Molecular Identification of Anisakis Larvae Extracted by Gastrointestinal Endoscopy from Health Check-up Patients in Korea.

Anisakiasis is a zoonotic disease induced by anisakid nematodes, and endoscopic inspection is used for a diagnosis or remedy for it. Anisakis simplex, Anisakis physeteris, and Pseudoterranova decipiens had been reported to be the major species causing human infections, particularly, in Japan. However, in Korea, recent studies strongly suggested that Anisakis pegreffii is the major species of human infections. To support this suggestion, we collected anisakid larvae (n=20) from 20 human patients who were undergone gastrointestinal endoscopy at a health check-up center in Korea, and molecular identification was performed on the larvae using PCR-RFLP analysis and gene sequencing of rDNA ITS regions and mtDNA cox2. In addition, anisakid larvae (n=53) collected from the sea eel (Astroconger myriaster) were also examined for comparison with those extracted from humans. The results showed that all human samples (100%) were identified as A. pegreffii, whereas 90.7% of the samples from the sea eel were A. pegreffii with the remaining 9.3% being Hysterothylacium aduncum. Our study confirmed that A. pegreffii is the predominant species causing human anisakiasis in Korea, and this seems to be due to the predominance of this larval type in the fish (sea eels) popularly consumed by the Korean people. The possibility of human infection with H. aduncum in Korea is also suggested.

Genetic diversity of infective larvae of Gnathostoma spinigerum (Nematoda: Gnathostomatidae) in freshwater swamp eels from Thailand.

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.

Neoascarophis sinensis n. sp. (Nematoda: Cystidicolidae), a parasite of Conger myriaster (Brevoort) (Anguilliformes: Congridae) in Chinese waters.

Neoascarophis sinensis n. sp. collected from the whitespotted conger Conger myriaster (Brevoort) (Anguilliformes: Congridae) in the Yellow and East China Seas, is described using both light and scanning electron microscopy. The new species is characterised mainly by the body size (8.5-10.5 mm in the males, 9.5-14.0 mm in the females), the location of the vulva (near equatorial region of the body), the non-bifurcate deirids, the lengths of the vestibule (40-50 µm in the males, 30-60 µm in the females) and glandular oesophagus (2.5-3.1 mm in the males, 3.1-3.5 mm in the females) and the morphology and length of the spicules (left spicule 400-410 µm, right spicule 130-150 µm). Neoascarophis sinensis n. sp. is the first species of Neoascarophis Machida, 1976 reported from the anguilliform fish and is also the only species of this genus found in the Chinese waters.

A new species of microphallid (Trematoda: Digenea) infecting a novel host family, the Muraenidae, on the northern Great Barrier Reef, Australia.

A new species of microphallid, Longiductotrema tethepae n. sp., is reported from a muraenid eel Gymnothorax pseudothyrsoideus (Bleeker) on the northern Great Barrier Reef. The new species is described based on adults from Gy. pseudothyrsoideus and metacercariae from a grapsid crab, Grapsus albolineatus Latreille in Milbert, collected from off Lizard Island, Queensland, Australia. The new species is assigned to Longiductotrema Deblock & Heard, 1969 based on morphological characters (presence of a cirrus-sac; a long metraterm, intensively ensheathed by gland-cells; an entirely postcaecal uterus; vitellarium composed of two lateral clusters each of about ten follicles, situated in the testicular and post-testicular areas). Longiductotrema tethepae n. sp. is the third species assigned to the genus, differing from its congeners in having a distinctly larger body dimensions, a smaller pharynx in relation to oral sucker, the anterior limits of the vitelline fields at the level of the testes (vs at the level of the ovary) and in its parasitism of a muraenid fish (vs birds). Additionally, the new species differs from L. floridense Deblock & Heard, 1969 in having a shorter metraterm and from L. scandolensis Deblock & Bartoli, 1988 in having a less elongate forebody in relation to body length, shorter caeca and prepharynx, and slightly larger eggs. Phylogenetic analyses, based on partial 28S rRNA gene sequences, showed that the present species is sister to all other microphallids for which sequence data are available. This is the fourth report of a microphallid from a marine eel, the first from the Muraenidae Rafinesque and the first from a marine fish in the Indo-west Pacific. A summary of all species of the Microphallidae parasitising fish is provided.

Richness and diversity of helminth species in eels from a hypersaline coastal lagoon, Mar Menor, south-east Spain.

The composition and diversity of parasite communities and intestinal components, as well as infra-community structure, were assessed in eels Anguilla anguilla, from Mar Menor, a permanent Mediterranean hypersaline coastal lagoon. Data were used to determine whether this helminth community differs in composition and structure from that of eels in lagoons with lower salinity regimes and higher freshwater inputs. A total prevalence of 93% was detected. Specifically, parasites were identified as Deropristis inflata, Bucephalus anguillae, Contracaecum sp., Anguillicoloides crassus and two plerocercoid larvae belonging to the order Proteocephalidae, the marine species representing 91% of the isolated helminths. In the total community, digenetic trematodes were the dominant group of helminths, and D. inflata, an eel specialist, dominated both the component community and the infra-community. Richness and diversity were low but similar to those reported in other saline lagoons, and maximum species per eel did not exceed four. At the infra-community level, higher abundance than in other brackish or marine Mediterranean environments was detected. The findings provide further evidence of the similarity in composition and structure of helminth communities in eels from various Mediterranean coastal lagoons. Moreover, salinity-dependent specificities are well supported and reflect the life history of individual eels.

Experimental anisakid infections in mice.

Anisakidosis is a human parasitic disease caused by infections with members of the Anisakidae family. Accidental infection after fish intake affects the gastrointestinal tract as a consequence of mechanical damage caused by migrating larvae. Infections can also trigger allergies, hives, severe asthma or anaphylaxis with angioedema. Although mouse models of intraperitoneal antigenic stimulation exist, enabling immunological studies, few models using gastric introduction of live larvae are available for the study of immunological and gastrointestinal damage in mice. This study was designed to characterize serum reactivity against Anisakis spp. and Contracaecum spp. in Balb/c mice following orogastric inoculation and to assess gastrointestinal damage. These anisakid species were classified at the Universidade Federal Fluminense (UFF) School of Veterinary Medicine and materials for live larval inoculation were developed at the UFF Immunobiology laboratory. Live larvae were inoculated following injection with a NaCl solution. Blood samples were collected and sera screened for immunoglobulin (Ig)E and IgG anti-larva responses to both nematodes, specific for somatic and excretory/secretory antigens, by enzyme-linked immunosorbent assay (ELISA). The means of the optical densities were analysed using analysis of variance (ANOVA) with Tukey's post-hoc test and the general linear model. This analysis identified the presence of anti-IgG seroreactivity to both somatic and excretory/secretory Anisakis antigens in inoculated animals compared with controls (P< 0.001), and no gastric or intestinal damage was observed. These experiments demonstrated that introduction of live Contracaecum spp. into the gastrointestinal tract did not elicit serum sensitization in animals.

Can differences in life cycle explain differences in invasiveness? - A study on Anguillicola novaezelandiae in the European eel.

Anguillicola crassus is the most invasive species of its genus and it is a successful colonizer of different eel species worldwide. It is so far the only species of the genus Anguillicola whose life cycle has been studied completely. To analyse whether differences in life cycle may explain differences in invasiveness, we infected European eels with Anguillicola novaezelandiae under laboratory conditions. Anguillicola novaezelandiae shows a synchronized development in the European eel. Eggs with second-stage larvae appeared 120 days after infection. No density-dependent effect in parasite development could be found for A. novaezelandiae. The present study shows that the life cycle of A. novaezelandiae differs on final host level compared with A. crassus in ways which result in a less successful invasion of new host species.

Morphological and molecular characterisation of Heliconema hainanensis sp. nov. (Spirurina: Physalopteridae) from congers in the South China Sea, with a key to the species of Heliconema.

Heliconema hainanensis sp. nov. collected from Uroconger lepturus (Richardson) (Anguilliformes: Congridae), Muraenesox cinereus (Forsskål) and Congresox talabonoides (Bleeker) (Anguilliformes: Muraenesocidae) in the South China Sea was described using light and scanning electron microscopy. The new species differs from its congeners by the following morphology: pseudolabia, the number and arrangement of caudal papillae (4 pairs of pedunculate precloacal papillae arranged in 2 groups of 2 and 2 pairs and 6 pairs of pedunculate postcloacal papillae arranged in 4 groups of 1, 2, 1 and 2 pairs), the length of spicules [left spicule 0.51-0.69 mm, right spicule 0.20-0.27 mm, spicule (right:left) ratio 1:2.20-2.69] and the morphology of the female tail tip. In addition, specimens of the new species collected from the three different hosts and specimens of an unidentified species of Heliconema collected from U. lepturus were characterised using molecular methods by sequencing the internal transcribed spacer (ITS) of ribosomal DNA. Analyses and comparison of the ITS sequence of H. hainanensis sp. nov. with Heliconema sp. support the validity of the new species based on morphological observations. An identification key to the species of Heliconema is also provided.

Galectins in the abdominal cavity of the conger eel Conger myriaster participate in the cellular encapsulation of parasitic nematodes by host cells.

Congerin is a proto-type galectin distributed on the skin and mucosal epithelia of the upper digestive tract of the Japanese conger eel Conger myriaster. It has at least 2 isotypes, namely, congerin I and II, and plays a role in bio-defense at the body surface. In the current study, we identified both isotypes in the peritoneal fluid and peritoneal cells of C. myriaster by western blot and mass spectrometry (MS)/MS analysis. Cucullanus nematodes parasitize the abdominal cavity of C. myriaster, and immunohistochemical analyses demonstrated that congerins can bind to both the body surface of the encapsulated nematodes and the encapsulating cells. Furthermore, adhesion of the peritoneal cells to Sepharose particles was greatly accelerated when the microspheres were coated with congerin. Indeed, this effect was significantly hampered by the addition of lactose. These results indicate that congerin participates in the cellular encapsulation of the Cucullanus nematode via the induction of cellular adhesion to the parasites depending on lectin-glycoside recognition.

Morphological and molecular evidence for a new species of the genus Raphidascaris (Nematoda: Anisakidae) from marine fishes from the South China Sea.

A new anisakid nematode, Raphidascaris (Ichthyascaris) longispicula sp. nov., is described from the intestine and stomach of the marine fish Uroconger lepturus (Richardson) (Anguilliformes: Congridae) from the South China Sea (Guangdong and Hainan Province, respectively). The new species differs from all congeners in the subgenus Ichthyascaris by the short ventricular appendix (0.36-0.49 mm long), the number and arrangement of caudal papillae (25-28 pairs of preanal, 1-2 pairs of paranal, and 6-8 pairs of postanal), and the very long spicules (1.13-1.32 mm long, representing 9.34-10.3% of body length). The sequences of the internal transcribed spacer of ribosomal DNA of R. (I.) longispicula sp. nov. are analyzed and compared with the closely related nematode sequences. Molecular analyses seem to support the validity of this new nematode species based on morphological observation.

Aporocotyle mariachristinae n. sp., and A. ymakara Villalba & Fernández, 1986 (Digenea: Aporocotylidae) of the pink cusk-eel, Genypterus blacodes (Ophidiiformes: Ophidiidae) from Patagonia, Argentina.

Aporocotyle mariachristinae n. sp. and A. ymakara Villalba & Fernández, 1986 were collected from the bulbus arteriosus and ventral aorta of pink cusk-eels, Genypterus blacodes (Forster, 1801) from Patagonia, Argentina. A. mariachristinae n. sp. can be distinguished from all the species of Aporocotyle by the asymmetrical extension of posterior caeca (right posterior caecum longer, terminating at the area between mid-level of ovary and posterior body end; left posterior caecum shorter, terminating at the area between mid-level of cirrus sac and posterior to reproductive organs), the distribution of spines along the ventro-lateral body margins and the number of testes. The new species clearly differs from A. ymakara, from the same host species, in the esophagus / body length ratio, the absence of distal loops at caeca, the anterior caeca / posterior caeca length ratio, and the number of testes. Additionally, in A. ymakara the left posterior caecum may be longer than right posterior caecum, while in the new species left posterior caecum is always shorter. The specimen of A. ymakara collected from Argentina is also described. We also provide observations of the distribution of spines in different species of Aporocotyle, including new specimens of A. argentinensis Smith, 1969 from Merluccius hubbsi Marini, 1933. Molecular sequence data obtained from partial 18S and 28S rDNA regions were compared between the new species and other two species of Aporocotyle (A. argentinensis and A. spinosicanalis Williams, 1958). This is a new locality record for A. ymakara, extending the known geographical distribution for this species from Chile to Argentina, and the first report of two species of Aporocotyle in the same host species and locality.

Prosorhynchus crucibulum (Digenea: Bucephalidae) miracidium morphology and its passive transmission pattern.

The characterization of Prosorhynchus crucibulum (Rudolphi, 1819) Odhner, 1905 egg and miracidium is important in order to better understand the transmission dynamics between the definitive host and the primary host, the mussel. In this way, the objective of this work was to study the miracidia morphology, in order to evaluate if this species belongs to the group of passive or active transmission larvae. The morphology of eggs is similar to the ones presented by other Prosorhynchus species, with a small size of 26 × 17 µm, and four-five times smaller than the ones of Fasciola hepatica. The number of eggs produced per worm was around 6,760 (4,236-8,401), which was four-five times higher than in F. hepatica. The miracidia presented small dimensions 24 × 15 µm (23-25 × 13-15 µm range), a long stylet, two ciliated epithelial plates, very long cilia (12.7 µm) and absence of terebratorium and eyespots. Those features of the miracidia suggest that P. crucibulum belongs to the group of passively infecting larvae.

More than meets the eye: detecting cryptic microgeographic population structure in a parasite with a complex life cycle.

Nonrandom recruitment of parasites among hosts can lead to genetic differentiation among hosts and mating dynamics that promote inbreeding. It has been hypothesized that strictly aquatic parasites with intermediate hosts will behave as panmictic populations among hosts because ample opportunity exists for random mixing of unrelated individuals during transmission to the definitive host. A previous allozyme study on the marine trematode Lecithochirium fusiforme did not support this hypothesis; in that, there was genetic differentiation among, and significant heterozygote deficiencies within, definitive hosts. We revisit this system and use microsatellites to obtain multilocus genotypes. Our goal was to determine whether cryptic subgroups and/or the presence of clones could account for the apparent deviation from 'panmixia'. We find strong evidence for cryptic subdivision (three genetic clusters) that causes the Wahlund effect and differentiation among definitive hosts. After accounting for these cryptic groups, we see panmictic genetic structure among definitive hosts that is consistent with the 'high mixing in aquatic habitats' hypothesis. We see evidence for cotransmission of clones in all three clusters, but this level of clonal structure did not have a major impact in causing deviations from Hardy-Weinberg equilibrium, and only affected genetic differentiation among hosts in one cluster. A cursory examination of the data may have led to incorrect conclusions about nonrandom transmission. However, it is obvious in this system that there is more than meets the eye in relation to the actual make-up of parasite populations. In general, the methods we employ will be useful for elucidating hidden patterns in other organisms where cryptic structure may be common (e.g. those with limited morphology or complex life histories).

A new gonad-infecting species of Philometra (Nematoda: Philometridae) from the red cusk-eel Genypterus chilensis (Osteichthyes: Ophidiidae) off Chile.

A new nematode species, Philometra genypteri sp. n. (Philometridae), is described from male and female specimens found in the ovary of red cusk-eel, Genypterus chilensis (Guichenot) (Ophidiidae, Ophidiiformes), from the eastern South Pacific Ocean off the coast of northern Chile. Based on light and scanning electron microscopy examination, the new species differs from most other gonad-infecting Philometra spp. in the length of spicules (126-135 µm), a gubernaculum with dorsal lamella-like structures on its distal end, and the number and arrangement of genital papillae in the male. From a few congeneric, gonad-infecting species with unknown males, it can be distinguished by some morphological and biometrical features found in gravid female (absence of caudal projections, length of first-stage larvae or oesophagus, moderately developed anterior oesophageal inflation) and by the host type (fish family) and geographical distribution. P. genypteri is the first philometrid species reported from a fish belonging to the order Ophidiiformes and the second nominal species of Philometra recorded from marine fishes of the eastern South Pacific.

Two new species of flukes (Digenea: Bucephalidae: Prosorhynchinae) from the western Moray Gymnothorax woodwardi (Anguilliformes: Muraenidae) from off western Australia, with replacement of the pre-occupied generic name Folliculovarium Gu & Shen, 1983.

Two new species of bucephalid trematodes are described from the rectum and intestine of the western moray eel Gymnothorax woodwardi McCulloch (Anguilliformes: Muraenidae: Muraeninae) off Point Peron in Western Australia. Dollfustrema gibsoni n. sp. is distinguished by body size, a pharynx that is intertesticular and level (latero-dextrally) with the anterior portion of the cirrus-sac, an ovary positioned dextrally to the testes and slightly anterior to (in part) the anterior testis, a uterus that extends anteriorly to the vitelline follicles but not to the level of the rhynchus, and vitelline follicles that form a confluent arc anterior to the gonads. Muraenicola nom. nov. is proposed as a replacement generic name for the pre-occupied Folliculovarium Gu & Shen 1983 nec Singh & Sinha 1981. Muraenicola botti n. sp. is distinguished from its congeners by body size, the size of the cirrus-sac (relative to body size), and in possessing tegumental spines, testes that are oblique (rather than in tandem) and eight ovarian lobes. It differs further in having an intestinal caecum that extends anteriorly to the level of the vitelline follicles and in the position of the pharynx and cirrus-sac relative to each other (lateral in part) as well as to the gonads. M. botti n. sp. also lacks a metraterm. These are the first reports of these genera from fishes off Australia and from the southern hemisphere.

Pila ampullacea and Pomacea canaliculata, as new paratenic hosts of Gnathostoma spinigerum.

Aquatic snails, Pila ampullacea and Pomacea canaliculata were experimentally found to be suitable paratenic hosts for advanced third-stage larvae (L3) of the nematode Gnathostoma spinigerum, the causative parasite of gnathostomiasis in humans. G. spinigerum (L3) were found to be encapsulated in the tissue of the snail's foot and its internal organs. The infection, intensity and survival of third-stage larvae of G. spinigerum in both species of aquatic snails are described. This is the first evidence to reveal that not only vertebrates but also invertebrates (snails) can serve as paratenic hosts to this parasite. Aquatic snails are one of several sources of human gnathostomiasis in Thailand.

Studies of Myxidium giardi Cépède, 1906 infections in Icelandic eels identifies a genetically diverse clade of myxosporeans that represents the Paramyxidium n. g. (Myxosporea: Myxidiidae).

BACKGROUND: The myxosporean Myxidium giardi Cépède, 1906 was described infecting the kidney of the European eel, Anguilla anguilla (L.), having spindle-shaped myxospores and terminal sub-spherical polar capsules. Since then, numerous anguillid eels globally have been documented to have similar Myxidium infections. Many of these have been identified using the morphological features of myxospores or by the location of infection in the host, and some have been subsequently synonymised with M. giardi. Therefore, it is not clear whether M. giardi is a widely distributed parasite, infecting numerous species of eels, in multiple organs, or whether some infections represent other, morphologically similar but different species of myxosporeans. The aim of the present study was to assess the status of M. giardi infections in Icelandic eels, and related fish hosts in Malaysia and to use spore morphology and molecular techniques to evaluate the diversity of myxosporeans present. RESULTS: The morphologies of the myxospores from Icelandic eels were very similar but the overall dimensions were significantly different from the various tissue locations. Myxospores from the kidney of the Malaysian tarpon, Megalops cyprinoides (Broussonet), were noticeably smaller. However, the SSU rDNA sequences from the different tissues locations in eels, were all very distinct, with percentage similarities ranging from 92.93% to as low as 89.8%, with the sequence from Malaysia being even more dissimilar. Molecular phylogenies consistently placed these sequences together in a clade that we refer to as the Paramyxidium clade that is strongly associated with the Myxidium clade (sensu stricto). We erect the genus Paramyxidium n. g. (Myxidiidae) to accommodate these histozoic taxa, and transfer Myxidium giardi as Paramyxidium giardi Cépède, 1906 n. comb. as the type-species. CONCLUSIONS: There is not a single species of Myxidium (M. giardi) causing systemic infections in eels in Iceland. There are three species, confirmed with a robust phylogeny, one of which represents Paramyxidium giardi n. comb. Additional species probably exist that infect different tissues in the eel and the site of infection in the host fish is an important diagnostic feature for this group (Paramyxidium n. g. clade). Myxospore morphology is generally conserved in the Paramyxidium clade, although actual spore dimensions can vary between some species. Paramyxidium spp. are currently only known to infect fishes from the Elopomorpha.

The Influence of Sex, Parasitism, and Ontogeny on the Physiological Response of European Eels (Anguilla anguilla) to an Abiotic Stressor.

Migration of adult European eels (Anguilla anguilla) from freshwater feeding grounds to oceanic spawning grounds is an energetically demanding process and is accompanied by dramatic physiological and behavioral changes. Humans have altered the aquatic environment (e.g., dams) and made an inherently challenging migration even more difficult; human activity is regarded as the primary driver of the collapse in eel populations. The neuroendocrine stress response is central in coping with these challenging conditions, yet little is known about how various biotic factors such as sex, parasites, and ontogeny influence (singly and via interactions) the stress response of eels. In this study, mixed-effects and linear models were used to quantify the influence of sex, parasitism (Anguillicola crassus), life stage (yellow and silver eels), and silvering stage on the stress response of eels when exposed to a standardized handling stressor. The physiological response of eels to a standardized abiotic stressor (netting confinement in air) was quantified through measurements of blood glucose and plasma cortisol. The relationships between biotic factors and the activity of gill Na+/K+-ATPase was also examined. Analyses revealed that in some instances a biotic factor acted alone while in other cases several factors interacted to influence the stress response. Blood glucose concentrations increased after exposure to the standardized stressor and remained elevated after 4 h. Variation in plasma cortisol concentrations after exposure to the stressor were found to be time dependent, which was exacerbated by life stage and parasitism condition. Males and nonparasitized silver eels had the highest Na+/K+-ATPase activity. Silvering stage was strongly positively correlated with Na+/K+-ATPase activity in female eels. Collectively, these findings confirm that the factors mediating stress responsiveness in fish are complicated and that aspects of inherent biotic variation cannot be ignored.

Detection of ascaridoid nematode parasites in the important marine food-fish Conger myriaster (Brevoort) (Anguilliformes: Congridae) from the Zhoushan Fishery, China.

BACKGROUND: The whitespotted conger Conger myriaster (Brevoort) (Anguilliformes: Congridae) is an extremely marketable food fish, commonly consumed as sashimi or sushi in some Asian countries (i.e. Japan, Korea and China). Conger myriaster is also suspected as being an extremely important source of human anisakidosis. However, there is currently very little information on the levels of infection with ascaridoid nematode parasites in this economically important marine fish. The aims of the present study are to determine the species composition, prevalence and mean intensity of ascaridoid parasites of C. myriaster caught in the Zhoushan Fishery. RESULTS: A total of 1142 third-stage ascaridoid larvae were isolated from 204 C. myriaster. The overall prevalence of infection was 100% (mean intensity 5.6). Nine species of such larvae were accurately identified using integrative taxonomic techniques involving both morphological and genetic data; these included Anisakis pegreffii, A. typica and A. simplex (sensu stricto) × A. pegreffii, Hysterothylacium fabri, H. aduncum, H. sinense, H. amoyense, H. zhoushanense and Raphidascaris lophii. Although high levels of infection and species richness were revealed in C. myriaster, most of the ascaridoid parasites (1135 individuals) were collected from the body cavity and visceral organs of the fish and only seven individuals of A. pegreffii were found in the musculature. CONCLUSIONS: This study represents the first report C. myriaster from the Zhoushan Fishery being heavily infected with third-stage ascaridoid larvae. Among the ascaridoid larvae parasitic in this fish, an important etiological agent of human anisakidosis, A. pegreffii (L3), represents the predominant species. The genus Hysterothylacium has the highest species richness, with H. fabri (L3) being the most prevalent species. This high level of infection of A. pegreffii (L3) in C. myriaster suggests a high risk of anisakidosis or associated allergies for people consuming raw or poorly cooked fish originating from this marine area. These findings provide important basic information on the occurrence and infection parameters of ascaridoid nematodes in this economically important marine fish. They also have significant implications for the prevention and control of human anisakidosis when conger eels from the Zhoushan Fishery are consumed.

Three new species of Cucullanus (Nematoda: Cucullanidae) from marine fishes off New Caledonia, with a key to species of Cucullanus from Anguilliformes.

Based on light and scanning electron microscopical studies of nematode specimens from the digestive tract of some rarely collected anguilliform and perciform fishes off New Caledonia, three new species of Cucullanus Müller, 1777 (Cucullanidae) are described: C. austropacificus n. sp. from the longfin African conger Conger cinereus (Congridae), C. gymnothoracis n. sp. from the lipspot moray Gymnothorax chilospilus (Muraenidae), and C. incognitus n. sp. from the seabream Dentex fourmanoiri (Sparidae). Cucullanus austropacificus n. sp. is characterized by the presence of cervical alae, ventral sucker, alate spicules 1.30-1.65 mm long, conspicuous outgrowths of the anterior and posterior cloacal lips and by elongate-oval eggs measuring 89-108 × 48-57 µm; C. gymnothoracis n. sp. is similar to the foregoing species, but differs from it in the absence of cervical alae and the posterior cloacal outgrowth, in the shape and size of the anterior cloacal outgrowth and somewhat shorter spicules 1.12 mm long; C. incognitus n. sp. (based on female morphology) differs from other congeneric species parasitic in the Sparidae mainly in possessing cervical alae, the postequatorial vulva, phasmids situated at the mid-length of the tail and in the size of the eggs (75-84 × 45-66 µm). A key to species of Cucullanus parasitizing anguilliform fishes is provided.

TITLE: Trois nouvelles espèces de Cucullanus (Nematoda: Cucullanidae) de poissons marins au large de la Nouvelle-Calédonie, avec une clé des espèces de Cucullanus d'Anguilliformes. ABSTRACT: Sur la base d'une étude en microscopie photonique et électronique à balayage de spécimens de nématodes provenant du tube digestif de quelques poissons anguilliformes et perciformes rarement pêchés en Nouvelle-Calédonie, trois nouvelles espèces de Cucullanus Müller, 1777 (Cucullanidae) sont décrites : C. austropacificus n. sp. de Conger cinereus (Congridae), C. gymnothoracis n. sp. de Gymnothorax chilospilus (Muraenidae) et C. incognitus n. sp. de Dentex fourmanoiri (Sparidae). Cucullanus austropacificus n. sp. est caractérisé par la présence d'ailes cervicales, une ventouse ventrale, des spicules ailés de 1,30-1,65 mm de long, des excroissances remarquables des lèvres cloacales antérieure et postérieure et d'oeufs ovales et allongés mesurant 89-108 × 48-57 µm. C. gymnothoracis n. sp. est semblable à l'espèce précédente, mais en diffère en l'absence d'ailes cervicales et d'excroissance cloacale postérieure, par la forme et la taille de l'excroissance cloacale antérieure et par des spicules un peu plus courts de 1,12 mm. C. incognitus n. sp. (basé sur la morphologie de la femelle) diffère des autres espèces congénères parasites chez les Sparidae principalement par la possession d'ailes cervicales, une vulve postéquatoriale, des phasmides situés à mi-longueur de la queue et par la taille des oeufs (75­84 × 45­66 µm). Une clé des espèces de Cucullanus parasitant les poissons anguilliformes est fournie.