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This work aimed to review the main epidemiological data on zoonotic nematodes parasitizing tilapia of the genus Oreochromis (Perciformes: Cichlidae) with socioeconomic importance. The literature review was conducted in six specialized search engines, and a total of 320 articles were analyzed. After eliminating documents with duplicated information or those that did not refer to zoonotic nematodes in cichlids, 10 bibliographic sources were processed. The analysis showed that the available documentation refers mainly to the genera Gnathostoma in America and Contracaecum in Africa, while data are scarce in Europe, Asia, and Oceania. This work includes information on prevalence, distribution, and diagnosis, both from natural and artificial environments. In conclusion, data on the epidemiology of zoonotic nematodes that parasitize tilapia of the genus Oreochromis are scarce, so attention should be paid to monitoring economically important fish to prevent parasitological problems in the production chain. [ABSTRACT FROM AUTHOR]

ABSTRACT We report a case of eosinophilic meningitis associated with the ingestion of raw fish (Cichla sp.) from the Brazilian Amazon, likely caused by Gnathostoma. A 36-year-old male visited Juruena river on a fishing trip. After 50 days, the patient presented with an intense frontal headache. A cerebrospinal fluid examination revealed 63% eosinophilia. Another individual who ingested raw fish developed linear dermatitis on the abdominal wall. Anti-Gnathostoma serum antibodies were detected, and the patient made a full recovery after treatment with corticosteroids and albendazole. To date, autochthonous Gnathostoma spp. infections in Latin American countries have only caused linear panniculitis. This report raises awareness of gnathostomiasis-causing meningitis.

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The purpose of this article is to report a case of ocular gnathostomiasis presenting with acute anterior uveitis and uveitis glaucoma. observational case report and literature review. A 56-year-old Thai male was referred to a tertiary eye center with acute anterior uveitis and uveitis glaucoma in the right eye. A nematode was found in the right anterior chamber. Surgical removal of the nematode was successfully performed. Gnathostoma spinigerum was the nematode identified on pathological examination. Early detection of the parasite and timely surgical removal is the key to the management of ocular gnathostomiasis. [ABSTRACT FROM AUTHOR]

A 53-year-old woman from São Paulo, Brazil, developed migratory swelling and skin lesions after consuming raw fish during a trip to the Amazon region. Her family members also developed similar lesions. After failed self-treatment, the woman sought medical help and was eventually diagnosed with Gnathostoma spp. infection, a parasitic disease caused by larvae found in raw or undercooked freshwater fish. Treatment with albendazole resulted in the regression of the lesions. Gnathostomiasis is a zoonotic disease that is prevalent in tropical and subtropical regions and is often associated with the consumption of infected fish. [Extracted from the article]

The origin and early diversification of jawed vertebrates involved major changes to skeletal and soft anatomy. Skeletal transformations can be examined directly by studying fossil stem gnathostomes; however, preservation of soft anatomy is rare. We describe the only known example of a three-dimensionally mineralized heart, thick-walled stomach, and bilobed liver from arthrodire placoderms, stem gnathostomes from the Late Devonian Gogo Formation in Western Australia. The application of synchrotron and neutron microtomography to this material shows evidence of a flat S-shaped heart, which is well separated from the liver and other abdominal organs, and the absence of lungs. Arthrodires thus show the earliest phylogenetic evidence for repositioning of the gnathostome heart associated with the evolution of the complex neck region in jawed vertebrates. [ABSTRACT FROM AUTHOR]

Background: Several lists of marine fish from Azores have been published in the past. Most of those publications are difficult to access on line and several were not published in peer-reviewed journals. New information: This checklist updates all the chondrichthyan records for the Azores Exclusive Economic Zone (EEZ), according to the most recent taxonomic classification of cartilaginous fish, as well as providing information on the conservation status for all species. We also present recent literature data on rare species and recent records for Azores. This is the first comprehensive list of cartilaginous fishes from Azores to be published in the GBIF database. [ABSTRACT FROM AUTHOR]

Abstract: Gnathostomiasis is a parasitic infection caused by the third larval stage of nematodes of the genus Gnathostoma. The disease is endemic in some countries around the world. In the American continent, the majority of cases is concentrated in Mexico, Ecuador, and Peru. However, due to increasing traveling either at the intercontinental or intracontinental level, the disease is seen each time more frequently in tourists. Furthermore, countries, such as Brazil, that have never been considered endemic are reporting autochthonous cases. The disease usually presents as a deep-seated or slightly superficial migratory nodule in patients with history of eating raw fish, in the form of ceviche, sushi, or sashimi. Along with the clinical presentation, diagnostic criteria include either blood or tissue eosinophilia. In most instances, these criteria are enough for the attending physician to institute therapy. Chances of finding the parasite are low, unless the biopsy is taken from a very specific area that develops after antiparasitic treatment is started. The potential of other organ involvement with more serious consequences should always be kept in mind.

Abstract The genus Gnathostoma comprises 17 species, whose adult specimens are found in the stomach serosa of animals that consume raw fish; some species of the genus are zoonotic agents. The present study describes the presence of a nematode (Gnathostomatidae) parasitizing the digestive tract of Colomesus psittacus in the Ilha de Marajó in the eastern Brazilian Amazon. Thirty specimens of C. psittacus were collected in the municipality of Soure, Ilha de Marajó, state of Pará, Brazil, transported to the laboratory, necropsied and the helminths were collected and fixed. Of the 30 fish that were studied, 16.67% were parasitized with nematodes. The nematode larvae found encysted in the intestinal serosa have anterior region with two lips, each with a pair of papillae; a cephalic bulb armed with six rows of discontinuous spines; four cervical sacs; a claviform esophagus; cuticular striations along the body; a simple excretory pore; and a short tail ending in a mucron. These morphological structures are diagnostic characters of the genus Gnathostoma, whose adults parasitize the stomach of carnivorous mammals and, rarely, the stomach of fish. However, fish, amphibians, reptiles, and birds are intermediate hosts of the third-stage larvae (L3), and humans may act as accidental hosts.

The five years (2007-2012) consecutive parasitological investigations on freshwater crowfish, Xenentodon cancila conducted to learn the events in autogenic life cycle of Sturdynema multiembryonata. The S. multiembryonata is a roundworm with sturdy, spiny body in fresh water garfish peculiarly found taxonomically closer to gnathostomatoid roundworms. The developmental patterns and migratory behavior within the host was worked out critically. The findings were experimentally validated by oral feeding of eggs and developmental stages in dehelminthized experimental Swiss albino mice. The findings reflected exceptionally large body of advanced 3rd stage larva (AdvL3) displayed strong possibility of precocious development, which was at least four times in size than any of the gnathostomatoid worms reported so far. The presence of caudal papillae resembling roundish bosses described in Gnathostoma lamothei and G. miyazakii with peculiar single-spined ornamentation all over the body. The study concludes that the larvae of S. multiembryonata, reported here, may not enter into 4th stage of development, and advanced 3rd stage larvae (AdvL3) might transform into mature forms in a newer habitat, i.e. liver, within the body of newly reported definitive hosts, X. cancila. The establishment of larvae, without moulting, beyond the 3rd stage to attain maturity in the liver of experimental rodent hosts, corroborated the findings in natural fish definitive hosts. In the current investigation author wish to explore the precocious and autogenic development of S. multiembryonata, a roundworm with zoonotic potential which may provide a new dimension in the maintenance of healthy and disease free society based upon aquaculture. [ABSTRACT FROM AUTHOR]

Gnathostomiasis, an emerging food-borne parasitic zoonosis in Asia, is mainly caused by Gnathostoma spinigerum (Nematoda: Gnathostomatidae). Consumption of raw meat or freshwater fishes in endemic areas is the major risk factor. Throughout Southeast Asia, including Thailand, Lao PDR, Cambodia, and Myanmar, freshwater fish are often consumed raw or undercooked. The risk of this practice for gnathostomiasis infection in Lao PDR, Cambodia, and Myanmar has never been evaluated. Here, we identified larvae of Gnathostoma species contaminating freshwater fishes sold at local markets in these three countries. Public health authorities should advise people living in, or travelling to, these areas to avoid eating raw or undercooked freshwater fishes. Identification of larvae was done using molecular methods: DNA was sequenced from Gnathostoma advanced third-stage larvae recovered from snakehead fishes (Channa striata) and freshwater swamp eels (Monopterus albus). Phylogenetic analysis of a portion of the mitochondrial cytochrome c oxidase subunit I gene showed that the G. spinigerum sequences recovered from southern Lao PDR, Cambodia, and Myanmar samples had high similarity to those of G. spinigerum from China. Sequences of the nuclear ribosomal DNA internal transcribed spacer 2 region closely resembled sequences of G. spinigerum from Thailand, Indonesia, the USA, and central Lao PDR. This is the first molecular evidence of G. spinigerum from freshwater fishes in southern Lao PDR, Cambodia, and Myanmar. [ABSTRACT FROM AUTHOR]

The article focuses on the Body Brewery, a model that aims to address the incidence of temporomandibular joint problems. The central nervous system acts as the brewer and controls the ingredients as well as work with other systems including the cardiovascular and pulmonary systems. The gastrointestinal system operates with non-functioning or missing parts while the gnathostomatic system represents a small barrel in a corner of the brewery and is considered unique because of several factors. Muscle activity is said to be important within the gnathostomatic system which is a complicated unit in the body brewery.

La gnatostomiasis es una zoonosis parasitaria causada por algunas especies del género de helmintos Gnathostoma. La presentación clínica es muy variada y su diagnóstico constituye un desafío; es endémica en países tropicales y subtropicales, y la transmisión se asocia con el consumo de carne de animales acuáticos, cruda o mal cocida. En las últimas décadas, el creciente turismo internacional y el consumo de alimentos exóticos, han provocado un notable aumento de casos de la enfermedad. En nuestro país no se ha reportado ningún caso confirmado de gnatostomiasis. Se presenta el caso de un hombre colombiano de 63 años de edad, viajero frecuente al exterior, que consultó por presentar síntomas gastrointestinales. Durante la hospitalización desarrolló una lesión cutánea en el flanco abdominal derecho, de la cual se extrajo una larva cuya descripción morfológica permitió clasificarla como Gnathostoma spinigerum. Se trata de la primera confirmación de un caso importado de gnatostomiasis en Colombia. En este artículo se discuten las generalidades, la etiología, la patogenia y el tratamiento de la enfermedad, con especial énfasis en las características particulares de este paciente.

Copyright of Parasite (1252607X) is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fish-borne zoonotic nematodes may infect humans when fish or squid are ingested raw or inadequately cooked. Human infections may have serious consequences, including the unexpected deaths of infected people. This kind of disease is poorly known in general, and the characteristics of such infections in South American countries as a whole have never been assessed. In this paper the present status of fish-borne nematodiases in humans in South American countries is characterized. Potentially zoonotic nematode species are very common in both freshwater and marine fish in South America. Reports of human infections have only been found in some countries, and their incidence (especially with anisakids and Gnathostoma spp.) varies from country to country. Apparently they are more abundant in countries with strong traditions of eating raw fish, and are more frequent on the western coast of South America. So far fish-borne nematodes have been reported in Argentina, Brazil, Chile, Colombia, Ecuador and Peru. In recent years, cases of human infection have appeared in probably underestimated numbers. People need to be clearly informed about risky feeding habits, and physicians need to learn more about zoonotic diseases. [ABSTRACT FROM AUTHOR]

The acquisition of a movable jaw and a jaw joint are key events in gnathostome evolution. Jaws are derived from the neural crest derived pharyngeal skeleton and the transition from jawless to jawed vertebrates consists of major morphological changes, which must have a genetic foundation. Recent studies on the effects of bapx1 knockdown in fish and chicken indicate that bapx1 has acquired such a role in primary jaw joint development during vertebrate evolution, but evidence from amphibians is missing so far. In the present study, we use Ambystoma mexicanum, Bombina orientalis, and Xenopus laevis to investigate the effects of bapx1 knockdown on the development of these three different amphibians. Using morpholinos we downregulated the expression of bapx1 and obtain morphants with altered mandibular arch morphology. In the absence of bapx1 Meckeĺs cartilage and the palatoquadrate jaw joint initially develop separately but during further development the joint cavity between both fills with chondrocytes. This results in the fusion of both cartilages and the loss of the jaw joint. Despite this the jaw itself remains usable for feeding and breathing. We show that bapx1 plays a role in jaw joint maintenance during development and that the morphants morphology possibly mirrors the morphology of the jawless ancestors of the gnathostomes. [ABSTRACT FROM AUTHOR]

Placoid and polyodontode scales of stem chondrichthyans have been found in the early Lochkovian "Ditton Group" of the Brown Clee Hill district, Shropshire, England and at Talgarth, south Wales. One of the forms is assigned to a new species of Altholepis Karatajūtė-Talimaa, 1997, a genus already recognised from Lochkovian shallow marine deposits in Celtiberia, Spain and the Northwest Territories, Canada as well as the type locality in Podolia, Ukraine. Altholepis salopensis sp. nov. is based on small polyodontode scales with typically three to eight high odontodes; the scale form was previously considered to belong to acanthodian "Nostolepis" robusta (Brotzen, 1934). The structure of other scales formerly assigned to "Nostolepis" robusta has led us to erect a new genus Jolepis for this scale form, which differs from Altholepis in lacking an ordered layout of odontodes. Jolepis robusta (Brotzen, 1934), originally (and possibly still) considered to be an acanthodian, is also known from the Baltic countries, Russia, and northern Germany (ex erratic limestones). Scales of acanthodian Parexus recurvus Agassiz, 1845, and/or possibly from the stem chondrichthyan Seretolepis elegans Karatajūtė-Talimaa, 1968 (scales of these two taxa are barely distinguishable), and of stem chondrichthyan Polymerolepis whitei Karatajūtė-Talimaa, 1968 are also present. Altholepis, Jolepis gen. nov., Seretolepis Karatajūtė-Talimaa, 1968 and Polymerolepis Karatajūtė-Talimaa, 1968 are found in marine deposits elsewhere; the British occurrence of these taxa adds to the debate on the sedimentological origins of the Lower Old Red Sandstone deposits in the Welsh Borderland. The geographic range of several early sharks is now known to extend around the Old Red Sandstone continent and beyond. [ABSTRACT FROM AUTHOR]

While infection by Gnathostoma turgidum (Stossich) in the definitive host, the Virginian opossum, Didelphis virginiana (Kerr), has been described in wildlife, the complete life cycle of the parasite is unknown. Development of early third-stage larvae of Gnathostoma spp. in vitro-infected cyclopoids has been evaluated previously. However, factors involved in viability of copepods as first-intermediate hosts for G. turgidum and that maintain the life cycle of the parasite in endemic areas of gnathostomosis have not been well studied. In this study, in vitro capability of Mesocyclops edax (Forbes) to ingest second-stage larvae of G. turgidum, and density-dependence relationship with the parasitic load were determined. Average ingestion of 1:5, 1:10, and 1:15 densities were 3.5 ± 0.3, 7.5 ± 0.6, and 10.8 ± 1.0, respectively; whereas parasitic loads of each density in M. edax after interaction were 1.7 ± 0.3, 2 ± 0.3, and 1.8 ± 0.3. Parasitic loads of copepods exposed to each density of second-stage larvae were not statistically different. Ingestion capacity by M. edax in vitro for larvae was directly proportional to density of larvae. However, the parasitic load tended to remain constant regardless of density of larvae to which the copepod was exposed. The behavior might be limited by the size of the host or co-evolutionary strategies that favor viability and maintenance of the life cycle of the parasite in wildlife. [ABSTRACT FROM AUTHOR]

The subdivision of the gnathostome neurocranium into an anterior neural crest-derived moiety and a posterior mesodermal moiety has attracted the interest of researchers for nearly two centuries. We present a synthetic scenario for the evolution of this structure, uniting developmental data from living cyclostomes and gnathostomes with morphological data from fossil stem gnathostomes in a common phylogenetic framework. Ancestrally, vertebrates had an anteroposteriorly short forebrain, and the neurocranium was essentially mesodermal; skeletal structures derived from premandibular ectomesenchyme were mostly anterior to the brain and formed part of the visceral arch skeleton. The evolution of a one-piece neurocranial 'head shield' in jawless stem gnathostomes, such as galeaspids and osteostracans, caused this mesenchyme to become incorporated into the neurocranium, but its position relative to the brain and nasohypophyseal duct remained unchanged. Basically similar distribution of the premandibular ectomesenchyme is inferred, even in placoderms, the earliest jawed vertebrates, in which the separation of hypophyseal and nasal placodes obliterated the nasohypophyseal duct, leading to redeployment of this ectomesenchyme between the separate placodes and permitting differentiation of the crown gnathostome trabecula that floored the forebrain. Initially this region was very short, and the bulk of the premandibular cranial part projected anteroventral to the nasal capsule, as in jawless stem gnathostomes. Due to the lengthening of the forebrain, the anteriorly projecting 'upper lip' was lost, resulting in the modern gnathostome neurocranium with a long forebrain cavity floored by the trabeculae. [ABSTRACT FROM AUTHOR]

Human gnathostomiasis is a food-borne zoonosis caused by a tissue nematode of the genus Gnathostoma. The disease is highly endemic in Asia, including Thailand. The freshwater swamp eel (Monopterus albus), the second intermediate host of the gnathostome nematode, has an important role in transmitting the infection in Thailand. Surveys on the infective larvae of Gnathostoma spinigerum based on morphological features in freshwater swamp eels have been performed continuously and reported in Thailand. However, there is still limited molecular data on intra-species variations of the parasite. In this study, a total of 19 third-stage larvae of morphologically identified G. spinigerum were collected from 437 liver samples of freshwater swamp eels purchased from a large wholesale market in Bangkok, Thailand. Molecular characterization based on mitochondrial cytochrome c oxidase subunit I (COI) sequences was performed to elucidate their genetic variations and phylogenetic relationship. Among the 19 infective larvae recovered from these eels, 16 were sequenced successfully. Phylogenetic analyses inferred from the partial COI gene showed the presence of three distinct COI haplotypes. Our findings confirm the presence of G. spinigerum as the main species in Thailand. [ABSTRACT FROM AUTHOR]

Human gnathostomiasis caused by third-stage Gnathostoma spinigerum larvae ( G. spinigerum L3) is an important zoonotic disease in tropical areas of the world. The excretory-secretory products (ES) that are excreted by infective larva play a significant role in host immune evasion and tissue destruction. To investigate the poorly understood mechanisms of G. spinigerum L3 pathogenesis, we focused on the potential effect of ES on inducing apoptosis in human immune cells by using human peripheral blood mononuclear cells (PBMCs) as a model. Early and late apoptosis of PBMCs were assessed following the exposure of these cells to G. spinigerum L3 ES (0.1, 0.5, and 1.0 μg/ml) for 6-48 h. The apoptotic cells were identified by flow cytometric staining of PBMC with FITC-annexin V and propidium iodide. The expression of regulatory genes related to apoptosis mechanisms in ES-treated PBMCs was investigated using a Human Apoptosis RT Profiler™ PCR Array. The results showed significant levels of early phase apoptosis at 18 h and of late phase apoptosis at 24 h. We speculate that this apoptosis in PBMCs occurs via the extrinsic pathway. Apoptosis in the ES-induced PBMCs was observed as quickly as 90 min after exposure, and the highest effect was observed at 18-24 h. Furthermore, ES can trigger apoptosis lasting for 48 h. Our findings expand the understanding of one of the mechanisms involved, immune-evasive strategy mechanism used by G. spinigerum larvae during human gnathostomiasis. [ABSTRACT FROM AUTHOR]

Background: The origin of jawed vertebrates was marked by profound reconfigurations of the skeleton and muscles of the head and by the acquisition of two sets of paired appendages. Extant cartilaginous fish retained numerous plesiomorphic characters of jawed vertebrates, which include several aspects of their musculature. Therefore, myogenic studies on sharks are essential in yielding clues on the developmental processes involved in the origin of the muscular anatomy. Results: Here we provide a detailed description of the development of specific muscular units integrating the cephalic and appendicular musculature of the shark model, Scyliorhinus canicula. In addition, we analyze the muscle development across gnathostomes by comparing the developmental onset of muscle groups in distinct taxa. Our data reveal that appendicular myogenesis occurs earlier in the pectoral than in the pelvic appendages. Additionally, the pectoral musculature includes muscles that have their primordial developmental origin in the head. This culminates in a tight muscular connection between the pectoral girdle and the cranium, which founds no parallel in the pelvic fins. Moreover, we identified a lateral to ventral pattern of formation of the cephalic muscles, that has been equally documented in osteichthyans but, in contrast with these gnathostomes, the hyoid muscles develop earlier than mandibular muscle in S. canicula. Conclusion: Our analyses reveal considerable differences in the formation of the pectoral and pelvic musculatures in S. canicula, reinforcing the idea that head tissues have contributed to the formation of the pectoral appendages in the common ancestor of extant gnathostomes. In addition, temporal differences in the formation of some cranial muscles between chondrichthyans and osteichthyans might support the hypothesis that the similarity between the musculature of the mandibular arch and of the other pharyngeal arches represents a derived feature of jawed vertebrates. [ABSTRACT FROM AUTHOR]

Background: Fishes are extremely speciose and also highly disparate in their fin configurations, more specifically in the number of fins present as well as their structure, shape, and size. How they achieved this remarkable disparity is difficult to explain in the absence of any comprehensive overview of the evolutionary history of fish appendages. Fin modularity could provide an explanation for both the observed disparity in fin configurations and the sequential appearance of new fins. Modularity is considered as an important prerequisite for the evolvability of living systems, enabling individual modules to be optimized without interfering with others. Similarities in developmental patterns between some of the fins already suggest that they form developmental modules during ontogeny. At a macroevolutionary scale, these developmental modules could act as evolutionary units of change and contribute to the disparity in fin configurations. This study addresses fin disparity in a phylogenetic perspective, while focusing on the presence/absence and number of each of the median and paired fins. Results: Patterns of fin morphological disparity were assessed by mapping fin characters on a new phylogenetic supertree of fish orders. Among agnathans, disparity in fin configurations results from the sequential appearance of novel fins forming various combinations. Both median and paired fins would have appeared first as elongated ribbon-like structures, which were the precursors for more constricted appendages. Among chondrichthyans, disparity in fin configurations relates mostly to median fin losses. Among actinopterygians, fin disparity involves fin losses, the addition of novel fins (e.g., the adipose fin), and coordinated duplications of the dorsal and anal fins. Furthermore, some pairs of fins, notably the dorsal/anal and pectoral/pelvic fins, show non-independence in their character distribution, supporting expectations based on developmental and morphological evidence that these fin pairs form evolutionary modules. Conclusions: Our results suggest that the pectoral/pelvic fins and the dorsal/anal fins form two distinct evolutionary modules, and that the latter is nested within a more inclusive median fins module. Because the modularity hypotheses that we are testing are also supported by developmental and variational data, this constitutes a striking example linking developmental, variational, and evolutionary modules. [ABSTRACT FROM AUTHOR]

Gnathostomiasis is a foodborne zoonotic parasitosis caused by Gnathostoma nematodes. It has caused significant public problems worldwide, but its molecular biology is limited. The purpose of this study was to decode the complete mitochondrial (mt) genomes of Gnathostoma nipponicum and Gnathostoma sp., and compare their mt sequences with other Gnathostoma species. The complete mt genome sequences were amplified by long-range PCR and determined by subsequent primer walking. The complete mt genomes of G. nipponicum and Gnathostoma sp. were 14,093 bp and 14,391 bp, respectively. Both of the two mt genomes contain 12 protein-coding genes (PCGs), 2 ribosomal RNA genes and 22 transfer RNA genes. The gene order and transcription direction are the same as G. spinigerum and G. doloresi . The sequence difference across the entire mt genomes varied from 14.4% to 18.2% between G. nipponicum , Gnathostoma sp., G. spinigerum and G. doloresi of Japan and China isolates. Phylogenetic analyses by Bayesian inference (BI) using concatenated amino acid sequences of 12 PCGs showed that G. nipponicum and Gnathostoma sp. are two distinctive species of Gnathostoma , and G. nipponicum are more closely related to Gnathostoma sp. than to G. spinigerum . The mtDNA datasets provide abundant resources of novel markers, which can be used for the studies of molecular epidemiology and diagnosis of Gnathostoma spp. [ABSTRACT FROM AUTHOR]

To date, more than 20 species of the genus Gnathostoma have been described as parasites of mammals, 9 of them in the Americas. However, the taxonomic status of some of these species has been questioned. The main goal of this study is to clarify the validity of the American species included in the genus. In order to complete this objective, we analyze type and/or voucher specimens of all these species deposited in 6 scientific collections, through morphometric and ultrastructural studies. Based on diagnostic traits as host specificity, site of infection, body size, cuticular spines, presence of 1 or 2 bulges in the polar ends of eggs, as well as eggshell and caudal bursa morphology, we re-establish Gnathostoma socialis (Leidy, 1858) and confirm the validity of other 6 species: Gnathostoma turgidum Stossich, 1902, Gnathostoma americanum Travassos, 1925, Gnathostoma procyonis Chandler, 1942, Gnathostoma miyazakii Anderson, 1964, Gnathostoma binucleatum Almeyda-Artigas, 1991, and Gnathostoma lamothei Bertoni-Ruiz, García-Prieto, Osorio-Sarabia and León-Règagnon, 2005. Gnathostoma didelphis Chandler, 1932 and Gnathostoma brasiliensis Ruiz, 1952 are considered synonyms of G. turgidum. Finally, based on a wide revision of specimens deposited in 6 American collections, we conclude that records of Gnathostoma spinigerum Owen, 1836 in the Americas are invalid.A la fecha, se han descrito más de 20 especies del género Gnathostoma parásitas de mamíferos, 9 de ellas en America. Sin embargo, el estado taxonómico de algunas ha sido cuestionado. El objetivo de este estudio es aclarar la validez de las especies americanas incluidas en el género. Para ello, se analizaron ejemplares tipo o de referencia de todas las especies, depositados en 6 colecciones científicas, mediante estudios morfométricos y ultraestructurales. Con base en rasgos diagnósticos como especificidad hospedatoria, sitio de infección, dimensiones corporales, espinas cuticulares (número de puntas, densidad, forma y distribución), presencia de uno ó dos tapones polares en los huevos, así como morfología de la bursa, patrón papilar y de la cubierta de los huevos, se re-establece a Gnathostoma socialis (Leidy, 1858) y se confirma la validez de otras 6 especies: Gnathostoma turgidum Stossich, 1902, Gnathostoma americanum Travassos, 1925, Gnathostoma procyonis Chandler, 1942, Gnathostoma miyazakii Anderson, 1964, Gnathostoma binucleatum Almeyda-Artigas, 1991 y Gnathostoma lamothei Bertoni-Ruiz, García-Prieto, Osorio Sarabia y León-Règagnon, 2005. Gnathostoma didelphis Chandler, 1932 y Gnathostoma brasiliensis Ruiz, 1952 son consideradas sinónimos de G. turgidum. Basados en una amplia revisión de material depositado en 6 colecciones Americanas, se invalidan los registros de Gnathostoma spinigerum Owen, 1836 en America.

A gnatostomíase é parasitose endêmica em alguns países asiáticos, causada pela ingestão da larva do nematódio Gnathostoma sp, que pode ocorrer no consumo de carne crua de peixes de água doce. Atinge vários órgãos, entre eles a pele, manifestando-se frequentemente como lesão subcutânea migratória. Países da América Central e do Sul como México e Peru vêm apresentando número crescente de casos da doença desde 1970. Este trabalho registra o primeiro caso notificado e publicado no Brasil e alerta para o surgimento dessa doença em áreas anteriormente não endêmicas. Relata-se caso de paciente, com história de viagem ao Peru, que evoluiu com quadro cutâneo compatível com gnatostomíase.Gnathostomiasis is an endemic disease in Asian countries caused by the ingestion of larval stage of Gnathostoma sp roundworms that may be acquired by eating raw fresh-water fish. It can reach many organs and the skin is one of them, characterized by creeping eruptions and/or migrating erythema. Since 1970 the number of patients affected seems to be increasing in Central and South America countries like Mexico and Peru. This is the first notification and publication of gnathostomiasis in Brazil, and it serves as an alert to the possibility of the emergence of this disease in non-endemic areas. We report a case of a man who traveled to Peru and developed cutaneous features accordant with gnathostomiasis.

In vertebrates, there are four major genes in the RH (Rhesus) gene family, RH , RHAG , RHBG , and RHCG . These genes are thought to have been formed by the two rounds of whole-genome duplication (2R-WGD) in the common ancestor of all vertebrates. In our previous work, where we analyzed details of the gene duplications process of this gene family, three nucleotide sequences belonging to this family were identified in Far Eastern brook lamprey ( Lethenteron reissneri ), and the phylogenetic positions of the genes were determined. Lampreys, along with hagfishes, are cyclostomata (jawless fishes), which is a sister group of gnathostomata (jawed vertebrates). Although those results suggested that one gene was orthologous to the gnathostome RHCG genes, we did not identify clear orthologues for other genes. In this study, therefore, we identified three novel cDNA sequences that belong to the RH gene family using de novo transcriptome analysis of another cyclostome: the brown hagfish ( Eptatretus atami ). We also determined the nucleotide sequences for the RHBG and RHCG genes in a red stingray ( Dasyatis akajei ), which belongs to the cartilaginous fishes. The phylogenetic tree showed that two brown hagfish genes, which were probably duplicated in the cyclostome lineage, formed a cluster with the gnathostome RHAG genes, whereas another brown hagfish gene formed a cluster with the gnathostome RHCG genes. We estimated that the RH genes had a higher evolutionary rate than the RHAG , RHBG , and RHCG genes. Interestingly, in the RHBG genes, only the bird lineage showed a higher rate of nonsynonymous substitutions. It is likely that this higher rate was caused by a state of relaxed functional constraints rather than positive selection nor by pseudogenization. [ABSTRACT FROM AUTHOR]

Ten species of the genus Lista are recognized from China. Among them, five species are described as new to science, namely, L. angustusa sp. n., L. gilvasa sp. n., L. longifundamena sp. n., L. menghaiensis sp. n., and L. sichuanensis sp. n. Diagnoses are provided for the genus and five previously described species, L. haraldusalis (Walker, 1859), L. insulsalis (Lederer, 1863), L. ficki (Christoph, 1881), L. plinthochroa (West, 1931), and L. variegata (Moore, 1888), that occur in China. Two species, L. plinthochroa and L. variegata, are reported from China for the first time. All adults and their genital structures are illustrated. A key to the Chinese species is provided. [ABSTRACT FROM AUTHOR]

Background: Spinal gnathostomiasis results in serious multiorgan impairments. Magnetic resonance imaging (MRI) and serology help in diagnosis, and assessing the severity and extent of the disease. However, the physiology of neural pathway could not be demonstrated. Electrodiagnosis may have a role in demonstrating the functions of the central and peripheral neural pathways and prognostic assessment of the disease. Material and Method: An 18-year-old man presented with radicular pain and rapid progressive weakness of lower extremities, leading to paraplegia in three days. A clinical evaluation and laboratory tests, including serology, MRI, and electrodiagnosis, were performed. Results: The investigation showed L1 paraplegia with urinary retention. The serial MRI of T-spine showed longitudinal T2 hypointense lesion along the lower thoracic spinal cord, representing track-like hemorrhage with spinal cord edema at the onset of symptoms, nodular enhancement of T11-T12 spinal cord, and enhancing and clumping of cauda equina nerve roots in the MRI at two months after the first MRI. The CSF and serum for Gnathostoma antibody were positive. Intravenous corticosteroid and oral albendazole were given. Three months after treatment, the symptoms improved in sensation but not in motor function. The electrodiagnosis was performed. There were very small amplitudes and no response in bilateral tibial and peroneal motor nerve conduction studies (NCS) respectively. The bilateral sural sensory NCS were normal. Neither tibial somato-sensory evoke potentials (SSEP) nor motor evoke potential (MEP) was recorded. No further improvement of patient's clinical status at eight months after onset was observed. Conclusion: Electrophysiological findings demonstrated the function of spinal cord and peripheral nerves in the patient with spinal gnathostomiasis. There were correlations between MRI and electrophysiological findings that confirmed pathophysiology of the disease. Absence of SSEP and MEP response correlated with poor neurological outcomes in radiculomyelitis caused by Gnathostoma spp. infection. [ABSTRACT FROM AUTHOR]

Gnathostoma doloresi is one of the neglected pathogens causing gnathostomiasis. Although this zoonotic parasite leads to significant socioeconomic concerns globally, little is known of its genetics and systematics. In the present study, we sequenced and characterized the complete mitochondrial (mt) genomes of G. doloresi isolates from China and Japan. The lengths of the mt genomes of the G. doloresi China and Japan isolates are 13,809 and 13,812 bp, respectively. Both mt genomes encode 36 genes, including 12 protein-coding genes (PCGs), 2 ribosomal RNA genes, and 22 transfer RNA genes. The gene order, transcription direction, and genome content are identical with its congener G. spinigerum. Phylogenetic analyses based on concatenated amino acid sequences of 12 PCGs by Bayesian inference (BI) indicated that G. doloresi are closely related to G. spinigerum. Our data provide an invaluable resource for studying the molecular epidemiology, phylogenetics, and population genetics of Gnathostoma spp. and should have implications for further studies of the diagnosis, prevention, and control of gnathostomiasis in humans and animals. [ABSTRACT FROM AUTHOR]

It has been postulated that the emergence of vertebrates was made possible by the acquisition of neural crest cells, which then led to the development of evolutionarily advantageous complex head structures ( Gans and Northcutt, 1983 ). In this regard the contribution of one important neural crest derivative—the peripheral myelin sheath—to the success of the vertebrates has to be pointed out. Without this structure, the vertebrates, as we know them, simply could not exist. After briefly reviewing the major functions of the myelin sheath we will ask and provide tentative answers to the following three questions: when during evolution has myelin first appeared? Where has myelin initially appeared: in the CNS or in the PNS? Was it necessary to acquire a new cell type to form a myelin sheath? Careful examination of fossils lead us to conclude that myelin was acquired 425 MY ago by placoderms, the earliest hinge-jaw fishes. I argue that the acquisition of myelin during evolution has been a necessary prerequisite to permit gigantism of gnathostome species, including the sauropods. I propose that this acquisition occurred simultaneously in the PNS and CNS and that myelin forming cells are the descendants of ensheathing glia, already present in invertebrates, that have adapted their potential to synthesize large amount of membrane in response to axonal requirements. This article is part of a Special Issue entitled SI: Myelin Evolution . [ABSTRACT FROM AUTHOR]

Background: Pharyngeal segmentation is a defining feature of vertebrate embryos and is apparent as a series of bulges found on the lateral surface of the embryonic head, the pharyngeal arches. The ancestral condition for gnathostomes is to have seven pharyngeal segments: jaw, hyoid, and five posterior branchial arches. However, within the sarcopterygians, the pharyngeal region has undergone extensive remodelling that resulted in a reduction in the number of pharyngeal segments, such that amniotes have only five pharyngeal arches. The aim of this study is to probe the developmental basis of this loss of pharyngeal segments. Results: We have therefore compared the development of the pharyngeal arches in an amniote, the chick, which has five segments, with those of a chondrichthyan, the catshark, which has seven segments. We have analysed the early phase of pharyngeal segmentation and we find that in both the most anterior segments form first with the posterior segments being added sequentially. We also documented the patterns of innervation of the pharynx in several vertebrates and note that the three most anterior segments receive distinct innervation: the first arch being innervated by the Vth nerve, the second by the VIIth and the third by the IXth. Finally, we have analysed Hox gene expression, and show that the anterior limit of Hoxa2 aligns with the second pouch and arch in both chick and catshark, while Hoxa3 is transiently associated with the third arch and pouch. Surprisingly, we have found that Hoxb1 expression is spatially and temporally dynamic and that it is always associated with the last most recently formed pouch and that this domains moves caudally as additional pouches are generated. Conclusion: We propose that the first three pharyngeal segments are homologous, as is the posterior limit of the pharynx, and that the loss of segments occurred between these two points. We suggest that this loss results from a curtailment of the posterior expansion of the pharyngeal endoderm in amniotes at relatively earlier time point, and thus the generation of fewer segments. [ABSTRACT FROM AUTHOR]

A 21-year-old vegetarian lady presenting with migratory erythema and pain in her right hand subsequently developed a blister on the palm. A worm-like structure came out of the wound and was identified as Gnathostoma spp. adult male worm. It is a very rare cause of creeping eruptions and so far only one case of cutaneous gnathostomiasis caused by a larva has been reported from India. This is the first case of cutaneous gnathostomiasis due to an adult Gnathostoma spp. in India.