Marine fish imported from Argentina as source of human diphyllobothriosis in Europe? Ecological evidence from dolphins.

Diphyllobothriosis caused by the Pacific broad tapeworm Adenocephalus pacificus (syn. Diphyllobothrium pacificum) is an emerging parasitic disease reported also from non-endemic areas, including Europe (Spain). The origin of these human cases is unknown but should be related to fresh marine fish imported from endemic areas. In this study, we molecularly confirmed common dolphins Delphinus delphis off Argentina as euparatenic transit hosts of A. pacificus. Preliminary analysis of their stomach content, together with data from previous studies from the Southwest Atlantic, showed that common dolphins feed almost exclusively on schooling Argentine hake Merluccius hubbsi and Argentine anchovy Engraulis anchoita. Therefore, we suggest that Argentine hake and Argentine anchovy may represent the intermediate hosts of A. pacificus in the Southwest Atlantic, but also in Europe to where M. hubbsi is imported on ice (unfrozen).

Diphyllobothrium sprakeri n. sp. (Cestoda: Diphyllobothriidae): a hidden broad tapeworm from sea lions off North and South America.

BACKGROUND: The systematic of several marine diphyllobothriid tapeworms of pinnipeds has been revised in recent years. However, 20 species of Diphyllobothrium from phocids and otariids are still recognized as incertae sedis. We describe a new species of Diphyllobothrium from the intestine of California sea lions Zalophus californianus (Lesson) (type-host) and South American sea lions Otaria flavescens (Shaw). METHODS: Zalophus californianus from the Pacific coast of the USA and O. flavescens from Peru and Argentina were screened for parasites. Partial fragments of the large ribosomal subunit gene (lsrDNA) and the cytochrome c oxidase subunit 1 (cox1) mitochondrial gene were amplified for 22 isolates. Properly fixed material from California sea lions was examined using light and scanning electron microscopy. RESULTS: A total of four lsrDNA and 21 cox1 sequences were generated and aligned with published sequences of other diphyllobothriid taxa. Based on cox1 sequences, four diphyllobothriid tapeworms from O. flavescens in Peru were found to be conspecific with Adenocephalus pacificus Nybelin, 1931. The other newly generated sequences fall into a well-supported clade with sequences of a putative new species previously identified as Diphyllobothrium sp. 1. from Z. californianus and O. flavescens. A new species, Diphyllobothrium sprakeri n. sp., is proposed for tapeworms of this clade. CONCLUSIONS: Diphyllobothrium sprakeri n. sp. is the first diphyllobothriid species described from Z. californianus from the Pacific coast of North America, but O. flavescens from Argentina, Chile and Peru was confirmed as an additional host. The present study molecularly confirmed the first coinfection of two diphyllobothriid species in sea lions from the Southern Hemisphere.

p class="ZootaxaTitle">An annotated list of the Acanthocephala from Argentina.

A detailed list of acanthocephalans from Argentina was generated based on 205 published records. The list includes 52 named and 35 undetermined species of Acanthocephala infecting 6 species of invertebrate (2 amphipods, 3 decapods and 1 insect) and 155 species of vertebrate (one cartilaginous fish, 95 bony fishes, 10 amphibians, 3 reptiles, 13 birds and 33 mammals) host species in the Argentinean territory. The present list contains information on the invertebrate and vertebrate host(s), site of infection, developmental stage and locality(ies) of the acanthocephalans listed and references. For some species of acanthocephalans, information about repositories of the type material, voucher specimens, and DNA sequences of individual taxa are also presented. Finally, a host-Acanthocephala list is also provided. The data compiled revealed considerable gaps in the knowledge of the diversity, taxonomy, distribution, and life cycles of the acanthocephalans from Argentina.

Host Switching of Zoonotic Broad Fish Tapeworm (Dibothriocephalus latus) to Salmonids, Patagonia.

Diphyllobothriosis is a reemerging zoonotic disease because of global trade and increased popularity of eating raw fish. We present molecular evidence of host switching of a human-infecting broad fish tapeworm, Dibothriocephalus latus, and use of salmonids as intermediate or paratenic hosts and thus a source of human infection in South America.

Molecular data support monophyly of the recently erected Riggenbachiella (Cestoda: Proteocephalidae), parasites of Neotropical catfishes.

Proteocephalid tapeworms (Cestoda) are one of the dominant groups of intestinal parasites of Neotropical catfishes (Siluriformes), especially pimelodids (de Chambrier et al. 2015). The long and convoluted taxonomic history of species of Chambriella Rego, Chubb Pavanelli, 1999 has been disentangled only recently by Alves et al. (2017). These authors erected a new genus, Riggenbachiella Alves, de Chambrier, Luque Scholz, 2017, to accommodate R. amazonense Alves, de Chambrier, Luque Scholz, 2017 (type-species) and R. paranaense (Pavanelli Rego, 1989) (previously Chambriella paranaensis), parasites of pimelodid catfishes.

Morphological and molecular characterisation of Aporocotyle margolisi Smith, 1967 (Digenea: Aporocotylidae) from the North Pacific hake Merluccius productus (Ayres) (Gadiformes: Merlucciidae) off Oregon, USA.

Aporocotylid blood flukes conspecific with Aporocotyle margolisi Smith, 1967 were collected from the bulbus arteriosus of the North Pacific hake Merluccius productus (Ayres). This study revisits the morphology of A. margolisi, including drawings, measurements and scanning electron microscopy images, and provides for the first time molecular data for the large subunit of the ribosomal RNA (28S rDNA) and the mitochondrial cytochrome c oxidase subunit 1 (cox1) genes for this species. A 28S rDNA phylogenetic study of A. margolisi, and all available Aporocotyle spp., was also performed. The distribution range of A. margolisi is extended to the Pacific coast of the USA. We provide a morphological comparison of Aporocotyle spp. from the Pacific coast in North America as well as other Aporocotyle spp. infecting hake. Comparisons with the original description revealed that the new specimens of A. margolisi were considerably larger with respect to all morphological features, except for shorter spines. Molecular results showed a close relationship between A. margolisi and A. argentinensis Smith, 1969 from the Argentine hake Merluccius hubbsi Marini. The phylogenetic relationships of Aporocotyle spp. point to a possible co-speciation of hakes species and these blood fluke parasites.

First Freshwater Bothriocephalidean (Cestoda) from Tropical South America, Closely Related to African Taxa.

Regobothrium microhamulinum n. gen. and n. sp. (Bothriocephalidea: Bothriocephalidae) is proposed to accommodate a new cestode from flatfish Catathyridium jenynsii (Chabanaud, 1922) (Pleuronectiformes: Acharidae; type host) and another 3 freshwater fishes of the orders Characiformes, Cyprinodontiformes, and Siluriformes in the Neotropical Region. The new genus is placed in the Bothriocephalidae because it possesses medioventral uterine and mediodorsal genital pores and a follicular vitellarium. Regobothrium n. gen. is characterized by possessing a tiny, slightly subovate scolex narrower than the strobila, with an apical disc armed with 2 semicircles of 15-17 tiny hooks in each and an acraspedote strobila. Regobothrium n. gen. differs from all bothriocephalid cestodes that have a scolex armed with hooks by their small size (maximum length less than 20 µm) and a triangular shape with the basal part (handle or basal plate) shorter than the distal coniform part (blade). In the other hooked bothriocephalids, hooks have a longer handle than a blade. Regobothrium microhamulinum n. gen. and n. sp. is the third bothriocephalidean cestode described from freshwater teleosts in South America but the first out of Patagonia. Molecular phylogenetics consider Regobothrium as a member of a lineage consisting of (up to now exclusively) freshwater bothriocephalids from the Ethiopian biogeographic region, thus indicating Gondwanan relationship.

Pacific Broad Tapeworm Adenocephalus pacificus as a Causative Agent of Globally Reemerging Diphyllobothriosis.

The Pacific broad tapeworm Adenocephalus pacificus (syn. Diphyllobothrium pacificum) is the causative agent of the third most common fish-borne cestodosis among humans. Although most of the nearly 1,000 cases among humans have been reported in South America (Peru, Chile, and Ecuador), cases recently imported to Europe demonstrate the potential for spread of this tapeworm throughout the world as a result of global trade of fresh or chilled marine fish and travel or migration of humans. We provide a comprehensive survey of human cases of infection with this zoonotic parasite, summarize the history of this re-emerging disease, and identify marine fish species that may serve as a source of human infection when eaten raw or undercooked.

Sharpilosentis peruviensis n. g., n. sp. (Acanthocephala: Diplosentidae) from freshwater catfishes (Siluriformes) in the Amazonia.

Sharpilosentis peruviensis n. g., n. sp. is described from the catfishes Duopalatinus cf. peruanus Eigenmann & Allen (type-host) and Oxydoras niger (Valenciennes) in the River Amazon basin, Peru. The new species belongs to the subfamily Diplosentinae Tubangui & Masilungan, 1937 of the family Diplosentidae Tubangui & Masilungan, 1937 because of its possession of an unarmed trunk, a cylindrical proboscis, proboscis hooks arranged in longitudinal rows and two tubular cement glands of the same length in males. Sharpilosentis n. g. differs from the other genera of the Diplosentidae in the morphology of the reproductive system: males have a large muscular penis covered with small tubercles and the vulva of females is devoid of muscular sphincters and the cephalic ganglion is located between the second and third part of the proboscis receptacle. In addition, proboscis hooks are of three types: large hooks with simple roots in the anterior part of the proboscis, transitional 6th hook in one from two adjacent rows with bifurcated root in the distal part and small hooks without roots in the posterior part of the proboscis. A partial sequence for the mitochondrial cox1 gene is provided for this new taxon. The taxonomic composition of the family Diplosentidae is discussed.

A checklist of the helminth parasites of marine mammals from Argentina.

Based on published records and new data accumulated by the authors, we generated a list of the helminth parasites of marine mammals from off the coast of Argentina. We found 49 reports of helminths parasitizing cetaceans and pinnipeds from Argentina from 1952 to 2015. The list includes 54 taxa of helminths (8 acanthocephalans, 24 nematodes, 11 cestodes and 11 trematodes) associated with 18 species of cetaceans and 5 species of pinnipeds. Most of the records represent adults (5 acanthocephalans, 16 nematodes, 6 cestodes and 11 trematodes), followed by larvae (10 nematodes and 3 metacestodes) and juveniles (4 acanthocephalans and 2 cestodes). The checklist contains 24 named species (5 acanthocephalans, 8 nematodes, 4 cestodes and 7 trematodes) and 30 undetermined helminth taxa (3 acanthocephalans, 16 nematodes, 7 cestodes and 4 trematodes). The present account contains a parasite/host lists and information on the habitat, developmental stage and distribution of the parasites listed, repositories of their type and voucher specimens and references. A host-parasite list is also presented. The data compiled on the helminth of marine mammals from Argentina in the present study revealed gaps in the knowledge of their taxonomic identification, composition, distribution, host specificity and life cycles. These gaps are also briefly discussed in order to provide an outline for future research.

A new species of Bothriocephalus Rudolphi, 1808 (Eucestoda: Bothriocephalidea) from the channel bull blenny Cottoperca gobio (Günther) (Perciformes: Bovichtidae) on the Patagonian shelf off Argentina.

Bothriocephalus timii n. sp. is the first tapeworm species reported from a bovichtid fish. The new species was commonly found (prevalence 85%) in the intestine of Cottoperca gobio (Günther) collected on the Patagonian shelf off Argentina. It is characterised by a strobila with segments and proglottides usually longer than wide, having posterolateral wing-like expansions with a medial notch on both the dorsal and ventral surfaces; a scolex with an apical disk; elongate bothria opening posteriorly, with laterally and longitudinally extended convex lappets; testes 42-185 in number, in one layer, arranged in two lateral continuous bands along the strobila; an elongate cirrus-sac, situated obliquely, with the proximal part curved anteriolaterally; and an ovary which is usually butterfly-shaped. The new species is morphologically similar to B. bengalensis Devi, 1975 from Carangoides plagiotaeniata Bleeker, B. branchiostegi Yamaguti, 1952 from Branchiostegus japonicus Houttuyn, B. carangis Yamaguti, 1968 from C. ferdau Forsskål and B. gadellus Blend & Dronen, 2003 from Gadella imberbis (Vaillant) based on the presence of posterolateral wing-like expansions with a medial notch on dorsal and ventral surfaces of segments and proglottides along the strobila. Bothriocephalus timii n. sp. differs from B. bengalensis, B. branchiostegi and B. carangis in the absence of a vaginal sphincter and from B. gadellus in the number of testes and the size of scolex. Unpublished molecular data suggest that B. timii is most closely related to B. australis Kuchta, Scholz & Justine, 2009 from Platycephalus spp. and B. scorpii (Müller, 1776) from Myoxocephalus scorpius (Linnaeus). The genus Indobothrium Sedova & Gulyaev, 2009 is herein considered a junior synonym of Bothriocephalus Rudolphi, 1808.

Taxonomic status of Woodland's enigmatic tapeworms (Cestoda: Proteocephalidea) from Amazonian catfishes: back to museum collections.

Poorly known proteocephalidean cestodes of peculiar morphology, described by Woodland (1934) from pimelodid catfishes in Amazonia, Brazil, were studied. Re-examination of their type-specimens and evaluation of newly-collected material from Brazil and Peru made it possible to clarify their taxonomic status. Brayela karuatayi (Woodland, 1934), the type-species of the monotypic Brayela Rego, 1984, which has never been recorded since its original description, is redescribed and its scolex morphology, which has been misinterpreted in the original description, was studied using scanning electron microscopy (SEM). The actual definitive host of B. karuatayi is not a species of Glanidium Lütken (Auchenipteridae), but coroatá, Platynematichthys notatus (Jardine) (Pimelodidae). Peru is a new geographical record for B. karuatayi. The definitive host of other two proteocephalidean cestodes, Megathylacus jandia Woodland, 1934 and Proteocephalus jandia Woodland, 1934, is not a species of Rhamdia Bleeker (family Heptapteridae), but the pimelodid Zungaro zungaro (Humboldt) [syn. Paulicea luetkeni (Steindachner)]. Proteocephalus jandia is in fact conspecific with Travassiella avitellina Rego & Pavanelli, 1987, type-species of Travassiella Rego & Pavanelli, 1987. As a result, a new combination, Travassiella jandia (Woodland, 1934), is proposed. Megathylacus jandia Woodland, 1934 is considered conspecific with M. brooksi Rego & Pavanelli, 1985 described from the congeneric host [Zungaro jahu (Ihering)] from the Paraná River in Brazil; the latter species becomes its new junior synonym. The validity of M. travassosi Pavanelli & Rego, 1992, a parasite of Pseudoplatystoma corruscans (Spix & Agassiz) in the Paraná River basin in Brazil, is confirmed by a study of its type- and voucher specimens. The present account provides strong arguments to always study museum specimens in taxonomic studies; it also represents an evidence of the importance of depositing types and vouchers in internationally recognised collections. Based on the new information provided in this study, the generic diagnoses of Brayela and Megathylacus Woodland, 1934 are amended.

First identification of eggs of the Asian fish tapeworm Bothriocephalus acheilognathi (Cestoda: Bothriocephalidea) in human stool.

We report the first case of egg isolation of the Asian fish tapeworm Bothriocephalus acheilognathi (Bothriocephalidea) from human stool. A male patient from Saint Laurent du Maroni (French Guiana) presenting abdominal pain was examined in France for the diagnosis of intestinal parasites. Diphyllobothrium-like eggs were observed in his stool. However, molecular phylogenetic analyses based on sequences of rDNA and COI genes showed that the eggs observed belong to a bothriocephalidean cestode B. acheilognathi. The adult life stages of B. acheilognathi cestodes are known as invasive parasites of a wide spectrum of fish; however, they have not been described to parasitize any mammals. This human infection seems to be accidental and represents a parasite passage through human intestine after the consumption of an infected fish host.

New species and geographical records of dactylogyrids (Monogenea) of catfish (Siluriformes) from the Peruvian Amazonia.

Three new species of gill monogeneans (Dactylogyridae: Ancyrocephalinae) are described from siluriform catfish from Iquitos, Peru: Demidospermus mortenthaleri n. sp. from Brachyplatystoma juruense (Boulenger), Demidospermus brevicirrus n. sp. from Pimelodus sp., and Aphanoblastella aurorae n. sp. from Goeldiella eques (Müller & Troschel). Demidospermus mortenthaleri is characterized by a male copulatory organ (MCO) with a small loop at its middle portion; 2 types of hooks, of which pairs 5 and 6 are longer than the remaining hooks; a proximal subunit round and highly depressed thumb; and a sclerotized vagina with a round pad at the vaginal aperture. Demidospermus brevicirrus is distinguished from other congeners by the presence of a short, straight, and robust MCO and boot-shaped accessory piece with a hooked projection directed posteriorly. Aphanoblastella aurorae is the only species of the genus that possesses an arrow-shaped sclerotized vagina and a medial process on the dorsal bar. Another 6 dactylogyrids described previously are recorded for the first time from the Peruvian Amazonia: Cosmetocleithrum bulbocirrus Kritsky, Thatcher and Boeger, 1986 ; Vancleaveus fungulus Kritsky, Thatcher and Boeger, 1986 ; V. janauacaensis Kritsky, Thatcher and Boeger, 1986 ; V. platyrhynchi Kritsky, Thatcher and Boeger, 1986 ; Unilatus unilatus Mizelle and Kritsky, 1967 ; and U. brittani Mizelle, Kritsky and Crane, 1968 . Based on observations of specimens collected in the Peruvian Amazonia, new morphological data for these species are provided. Comparison of new specimens of U. unilatus and U. brittani with those of Unilatus brevispinus Suriano, 1985 and Unilatus longispinus Suriano, 1985 , both originally described from Brazil, has shown that they are conspecific. Therefore, the latter species were synonymized with U. unilatus and U. brittani , respectively. In addition, 56 undescribed monogeneans found in catfish from the Peruvian Amazonia, some of them probably belonging to new genera, are listed.

Is the human-infecting Diphyllobothrium pacificum a valid species or just a South American population of the holarctic fish broad tapeworm, D. latum?

Using ITS2 gene sequences, the validity of the tapeworm Diphyllobothrium pacificum (Nybelin, 1931), infecting humans on the Pacific coast of South America and in Japan, was assessed. ITS2 sequences of this cestode differed markedly (sequence similarity 79.0-80.2%) from those of the most common human-infecting cestode, the broad fish tapeworm Diphyllobothrium latum (L.), as well as other four species of Diphyllobothrium, including potential human parasites (D. cordatum, D. dendriticum, and D. lanceolatum) and two species of Spirometra (sequence similarity 77.5-81.9%). Interspecific sequence similarity between all but one (D. pacificum) species was 86.1-99.6%, whereas individual isolates of D. dendriticum and D. ditremum exhibited intraspecific sequence similarity of 97.0-98.0% and 98.2-99.9%, respectively. Phylogenetic trees constructed from ITS2 sequences show a markedly distant position of D. pacificum from other species analyzed and also indicate the possible paraphyly of Spirometra.

Redescription of Alinema amazonicum (Travassos, 1960) n. comb., a philometrid nematode with unusual morphology.

Nematodes (1 male and numerous females) of the Philometridae were collected from the mesentery of 2 species of pimelodid catfishes, Calophysus macropterus and Perrunichthys perruno, from the Amazon River basin (fishmarket in Iquitos, Loreto District) in Peru. A detailed study of their morphology (including scanning electron microscopy) and a reexamination of the type and voucher specimens of Philometra amazonica Travassos, 1960, from Brazilian catfishes confirmed that they belong to this species and that Philometra (Alinema) alii Rasheed, 1963 is its junior synonym. Because of some marked morphological peculiarities of this species (presence of minute peribuccal sclerotized formations, a functional vagina and vulva in gravid female, and structure of the male tail), the validity of an independent genus, Alinema Rasheed, 1963, is confirmed, to which this species is transferred as Alinema amazonicum (Travassos, 1960) n. comb. This is the first record of this parasite from Peru, and P. perruno represents its new host record.

Cestodes of the family Dilepididae (Cestoda:Cyclophyllidea) from fish-eating birds in Mexico: a survey of species.

A survey of adults of dilepidid tapeworms (Cyclophyllidea) from piscivorous birds from Mexico is presented on the basis of the taxonomic evaluation of freshly collected and voucher specimens. The following species are reported (first records from Mexico marked with an asterisk): Cyclustera capito (Rudolphi, 1819); *C. ibisae (Schmidt & Bush, 1972); *Dendrouterina ardeae Rausch, 1955; *D. herodiae Fuhrmann, 1912; *D. papillifera (Fuhrmann, 1908); Glossocercus auritus (Rudolphi, 1819); *Neogryporhynchus cheilancristrotus (Wedl, 1855); Paradilepis caballeroi Rysavy & Macko, 1973; Paradilepis sp.; Parvitaenia cochlearii Coil, 1955; and Valipora mutabilis Linton, 1927. Dendrouteria herodiae is reported from America for the first time. New definitive hosts are Phalacrocorax olivaceus for C. capito, N. cheilancristrotus and P. caballeroi; Casmerodius albus and Egretta thula for G. auritus; and E. thula for D. herodiae. Data on the morphology of the rostellar hooks of all species, their hosts and distribution in Mexico are provided.