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Background: Filarial worms are important vector-borne pathogens of a large range of animal hosts, including humans, and are responsible for numerous debilitating neglected tropical diseases such as, lymphatic filariasis caused by Wuchereria bancrofti and Brugia spp., as well as loiasis caused by Loa loa. Moreover, some emerging or difficult-to-eliminate filarioid pathogens are zoonotic using animals like canines as reservoir hosts, for example Dirofilaria sp. 'hongkongensis'. Diagnosis of filariasis through commonly available methods, like microscopy, can be challenging as microfilaremia may wane below the limit of detection. In contrast, conventional PCR methods are more sensitive and specific but may show limited ability to detect coinfections as well as emerging and/or novel pathogens. Use of deep-sequencing technologies obviate these challenges, providing sensitive detection of entire parasite communities, whilst also being better suited for the characterisation of rare or novel pathogens. Therefore, we developed a novel long-read metabarcoding assay for deep-sequencing the filarial nematode cytochrome c oxidase subunit I gene on Oxford Nanopore Technologies' (ONT) MinION™ sequencer. We assessed the overall performance of our assay using kappa statistics to compare it to commonly used diagnostic methods for filarial worm detection, such as conventional PCR (cPCR) with Sanger sequencing and the microscopy-based modified Knott's test (MKT). Results: We confirmed our metabarcoding assay can characterise filarial parasites from a diverse range of genera, including, Breinlia, Brugia, Cercopithifilaria, Dipetalonema, Dirofilaria, Onchocerca, Setaria, Stephanofilaria and Wuchereria. We demonstrated proof-of-concept for this assay by using blood samples from Sri Lankan dogs, whereby we identified infections with the filarioids Acanthocheilonema reconditum, Brugia sp. Sri Lanka genotype and zoonotic Dirofilaria sp. 'hongkongensis'. When compared to traditionally used diagnostics, such as the MKT and cPCR with Sanger sequencing, we identified an additional filarioid species and over 15% more mono- and coinfections. Conclusions: Our developed metabarcoding assay may show broad applicability for the metabarcoding and diagnosis of the full spectrum of filarioids from a wide range of animal hosts, including mammals and vectors, whilst the utilisation of ONT' small and portable MinION™ means that such methods could be deployed for field use. [ABSTRACT FROM AUTHOR]

Naturalist Charles Bonnet wrote three publications on the tapeworm—in 1750, 1777, and 1780—now largely forgotten. This article considers how these texts reveal both the challenges of researching intestinal worms and the practices used to examine tapeworms. Bonnet's publication of 1777 is particularly informative as it provides a rare and detailed account of an artist conducting research alongside the naturalist. Bonnet explains how the Danish artist Henrik Plötz manipulated, described, magnified, and drew tapeworm fragments to help the naturalist see them more clearly with the naked eye. The attentive observation often associated with eighteenth-century naturalism played a diminished role in their efforts to discern the tapeworm's anatomy. [ABSTRACT FROM AUTHOR]

Studies of parasitism in chinstrap penguins (Pygoscelis antarctica) are infrequent and mainly refer to the identification and description of its parasites, with little ecological data. In an attempt to address that lack of knowledge, we collected endo- and ecto-parasites from 326 live and four dead of chinstrap penguins, in three different localities of Antarctica not studied before. Three species of endoparasites and two of ectoparasites were found parasitizing birds: two tapeworms, Tetrabothrius pauliani (Cestoda: Tetrabothriidae) and Parorchites zederi (Cestoda: Dilepididae); one roundworm, Stegophorus macronectes (Nematoda: Acuariidae), and one feather louse: Austrogoniodes gressitti (Insecta: Phthiraptera: Philopteridae). Ticks (Ixodes uriae—Acari: Ixodidae) were collected from the ground near the penguin nesting colonies at two localities, Shirreff Cape and Narebsky Point. New ecological data are given for the two species of ectoparasites. No parasites were found in the blood collected from 300 live penguins. [ABSTRACT FROM AUTHOR]

A 49-year- old woman with a history of abdominal discomfort and raw beef intake vomited a long adult Taenia after an episode of acute febrile illness. This case report describes that Taeniasis can rarely present with oral expulsion of the tapeworm. Acute physiologic stress due to illness or surgery could be implicated. [ABSTRACT FROM AUTHOR]

Parasitic worms (i.e. helminths) commonly infect multiple hosts in succession before reproducing. At each life cycle step, worms may fail to infect the next host, and this risk accumulates as life cycles include more successive hosts. Risk accumulation can be minimized by having high establishment success in the next host, but comparisons of establishment probabilities across parasite life stages are lacking. We compiled recovery rates (i.e. the proportion of parasites recovered from an administered dose) from experimental infections with acanthocephalans, cestodes and nematodes. Our data covered 127 helminth species and 16 913 exposed hosts. Recovery rates increased with life cycle progression (11%, 29% and 46% in first, second and third hosts, respectively), because larger worm larvae had higher recovery, both within and across life stages. Recovery declined in bigger hosts but less than it increased with worm size. Higher doses were used in systems with lower recovery, suggesting that high doses are chosen when few worms are expected to establish infection. Our results indicate that growing in the small and short-lived hosts at the start of a complex life cycle, though dangerous, may substantially improve parasites' chances of completing their life cycles. [ABSTRACT FROM AUTHOR]

Parasitic worms with complex life cycles have several developmental stages, with each stage creating opportunities to infect additional host species. Using a data set for 973 species of trophically transmitted acanthocephalans, cestodes, and nematodes, we confirmed that worms with longer life cycles (i.e., more successive hosts) infect a greater diversity of host species and taxa (after controlling for study effort). Generalism at the stage level was highest for middle life stages, the second and third intermediate hosts of long life cycles. By simulating life cycles in real food webs, we found that middle stages had more potential host species to infect, suggesting that opportunity constrains generalism. However, parasites usually infected fewer host species than expected from simulated cycles, suggesting that generalism has costs. There was no trade-off in generalism from one stage to the next, but worms spent less time growing and developing in stages where they infected more taxonomically diverse hosts. Our results demonstrate that life-cycle complexity favors high generalism and that host use across life stages is determined by both ecological opportunity and life-history trade-offs. [ABSTRACT FROM AUTHOR]

Introduction: Members of the onchoproteocephalidean genus Phoreiobothrium Linton, 1889 infect carcharhinid and sphyrnid sharks. Although the Persian Gulf harbors a rich fauna of sharks, the taxonomic diversity of Phoreiobothrium in this region has been explored little. A new species of Phoreiobothrium is herein described from Carcharhinus sorrah (Müller et Henle) off southern Iran. Methods: Cestodes were isolated from the spiral intestine of Carcharhinus sorrah, fixed in 10% seawater-buffered formalin, and stored in 70% ethanol. For morphological examinations, worms were stained using acetic carmine; a subset was prepared for SEM. Results: Phoreiobothrium sorrahcola n. sp. is the first record of the genus from C. sorrah and most closely resembles Phoreiobothrium rozatii Alijanpour Darvishi et Haseli, 2019 recently described from the Gulf of Oman. However, it differs from P. rozatii in its possession of the rectangular, rather than triangular, bothridia, a longer cephalic peduncle (878–1300 vs 466–841), the longer axial prongs of lateral and medial hooks (B 56–80 vs 43–52; B' 66–98 vs 46–62), and a greater maximum width of worm at level of scolex (302–415 vs 215–298). Conclusions: With the description of this new species, three species of Phoreiobothrium have been reported so far from the southern waters of Iran. Phoreiobothrium now includes 17 valid species infecting 16 shark species. [ABSTRACT FROM AUTHOR]

The origin, differentiation and functional ultrastructure of oncospheral or egg envelopes in Echinococcus multilocularis Leuckart, 1863 were studied by transmission electron microscopy (TEM) and cytochemistry. The purpose of our study is to describe the formation of the four primary embryonic envelopes, namely vitelline capsule, outer envelope, inner envelope and oncospheral membrane, and their transformation into the oncospheral or egg envelopes surrounding the mature hexacanth. This transformation takes place in the preoncospheral phase of embryonic development. The vitelline capsule and oncospheral membrane are thin membranes, while the outer and inner envelopes are thick cytoplasmic layers formed by two specific types of blastomeres: the outer envelope by cytoplasmic fusion of two macromeres and the inner envelope by cytoplasmic fusion of three mesomeres. Both outer and inner envelopes are therefore cellular in origin and syncytial in nature. During the advanced phase of embryonic development, the outer and inner envelopes undergo great modifications. The outer envelope remains as a metabolically active layer involved in the storage of glycogen and lipids for the final stages of egg development and survival. The inner envelope is the most important protective layer because of its thick layer of embryophoric blocks that assures oncospheral protection and survival. This embryophore is the principal layer of mature eggs, affording physical and physiological protection for the differentiated embryo or oncosphere, since the outer envelope is stripped from the egg before it is liberated. The embryophore is very thick and impermeable, consisting of polygonal blocks of an inert keratin-like protein held together by a cementing substance. The embryophore therefore assures extreme resistance of eggs, enabling them to withstand a wide range of environmental temperatures and physicochemical conditions. [ABSTRACT FROM AUTHOR]

Mesocestoides vogae is a cestode of the order Cyclophyllidea, and its second intermediate hosts are mammals, birds, amphibians, and reptiles. The parasite forms a tetrathyridium in the second intermediate host and multiplies asexually, sometimes to the point of filling the host's abdominal cavity. Proliferated tetrathyridium may cause lethal conditions in the host. During the asexual multiplication period, the scolex first replicates into two and then divides into two worms. In this study, to investigate the factors that promote the replication, tetrathyridia were cultured under various in vitro conditions. When several worms which already had two scolexes were cultured together, the division into two worm bodies was complete, but when single worm was cultured, the division hardly proceeded. The result indicates that the division progression of tetrathyridia with two scolexes requires the presence of other worms. In contrast, tetrathyridia with only one scolex did not initiate the division process, whether cultured together or alone. Then, the necessity of direct contact between the bodies of the worms to promote the division of tetrathyridia with two scolexes was assessed. For this, the well of the culture plate was partitioned into upper and lower parts using a mesh, and 20 worms in the upper part and single worm in the lower part were cultured. In all examined wells, worms in the upper part showed complete division, whereas the worms in the lower part rarely completed the division. Thus, direct contact between tetrathyridium promotes the division of tetrathyridia bearing two scolexes. [Display omitted] • Tetrathyridium with two scolexes did not divide when cultured singly. • Tetrathyridium with two scolexes divided when cultured in groups. • Tetrathyridium with one scolex did not replicate when cultured. • Direct contact with other worms induced division of tetrathyridium with two scolexes. [ABSTRACT FROM AUTHOR]

Metacestodes are often found in the body cavity of the common bully (Gobiomorphus cotidianus McDowall), from freshwater habitats in Otago, New Zealand. Identification of metacestodes relies only on the number, size and shape of the rostellar hooks. To attempt species determination, we cultivated metacestodes in vitro for up to 23 days, during which they matured to at least the male stage of development, although female organs were not discernable. Identified as members of the genus Paradilepis Hsü, 1935 (family Gryporhynchidae), these specimens are compared to previously described species, in particular P. minima (Goss, 1940), from Australia, the closest species, both geographically and morphologically. Although the size of scolex, suckers and proglottids differ significantly from those of P. minima, we are cautious about interpreting ‘adults’ grown in vitro, because we are unsure whether the artificial conditions alter development. For this reason, and because of the lack of female organs, we refrain from erecting a new species, and refer to the specimens as Paradilepis cf. minima until such time as the adults are found in the definitive host. With this proviso we present here a description of the in vitro-grown worms and the metacestodes as a preliminary study of this cestode. A molecular analysis of small subunit (SSU) rDNA sequences, shows the position of P. cf. minima and another gryporhynchid, Neogryporhynchus cheilancristrotus (Wedl, 1855), to be equivocal, but confirms their exclusion from the Dilepididae and Hymenolepididae. This is the first record of a gryporhynchid from New Zealand, and the first from the fish family Eleotridae. [ABSTRACT FROM PUBLISHER]

Distribution records of 152 adult helminth taxa parasites of freshwater fishes in Mexico were analysed to determine areas of high richness and endemism. Distribution maps were prepared for each taxon and overlaid onto a map of Mexico divided into 1 × 1 degree grid-cells. Richness was determined by counting recorded helminth species in each grid-cell. A corrected weighted endemism index was calculated for each grid-cell, and the relationship between richness and endemicity was analysed with an Olmstead–Tukey corner test of association. Five areas of high richness and endemism were identified: (1) Los Tuxtlas and the Papaloapan river basin, on the Gulf of Mexico; (2) the Grijalva-Usumacinta basin near the Gulf of Mexico coastal plain; (3) the Yucatan Peninsula; (4) the Sierra de Manantlán Biosphere Reserve in western Mexico; and (5) the Pátzcuaro lake, in central Mexico. The distribution of richness and endemism of helminth parasites of freshwater fishes in Mexico is congruent with distributional patterns described for other freshwater taxa in Mexico. Patterns of richness and/or endemism in the studied areas can be explained by the ichthyological composition of their bodies of water. The present study establishes an objective way of analysing the relationship between richness and endemicity, and suggests that helminths can make valuable contributions to regionalization of geographical areas and for identification of rich and biologically complex areas with potential for conservation of aquatic systems. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 435–444. [ABSTRACT FROM AUTHOR]

Pumilio proteins are proposed to have a conserved primordial function in the maintenance of proliferation in stem cells through post-transcriptional regulation. In this work, a search for pumilio homology domain (PUM-HD) sequences of pumilio genes from several Platyhelminthes species was performed, including representatives form Cestoda, Trematoda and Tricladida. Only one PUM-HD sequence was found in each triclad species; however, two PUM-HD homologues were found in all the parasitic species. These sequences formed two clearly separated clades: PlatyPum1, with sequences from all species, and PlatyPum2, composed exclusively of neodermatan sequences. Therefore, at least one duplication of the pumilio gene must have occurred before the divergence of cestodes and trematodes. Further duplications of PUM-HD were found in Fasciola hepatica, but these consist of retropseudogenes. This is the first comparative analysis of PUM-HD sequences in the Platyhelminthes and, more generally, in any lophotrochozoan phylum. [ABSTRACT FROM AUTHOR]

Abstract: The penetration of the intestinal mucosal wall is supposed to be critical for helminth parasite infestation, but has rarely been analyzed in detail. We here studied the establishment process of Schistocephalus solidus tapeworms in their second intermediate host, the three-spined stickleback, from oral uptake after experimental exposure, to passage through the gastro-intestinal tract and arrival in the fish body cavity. Using histological techniques, we found tapeworms to penetrate the intestine within 14–24h, spending most of the time in the stomach lumen and only a very short period in the intestine. Unexpectedly, tapeworms lost their outer layer, together with the cercomer, in the intestine lumen rather than later during intestine wall penetration. Once exposed, the underlying tegument with microtriches might serve to facilitate migration of the parasite into the body cavity. [Copyright &y& Elsevier]

This species is particularly useful for the study of the differentiation of larvae into adult worms (strobilation). Tetrathyridia, including those undergoing asexual binary fission and those 24, 48 and 72h after strobilation induction, as well as fully strobilated adult worms were assessed. Overall, valuable images from the M. corti strobilation process were generated, providing relevant information for a better understanding of the sequence of events underlying cestode strobilation. [Extracted from the article]

Temnocephala iheringi is the most common temnocephalan inhabiting the mantle cavity of the apple snail Pomacea canaliculata, a freshwater neotropical gastropod that has become a serious rice pest in Southeastern Asia. T. iheringi has been recorded from Mato Grosso (Brazil) to water bodies associated with the Río de la Plata river (Argentina). During an extensive survey in the southern limit of the native area of P.␣canaliculata the presence of T. iheringi eggs was recorded in several apple snail populations, extending the known distribution of the commensal more than 400 km southwards. The aim of this study was to understand the factors affecting the distribution and abundance of T. iheringi among populations of P.␣canaliculata. Only 23% of the apple snail populations inhabiting streams harboured temnocephalans while the occurrence among lentic ones was 71%. T. iheringi was found mostly in populations of apple snails living in non-alkaline sites and where snails attaining sizes larger than 4 cm were very common. The prevalence of the temnocephalans in lentic populations was higher than 90%. The number of eggs on the shell (not including the umbilicus) ranged between 0 and 470 and was different among populations of P.␣canaliculata. The prevalence and number of eggs were lower in the lotic populations, except for a stream population immediately downstream of a lake with commensals. There was no difference between males and females of P. canaliculata neither in the prevalence nor in the number of eggs on the shell. The southernmost population of the world of P. canaliculata harbours commensals that tolerate cold winter water temperatures (4–5 °C) as well as its host. On the other hand, T. iheringi was found only in sites with bicarbonate concentrations lower than 6.6 meq l−1, suggesting that the tolerance of the commensal is very much lower than that of the apple snail (up to 9.95 meq l−1). The number of worms inside each snail or the life history variation of P. canaliculata could explain the influence of the size of the snails on the occurrence of T. iheringi. In the big-sized snails, where the number of commensals is higher, the probability of survival of at least one worm is also higher, specially during the hibernation period, when crawling and feeding are null and snails remain buried. On the other hand, P. canaliculata snails from lentic populations are generally bigger and mostly iteroparous, while those inhabiting streams are smaller and semelparous. In these populations the snails have access to mate only with snails of their same cohort, while in iteroparous populations they can copulate with individuals of other cohorts, allowing the inter-generation transmission of worms and the long term persistence of the population of commensals. [ABSTRACT FROM AUTHOR]

This study describes two new freshwater otoplanid species (Platyhelminthes, Proseriata), Itaspiella parana n. sp. and Philosyrtis rauli n. sp., from interstitial habitats of the middle Paraná river (Argentina) and lower Uruguay river (Uruguay), respectively. Kata sp. from the Uruguay river is briefly characterized. This is the first report of otoplanids from freshwater environments of South America. The studied areas are particular biotopes. At present, only a few studies on the turbellarian fauna and its ecology have been carried out in the Paraná river and the records presented here are the first for the Uruguay river. The main difference between other known otoplanid species and Itaspiella parana, Philosyrtis rauli and Kata sp. is their ecological characterization. Until now the family Otoplanidae was known only from marine environments, with a few exceptions. [ABSTRACT FROM AUTHOR]

Macrostomum lignano n. sp. is a member of the Macrostomorpha, the basal-most subtaxon of the Platyhelminthes–Rhabditophora. This new species can be easily cultured in the laboratory and has been already the subject of several developmental/evolutionary studies. The small size, with only about 25 000 cells constituting the major bilaterian organ systems, makes this simultaneous hermaphrodite a possible candidate for a new model organism that is phylogenetically more basal than any of the model organisms currently used in such studies within the Bilateria. M. lignano belongs to the largest genus of the Macrostomorpha. Over 100 marine, fresh water and brackish water species are contained in the genus Macrostomum, some of them with worldwide distribution pattern. Within it, M. lignano is a member of the M. tuba-species group, which we have summarized here. In the species description, we have used a novel approach to document such small soft-bodied meiobenthic organisms: we provide extensive digital micrographical documentation, which are deposited as a CD together with the type material. [ABSTRACT FROM AUTHOR]

Sixty-two individuals representing four species and three families of African lizards, Chamaeleo dilepis (Chamaeleonidae); Nucras tessellata (Lacertidae); Pachydactylus rugosus and Palmatogecko rangei (Gekkonidae) were examined for helminths. Two species of Cestoda, Oochoristica truncata and cysticereoids of an undetermined cyclophyilidean species, and six species of Nematoda, Abbreviata paradoxa, Maxvachonia dimorpha, Parapharyngodon rotundatus, Spauligodon petersi, Spauligodon smithi and Strongyluris elegans, were found. Nine new host records are reported. [ABSTRACT FROM AUTHOR]

Investigates the induction of Mesocestoides (M.) corti (Cestoda) tetrathyridia in in vitro segmentation. Ability of the M. corti to reproduce asexually; Establishment of conditions that increase the efficiency of in vitro M. corti larvae (tetrathyridia) segmentation through testing the effects of an inducing agent and some physical parameters in culture; Pretreatment with a high concentration of trypsin that induced segmentation and sexual differentiation of tetrahyridia in vitro.

Evolutionary theory predicts an influence of mating group size on sex allocation in simultaneous hermaphrodites. We experimentally manipulated the social situation during reproduction in a simultaneous hermaphrodite parasite, the tapeworm Schistocephalus solidus, by placing worms as singles, pairs or triplets into an in vitro system that replaces the final host. We then determined the reproductive allocation patterns after 24 h (i.e. before the start of egg release) and after 72 h (i.e. around the peak of egg release rate) using stereology. After 24 h, sex allocation strongly depended on worm volume (which is determined in the second intermediate host), but was not significantly affected by the social situation experienced during reproduction. After 72 h, worms in groups had less vesicular sperm (i.e. sperm to be used in future inseminations) than singles. They also stored significantly more received sperm in their seminal receptacles than singles, suggesting that more sperm had been transferred in groups. Moreover, worms in triplets stored significantly more received sperm than worms in pairs, suggesting that they either mated more often and/or transferred more sperm per mating. This suggests a behavioural response to the increased risk of sperm competition in triplets. We further discuss the relative importance of sex allocation decisions at different life-history stages. [ABSTRACT FROM AUTHOR]

Comments on the unequivocal features of tapeworms of the genus Taenia that infect human beings. Occurrence of three types of tapeworms in the adult stage of humans; Names of the identified number of worms that infect human beings; Distinction of the morphological features that allows the crucial identification of worms.

The article focuses on the prevention of the parasitic worm disease in horses. Highlighted are types of worms affecting horses including large red worms, round worm, tapeworms and thread worms. Discussed are concepts of worm control programme including treatments on needs of individual animal and management policies.

The article briefly discusses the exposure of Nigerian children to parasite worms. Children born in a Nigerian village is almost bombarded by parasitic worms soon after birth throughout their life. In both rural and urban environments, the water used for drinking and domestic purposes is a source of schistosomiasis and guinea worm. The vegetables and meat that they consume is a source of tapeworm, roundworms and whipworm and also lung fluke where freshwater crustacea are consumed. The soil on which they walk barefoot infects them with hookworm and strongyloidiasis and the profusion of biting insects with onchocerciasis and filariasis. Non-biting insects, dogs, cats, goats and poultry in the houses and yards assist the mechanical spread of the intestinal helminths, and the use of human night soil as manure increases the risk.