorous animals (mostly canids). Its life cycle includes an adult stage in the intestines of carnivores and a larval stage (metacestode) in tissues of herbivores or omnivores. Humans are accidental/aberrant hosts and harbor the metacestode only. The disease presents as a continuously growing tumor-like liver mass with local or metastatic spread to distant organs, with mortality approaching 90% if untreated or partially treated. Diagnosis is based on characteristic imaging, serology and histopathology, and confirmation by nucleic acid amplification test. The geographical distribution of E. multilocularis covers most of the northern hemisphere, with human cases in Europe, Japan, Central Asia, and now North America. The recent establishment of a new parasite strain that is pathogenic to humans in Canada and the United States poses an emerging medical and public health threat and warrants a reassessment of our approach to this parasite. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new family in the tapeworm order Rhinebothriidea is erected. • Four new species of Mixobothrium are described from three species of endangered sawfish and one of their relatives. • The Mixobothriidae n. fam. are characterized by bothridia with three distinct regions. • Morphology and a phylogenetic analysis that includes new 28SrDNA sequence data support establishment of the new family. • A long-standing mystery about the evolutionary affinities of an undescribed lineage of rhinebothriideans is resolved. The parasites of hosts of conservation concern are often poorly known. This is the case with the iconic group of elasmobranchs known as the sawfish of the genus Pristis , all four species of which are considered as Endangered or Critically Endangered by the International Union for Conservation of Nature (IUCN, Switzerland). Examination of cestodes from three species of sawfish (Pristis pristis , Pristis clavata , and Pristis zijsron) in Australia and one of their close relatives, the also critically endangered widenose guitarfish, Glaucostegus obtusus , in India, collected over the past 25 years, yielded four new species of tapeworms which are described herein. All four belong to the previously monotypic Mixobothrium ; the diagnosis of the genus is revised to accommodate the new species. Among the new taxa is a species that had been included in previous molecular phylogenies but whose identity and affinities within the order Rhinebothriidea, and thus also its familial placement, were unclear. This species exhibits the morphological features of Mixobothrium and thus its identity is, at long last, revealed. Sequence data generated for the 28S rDNA gene for three of the new species, as well as an additional new but yet undescribed species from Pristis pectinata from Florida (USA), confirms the uniqueness of this group among the rhinebothriideans. The new family Mixobothriidae is established to house these taxa. The members of this family differ from all but one of the five other families of rhinebothriideans in lacking apical suckers on their bothridia. They are also distinctive in that their bothridia are divided into three regions. The anterior and posterior regions have similar locular configurations to one another and differ from the locular configuration of the middle region. As a consequence, the bothridia are symmetrical along both their vertical and horizontal axes. We predict that a focus on species of guitarfish in the genus Glaucostegus will be the most productive approach for discovering additional diversity in this family of cestodes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Parasitic organisms exhibit remarkable diversity in their life cycles. • Less than an estimated 5% of marine parasite life cycles are resolved. • New insights into the life cycle of parasites in a New Zealand coastal ecosystem are provided. • Host species and taxa most important for parasite life cycles were identified. • This study acts as a starting point to understand how parasites travel through natural systems to complete their life cycles. Parasitic helminths exhibit remarkable diversity in their life cycles, although few parasite species have their whole life cycles resolved. Owing to the fact that parasite life stages within hosts are often not comparable using morphological data, genetic data provides convincing evidence of transmission pathways between intermediate and definitive hosts. We took this approach to an ecosystem level, genetically matching parasite (acanthocephalan, cestode, nematode and trematode) life stages across a broad taxonomic range of intermediate and definitive hosts (invertebrates, seabirds, elasmobranchs and teleost fish) in Otago's (New Zealand) coastal marine ecosystem. We identified which transmission routes are utilized by the most parasite species and assessed which intermediate hosts are most important in facilitating the transmission of parasites in this ecosystem. Our findings reveal 59 new records of larval parasites infecting their respective intermediate hosts and 289 transmission pathways utilized by 35 helminth species to complete their life cycles. Sprat, triplefin and arrow squid all hosted the highest number of larval parasite species, suggesting they play important roles as intermediate hosts. We then used the new life cycle data to provide a synthetic overview of the life cycles known for various parasite groups in New Zealand. This study highlights how studying parasite life cycles can enhance our understanding of the ecology and evolution of parasites and hosts in natural systems, beyond simply resolving life cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • – Genomic resources provide classical molecular markers for advancing cestode alpha-taxonomy. • – Molecular phylogenetics supports the existence of multiple species of Proteocephalus in salmonid fishes. • – European and North American whitefish host two different species of Proteocephalus. • – Proteocephalus exiguus and P. fallax , two species previously synonymised with P. longicollis , are resurrected. High-throughput sequencing strategies became commonly employed to study non-model parasites, but the corresponding genomes and transcriptomes were seldom mined following the original publication. Similar to the data generated with genome skimming techniques based on shallow-depth shotgun genomes, various genomic and transcriptomic resources can be screened for useful molecular phylogenetic markers traditionally characterised with Sanger sequencing. Here, we provide an example of a strategy using reduced-representation genomic as well as transcriptomic data to obtain broad insights into the molecular diversity of the cestode Proteocephalus longicollis , a common parasite of salmonids distributed throughout the Holarctic region. We extract popular mitochondrial and nuclear ribosomal markers from various genomic resources for hundreds of parasite specimens from multiple European whitefish populations and compare those with Proteocephalus representatives from other species of salmonids and various geographical regions. In contrast with the previous morphology-based assessments, molecular phylogeny reveals a high degree of genetic divergence between Proteocephalus isolates from different salmonids, contrastingly low genetic differentiation within the parasite's populations hosted by the European whitefish (Coregonus lavaretus species complex), and a sister species relationship of Proteocephalus from European whitefish and Proteocephalus percae , a parasite of European perch (Perca fluviatilis). Proteocephalus spp. from North American lake whitefish, brown trout and Arctic charr each formed clearly distinct lineages. These results advance our understanding of the interrelationships of the Proteocephalus -aggregate, a well-recognized clade of Holarctic freshwater fish proteocephalids, and support resurrection of some of the nominal species of Proteocephalus , including Proteocephalus exiguus La Rue, 1911 from North American coregonids and Proteocephalus fallax La Rue, 1911 from European C. lavaretus , reserving Proteocephalus longicollis (Zeder, 1800) exclusively for parasites of Salmo trutta. [ABSTRACT FROM AUTHOR]

[Display omitted] • Four spliced leader (SL)-RNAs are indiscriminately trans -spliced throughout the life cycle of Hymenolepis microstoma. • Trans -splicing of polycistronic transcripts represents a minor proportion of events. • Trans -splicing of monocistrons is associated with the acceptor sites of introns in the 5′ untranslated regions. • Internal trans -splicing can result in isoforms with different predicted localizations. • SL insertions can be used to improve existing gene models. Spliced leader (SL) trans -splicing is a key process during mRNA maturation of many eukaryotes, in which a short sequence (SL) is transferred from a precursor SL-RNA into the 5′ region of an immature mRNA. This mechanism is present in flatworms, in which it is known to participate in the resolution of polycistronic transcripts. However, most trans -spliced transcripts are not part of operons, and it is not clear if this process may participate in additional regulatory mechanisms in this group. In this work, we present a comprehensive analysis of SL trans- splicing in the model cestode Hymenolepis microstoma. We identified four different SL-RNAs which are indiscriminately trans -spliced to 622 gene models. SL trans -splicing is enriched in constitutively expressed genes and does not appear to be regulated throughout the life cycle. Operons represented at least 20% of all detected trans -spliced gene models, showed conservation to those of the cestode Echinococcus multilocularis , and included complex loci such as an alternative operon (processed as either a single gene through cis -splicing or as two genes of a polycistron). Most insertion sites were identified in the 5′ untranslated region (UTR) of monocistronic genes. These genes frequently contained introns in the 5′ UTR, in which trans -splicing used the same acceptor sites as cis -splicing. These results suggest that, unlike other eukaryotes, trans -splicing is associated with internal intronic promoters in the 5′ UTR, resulting in transcripts with strong splicing acceptor sites without competing cis-donor sites, pointing towards a simple mechanism driving the evolution of novel SL insertion sites. [ABSTRACT FROM AUTHOR]

The tapeworm Dipylidium caninum is the most widely distributed cestode infecting dogs, cats, and sometimes humans, worldwide. The diagnosis of the infection caused by D. caninum is achieved via the visualization of proglottids in feces or with traditional microscopic tests, but both lack sensitivity. The present study has evaluated and compared the diagnostic performance of a PCR protocol on different feline biological samples to detect D. caninum. A sample of feces, a Scotch tape test from the perianal area, and a rectal swab were collected from a total of 100 privately owned cats from Italy and Greece. All fecal samples were subjected to macroscopic examination and to floatation. Based on the results of the above tests the cats were divided in three groups, i.e. (i) cats positive for D. caninum (regardless of positivity for other endoparasites (Group A; n = 50 cats), (ii) cats negative for D. caninum but infected by other helminths (Group B; n = 25 cats), and (iii) cats negative for intestinal endoparasites (Group C; n = 25 cats). For each sample, the DNA was extracted from feces, floatation supernatant, Scotch tape test and rectal swabs and subjected to PCR. For 33 cats from Group A, at least one sample type scored positive at PCR. Of these, all were PCR-positive in the floatation aliquot, while nine and one cats were positive by PCR on feces and Scotch tape test, respectively. Swabs were negative by PCR for all the cats. None of the samples from cats of Groups B and C was positive by any PCR. Sequences obtained from amplicons generated from samples of cats enrolled in Italy had 99–100 % identity with the recently described D. caninum feline genotype. The data presented here suggest that PCR could be a useful tool for diagnosing D. caninum infections, under certain circumstances, e.g. when proglottids are unidentified, unseen or overlooked, even though it has limitations, e.g. false negative results due to fecal PCR inhibitors, uneven distribution of parasitic elements, or to intermittent proglottid and/or egg shedding. Thus, it may not be, currently, the best diagnostic choice for dipylidiosis. • The zoonotic tapeworm Dipylidium caninum affects companion animals worldwide. • The diagnosis of dipylidiosis is difficult due to limitations in sensitivity. • The study compared the diagnostic performance of different methods to detect D. caninum. [ABSTRACT FROM AUTHOR]

Gastrointestinal parasites in stray cats are of significant clinical and zoonotic importance and pose a potential threat to public health. Hence, the current review has practical implications as it aims to present the diversity and the prevalence of cat parasites in Middle Eastern countries. The research process was rigorous and thorough, spanning from 2000 to 2023. Data collection and analysis were conducted utilizing multiple international and national databases, including Google Scholar, Scopus, PubMed, and Irandoc. This meticulous approach ensures the reliability and validity of the findings, providing a solid foundation for further research and preventive measures. A total of 159 articles were collected and comprehensively reviewed. Among these, 85 articles were from Iran, 25 from Türkiye, 20 from Iraq, 11 from Egypt, five from Qatar, three from Cyprus, three from Kuwait, and one each from the UAE, Saudi Arabia, Syria, Lebanon, Jordan, Israel, and Palestine. Toxocara cati was the most prevalent nematode, exhibiting the highest prevalence in Iran, ranging from 8% to 90%, followed by Egypt, with a range of 8.23% to 58.7%. In comparison, the lowest prevalence was recorded in Qatar at 8%. Hydatigera taeniaeformis , a common cestode in the feline, showed the highest prevalence in Qatar, with a range of 73.6% to 75.8%, while the lowest was in Kuwait at 0.8%. In Iran, the prevalence ranged from 0.9% to 64.7%. Toxoplasma gondii , a cosmopolitan protozoan, showcased the highest prevalence in Lebanon at 78.1% and the lowest in the UAE at 0.8%. In Iran, the prevalence ranged between 1.2% and 90%. Additionally, noteworthy patterns regarding the distribution and potential risk factors associated with these parasites were observed. While gender variations were not significant, environmental conditions such as high humidity and absence of sunlight exposure, along with the age and behavior of cats, were among the risk factors associated with the prevalence of parasites. The prevalence of parasites among stray cats in Iran and other Middle Eastern countries remains notably high. This emphasizes the urgent need for a series of control and preventive measures. Implementing effective anti-parasitic strategies and emphasizing the development of multiple diagnostic methods are essential. [ABSTRACT FROM AUTHOR]

A new genus, Cordicestus , is proposed to accommodate proteocephalid tapeworms parasitising gars (Lepisosteiformes: Lepisosteidae) in North and Central America that were previously placed in the polyphyletic genus Proteocephalus Weinland, 1858. The new genus differs from other proteocephalid genera by the particular morphology of the scolex, which is small, protrudes apically but has no apical organ, and bears flat, heart-shaped (= cordis) suckers. In addition, the species of the new genus have an elongated cirrus sac with an almost straight internal vas deferens and wide, sinuous ventral osmoregulatory canals with secondary canals directed outwards. The type species of the new genus, Cordicestus singularis (La Rue, 1911) n. comb., is redescribed based on new material from the shortnose gar, Lepisosteus platostomus Rafinesque (type host), and the spotted gar, L. oculatus Winchell, in the United States. Cordicestus rafaeli n. sp. is described from the tropical gar, Atractosteus tropicus Gill, in Mexico. The new species differs from its relatives primarily by the presence of craspedote proglottids (acraspedote in other species) and some biometric features. All species of Cordicestus are revised, including unidentified specimens from A. tropicus and the Cuban gar A. tristoechus (Bloch and Schneider) in Nicaragua and Cuba, respectively, which may be new species, and a key to the identification of these taxa is provided. Molecular data available for two nominal species of the new genus indicate the possible existence of another species of Cordicestus in Lepisosteus in the USA. [ABSTRACT FROM AUTHOR]

A new genus, Laruella n. gen., is proposed for the proteocephalid cestode L. perplexa (La Rue, 1911) n. comb. (syn. Proteocephalus perplexus La Rue, 1911), a parasite of a 'living fossil', the bowfin (Amia calva), in North America. The new genus is differentiated from other proteocephalid genera by having a massive four-lobed scolex without an apical organ and bearing suckers possessing tear-shaped sphincters on their inner rim, vitelline follicles forming L-shaped lateral fields, with the vitellarium turned inwards (medially) ventrally alongside the posterior margin of the ovary, a ring-like vaginal sphincter situated at a considerable distance from the genital atrium, and ellipsoid eggs resembling those of bothriocephalid and diphyllobothriid tapeworms, except for the absence of an operculum. Phylogenetic relationships of the new genus are not resolved, but it belongs to the so-called Neotropical clade of the Proteocephalidae, which is composed mainly of Neotropical tapeworms of siluriforms and other teleosts, but also Nearctic and Palaearctic species of Ophiotaenia La Rue, 1911 from snakes and amphibians. A morphologically similar species, Proteocephalus ambloplitis (Leidy, 1887) from bass (Micropterus spp.) in North America, is provisionally retained in Proteocephalus Weinland, 1858 because its relationships to L. perplexa are not yet clear. The former species differs from L. perplexa by the presence of a large apical organ, large, elongate vaginal sphincter situated near the genital atrium, vitelline follicles limited to lateral longitudinal fields, strongly coiled vas deferens within the cirrus sac, and a convoluted vaginal canal anterior to the ovarian isthmus. Laruella perplexa reportedly has a s broad spectrum of hosts but most are likely postcyclic or accidental hosts. A list of cestode parasites reported from bowfin is provided; it includes eight species and three taxa not identified to the species level. However, only three adult cestodes, L. perplexa and two species of Haplobothrium Cooper, 1914, are typical tapeworm parasites of bowfin, but previous molecular studies indicate possible existence of a putative new species in bowfin. [Display omitted] • A new genus, Laruella n. gen. (Cestoda), is proposed for Proteocephalus perplexus , a parasite of a 'living fossil' Amia calva. • Laruella perplexa new comb. is redescribed and a list of cestode parasites of bowfin is provided. • Only three adult cestodes, L. perplexa and two species of Haplobothrium , are considered as typical parasites of owfin. • Molecular studies indicate possible existence of (a) putative new species of fish tapeworm(s) in bowfin. [ABSTRACT FROM AUTHOR]

A new cestode species of the genus Echeneibothrium van Beneden, 1850 was collected from a rajiform skate in the Argentine Sea: Echeneibothrium cristinae sp. nov. parasitizing Bathyraja cousseauae Díaz de Astarloa & Mabragaña, 2004, from coastal waters off Tierra del Fuego Province. This species differs from congeners by a particular combination of the following features: total length, number of proglottids, number of loculi and presence of a medial longitudinal septum on the distal bothridial surface, length of bothridial stalks, size of the cirrus sac, position of the ovarian isthmus and course of the vagina. In addition, two known Echeneibothrium species, originally reported in Dipturus chilensis (Guichenot, 1848) from the Chilean Sea, were collected from a new host in the Argentine Sea: Echeneibothrium multiloculatum Carvajal & Dailey, 1975 and Echeneibothrium williamsi Carvajal & Dailey, 1975, parasitizing the rajiform skate Dipturus brevicaudatus (Marini, 1933) from coastal waters off Buenos Aires Province (E. multiloculatum) and Patagonia (both species). Emendations were made to the descriptions and redescriptions of these species, including the modification of measurement ranges for several characters and the addition of important morphological information omitted in previous studies. Finally, a phylogenetic analysis based on morphological characters was performed to determine the inter-relationships within the family Echeneibothriidae, this study being the first to consider representatives of all known genera belonging to that family. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cestode genomes contain six SIRT-encoding genes classified into classes I, III and IV. • Class I SIRTs are the most expressed in several developmental stages of Echinococcus. • SIRT2 inhibitor Mz25 has a strong cestocidal activity in Mesocestoides vogae larvae. • Mz25 cestocidal activity is irreversible and time- and dose-dependent. Anti-parasitic treatment of neglected tropical diseases caused by cestodes such as echinococcosis and cysticercosis relies on a small number of approved anthelmintic drugs. Furthermore, the treatment is usually prolonged and often partially effective and not well tolerated by some patients. Therefore, the identification of novel drug targets and their associated compounds is critical. In this study, we identified and characterised sirtuin enzymes in cestodes and evaluated the cestocidal potential of sirtuin inhibitors as new cestocidal molecules. Sirtuins are a highly conserved family of nicotinamide-adenine dinucleotide-lysine deacylases involved in multiple cellular functions. Here, we described the full repertoire of sirtuin-encoding genes in several cestode species. We identified six sirtuin-encoding genes that were classified into sirtuins Class I (SIRT1, SIRT2, and SIRT3), Class III (SIRT5), and Class IV (SIRT6 and SIRT7). In Echinococcus spp., sirtuin genes showed transcriptional expression throughout several developmental stages, sirtuin 2 (SIRT2) being the most expressed. To evaluate the potential of sirtuin inhibitors as new cestocidal molecules, we determined the in vitro effect of several Class I sirtuin inhibitors by motility assay. Of those, the selective SIRT2 inhibitor Mz25 showed a strong cestocidal activity in Mesocestoides vogae (syn. Mesocestoides corti) tetrathyridia at various concentrations. The Mz25 cestocidal activity was time- and dose-dependent with a half-maximal inhibitory concentration value significantly lower than that of albendazole. Additionally, Mz25 induced extensive damage in the general morphology with marked alterations in the tegument and ultrastructural features. By homology modelling, we found that cestode SIRT2s showed a high conservation of the canonical sirtuin structure as well as in the residues related to Mz25 binding. Interestingly, some non-conservative mutations were found on the selectivity pocket (an Mz25-induced structural rearrangement on the active site), which represent a promising lead for developing selective cestode SIRT2 inhibitors derived from Mz25. Nevertheless, the Mz25 molecular target in M. vogae is unknown and remains to be determined. This report provides the basis for further studies of sirtuins to understand their roles in cestode biology and to develop selective sirtuin inhibitors to treat these neglected tropical diseases. [ABSTRACT FROM AUTHOR]

Cysticercosis is caused by Taenia solium, a cestode or tapeworm that preferentially affects the subcutaneous tissue, brain, muscle, and the eye. It is traditionally a disease of low socioeconomic regions, but large-scale population migration has made it a matter of global concern. Its ocular invasion is a potentially blinding disease. In the last two decades, there has been considerable discussion of cysticercosis; however, most comes from a limited number of case observations. Thus, to overcome this limitation, we summarize and analyze twenty years of medical literature (from 2000 to 2020) on cysticercosis in ophthalmology. [ABSTRACT FROM AUTHOR]

Objective: This study aims to search for reliable serological biomarkers allowing the early prediction of cystic echinococcosis (CE) post-operative outcomes.Methods: We applied immunoprecipitation (IP) of Echinococcus granulosus protoscolex antigens with pediatric CE patients' plasma collected at 1-month and 1-year post-surgery, followed by Liquid Chromatography with tandem mass spectrometry (LC-MS/MS). We compared IP proteomic content from relapsed patients within the first-year post-surgery (RCE) to cases with no relapses until 3 post-operative years (NRCE). Selected proteins were recombinantly synthesized and assessed for their prognostic performance by Enzyme-linked immunosorbent assay (ELISA).Results: A total of 305 immunoreactive parasitic proteins were identified, 59 of which were significantly more abundant in RCE than NRCE for both time-points. Four proteins showed the most promising characteristics for predicting CE outcomes: cytoplasmic malate dehydrogenase (Eg-cMDH), citrate synthase (Eg-CS), annexin A6 and severin. ELISA-IgG against the four markers were significantly lower at 1-year post-surgery than 1-month in NRCE, in contrast to RCE that displayed either stable or higher levels. The Eg-cMDH and Eg-CS showed the best prognostic performance, with respective probabilities of being "relapse-free" of 83% and 81%, if a decrease of IgG levels occurred between 1-month and 1-year post-surgery.Conclusion: The Eg-cMDH and Eg-CS are promising biomarkers to predict early CE post-surgical outcomes. [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]

[Display omitted] • The first tegument ultrastructure of Echinococcus ortleppi protoscoleces was reported. • A 3D reconstruction of tegumental territories in protoscoleces was obtained. • A novel structure, termed the 'tegumental vesicular body' (TVB), was described. • The TVB was suggested to be involved in possibly endocytic/exocytic routes. • An endocytic route for host proteins across the tegument was suggested. Cystic echinococcosis is a globally distributed zoonosis caused by cestodes of the Echinococcus granulosus sensu lato (s.l.) complex, with Echinococcus ortleppi mainly involved in cattle infection. Protoscoleces show high developmental plasticity, being able to differentiate into either adult worms or metacestodes within definitive or intermediate hosts, respectively. Their outermost cellular layer is called the tegument, which is important in determining the infection outcome through its immunomodulating activities. Herein, we report an in-depth characterization of the tegument of E. ortleppi protoscoleces performed through a combination of scanning and transmission electron microscopy techniques. Using electron tomography, a three-dimensional reconstruction of the tegumental cellular territories was obtained, revealing a novel structure termed the 'tegumental vesicular body' (TVB). Vesicle-like structures, possibly involved in endocytic/exocytic routes, were found within the TVB as well as in the parasite glycocalyx, distal cytoplasm and close inner structures. Furthermore, parasite antigens (GST-1 and AgB) were unevenly localised within tegumental structures, with both being detected in vesicles found within the TBV. Finally, the presence of host (bovine) IgG was also assessed, suggesting a possible endocytic route in protoscoleces. Our data forms the basis for a better understanding of E. ortleppi and E. granulosus s.l. structural biology. [ABSTRACT FROM AUTHOR]

The first survey of caryophyllidean tapeworms parasitising catostomid and cyprinid fish in Mexico is provided, including new host and geographical records. Isoglaridacris brevicollis n. sp. is described from the Nazas sucker, Catostomus nebuliferus Garman (type host), in Durango, C. bernardini Girard in Sonora, and Moxostoma austrinum Bean (Cypriniformes: Catostomidae) in Jalisco. The new species differs from congeners mainly in the shape of the scolex, which is rounded, and by the absence of a defined neck (distinct, often long in other congeners). Pseudoglaridacris confusa found in Ictiobus meridionalis (also a member of the family Catostomidae) from Oaxaca and Veracruz represents the southern-most report of species of this Nearctic genus. Three morphotypes of the Holarctic Archigetes Leuckart, 1878 were found in two leuciscid fishes (Notropis caliensis and N. nazas) and in silverside Chirostoma sp. (Atherinidae). It is the first record of any caryophyllidean in atheriniform fish. The first record of Khawia japonensis (Yamaguti, 1934) (syn. K. iowensis Calentine et Ulmer, 1961), a parasite of common carp (Cyprinus carpio L.), in Mexico represents another evidence of its invasive potential. The caryophyllidean fauna of Mexican freshwater fish is depauperate compared to that in the United States and Canada, which seems to be related to a much lower number of species of suckers (Catostomidae) occurring in Mexico, possibly also to the lower number of fish in the population. [Display omitted] • We present the first systematic survey of caryophyllidean tapeworms (Cestoda) in Mexico. • A new species of Isoglaridacris is described from endemic suckers (Catostomidae). • This is the first report of any caryophyllidean from atheriniform fish. • Khawia japonensis , a parasite of common carp, is reported as an invasive species in Mexico. [ABSTRACT FROM AUTHOR]

Cysticercus fasciolaris (C. fasciolaris) is the larval stage of a cestode parasite named Taenia taeniaeformis (T. taeniaeformis). C. fasiolaris is found in small rodents, especially rats. Rattus species are listed as intermediate hosts of this parasite, and cats are the main definitive host of C. fasiolaris. The objective of this study was to study the pathological, microscopic, and molecular aspects of C. fasciolaris in rodents residing in human residence areas. One hundred and two rodents were trapped in human settlements and dissected for larva-containing cyst examinations in the body cavity. The larvae of C. fasciolaris were investigated using histopathological examination, microscopic observations under a stereomicroscope and scanning electron microscope, and molecular detection using polymerase chain reaction. The prevalence of hepatic cysts containing larvae was 8.91% (95% CI = 4.16–16.24). In addition, the older larvae also had longer micropapillae. Histopathological investigation revealed normal hepatic tissue containing larvae and a scanty fluid cyst. The cyst capsule contains mostly mononuclear cells and spindle cells in all infected rats. The molecular detection using two primer sets revealed the amplicons were similar to the clade of C. fasciolaris. In the future, more investigation is necessary to fully understand the parasite's molecular pathogenesis and virulent molecules, which are less obvious. • The prevalence of Cysticercus cysts in the livers of captured rats was 8.91%. • Cysticercus fasciolaris larvae were coiled in fluid space, surrounded by a fibrous cyst wall embedded in the liver parenchyma. • The infected liver tissues presented the filtration of mononuclear cells with no liver parenchyma change. • The rostellum, hook, and micropapillae structures of C. fasciolaris can be used to determine larval development. • The partial sequences of 28 S rRNA and COI genes that were obtained in this study matched T. taeniaeformis. [ABSTRACT FROM AUTHOR]

Tapeworm infection in horses can cause serious health concerns, and recent data have documented treatment failures in the most common species, Anoplocephala perfoliata. The threat of anthelmintic resistance in A. perfoliata is of particular concern because of poor diagnostic performance of standard egg counting techniques for detecting this parasite. This study compared the performance of three diagnostic techniques 1) Mini-FLOTAC, 2) Cornell-Wisconsin, and 3) Proudman and Edwards used to detect and quantify A. perfoliata eggs in naturally infected horses. Eighteen adult female horses from the University of Kentucky's historic parasitology herd were included in this study. Fecal samples were collected from all horses at five collection time points two weeks apart and analyzed with the three techniques. A total of 90 samples were collected and 270 counts determined in the study. The proportions of positive samples determined by the three techniques were significantly different from each other (p<0.05): Mini-FLOTAC (16%), Cornell-Wisconsin (47%), and Proudman and Edwards (70%). The Proudman and Edwards technique counted consistently higher numbers of tapeworm eggs compared to the other two techniques throughout the study [p < 0.05]. Total raw counts of tapeworm eggs across the study for each technique were 16, 88, and 410 for the Mini-FLOTAC, Cornell-Wisconsin, and Proudman and Edwards, respectively. This study demonstrated that the Proudman and Edwards technique was superior in diagnosing A. perfoliata infection. Future work needs to assess this technique's potential for Fecal Egg Count Reduction Testing (FECRT). • Mean counts of each technique did not change significantly over the study period. • Proudman and Edwards' technique had the highest percent positive counts. • 65.6% of all eggs counted were attributed to 33.3% (6/18) of the horses. • All techniques performed statistically differently from each other. • The Cornell-Wisconsin technique considerably outperformed the mini-FLOTAC technique. [ABSTRACT FROM AUTHOR]

[Display omitted] • This is the first known study on extracellular vesicles of the model tapeworm Hymenolepis diminuta. • Subsequent stages of shedding of microvesicles from the tegument were observed using TEM. • A role of dense bodies in biogenesis of "chain-forming" specific subtype of extracellular vesicles (EVs) was indicated. • Parasite- and host-origin proteins identified in EVs were purified from cultivation medium. • Potential drug targets and vaccine candidates were detected. We provided the first known evidence of the presence and release of extracellular vesicles in adults of important model tapeworm Hymenolepis diminuta. Two different subtypes have been observed on the surface of the worm and among the secretory products confirmed by several microscopical methods. Proteomic analysis revealed the presence of parasite-specific proteins as well as those of the host in purified extracellular vesicles. Among the protein cargo, we identified potential drug targets, vaccine candidates and H. diminuta antigens. Finally, the protein composition further revealed proteins participating in the endosomal complex required for transport-dependent biogenesis pathway. [ABSTRACT FROM AUTHOR]

Ophiotaenia echidis n. sp. (Cestoda: Proteocephalidae) is described from the intestine of one of the world's deadliest snakes, the saw-scaled viper Echis carinatus sochureki Stemmler (Ophidia: Viperidae) in the United Arab Emirates. The new species differs from other species of the non-monophyletic Ophiotaenia by the position of testes in two longitudinal lines on both sides of the uterus, and by the large size of an embryophore (diameter of 44–55 μm versus less than 40 μm in other species). Phylogenetic reconstructions based on lsr DNA and concatenated lsr DNA + COI datasets place the new species among proteocephalids from unrelated zoogeographical realms but mostly infecting venomous snakes. In all analyses, O. echidis n. sp. exhibited a strongly supported sister relationship with O. lapata Rambeloson, Ranaivoson et de Chambrier, 2012, a parasite of a pseudoxyrhophiid snake endemic to Madagascar. Despite a shared close evolutionary history between these taxa, morphological synapomorphies remain unclear, which impedes the erection of a new genus to accommodate them. A list of the 71 tapeworms of the former, non-monophyletic subfamily Proteocephalinae, parasitising snakes and lizards, including species inquirendae , and the phylogenetically closely related Thaumasioscolex didelphidis from opossum, with selected characteristics, is also provided, together with a checklist of helminth parasites reported from E. carinatus. [Display omitted] • We describe the first proteocephalid cestode from the saw-scaled viper Echis carinatus. • The new ' Ophiotaenia ' is typified by the position of testes and embryophore size. • The new species phylogenetically clusters with snake cestodes from unrelated regions. • The transmission mechanism remains unknown but likely involves some arthropod prey. [ABSTRACT FROM AUTHOR]

• A comprehensive multigene molecular phylogeny of the earliest diverging Eucestoda order is presented. • Phylogenetic reconstructions reveal important new relationships and challenge the accepted taxonomy of the group. • Strong biogeographical and definitive host-use patterns were revealed. • A new taxonomic re-arrangement of the order guided by molecular data is proposed, with the extant family names preserved. • A hypothetical scenario of the evolution of caryophyllidean tapeworms is presented. Tapeworms of the order Caryophyllidea are the earliest diverging 'true' tapeworms (Eucestoda) and parasitise cypriniform and siluriform fishes almost exclusively. They are typified by a monozoic (non-proglottised) body plan, which is a characteristic shared with early diverging 'cestodarians' Gyrocotylidea and Amphilinidea. Here we present the most comprehensive multi-gene molecular phylogeny of this group, to date. Specimens of 63 species from 32 genera (~50% and ~75% of known species and genus diversity, respectively) were gathered during an intense and targeted 15-year collecting effort. Phylogenetic reconstructions provide high nodal support for three major lineages, which only partly correspond to currently recognised families. The three well-supported clades were as follows: Clade A was in an unsupported position at the base of the tree and was almost exclusively comprised of parasites of catfishes (Siluriformes) from the Afrotropical and Indomalayan regions, including the type genus of the Lytocestidae (Lytocestus). Clade B formed the sister group to the remaining taxa (Clade C) and was composed of species that parasitise cyprinids and loaches (Cypriniformes: Cyprinoidei and Cobitoidei) from the Palaearctic Region. This clade included the type genus of the Caryophyllaeidae (Caryophyllaeus). Clade C comprised Nearctic species from suckers and minnows (Cypriniformes: Catostomidae and Cyprinoidei), which were previously accommodated in two families, i.e. Capingentidae and Caryophyllaeidae. This clade included the type genus of the Capingentidae (Capingens). In addition to Clades A–C, Balanotaenia bancrofti from the monotypic Balanotaeniidae, which parasitises plotosid catfishes in Australia, and Lytocestoides tanganyikae , which parasitises African cichlids, formed a poorly supported clade at the base of the tree. Whereas morphological characteristics traditionally used to differentiate caryophyllidean families do not characterise molecular lineages, host association and biogeographical distribution play a key role in the circumscription of the three well-supported clades revealed by molecular data. Thus, the taxonomic rearrangement proposed herein was guided by the molecular clades. The names of all four extant families were preserved and family affinity was determined by topological clustering with the type genera of the families. The family diagnoses of the Lytocestidae, Caryophyllaeidae and Capingentidae are amended. Biogeographic patterns are indicative of separate Gondwanan and Laurasian radiations having taken place. Regarding the Gondwanan radiation in the Siluriformes, the topology in Clade A indicates an Asian origin with a subsequent African colonisation. Concerning Laurasia, separate radiations appear to have taken place in the Cypriniformes in the temperate zones of North America and Eurasia. Complete absence of caryophyllideans in the Neotropical Region, where numerous catfishes occur, may be due to the Gondwanan radiation having taken place after the continental separation of Africa and South America. [ABSTRACT FROM AUTHOR]

Simultaneous infection with multiple parasite species in an individual host is often observed in wild populations. The understanding of parasite species distribution across populations of wild animals is of basic and applied importance, because parasites can have pronounced effects on the dynamics of host population. Here, we quantified prevalence and endoparasite species richness in moose and explored sex-biased polyparasitism using diagnostic PCR method coupled with DNA sequencing of moose faecal samples from the Biebrza River valley, North-Eastern Poland. This is the largest moose population in Central Europe that has not been harvested for almost 20 years. We also evaluated the appropriate quantity of faeces for detecting DNA of parasite species. Faecal samples were screened for molecular markers of 10 different species of endoparasites. Endoparasite prevalence was high in the studied population. Almost all of the samples (98%) tested positive for at least one parasite species, and we found polyparasitism in the majority of the tested individuals. The number of different parasite species found in a single individual ranged from 0 to 9. The parasite species richness was significantly higher in male than in female individuals. The most prevalent were liver fluke Parafasciolopsis fasciolaemorpha and gastrointestinal nematodes Ostertargia sp. Of the ten endoparasite species detected, only the prevalence of the tapeworm Moniezia benedeni was significantly higher in males than in females. Additionally, we identified co-occurrence associations of parasite species, which tended to be random, but we noted some evidence of both positive and negative associations. Our findings promote applications of molecular methods for parasite species identification from non-invasively collected faecal samples in management and scientific study of moose population, which should include investigation of parasite status, and in health monitoring programs for other wild cervids. Image 1 [ABSTRACT FROM AUTHOR]

• All five species of lamnids and the only pseudocarchariid each host one or two unique species of Clistobothrium. • Larval stages and intermediate hosts are known for only four of these eight species of Clistobothrium. • Adults and their definitive hosts remain unknown for three larval forms from marine mammals. • The search for the marine mammal-consuming definitive host of these larvae continues. This study aimed to locate the adults, and thus also the definitive hosts, of three species of marine mammal-parasitising larval cestodes that have molecular affinities with Clistobothrium. New collections led to the discovery of adults of two new species of Clistobothrium , one from the longfin mako shark and one from the salmon shark. New material of Clistobothrium tumidum was collected from the great white shark and new material of a previously reported undescribed species of Clistobothrium was collected from the porbeagle shark. Larvae of Clistobothrium were opportunistically collected from sockeye salmon and four species of small squaliform sharks. Sequence data for the D1–D3 region of the 28S rDNA gene were generated for all but one of these taxa. The tree resulting from maximum likelihood analysis of those data, in combination with comparable data from GenBank, indicates that squaliform sharks can serve as intermediate hosts for the species from the porbeagle shark. The larvae from salmon exhibit a unique molecular signature and, based on diet data, may be conspecific with adults from the salmon shark. Informed by sequence data for new material of Monorygma and existing data for Phyllobothrium , the larvae provisionally identified as Monorygma grimaldii and Phyllobothrium delphini were formally transferred to Clistobothrium. Especially puzzling was that the molecular signatures of none of the eight species of Clistobothrium match those of the three marine mammal-parasitising larval forms. We are at a loss as to where else to look for the three corresponding adult forms. The great white shark remains the most likely candidate given it consumes marine mammals with some regularity, but seems unlikely to host five species of Clistobothrium. Alternatively, we are left wondering if the large marine mammal predator Carcharocles megalodon may not be extinct after all. [ABSTRACT FROM AUTHOR]

• Species diversity of two parasitic flatworm groups in the Holarctic was analysed. • A database of published host-parasite records for each of two continents was compiled. • Parasite species richness between Europe and North America was compared. • Determinants of species richness were investigated. • This work included a focus on host specificity, site of attachment and co-evolutionary studies. Cypriniformes, which exhibit a wide geographical distribution, are the most species-rich group of freshwater fishes. Despite considerable research on their parasites, no reliable estimates of their parasite diversity on a large geographical scale are available. In the present review, we analyse species richness of two parasitic flatworm groups (monogeneans and tapeworms) reported from cypriniform fishes in the two most intensively studied parts of the Holarctic region, Europe and North America. We also review knowledge on parasite speciation and host-parasite coevolution, and emphasise the risk of parasite co-introduction resulting from transfers of cypriniforms among different continents. As parasite diversity in European cypriniforms has been more intensively explored, we predicted a lower level of knowledge on parasite diversity in North American fishes, despite North America having a higher diversity of cypriniforms than Europe. Our data revealed a higher mean species richness of monogeneans and tapeworms per cypriniform species in Europe compared with North America. We showed that species richness of both parasite taxa in both continents is strongly affected by sample size, but that fish traits also play an important role in determining monogenean and tapeworm species richness in European cyprinoids. We recorded higher host specificity for cypriniform parasites in North America, even within parasite genera shared by cypriniforms on both continents. The host range of monogeneans parasitising cyprinoids on both continents was affected by phylogeny, indicating an effect of parasite life history on host specificity. The difference in parasite host range between the two continents could potentially be explained by either the low overall level of sampling activity in North America or an underestimation of parasite diversity in Europe. We suggest that future research efforts be focussed on cypriniforms in order to obtain reliable data for robust assessments of parasite species richness and phylogenies, to assess host-parasite coevolution and to reveal fish biogeography. [ABSTRACT FROM AUTHOR]

• Adult cyclophyllidean tapeworms are reported from fish for the first known time. • We provide a unique example of host switching from birds to freshwater fish in Africa. • There is a common occurrence in six species of elephantfishes throughout Africa. • Molecular data indicate relatedness with dilepidid tapeworms from swifts in Africa. Tapeworms (Cestoda) of the order Cyclophyllidea include over 3,000 species of intestinal parasites of tetrapods, especially birds and mammals including humans. However, adults of cyclophyllideans have never been found in bony fishes, even though hundreds of thousands of these hosts have been examined for parasites globally over more than 250 years. In the present paper, we report on a unique example of host switching of a tapeworm from birds to teleost fish in Africa. A new genus, Ichthyolepis (Cyclophyllidea: Dilepididae), is erected to accommodate Ichthyolepis africana n. sp., which is the first cyclophyllidean tapeworm that sexually matures in teleost fishes. The new species parasitises several freshwater elephantfishes (Mormyriformes: Mormyridae) including Marcusenius macrolepidotus (type host) in South Africa, Marcusenius senegalensis in Senegal, Mormyrus caschive , M. niloticus and Pollimyrus isodori in the Sudan, and Mormyrus kannume in Egypt. Ichthyolepis n. gen. is typified by a large musculo-glandular apical apparatus with rostellar pouch and a rostellum armed with robust hooks similar in size, but different in shape, deep, sandglass-shaped genital atrium, vaginal atrium and cirrus armed with tiny spines, thick-walled, subspherical cirrus sac, large, lobulated ovary occupying a large part of the median pre-equatorial field of mature proglottids, numerous testes filling almost entirely the postequatorial median field of proglottids, long and narrow, sleeve-like lateral uterine diverticula, and spindle-shaped eggs. Molecular phylogenetics considers Ichthyolepis as a member of the lineage consisting of dilepidids from swifts (Apodidae) in Africa. All fish hosts of the new tapeworm are bottom feeders, live in muddy biotopes and are insectivorous, which indicates that its intermediate hosts may be insect larvae. [ABSTRACT FROM AUTHOR]

Grazing mammals, ungulates, pose two evolutionary puzzles as helminth hosts. First, why do some helminths infect intermediate hosts prior to infecting ungulates, given that grazers could directly consume propagules on vegetation? Second, ungulates are large and long-lived, so why are they occasionally intermediate instead of definitive hosts, as in taeniid cestodes? We comprehensively surveyed helminth life cycles and transmission involving ungulates. We identified six transmission routes and found that ungulate helminth parasitism has evolved some 25 times. Direct egg transmission to ungulates is rare, and we suggest this is due to a transmission barrier caused by ungulate faecal avoidance. Our survey confirmed that ungulates are almost always definitive hosts, and we discuss the exceptional cases when they are not. Ungulate helminth life cycles follow six major transmission routes. Helminth parasitism of ungulates has evolved some 25 times. The most common way this has occurred is by ungulates consuming invertebrate intermediate hosts in herbage, colonisation resulting most probably by host switching. Egg-to-ungulate transmission is rare, probably due to the trophic vacuum arising from ungulate faecal avoidance behaviour. However, two very large radiations of nematodes and trematodes have larvae that migrate to herbage, which serves the role of intermediate host, and in nematodes potentially circumvents host faecal avoidance. Helminths use ungulates as definitive rather than intermediate hosts, probably because they represent a relatively high-growth, low-mortality habitat. Taeniid cestodes are a rare exception, posing interesting unresolved questions. [ABSTRACT FROM AUTHOR]

According to the latest taxonomy of Spirometra species, six species (lineages) have been tentatively classified as valid. These species are Spirometra erinaceieuropaei , S. folium, S. mansoni , undescribed Spirometra sp. 1, and S. decipiens complex 1 and 2. Among these species, the undescribed species was first discovered as plerocercoid larvae in wild boars in Japan and further studies have confirmed that this species is a new taxon belonging to the genus Spirometra. Here, we describe Spirometra asiana sp. nov., which is difficult to distinguish morphologically from known Spirometra species. However, it is genetically easily distinct from other Spirometra species, thus facilitating identification. We also emphasize that S. mansoni and S. asiana, but not S. erinaceieuropaei , are etiological agents that cause human sparganosis and/or spirometrosis in Asia. [Display omitted] • Spirometra species found in wild boar and dog in Japan was described as new taxon. • The species was named Spirometra asiana after biogeography of the species. • S. asiana is morphologically similar with other species including S. mansoni. • Plerocercoids of S. asiana are larger and broader than those of S. mansoni. • S. asiana is genetically closely related to S. mansoni than S. erinaceieuropaei. • Genetic diversity of cox1 in S. mansoni is high, whereas that in S. asiana is low. [ABSTRACT FROM AUTHOR]

• We found identical mitochondrial gene orders (GO) in distant lineages of the Neodermata clade. • This 'common GO' was identified as the ancestral GO for all Neodermata (and most internal nodes). • The subclass Polyopisthocotylea is the earliest neodermatan branch (inferred by mitogenomes and GO). • Highly rearranged GOs of some of the Monogenea and Trematoda corroborate the saltatory nature of GO evolution. • Conserved GOs tend to produce artefactual phylogenetic relationships. Recent mitogenomic studies have exposed a gene order (GO) shared by two classes, four orders and 31 species ('common GO') within the flatworm subphylum Neodermata. There are two possible hypotheses for this phenomenon: convergent evolution (homoplasy) or shared ancestry (plesiomorphy). To test those, we conducted a meta-analysis on all available mitogenomes to infer the evolutionary history of GO in Neodermata. To improve the resolution, we added a newly sequenced mitogenome that exhibited the common GO, Euryhaliotrema johni (Ancyrocephalinae), to the dataset. Phylogenetic analyses conducted on two datasets (nucleotides of all 36 genes and amino acid sequences of 12 protein coding genes) and four algorithms (MrBayes, RAxML, IQ-TREE and PhyloBayes) produced topology instability towards the tips, so ancestral GO reconstructions were conducted using TreeREx and MLGO programs using all eight obtained topologies, plus three unique topologies from previous studies. The results consistently supported the second hypothesis, resolving the common GO as a plesiomorphic ancestral GO for Neodermata, Cestoda, Monopisthocotylea, Cestoda + Trematoda and Cestoda + Trematoda + Monopisthocotylea. This allowed us to trace the evolutionary GO scenarios from each common ancestor to its descendants amongst the Monogenea and Cestoda classes, and propose that the common GO was most likely retained throughout all of the common ancestors, leading to the extant species possessing the common GO. Neodermatan phylogeny inferred from GOs was largely incongruent with all 11 topologies described above, but it did support the mitogenomic dataset in resolving Polyopisthocotylea as the earliest neodermatan branch. Although highly derived GOs might be of some use in resolving isolated taxonomic and phylogenetic uncertainties, we conclude that, due to the discontinuous nature of their evolution, they tend to produce artefactual phylogenetic relationships, which makes them unsuitable for phylogenetic reconstruction in Neodermata. Wider and denser sampling of neodermatan mitogenomic sequences will be needed to infer the evolutionary pathways leading to the observed diversity of GOs with confidence. [ABSTRACT FROM AUTHOR]

Water is one of the possible transmission routes for water- and foodborne parasites to humans. Echinococcus multilocularis is a parasite, which causes alveolar echinococcosis (AE). Nevertheless, no environmental studies have been performed as yet to confirm the occurrence of E. multilocularis in water supplies. Accordingly, 105 water samples of 50 L volume were collected from surface waters (lakes, rivers, canals) and wells in the Warmia-Masuria Province (Echinococcus endemic area) and Pomerania Province (Echinococcus non-endemic area), Poland. The water was filtered and subsequently analysed with nested PCR and real-time PCR. E. multilocularis DNA was found in two (1.9%) samples, which originated from two lakes localised in the Warmia-Masuria Province. Sequencing of the positive samples confirmed that the PCR products were fragments of the E. multilocularis mitochondrial 12S rRNA gene. This is the first investigation describing E. multilocularis detection in environmental water samples, using molecular diagnostic tools. The results indicate that water could be considered as a potential source of E. multilocularis infections in humans and animals, in endemic areas. Image 1 • E. multilocularis DNA has been detected in lakes in endemic areas. • Water should be considered as potential source of AE in humans. • Capsule filtration in situ is useful for recovery of tapeworm eggs from water. • Real-time PCR and nested PCR are efficient in screening water for E. multilocularis. [ABSTRACT FROM AUTHOR]

The cestode Hymenolepis diminuta is highly prevalent in wild rat populations and has also been observed rarely in humans, generally causing no apparent harm. The organism has been studied for decades in the laboratory, and its colonization of laboratory rats has recently been shown as protective against some inflammation-associated disorders. Recently, H. diminuta has become a leading candidate for helminth therapy, an emerging method of "biota enrichment" used to treat or prevent inflammatory diseases of humans in Western society. While most of the experimental isolates of H. diminuta are identified based on typical morphological features, hymenolepidid tapeworms may represent complexes of cryptic species as detected by molecular sequence data. In the present study, we explored the diversity of laboratory-kept strains using partial sequences of two genes (lsrDNA and cox 1) and determined that H. diminuta isolates currently considered for therapeutic purposes in the US and Europe belong to a single, genetically nearly uniform lineage, showing only little genetic deviation from wild-caught isolates. Unlabelled Image • Hymenolepis diminuta stands as the only cestode being considered for therapeutic use. • H. diminuta is maintained in cultures under laboratory conditions worldwide. • Laboratory isolates of H. diminuta do not genetically differ from isolates from wild rats. • Scientists deal with genetically uniform population of H. diminuta under laboratory conditions. [ABSTRACT FROM AUTHOR]

• The performance of racehorses with epiglottic entrapment was compared pre- and post-surgery, and to unaffected controls. • There was a significant difference in racing performance for case horses racing with and without epiglottic entrapment. • There was no significant difference in post-surgical racing performance between case and control horses. • The intra-oral surgical correction of epiglottic entrapment is a suitable technique. Epiglottic entrapment is a condition in racing horses, associated with abnormal respiratory noises and exercise intolerance. Epiglottic entrapment has been linked to both poor and superior athletic performance, leading to concerns regarding whether surgery is indicated, and whether surgical correction may have a deleterious effect on future race performance. The objective of the current study was to assess the race-day performance of horses racing with epiglottic entrapment and the effect of surgical correction on performance outcomes using an intra-oral technique in anaesthetised horses. A case-control study was conducted at the Singapore Turf Club from 2008 to 2011. Controls were selected 1:1 to cases, based on Malaysian Racing Authority number. The performance of horses racing with epiglottic entrapment was recorded and post-surgery race performance was described. Further, post-surgery race performance was compared between cases and with non-case controls. Twenty horses raced with epiglottic entrapment were retrospectively enrolled. There was a significant difference in racing performance in case horses racing with and without epiglottic entrapment (P < 0.001). Fourteen horses finished in the top three post-surgery, compared to one horse finishing in the top three when running with epiglottic entrapment present. There was no significant difference between the performance of case horses (n = 33) post-surgery and controls (number of wins P = 0.20; and places P = 0.62). The intra-oral release of epiglottic entrapment is a suitable technique to resolve epiglottic entrapment. This study may assist veterinarians advising clients in the decision-making process when epiglottic entrapment is diagnosed in a racehorse. [ABSTRACT FROM AUTHOR]

Abstract The systematic position of Urotrema Braun, 1900 and the family Urotrematidae Poche, 1926 have always been controversial. Due to its unusual morphological characteristics, lack of knowledge of the life cycle or details of its excretory system, this family was placed within different higher taxonomic groups of digeneans. Despite being one of the most enigmatic digenean families in terms of its phylogenetic affinities, DNA sequence data for Urotrematidae were lacking. Here, we evaluate the phylogenetic relationships of Urotrema using newly obtained partial sequences of the 28S rRNA gene from Urotrema specimens collected in North, Central and South America including the type species U. scabridum Braun, 1900, as well as previously published sequences of digeneans. Our study has demonstrated that Urotrema is phylogenetically closest (100% branch support) to members of Parabascus Looss, 1907 belonging to the family Pleurogenidae Looss, 1899. Thus, the family Urotrematidae becomes a junior synonym of the Pleurogenidae. Urotrema forms a 100% supported clade among the Pleurogenidae, parasitic in warm-blooded vertebrates. However, the phylogenetic relationships and exact systematic position of the remaining 3 genera currently placed in the Urotrematidae remains unclear and requires additional studies as their allocation is mostly based on the terminal posterior position of the genital pore and cirrus-sac. According to our results the genus Parabascus appears to be paraphyletic and requires further detailed phylogenetic and morphological analyses. Graphical abstract Unlabelled Image Highlights • Affinities of Urotrema was unknown and its systematic position unclear. • Phylogenetic position of Urotrema has been studied using 28S rDNA sequences. • Urotrema belongs to the Pleurogenidae and is phylogenetically closest to Parabascus. • Urotrematidae is synonymized with Pleurogenidae. • Details of excretory vesicle morphology in Urotrema are presented. [ABSTRACT FROM AUTHOR]

Abstract We describe a case of microscopic liver lesion caused by larval cestode in a frugivorous bat (Molossus molossus) from the Western Brazilian Amazon. Histopathological analysis of liver indicated the occurrence of metacestode associated with multifocal histiocytic response and the phylogenetic analysis of Cox-I and 18S rDNA genes indicated that the parasite belonged to the family Paruterinidae. This is the first identification of cestodes of the family Paruterinidae in bats and may suggest a broad range of paruterinid tapeworm hosts to be investigated in the Brazilian Amazon. Graphical abstract Unlabelled Image Highlights • First report of a metacestode parasitism in the chiropteran liver. • The molecular analysis indicated that the parasite belongs to the Paruterinidae family. • Histopathological characterization of hepatic lesion caused by a metacestode in neotropical bat; and • The results may suggest a broad range of occurrence of paruterinid tapeworms in the Brazilian Amazon. [ABSTRACT FROM AUTHOR]

Abstract Ethnopharmacological relevance This study aimed to evaluate the in vitro activity of the essential oil of Pinus nigra subsp. pallasiana against protoscoleces of Echinococcus granulosus sensu lato. In traditional Turkish folk medicine, the essential oils and resin of P. nigra and P. sylvestris are used externally for wound healing. They are also used in cattle for treating worms and as boiling essence against cold and stomachache. Protoscoleces were aseptically aspirated from sheep livers having hydatid cysts. Materials and methods Three concentrations (10, 30, and 50 mg/mL) of the essential oil from P. nigra subsp. pallasiana cones were used for 10–60 min. The essential oil was applied to protoscoleces of hydatid cyst to determine the scolicidal activity of the essential oil. Viability of protoscoleces was observed by 0.1% eosin staining. Results The rate of dead protoscoleces was found to be 2.27% in the control group, which was not treated with essential oil. The rate of dead protoscoleces increased to 61.69%, 69.39%, 75.98% and 71.76% respectively after, 10, 20, 30, and 60 min when the protoscoleces were exposed to the P. nigra subsp. pallasiana essential oil at 10 mg/mL concentration. When protoscoleces were exposed to the essential oil of P. nigra subsp. pallasiana for 10, 20, 30, and 60 min at 30 mg/mL concentration , the mortality rates of protoscoleces were determined as 3.82%, 91.33%, 94.67% and 96.74%, respectively. The mortality rate of 100% was determined at 50 mg/mL concentration after 60 min of exposure. According to statistical analysis, P. nigra subsp. pallasiana essential oil at all concentrations had significant scolicidal effects compared to the control group at all exposure times. Conclusions The essential oil of P. nigra subsp. pallasiana needles showed scolicidal activity and it could be a new scolicidal agent for using in hydatid cyst treatment. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • An effective and side effect free scolicidal is crucial for cystic echinococcosis surgery. • We studied the scolicidal potential of two plant essential oils and their main constituents. • Both essential oils showed full toxicity at 100ug/ml after 60 min. • β-citronellol and β-pinene were both fully toxic at 10 μg/mL after 120 min. Abstract Cystic echinococcosis is of great public health importance. Surgery is the efficient treatment for this infection. To minimize the risk of cyst intraoperative leakage, using scolicidals is crucial. To date, any efficacious scolicidal without side effect has not been introduced. Since essential oils of Pelargonium roseum and Ferula gummosa have shown several bioactivities, we evaluated their potential against protoscoleces of E. granulosus using albendazole as positive control. Furthermore, chemical composition of both essential oils was analyzed by gas chromatography-mass spectrometry (GC-MS) analyses, and their main constituents were also evaluated for scolicidal activity. Different concentrations of essential oils and their two main constituents were tested for scolicidal activity. Mortality rate was measured by eosin staining. Results of GC-MS revealed citronellol and β-pinene as the main constituents of P. roseum and F. gummosa essential oils, respectively. After 60 min of exposure to 50 μg/mL of P. roseum and F. gummosa, mean mortality rate of protoscoleces was 100%. However, β-pinene and citronellol at the same time point with only 10 μg/mL concentrations resulted in approximately higher than 80% mortality. Essential oils of P. roseum and F. gummosa showed significant toxic effect on E. granulosus with 50% lethal concentration (LC 50) values of 8.52 and 17.18 μg/mL, respectively. Based on the LC 50 values, β-pinene (2.20 μg/mL) was the most potent scolicidal agent in the present study. The overall toxicity of β-pinene and citronellol was significantly higher than the whole essential oils of F. gummosa and P. roseum. Based on these results, β-pinene and citronellol can be considered as candidate ingredients for the development of green scolicidals. [ABSTRACT FROM AUTHOR]

Abstract The taxonomic concept for the family Paruterinidae is controversial, especially concerning the position of the genus Cladotaenia , since the latter genus has been placed sometimes in other families, i.e. in the Taeniidae or in the distinct family Cladotaeniidae; finding a solution based on morphological data is difficult and molecular data on paruterinids and related groups are scarce. In this study, the complete mitochondrial (mt) genome sequence of the type-species of the type-genus of the Paruterinidae, Paruterina candelabraria , was determined and annotated. Gene arrangements are identical with those of Cladotaenia vulturi but differing from those of species of the family Taeniidae by the order change between tRNA-SerUCN and tRNA-LeuCUN. Phylogenetic tree was constructed by Bayesian Inference (BI) analysis using the concatenated amino acid sequences of 12 protein-coding genes. The analysis clearly shows that the Paruterinidae and Taeniidae are sister-groups, and Cladotaenia is a sister taxon of Paruterina. This supports the position of the genus Cladotaenia in the family Paruterinidae and reveals the necessity for sequencing additional taxa of the Paruterinidae for better understanding of phylogenetic relationships within the group. [ABSTRACT FROM AUTHOR]

Highlights • Fish host infected with parasite differed in behavior from uninfected ones. • Were caught easily, active in swimming and stayed higher up in the water column. • The parasite had a significant impact on the fish host behavior at the infective stage. • Less developed parasite had little effect on the fish host behavior. • This parasite may affect the fish host's behavior and makes it vulnerable to predation. Abstract Ligula intestinalis is a tapeworm using copepods and cyprinid fish as intermediate hosts and fish-eating birds as final hosts. Since some parasites can increase their own fitness by manipulating the behavior of the intermediate host, we explored if this parasite affected predator avoidance, swimming activity and depth preference of the fish intermediate host, Engraulicypris sardella. We found that when L. intestinalis had reached a developmental stage that is able to establish in the bird host, it had a significant impact on E. sardella behavior, while the tapeworm that was not fully developed had little effect and fish hosts showed a behavior more similar to uninfected fish. These results are discussed with respect to two different processes: the manipulation hypothesis and the energy drain hypothesis. [ABSTRACT FROM AUTHOR]

Human diphyllobothriasis, caused by Dibothriocephalus nihonkaiensis, is prevalent globally, especially in regions where raw fish is consumed. Recent molecular diagnostic techniques have made species identification of tapeworm parasites and the determination of genetic variations among parasite populations possible. However, only a few studies done over a decade ago, have reported on the genetic variation among D. nihonkaiensis in Japan. The present study employed PCR-based mitochondrial DNA analysis to specifically detect D. nihonkaiensis from archived clinical samples, and to determine any genetic variation that may exist among the Japanese broad tapeworms from patients of Kanagawa Prefecture, Japan. Target genes were amplified from DNA extracted from the ethanol- or formaldehyde-fixed samples by PCR. Further sequencing and comparative phylogenetic analyses based on mitochondrial COI and ND1 sequences were also performed. In our results, all PCR-amplified and sequenced samples were identified as D. nihonkaiensis. Analysis of COI sequences revealed two haplotype lineages. However , clustering of almost all COI (and ND1) sample sequences into one of the two haplotype clades, together with reference sequences from different countries worldwide, revealed a common haplotype among D. nihonkaiensis samples in our study. Our results suggest a possible presence of a dominant D. nihonkaiensis haplotype, with a global distribution circulating in Japan. Results from this study have the potential to improve the management of clinical cases and establish robust control measures to reduce the burden of human diphyllobothriasis in Japan. [Display omitted] • Human diphyllobothriasis by Dibothriocephalus nihonkaiensis is prevalent in Japan. • Morphological identification of clinical samples can be ambiguous and inconclusive. • Molecular identification of parasites is recommended for species differentiation. • Morphologically-identified tapeworm samples were re-examined by molecular methods. • Data suggest a possible presence of a dominant D. nihonkaiensis haplotype in Japan. [ABSTRACT FROM AUTHOR]

The phenomenon of exocrine secretion via nervous cells into the host tissue has been discovered in cestodes. In five cestode species of different orders specialized "cup-shaped" free nerve endings located in the tegument have been found. Their ultrastructure is characterized by the presence of a septate junction, a thin support ring and neurosecretory vesicles 90–110 nm in diameter, which are secreted onto the surface of the tegument through a thin pore. The phenomenon is referred to in this article as the neuro-exocrine secretion. We observed a direct relationship between neurosecretory processes in the deep subtegument and free endings in a series of ultrathin sections in two species. The peripheral neurosecretory neurons of species studied are characterized by similar ultrastructural features: size and location; diameter of neurosecretory granules; absence of microtubules and mitochondria in the neurites. The size of neurosecretory granules has been found to decrease from perikaryon towards neurosecretory terminals that lead to the tegument. In two species, we examined the neurosecretion during incubation in the host's blood serum. Depending on the time of incubation we have shown the changes a) in the diameter of the cup-shaped endings, b) in the number of secretory vesicles in the endings; c) changes in number and diameter of neurosecretory vesicles in the processes of neurosecretory neurons in the subtegument. The detected changes differ in D.dendriticus and L.interrupta and, taken together, indirectly confirm the secretory specialization of the cup-shaped endings. Supposed targets for the neurosecretory neurons in the studied cestodes are the following: (a) eccrine frontal gland ducts, especially their terminal regions involved in the release of secretory products; (b) longitudinal and circular muscles in the subtegument region; (c) the basal membrane of the tegument. Besides the discovered secretion vesicles through the cup-shaped terminals, we observed vacuoles derived from the basal membrane of the tegument containing extracellular substances released into the host tissue. Their possible role in the release of neurosecretory substances is discussed. Considering the data acquired via immunocytochemical methods, an assumption about involvement of FMRFamide-like related peptides (FaRPs) in the neuro-exocrine secretion is proposed. Possible functions of the neuro-exocrine secretion are discussed in the context of host-parasite interactions. • The phenomenon of exocrine secretion via neurons to the host tissue is found in cestodes. • We suggest that specialized cup-shaped terminals belong to the neurosecretory neurons. • A new type of gland and a new mechanism of the neuro-exocrine secretion is discussed. [ABSTRACT FROM AUTHOR]

Amongst other factors, topographic features can influence the genetic variability among populations of marine organisms. This applies to host species but also to their parasites, which are poorly studied regarding this aspect, as well as with regard to their use as bioindicators. In the present work, the ribosomal DNA (28S rDNA) was used to assess genetic diversity of Grillotia (Cestoda, Trypanorhyncha) larvae in one of its paratenic hosts, namely Etmopterus spinax , across five different regions (off Scotland, Celtic, Alboran and Balearic Seas and off Cyprus) belonging to three major geographic areas (Northeast Atlantic, western and eastern Mediterranean). The obtained sequences revealed a total of 18 polymorphic sites and 17 haplotypes, as well as significant values of variance throughout the five different regions. Reconstructed phylogenetic trees highlighted that all Grillotia sp. sequences formed a monophyletic group, but divergent lineages split into different main clades which were in relation to the area of origin, with a consistent cluster of sequences from the Atlantic Ocean, as well as another from the Eastern Mediterranean. In contrast, low genetic differentiation was observed between samples from Balearic and Alboran Seas, and with respect to Grillotia sp. larvae from the Gulf of Naples analysed in a previous study. Geographical differences in parasite infection descriptors (prevalence, abundance, and intensity) were assessed, revealing significant differences among the sampled regions. The present study indicates that geographical distance and submarine barriers affect not only the connectivity of hosts but also their parasite infrapopulations by limiting interpopulation dispersal. It underlines the usefulness of parasites as biological tags for the study of susceptible and data-poor host species such as deep-water sharks and its potential implications for host population management and protection measures. [Display omitted] • Cestode larvae of Grillotia adenoplusia ex its paratenic host Etmopterus spinax. • RDNA (28S) revealed genetic diversity between NE Atlantic and Mediterranean regions. • Consistent sequence cluster for the NE Atlantic and Eastern Mediterranean. • Low genetic differentiation within Western Mediterranean. • Limited interpopulation dispersal apply not only to hosts, but also to parasites. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Phylogenetic analysis of genes related to neurotransmitter pathways in flatworms was performed. • Tapeworms lack canonical dopamine, histamine, octopamine/tyramine and GABA signaling. • Neural expression of cholinergic, serotonergic and glutamatergic markers occur in Hymenolepis microstoma. • There is neural and non-neural expression of a peptidergic marker in H. microstoma. Abstract Parasitic flatworms have complex neuromuscular systems that serve important functions in their life cycles. However, our understanding of neurotransmission in parasitic flatworms is limited. Pioneering studies have suggested the presence of several classical neurotransmitter systems, but their molecular components have not been characterized in most cases. Because these components are conserved in bilaterian animals, we searched the genomes of parasitic flatworms for orthologs of genes required for neurotransmitter synthesis, vesicular transport, reuptake, and reception. Our results indicate that tapeworms have lost the genes that are specifically required in other animals for synaptic signaling using the classical neurotransmitters dopamine, tyramine, octopamine, histamine and gamma-aminobutyric acid (GABA). These results imply that these signaling pathways are either absent in these parasites, or that they require completely different molecular components in comparison with other animals. The orthologs of genes related to histaminergic and GABA signaling are also missing in trematodes (although Schistosoma -specific histaminergic receptors have been previously described). In contrast, conserved genes required for glutamatergic, serotonergic and cholinergic signaling could be found in all analyzed flatworms. We analyzed the expression of selected markers of each pathway in the tapeworm Hymenolepis microstoma by whole-mount in situ hybridization. Each marker was specifically expressed in the nervous system, although with different patterns. In addition, we analyzed the expression of proprotein convertase 2 as a marker of peptidergic cells. This gene showed the widest expression in the nervous system, but was also expressed in other tissues, suggesting additional roles of peptidergic signaling in tapeworm development and reproduction. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The codon usage pattern is a conserved feature in Cestodes. • Optimal codons in the genes of the cestode species are ending in G or C. • Higher gene expression is associated with higher CUB and higher GC content. • Selection accounts for the 80% of CUB in parasites of the genus Echinococcus. • Translational efficiency seems to be associated with fundamental pathways. Abstract The species of the genus Echinococcus are parasitic platyhelminths that cause echinococcosis and exert a global burden on public and animal health. Here we performed codon usage bias and comparative genomic analyses using whole genome and expression data of three Echinococcus species. The study of 4,710,883 codons, two orders of magnitude more than in previous research works, showed that the codon usage in Echinococcus genes is biased towards the pyrimidines T and C ending codons, with an average effective number of codons equal to 57 revealing a low codon usage bias. The gene annotations and the expression profile of 7613 genes allowed to accurately determine 27 optimal codons for the Echinococcus species, most of them ending in G/C. Approximately the 30% of Echinococcus genes analysed exhibits higher codon usage bias as well as a higher expression profile. Neutrality-plots demonstrated that the selection pressure is the main evolutionary force shaping the codon usage with a contribution of 80%. Comparative genome analyses among several tapeworm species revealed that codon usage patterns are a conserved trait in cestodes parasites. Since cestodes parasites take advantage of the host protein synthesis pathways, this study could provide valuable information associated with the parasite-host relationship that would be useful to determine which host's factors are relevant for shaping the codon usage. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two potential glucose transporter genes were identified from E. multilocularis. • Full-length sequences EmGLUT1 and EmGLUT2 were obtained. • Functional expression analysis demonstrated clear glucose uptake by EmGLUT1. • Both EmGLUTs were stably expressed in each E. multilocularis developmental stage. Abstract Alveolar echinococcosis (AE) is a zoonotic parasitosis caused by larvae of the fox tapeworm, Echinococcus multilocularis. E. multilocularis is distributed widely in the Northern hemisphere, causing serious health problems in various animals and humans. E. multilocularis , like other cestodes, lacks a digestive tract and absorbs essential nutrients, including glucose, across the syncytial tegument on its external surface. Therefore, it is hypothesized that E. multilocularis uses glucose transporters on its surface similar to a closely-related species, Taenia solium. Based on this hypothesis, we cloned and characterized glucose transporter homologues from E. multilocularis. As a result, we obtained full-length sequences of 2 putative glucose transporter genes (EmGLUT1 and EmGLUT2) from E. multilocularis. In silico analysis predicted that these were classified in the solute carrier family 2 group. Functional expression analysis using Xenopus oocytes demonstrated clear uptake of 2-deoxy-D-glucose (2-DG) by EmGLUT1, but not by EmGLUT2 in this experimental system. EmGLUT1 was shown to have relatively high glucose transport activity. Further analyses using the Xenopus oocyte system revealed that 2-DG uptake of EmGLUT1 did not depend on the presence or concentration of Na+ nor H+, respectively. Immunoblot analyses using cultured metacestode, ex vivo protoscolex, and adult worm samples demonstrated that both EmGLUTs were stably expressed during each developmental stage of the parasite. Based on the above-mentioned findings, we conclude that EmGLUT1 is a simple facilitated glucose transporter and possibly plays an important role in glucose uptake by E. multilocularis throughout its life cycle. [ABSTRACT FROM AUTHOR]

Highlights • Low SCUO value (<0.50) for ATP6 gene in platyhelminths revealed low codon bias. • GC composition influenced codon usage bias of ATP6 gene in platyhelminths. • Over-represented codons were A/T-ending types. • Natural selection and mutation pressure influenced codon usage bias in ATP6 gene. • Neutrality analysis revealed natural selection played a major role in codon bias. Abstract Unequal usage of synonymous codons in the gene transcript for an amino acid is known as codon usage bias (CUB). It is a unique property of gene as well as genome. Mutation and natural selection are known to be the major factors that influence CUB. Other factors encompass gene expression level, GC content, codon position, recombination rate, RNA stability and gene length. CUB analysis helps in in-depth understanding of the molecular biology, genetics and genome evolution in a species. We used bioinformatic methods to explore the pattern of CUB in MT-ATP6 gene in different classes of platyhelminthes. The analysis is based on genetic code of translational table 14 of National Center of Biotechnology Information (NCBI) where the codon AAA codes for asparagine and TAA for tyrosine amino acid. The synonymous codon usage order (SCUO), an index of CUB, values in different classes namely cestoda, monogenea, rabditophora, trematoda and turbellaria of platyhelminths were found to be 0.43, 0.32, 0.49, 0.40 and 0.36, respectively which suggest that the codon usage bias of ATP6 gene was low (SCUO < 0.50). Highly significant correlation (p < 0.001) was found between SCUO and various GC contents indicating that GC composition had an influence on CUB. From the relative synonymous codon usage (RSCU) analysis on codons, we found most of the over-represented codons in all the classes were A/T ending types, which suggested that the preferred codons were influenced by compositional constraints. The PR2 plot revealed asymmetric usage of AT and GC bases among the four fold degenerate codon families with greater usage of G and T over A and C. Highly significant correlation (p < 0.001) was found between overall nucleotide composition and its 3rd codon position suggesting that both natural selection and mutation pressure might have influenced the CUB among different classes. Neutrality analysis revealed that natural selection might play a major role. Mutational responsive index (MRI) and translational selection (P2) values elucidated that selection for translational efficiency moderately affected the codon usage bias in MT-ATP6 gene. [ABSTRACT FROM AUTHOR]