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At least 55 records · Page 3Linked to original sources
PubMed2004

Growth, fecundity and sex ratio of adult whaleworm (Anisakis simplex; Nematoda, Ascaridoidea, Anisakidae) in three whale species from the North-East Atlantic.

The growth rate, fecundity, and sex ratio of Anisakis simplex in minke whales (Balaenoptera acutorostrata), porpoises (Phocoena phocoena) and long-finned pilot whales (Globicephala melas) was studied on the basis of material from the North Atlantic. A total of 8,135 mature A. simplex were collected from 24 minke whales, 11 porpoises and eight pilot whales. For both males and females, the prevalence was 100% for all three host species, with a mean intensity of 1,727, 262 and 139, respectively. The mean body length of adult female A. simplex was 126 mm in minke whales, 71 mm in the porpoises and 73 mm in pilot whales; and for males the averages were, respectively, 106 mm, 57 mm and 68 mm. Eggs from the uteri of 32 females of length 87-176 mm collected in minke whale stomachs were counted in a Fuchs-Rosenthal chamber. Total egg production was measured in 14 females cultivated at sea. The female growth period was estimated to be 30-60 days, and apparently all eggs were shed during the last week of life. A female of size 150 mm produces approximately 1.5 million eggs. In the cultivation experiment, about 85% of the total egg production was shed during the first 3 days after spawning started.

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PubMed2005

New locality records for third-stage larvae of Anisakis simplex (sensu lato) (Nematoda: Ascaridoidea) in euphausiids Euphausia pacifica and Thysanoessa raschii from Prince William Sound, Alaska.

Five euphausiid species (n=41,037) were collected in October 1997 from Prince William Sound, Alaska, and examined for parasites. New locality records are claimed for third-stage larvae (L3) of whaleworm Anisakis simplex (sensu lato) in two (0.019%) of 10,437 Thysanoessa raschii, and in one (0.013%) of 7,443 Euphausia pacifica. The L3 were about 19.5, 21.3 and 30.5 mm long. L3 were absent from 8,026 T. inermis, 10,302 T. longipes and 4,829 T. spinifera collected at the same time, and from 6,648 euphausiids representing the five species collected in July 1998. No individual harboured more than one parasite-a whaleworm L3, the ellobiopsid Thalassomyces fagei, a trypanorhynchid (tetrarhynchid) cestode (probably Nybelinia sp.), or a possible rhizocephalan. Controversy regarding the number of moults that occur in the egg of marine ascaridoids is discussed briefly.

Alaska↗
PubMed2001

Experimental infections of copepods and sticklebacks Gasterosteus aculeatus with small ensheathed and large third-stage larvae of Anisakis simplex (Nematoda, Ascaridoidea, Anisakidae).

Free-swimming ensheathed larvae of Anisakis simplex were shown experimentally to be ingested by the copepods Oitona similis and Acartia tonsa and by the nauplii of barnacles Balanus sp. The larvae did not grow in the copepod hemocoel. Experimental infections of various malacostracans were unsuccessful. Sticklebacks Gasterosteus aculeatus are naturally infected with larvae of A. simplex in coastal brackish water. Such sticklebacks may have acquired the infection by eating either a crustacean host or third-stage larvae (L3) from fish. Experimental infections of cod Gadus morhua with L3 from viscera of herring Clupea harengus showed that about one-third of the ingested larvae passed through the cod alimentary tract and were extruded whole but dead. Experiments showed that larvae from herring viscera survived and remained infective after at least 6 weeks in brackish water and seawater and that L3 from herring viscera were ingested by sticklebacks (and flounder Platichthys flesus), where they reencapsulated on the viscera; the L3 were alive 2 years later.

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PubMed1998

Distribution of whaleworm (Anisakis simplex, Nematoda, Ascaridoidea) L3 larvae in three species of marine fish; saithe (Pollachius virens (L.)), cod (Gadus morhua L.) and redfish (Sebastes marinus (L.)) from Norwegian waters.

The frequency distribution of Anisakis simplex L3 larvae between host tissues was investigated in three host species: saithe, cod and redfish. Fish were sampled from Norwegian coastal waters and examined for the presence of A. simplex in muscle and viscera. In all three of the host species, A. simplex larvae were most frequently detected in the viscera; the percentages of total infection for saithe, cod and redfish were 99.6%, 97.8% and 88.0%, respectively. In general, the distribution patterns of A. simplex L3 between muscle and viscera were not significantly affected by host size. The observations that distributions vary between species and are not affected by host size do not support an earlier hypothesis which states that A. simplex L3 distributions are determined by an optimal pre-encapsulation migratory distance within host tissues. In contrast, it is suggested that A. simplex L3 distributions are governed by the conditions encountered within host tissues, and are possibly related to the availability of nutrients.

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PubMed1995

Micro-evolutionary implications of allozymic and morphometric variations in sealworms Pseudoterranova sp. (Ascaridoidea: Anisakidae) among sympatric hosts from the southeastern Pacific Ocean.

We found significant morphometric and electrophoretic differences between sealworm larvae collected from four sympatric fish host species off the central coast of Chile. The South American sea lion, Otaria byronia, is a suitable host and most likely the only definitive host species in the study area. Morphological patterns of caudal papillae in adult males collected from sea lions and electrophoretic evidence from larvae and adults substantiate our conclusion that they belong to just one, new species yet to be described. The genetic and morphometric differences found between sealworm larvae from sympatric fish hosts may be due to selective pressures arising from the internal environment of the intermediate hosts, although they may serve only for passing sequential filters along the life cycle. The discussion deals with the roles that definitive and intermediate hosts may play in the micro-evolutionary processes of sealworms.

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PubMed1985

Growth and form of the fourth-stage larvae and early adults of Ascaris suum Goeze, 1782 (Nematoda: Ascaridoidea) developing in pigs.

The fourth-stage larvae and adults of Ascaris suum were studied as they developed in the pig intestine from 11 to 22 days after infection. This is a period of rapid growth, in which both sexes increase approximately ten-fold in body length. Further examination of females showed the length increase to be positively allometric with respect to body diameter. The genital primordium in early fourth stage is at the same relative position along the length of the body as it is in the newly hatched larva. During development from fourth stage to adulthood the greater growth of the posterior part of the worm causes the relative position of the developing vulva to shift anteriad.

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PubMed1984

Changes in the somatic musculature of the 4th-stage larvae of Ascaris suum Goeze, 1782 (Nematoda: Ascaridoidea) developing in swine.

Fourth-stage larvae of Ascaris suum, recovered from piglets at 11-22 days post-infection (p.i.), were examined by light microscopy for changes in the somatic musculature. During this time the estimated total number of muscle cells in the body increases from approximately 600 to 21 000 cells. This non-eutelic development appears to occur by division of platymyarian muscle cells into coelomyarian cells, thereby increasing the number of muscle cells/quadrant from 5 to 85. The incompleteness of these divisions results in sarcoplasmic connections among muscle cells, and between muscle cells and nerve chords. At 11 days p.i., immediately after the 3rd moult, the variation in muscle cell length in a quadrant, with the longest cells being at the lateral chords, has been established. The average muscle cell length at this point is 0.101 mm, the longest is 0.164 mm. These values have increased to 0.365 mm and 1.122 mm, respectively, by 22 days p.i. At 18 days p.i. those cells in the posterior section of the larva are still the shortest in the body.

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PubMed2001

Toxocara malaysiensis n. sp. (Nematoda: Ascaridoidea) from the domestic cat (Felis catus Linnaeus, 1758).

Toxocara malaysiensis n. sp. from the small intestine of the domestic cat (Felis catus L.) in Malaysia is described and illustrated. This ascaridoid nematode was previously assumed to be Toxocara canis, which it superficially resembles, or designated Toxocara sp. cf. canis. The new species differs from T. canis in the shape of the cervical alae in cross section, spicule length, and the lip structure. It is also distinct from other species assigned to Toxocara.

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PubMed2001

Heliconema minnanensis n. sp. (Physalopteroidae: Physalopteridae) and Raphidascaris trichiuri (Yin and Zhang) n. comb. (Ascaridoidea: Anisakidae) in marine fishes.

Heliconema minnanensis n. sp. is described from the Chiloscyllium plagiosum south of the Minnan-Taiwan Bank Fishing Ground, Taiwan Strait. It is characterized by having the following combination of features. There are no longitudinal ridges in the posterior part of the body; the male has 4 pairs of precloacal papillae and 6-7 pairs of postcloacal papillae. The right spicule averages 0.2 mm long (1.1% of body length), and the left spicule averages 1.2 mm long (5.6% of body length), making an average spicule ratio of 1:5.2. The female has a vulva located on the left side of a thick membrane and 56-65% of the body length from the anterior end. Raphidascaris trichiuri (Yin and Zhang, 1983) comb. n., known previously from males only, is transferred from Cloeoascaris and redescribed, including material of both sexes from Muraenesox cinereus from the type locality.

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PubMed1999

Centrids, a pair of asymmetrically arranged sense organs in Ascaris suum (Nematoda, Ascaridoidea).

Two prominent, asymmetrically placed cuticular somatic sensilla, called centrids, are reported in Ascaris suum Goeze, 1782, the pig roundworm. The right centrid is situated much more anteriorly on the body than is the left one. The centrids are globular in the fourth-stage larva and obviously void of an apical pore, suggesting at least a tactile function. In adult worms, the centrids are platelike, lacking a globular expansion. The observation on the presence of asymmetrically placed centrids in A. suum gives further impetus to the importance assigned to sense organs in the classification and identification of nematodes. The name centrid was originally chosen to indicate the placement of the papillae in the midbody region of worms. The name centrid, rather than, e.g. postdeirid, is proposed to be used when denoting asymmetrically oriented midbody sensilla among the Ascaridida and papillae, when shown homologous to these, of species within the Rhabditea generally. This proposal is in line with the name "Mittelkörperpapillen" originally adopted to denote homologous sensillae in Cucullanidae (Seuratoidea) by Törnquist in 1931.

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PubMed1975

Thynnascaris reliquens sp. n. and T. habena (Linton, 1900) (Nematoda: Ascaridoidea) from fishes in the northern Gulf of Mexico and eastern U.S. seaboard.

Thynnascaris reliquens sp. n. is described from the type host, the sheepshead, Archosargus probatocephalus (Walbaum), and other fishes of the northern Gulf of Mexico and southern Florida, including the Gulf toadfish, Opsanus beta (Goode and Bean); the spiny boxfish, Chilomycterus schoepfi (Walbaum); the slippery dick, Halichoeres bivittatus (Bloch); and the Atlantic croaker, Micropogon undulatus (Linnaeus). Its salient characters are: length up to approximately to 12.5 cm; lips broad, with pedunculate pulp and equatorially constricted flanges; esophagus 8 to 12% and spicles 3 to 6% of body length; preanal and postanal papillae up to 33 and 6 pairs, respectively. In the type host, some adults attained a considerably greater size than in other hosts, and their labial morphology changed as the maximum length was approached. Thynnascaris habena is redescribed from the oyster toadfish, Opsanus tau (Linnaeus), its type host, on the basis of examination of specimens collected from Massachusetts, Virginia, and Georgia. Thynnascaris melichthysi (Olsen, 1952) and T. ogcocephali (Olsen, 1952) are transferred from the genus Contracaecum as new combinations.

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PubMedDate not supplied

[Anisakidae larvae (Nematoda: Ascaridoidea) parasites of the bluewing searobin Prionotus punctatus (Bloch, 1793) (Osteichthyes: Triglidae) from the coastal zone of the State of Rio de Janeiro, Brazil].

Eighty specimens of Prionotus punctatus (Bloch, 1793) from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23 degrees 01 'S, 44 degrees 19 'W), were necropsied to study their metazoan parasites. Three species of larval nematodes anisakids were found, Anisakis sp., Hysterothylacium sp. and Raphidascaris sp. from the liver and mesenteries. These nematodes are described and a revision of available literature concerning nematodes belonging to these genera was made.

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PubMed1997

Genetic and ecological data on the Anisakis simplex complex, with evidence for a new species (Nematoda, Ascaridoidea, Anisakidae).

Isozyme analysis at 24 loci was carried out on anisakid nematodes of the Anisakis simplex complex, recovered from various intermediate/paratenic (squid, fish) and definitive (marine mammals) hosts from various parts of the world. A number of samples were found to belong to A. simplex sensu stricto and Anisakis pegreffii, widely extending the geographic ranges and the number of hosts of these 2 species. In addition, a new distinct gene pool was detected, showing different alleles with respect to A. simplex s. str and A. pegreffii at 5 diagnostic loci (99% level). Samples with this gene pool were assigned to a new species, provisionally labeled A. simplex C. Reproductive isolation between A. simplex C and the other 2 Anisakis species was directly assessed by the lack of hybrid and recombinant genotypes in mixed samples from sympatric areas, i.e., Pacific Canada for A. simplex C+A. simplex s. str., South Africa and New Zealand for A. simplex C+A. pegreffii, even when such samples were recovered from the same individual host. Similar levels of genetic divergence were observed among the three species (DNei from 0.36 to 0.45). At the intraspecific level, Canadian Pacific and Austral populations of A. simplex C were found to be genetically rather differentiated from one another (average DNei = 0.08), contrasting with the remarkable genetic homogeneity detected within both A. simplex s. str. and A. pegreffii (average DNei about 0.01). Accordingly, a lower amount of gene flow was estimated within A. simplex C (Nm = 1.6) than within the other 2 species (Nm = 5.4 and 17.7, respectively). Anisakis simplex C showed the highest average values of genetic variability with respect to both A. simplex s. str. and A. pegreffii, e.g., expected mean heterozygosity. Hr = 0.23, 0.16, and 0.11, respectively, in the 3 species. Data on geographic distribution and hosts of the 3 members so far detected in the A. simplex complex are given. Their ecological niche is markedly differentiated, with a low proportion of hosts shared. Intermediate and definitive hosts of A. simplex s. str. and A. pegreffii appear to belong to distinct food webs, benthodemersal, and pelagic, respectively; this would lead to different transmission pathways for the parasites.

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PubMed1998

Growth and structural features of the adult stage of Ascaris suum (Nematoda, Ascaridoidea) from experimentally infected domestic pigs.

For studying the morphogenesis of the adult stage of Ascaris suum, worms were obtained from experimentally infected domestic pigs. Structural and morphometric features of A. suum are analyzed by light and scanning electron microscopy. It was shown that the increase in length of the worm from days 35 to 56 is based on a region-specific lengthening of individual transverse annuli in the cuticle. An increased worm size also results in an increased diameter of different cuticular sense organs. It is shown that a pair of lateral midbody papillae, the centrids, are prominent sensilla in the adult male and female worm. The centrids have an asymmetric placement, the right centrid being more anterior on the worm than the left.

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PubMed1997

[Detection of intestinal parasites from main-land raccoon dogs, Nyctereutes procyonoides viverrinus, in southeastern Kanagawa Prefecture].

To obtain the basic data on the route of infection of intestinal parasites as zoonosis, we examined the feces from 87 main-land raccoon dogs, all of which were kept in the Yokohama Kanazawa Zoo (Kanagawa) between 1994-1996, for detection of intestinal parasites and evaluated the detection rates. Intestinal parasites were detected from 72 of the 87 raccoon dogs (82.8%). Among the parasites, Ancylostoma spp., Trichuris vulpis, Ascaridoidea and Isospora spp. were most commonly detected. Of the 72 raccoon dogs with parasites, 43 (59.7%) had mixed infection of more than two species of parasites. Since Ancylostoma spp., Ascaridoidea and Isospora spp., which are important causes of human diseases, were detected at relatively high rates, it was suggested that the raccoon dog could be a source of human infection of intestinal parasites.

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