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At least 19 recordsLinked to original sources
PubMed2005

The complete mitochondrial genome of Anisakis simplex (Ascaridida: Nematoda) and phylogenetic implications.

We determined the nucleotide sequence of the complete mitochondrial genome of the nematode species Anisakis simplex. The genome is circular, 13,916 bp in size and conforms to the general characteristics of nematode mitochondrial DNAs. The gene arrangement of A. simplex is the same as that of Ascaris suum and almost identical to those of rhabditid species with a minor exception concerning the relative position of the AT-rich and non-coding regions and radically different from those of spirurid species. Along with comparisons of gene arrangement, phylogenetic analyses (maximum parsimony, neighbour joining and maximum likelihood methods) based on concatenated amino acid sequences of 12 protein-coding genes from 13 nematode species provided strong support for the sister-group relationship between Ascaridida and Rhabditida. The Shimodaira-Hasegawa and Templeton's tests both rejected the alternative hypothesis of a closer relationship between Ascaridida and Spirurida. These results contradicted the traditional view of nematode classification and a recent molecular phylogenetic study of 18S rDNA data that assigned Ascaridida and Spirurida as being a sister-group. Mapping of gene arrangement across the phylogenetic tree lead to the assumption that the conserved gene arrangement found in Ascaridida-Rhabditida members might have been acquired after the most recent common ancestor of ascaridid/rhabditid members branched off from the basal stock of the rhabditid lineage.

Amino Acid Sequence↗
PubMed2001

New reports and a redescription of Porrocaecum heteropterum (Diesing, 1851) (Ascarididae), a rare nematode parasitic in South American.threskiornithid birds1.

Porrocaecum heteropterum (Diesing, 1851) (Nematoda, Ascarididae) is reported parasitising the white-faced ibis Plegadis chihi and the black-faced ibis Theristicus melanopis melanopis (Ciconiiformes, Threskiornithidae) from the Provinces of Buenos Aires and Neuquén, Argentina. This nematode has been reported very few times in the literature, mainly from Brazilian threskiornithids, and there have been no new reports following a redescription of the species given in 1957. This paper provides new host and locality records for this rather rare species, as well as some additional morphological data, mainly based on SEM studies, which complement the previous descriptions. The scarce and sporadic records of this species seem to indicate not only a defined host-specificity towards threskiornithid birds but also that the acquisition of this parasite is possible only when certain ecological barriers, including food availability, feeding habits and environmental conditions, are surmounted.

Animals↗
PubMed2001

[New/old opinions on the systematics and phylogenesis of the nematodes, with the special regard to Ascaridida, Ascaridoidea].

Traditional classification of the nematodes, based on morphological-ecological characters was evaluated in the context of molecular analysis of systematic taxons, with special regards to ascarids. Division of superfamily Ascaridoidea into 4 families (Heterocheilidae, Ascarididae, Anisakidae, Raphidascarididae) proposed by Fagerhholm (1991) seems to be proved by the molecular data of Nadler (1992, 1995) and Nadler & Hudspeth (1998).

Animals↗
PubMedDate not supplied

Experimental heteroxenous cycle of Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) in white mice and in cats.

Reports of natural infections of sylvatic carnivores by adult worms of species similar to Lagochilascaris minor in the Neotropical region led to attempts to establish experimental cycles in laboratory mice and in cats. Also, larval development was seen in the skeletal muscle of an agouti (Dasyprocta leporina) infected per os with incubated eggs of the parasite obtained from a human case. In cats, adult worms develop and fertile eggs are expelled in the feces; in mice, larval stages of the parasite develop, and are encapsulate in the skeletal muscle, and in the adipose and subcutaneous connective tissue. From our observations, we conclude that the larva infective for the mouse is the early 3rd stage, while for the final host the infective form is the later 3rd stage. A single moult was seen in the mouse, giving rise to a small population of 4th stage larvae, long after the initial infection.

Animals↗
PubMed2004

Cosmocerca vrcibradici n. sp. (Ascaridida: Cosmocercidae), Oswaldocruzia vitti n. sp. (Strongylida: Molineoidae), and other helminths from Prionodactylus eigenmanni and Prionodactylus oshaughnessyi (Sauria: Gymnophthalmidae) from Brazil and Ecuador.

Cosmocerca vrcibradici n. sp. and Oswaldocruzia vitti n. sp., intestinal parasites of Prionodactylus eigenmanni (type host) and P. oshaughnessyi, are described and illustrated. Of the 19 valid species of Cosmocerca, C. vrcibradici n. sp. represents the 12th Neotropical species and the first species to be reported from lizard hosts. Of the 76 valid species of Oswaldocruzia, O. vitti n. sp. represents the 14th Neotropical species and the eighth species to be reported from lizard hosts. In addition, 1 species of Digenea, Mesocoelium monas, and 1 species of Acanthocephala, Acanthocephalus saurius, were found.

Animals↗
PubMed2004

A new species of Pseudanisakis Layman & Borovkova, 1926 (Nematoda: Ascaridida) from Rioraja agassizii and Psammobatis extenta (Rajidae) in Brazilian southwestern Atlantic waters.

Pseudanisakis sulamericana n. sp. is described from the intestines of the rays Rioraja agassizii and Psammobatis extenta off the coast of Brazil. It can be readily differentiated from the three existing species of the genus. From P. tricupola Gibson, 1973, it differs in not having cupolas on the lips, having a dentigerous ridge of 90-95 denticles ( vs 65-78) in a continuous subtriangular ring around the mouth, and in having an ejaculatory duct which is shorter than the spicules. From P. rajae (Yamaguti, 1941), it differs in having a single rather than a double row of denticles. It appears most similar to P. baylisi Gibson, 1973, but differs from it in having a smaller body-size (7.5-27 vs 16-46 mm), shorter spicules (1.14-1.90 vs 1.90-3.80 mm) and especially in having much more conspicuous denticles on the lips. The present record confirms the presence of the genus in subtropical waters.

Animals↗
PubMed2002

Experimental life cycle of Lagochilascaris major leiper, 1910 (Nematoda: Ascarididae) in cats (Felis domesticus).

The life cycle of Lagochilascaris major was studied using eggs collected from a natural clinical case in a domestic cat. Twenty-seven white mice (Mus musculaus), 5 hamsters (Mesocricetus auratus), and 1 vesper mouse (Calomys callosus) were orally inoculated with 800-1,300 embryonated eggs. When examined from 73 to 246 days postinoculation (PI), encysted third-stage larvae were seen in skeletal muscles and less frequently in connective tissue, liver, and lungs. Twenty-two of the 23 cats orally inoculated with 40-430 encysted larvae from these rodents, and necropsied from 1 hr to 185 days PI, became infected. Third-stage larvae were located in the stomach, esophagus, and oropharynx from 1 to 24 hr PI. At 48 hr, larvae, from mainly the fourth stage, were only found, unilaterally or bilaterally, inside a "sac" in the region of the semilunar fold of the palatine tonsil at the base of the tongue. Adult worms were found in this location from 10 to 175 days PI. No fistulated abscess to the outside medium was found. Adult worms were also found in the middle ears of 2 cats showing purulent otitis. Eggs in the ear secretion were under different stages of development. Eggs in feces were first observed on days 14 and 15 PI, and 1 cat shed them until 178 days PI. Six infected cats were treated with fenbendazole at 50 mg/kg of body weight for 3 consecutive days, eliminating all the parasites present in the tonsils. The drug was not effective against the parasites present in the middle ear. No stage of the parasite was found in the tissues of 5 cats given 4,000-5,200 eggs orally and examined after 19 and 50 days PI. This indicates that the life cycle of L. major requires an obligate paratenic host and is characterized by heteroxenic cycle.

Animals↗
PubMed2003

Icosiella turgeocauda n. sp. (Nematoda: Onchocercidae) and Seuratascaris numidica (Nematoda: Ascarididae), parasites of the frog, Rana cancrivora (Anura: Ranidae), from Luzon, Republic of the Philippines.

Icosiella turgeocauda n. sp. from the intestinal mesenteries of Rana cancrivora collected at Luzon, Republic of the Philippines, is described and illustrated. Icosiella turgeocauda n. sp. represents the ninth species to be assigned to the genus and is easily differentiated from all the previously described species by the position of the vulva and the presence of bilateral umbos on the caudal end of the male. Seuratascaris numidica also was found. The Philippines represents a new location record for S. numidica.

Animals↗
PubMed1994

Visceral larva migrans in mice experimentally infected with Baylisascaris transfuga (Ascarididae: Nematoda).

Laboratory bred albino mice, weighing 20 to 25 g, were orally infected with 2000 Baylisascaris transfuga infective eggs each. Mice were randomly chosen and sacrificed on days 1, 2, 3, 10, 15, 24 and 70 post-infection. Samples of intestine, mesenteric lymph nodes, liver, lungs, heart, spleen, kidneys, uterus, brain and skeletal muscles were collected and processed for conventional histopathology. In the early infection the major necropsy findings were focal haemorrhages on the intestinal wall, liver, lungs and brain. Histologically, larvae were found in haemorrhagic areas. In the subacute-chronic infection white nodules were scattered through all the examined organs, except the brain. Histologically, the white nodules corresponded to granulomas containing larvae surrounded by lymphocytes, eosinophil leukocytes and macrophages. The migration of B. transfuga larvae in spleen, kidneys and uterus of infected mice appears to have not been reported by previous workers. The possible role of B. transfuga larvae in the Visceral Larva Migrans syndrome is discussed.

Animals↗
PubMedDate not supplied

[Preliminary study of the larvae (Nematode: Ascaridida) Paralichthys orbignyyanus parasite (Valenciennes, 1839) and Paralichthys patagonicus (Pisces: Pleuronectiformes)].

The present paper deals with a preliminary study of different larvae of nematoda found in two species of fish Paralichthys orbignyanus and Paralichthys patagonicus. In P. orbignyanus the genus Terranova type A was found. Both Anisakis type I and Hysterothylacium were present in P. patagonicus. Different types of larvae belonging to genera Terranova (B and B'), Contracaecum (A and B) and Raphidascaris occurred in both P. patagonicus and P. orbignyanus. The specimens of Nematoda were described and the corresponding morphometric indexes were determined. The abundance of Nematoda obtained in relation to the diet of the flounders led us to conclude that P. orbignyanus feeds basically on crabs and fish, while P. patagonicus has a more diverse diet.

Animals↗
PubMed1978

Morphological and histochemical observations on the intestinal epithelium of Ascardia galli (Nematoda: Ascaridida).

The intestinal epithelium of Ascardia galli has been studied with various cytological and cytochemical techniques. It consists of large epithelial cells resting on a thick collagenous basal lamina. Their luminal surface is provided with microvilli. The intestinal cells store considerable amounts of glycogen and neutral lipids. Some intracellular granular inclusions, which stain for proteins, phospholipids and lipoproteins, are distributed throughout the cytoplasm. The brush border is composed of microvilli whereas the outer surface coat consists of saliva resistant PAS-positive material. The detailed histochemical analysis of surface material has revealed that it is composed of nonacetylated acid mucopolysaccharides rich in hyaluronic acid with carboxylate polyanions. The brush border shows intense activities of acid phosphatase and glucose-6-phosphatase, moderate of ATPase, and lipase, weak of 5'-nucleotidase. Acid phosphatase-positive intracellular structures are seen in the intestinal epithelium which form distinct aggregations.

Acid Phosphatase↗
PubMed1990

The in vitro adherence of murine eosinophils, neutrophils and non-induced and induced macrophages to infective larvae of Toxocara canis (Nematoda, Ascarididae).

Infective larvae of the parasite nematode Toxocara canis were incubated in vitro with murine eosinophils, neutrophils and non-induced and induced macrophages. The interactions between the different types of cells and the worms were observed in the presence or absence of immune mouse serum and/or complement. Cells showed considerable differences in the manner, duration and outcome of this interaction. Despite the adhesion of cells to the larvae of T. canis, there was no evidence of damage to the worms. Scanning and transmission electron microscopic observations suggest that the cells adhere to the cuticular surface via an electron-dense material. This material might play a protective role against the helmintotoxic capacity of the inflammatory cells.

Animals↗
PubMed1991

Genetic evidence for three species within Pseudoterranova decipiens (Nematoda, Ascaridida, Ascaridoidea) in the North Atlantic and Norwegian and Barents Seas.

Genetic variation of 1017 specimens of codworm, Pseudoterranova decipiens, collected from fish and seals at 23 sampling locations in the North Atlantic and Norwegian and Barents Seas, was analysed on the basis of 16 enzyme loci. Three reproductively isolated species, provisionally designated P. decipiens A, B and C, were detected, showing distinct alleles at the following loci: Mdh-1, 6Pgdh, Np, Pgm, Est-2 (between species A and B); Mdh-3, 6Pgdh, Np, Sod-1, Adk, Pgm, Est-2, Mpi (between A and C); Mdh-1, Mdh-3, Sod-1, Adk, Pgm, Est-2, Mpi (between B and C). One F1 hybrid was observed between P. decipiens A and B, but this apparently does not lead to any gene exchange between the two species, which do not show any evidence of introgression. No hybrids or introgressed individuals were observed between P. decipiens C and either A or B. Genetic distances among conspecific populations were low (average Nei's D 0.001-0.005), even though they were collected thousands of kilometres apart, indicating high levels of gene flow within each of the three species. The values of Nei's index D were 0.44 between P. decipiens A and B, 0.57 between B and C, and 0.79 between A and C. Estimated evolutionary divergence times, using Nei's formula, range from 2 to 4 million years. Differences between P. decipiens A, B and C were also found with respect to genetic variability, morphology, geographical distribution and hosts. Mean heterozygosity values of 0.08, 0.05 and 0.02 were obtained for P. decipiens A, B and C, respectively. Preliminary morphological examination of adult males, previously identified by multilocus electrophoresis, revealed differences in the relative size and pattern of caudal papillae. P. decipiens B is widespread in the study area, whereas P. decipiens A was found only in the North-East Atlantic and Norwegian Sea. In this area P. decipiens A is most common in the grey seal, Halichoerus grypus, while the common seal, Phoca vitulina, is the main host for P. decipiens B. In Canadian Atlantic waters, where P. decipiens A is apparently absent, P. decipiens B infects both grey and common seals; a few specimens were also found in the hooded seal, Cystophora cristata. The only definitive host so far identified for P. decipiens C is the bearded seal, Erignathus barbatus; P. decipiens C appears to be widespread, occurring in both the North-West Atlantic and Barents Sea.

Animals↗
PubMed1993

Three sibling species within Contracaecum osculatum (Nematoda, Ascaridida, Ascaridoidea) from the Atlantic Arctic-Boreal region: reproductive isolation and host preferences.

Genetic variation within and between population samples from 22 locations of the Atlantic Arctic-Boreal region, including 1657 specimens morphologically assigned to Contracaecum osculatum, was electrophoretically analysed at 17 loci. Highly significant deviations from the Hardy-Weinberg equilibrium were found at various loci in several samples, owing to the existence of three distinct gene pools within C. osculatum (sensu lato) from the study area. These gene pools correspond to three biological species (provisionally designated A, B and C), characterized by distinct genotypes at several diagnostic loci. Reproductive isolation between C.osculatum A, B and C is confirmed by the lack of F1, recombinant, or backcross genotypes in sympatric areas, despite the occurrence of multiple infections. Mean heterozygosity per locus is on average 0.11 in species A, 0.10 in B and 0.07 in C. High levels of gene flow were found within each of the three species, the values of Nm (number of migrant individuals) ranging from 3.41 (C. osculatum C) to 5.77 (C. osculatum A). Average Nei's genetic distance is 0.46 between A and B, 0.50 between A and C and 0.77 between B and C. From these values, times of evolutionary divergence from 2 to 4 million years can be estimated. Genetic relationships among populations and species of the C. osculatum complex are illustrated by principal component analysis. The role of both geographical isolation and host preferences in the speciation of C. osculatum (sensu lato) is discussed. A morphological distinction of the three species has not yet been possible (sibling species). However, there is evidence that the name C. osculatum (sensu stricto) should be used for species C, which shows a geographical distribution and definitive host corresponding to the neotype of C. osculatum (sensu stricto). Finally, a comparison is made between the members of the C. osculatum complex from the Atlantic Arctic-Boreal region and those of the Pseudoterranova decipiens complex from the same area, as to: (i) times of evolutionary divergence, (ii) geographical distribution, and (iii) host preferences.

Alleles↗