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PubMed1992

A nematode hemoglobin gene contains an intron previously thought to be unique to plants.

Hemoglobin genes from plants and animals both have a characteristic chromosomal organization. Plant hemoglobin genes contains a unique intron inserted into the heme-binding domain of exon 2. This intron has not been previously reported in animal globin genes, and its loss was hypothesized to have occurred early in the evolution of hemoglobins. We report here a unique six-intron, seven-exon internally duplicated nematode hemoglobin gene that contains an intron equivalent to the plant central intron in its first repeat. This nematode hemoglobin gene has lost both the central and the normal third intron in its second repeat. The nematode globin also contains a unique intron between its secretory peptide leader sequence and its coding sequence, which is absent in other extracellular invertebrate globin genes. Possible models to explain the head-to-tail duplication of this gene are discussed.

Amino Acid Sequence↗
PubMed1985

Centromere ultrastructure in germ-line chromosomes of Parascaris.

Ultrastructural analysis of the centromere in germ-line mitotic chromosomes of Parascaris univalens and Parascaris equorum revealed that these chromosomes are holocentric. In thin longitudinal sections of both species the kinetochore appeared as a continuous plate (up to 3.8 micron long) and displayed a layered structure. This structure consisted of electron-dense inner and outer layers (average width 10 nm) separated by a less dense middle layer (25 nm wide), which had transverse electron-dense bars (10 nm wide) regularly spaced every 25-30 nm. Thus the ladderlike kinetochore profile observed in Parascaris gonial mitotic chromosomes represents a different type of organization from that of the classical trilaminar kinetochore found in both holocentric and monocentric chromosomes.

Animals↗
PubMed1976

The distribution of concanavalin A binding sites on the intestinal epithelium of the nematodes Ascaris suum and Parascaris equorum.

Receptors for Concanavalin A (Con A), were localized on the intestinal epithelium of the nematodes Ascaris suum and Parascaris equorum. Fixed tissue incubated in 3H-Con A showed labeling of the microvilli surface and basal membrane. Using Con A coupled with peroxidase, the tips of the microvilli of Ascaris suum and the tips and lateral surfaces of Parascaris equorum were stained. The basal membrane of both species was also labeld. No labeling was observed on control tissue incubated without Con A or on tissue incubated with Con A to which alpha-methyl-D-mannoside was added.

Animals↗
PubMed1986

The value of external morphology in the identification of larval anisakid nematodes: a scanning electron microscope study.

We studied larval nematodes of four genera of the Anisakidae using a scanning electron microscope (SEM). The anterior and posterior extremities and cuticular structures of the 3rd-stage larvae (L3) of Anisakis type I, Pseudoterranova decipiens, Contracaecum type B and Hysterothylacium were examined. The 4th-stage larvae (L4) of Anisakis type I, P. decipiens, recovered after infection into laboratory rats, and the L3 and L4 of Anisakis type I larvae from human were also examined in the same way. There were generic differences in the shape and size of the lip bulges, external papillary structures, the appearance of the boring tooth, the width and depth of the grooves and ridges of the cuticle and the caudal structures of the L3. In Anisakis type I and P. decipiens L3, changes were seen in the anterior extremity, cuticle and posterior extremity after molting to the L4. Similar changes can be expected in larvae infecting man. The L4 of Anisakis type I from rat and man were similar, while the L4 of Anisakis type I and P. decipiens showed differences. These ultrastructural differences might be of value in the identification of fragments recovered during endoscopy in man.

Animals↗
PubMed1988

Incubation in rats of a nematodal larva from cod to establish its specific identity: Contracaecum osculatum, (Rudolphi).

Infective, third-stage larvae of the genus Contracaecum from fish were cultured in vitro and fed to laboratory animals in order to obtain later developmental stages to permit their specific identification. The in vitro incubation was unsuccessful. In orally infected laboratory rats and hamsters, fourth-stage larvae were obtained from the stomach at 2-5 days postinfection (p.i.), but no adult worms developed. Larvae introduced surgically into the body cavity of laboratory rats yielded some adult worms from day 42 onwards. Adult males were identified as Contracaecum osculatum.

Animals↗
PubMed1984

Radiographic study of acute gastric anisakiasis.

The radiographic findings from 226 patients with acute gastric anisakiasis are reviewed. Suggestive but indeterminate findings such as coarse and broad gastric folds caused by mucosal edema were demonstrated in 224 patients (98%). In 179 patients (88%) mucosal edema was so extensive that it occupied more than half of the entire gastric wall. The most diagnostic radiographic finding, present in 139 patients, was the appearance of a threadlike filling defect about 3 cm in length, showing an anisakis larva itself. Careful demonstration of these radiographic findings is useful for the diagnosis of acute gastric anisakiasis.

Acute Disease↗
PubMed1988

Anisakiasis confirmed by radiography of the large intestine.

As yet, there has been no report of acute anisakiasis of the large intestine diagnosed by radiographic demonstration of the larvae. We present such a case, in which roentgenologic examination revealed Anisakis larvae in the ascending colon.

Adult↗
PubMed2001

Natural antibodies to nematode biotinyl-enzymes in human sera.

Biotinyl-enzymes are conservative molecules present in helminths, as well as in other animals, bacteria and plants. They have recently been found to be antigenic in mice, and a potential source of cross-reactivity among helminths. This study investigated the presence in human sera of antibodies reactive with biotinyl-enzymes from the nematodes Anisakis simplex, Toxocara canis and Ascaris suum. Biotinyl-enzymes from all these nematodes were recognized by IgG1 antibodies in sera from healthy subjects and from Anisakis-free patients infected with other parasites. Interestingly, IgE antibodies reactive with Anisakis simplex biotinyl-enzymes were present in about one third of the sera from Anisakis-free patients infected with other parasites. Our results also demonstrate that the anti-BE IgG1 and IgE antibodies present in the sera of Anisakis-free subjects are cross-reactive among helminths. We conclude that biotinyl-enzymes from nematodes are recognized by natural human antibodies, although Anisakis biotinyl-enzymes do not seem to be the cause of sensitization. Since sera from the Anisakis-free population also present these antibodies, as-yet unidentified factors (dietary components, intestinal inflammation and/or the presence of parasites) may contribute to the induction of anti-BE antibody background.

Adolescent↗
PubMed2002

Population dynamics of sealworm, Pseudoterranova decipienssensu lato, in sculpins, Myoxocephalus scorpius, from two areas in Norway between 1990 and 1996.

The abundance of sealworms (Pseudoterranova decipienss.l.) in sculpins (Myoxocephalus scorpius) was studied at Torbjørnskjaer, southeast Norway, and Vega, northern Norway, in samples from 1990 to 1996. The harbour seal ( Phoca vitulina) population at Torbjørnskjaer declined by 70% during the phocine distemper virus epizootic in 1988, and has increased during the 1990s. The abundance of sealworms in sculpins was relatively stable from 1992 to 1996 and any effect of the reduction in the number of harbour seals on the abundance of sealworms has been short-term. When correcting for size differences, young sculpins (2-4 years) from Torbjørnskjaer had higher abundances than those from Vega, while in old sculpins (5-7 years) the abundances seemed similar and stabilised. This happened at a younger age among the more heavily infected sculpins at Torbjørnskjaer than at Vega, and we interpret this as density dependence in the fish host.

Age Distribution↗
PubMed2003

Identification of tissue-embedded ascarid larvae by ribosomal DNA sequencing.

Polymerase chain reaction (PCR) was applied to identify tissue-embedded ascarid nematode larvae. Two sequences of the internal transcribed spacer (ITS) regions of ribosomal DNA (rDNA), ITS1 and ITS2, of the ascarid parasites were amplified and compared with those of ascarid-nematodes registered in a DNA database (GenBank). The ITS sequences of the PCR products obtained from the ascarid parasite specimen in our laboratory were compatible with those of registered adult Ascaris and Toxocara parasites. PCR amplification of the ITS regions was sensitive enough to detect a single larva of Ascaris suum mixed with porcine liver tissue. Using this method, ascarid larvae embedded in the liver of a naturally infected turkey were identified as Toxocara canis. These results suggest that even a single larva embedded in tissues from patients with larva migrans could be identified by sequencing the ITS regions.

Animals↗
PubMed2004

Parasitic helminth fauna of the cutlass fish, Trichiurus lepturus L., and the differentiation of four anisakid nematode third-stage larvae by nuclear ribosomal DNA sequences.

The helminth fauna of the gastrointestinal tract and abdominal cavity of cutlass fish, Trichiurus lepturus L., off the Taiwanese coast of the north-western Pacific was investigated. The following helminths were found: (1) nematodes--Anisakis simplex, Hysterothylacium aduncum, Porrocaecum decipiens, Raphidascaris trichiuri; (2) digeneans--adult Lecithochirium trichiuri; and (3) cestodes-plerocercoids of Proteocephalus spp. The third-stage larvae of these four anisakid nematodes were characterized genetically using a molecular approach. The nuclear ribosomal DNA region spanning the first internal transcribed spacer (ITS-1), the 5.8S gene and the second internal transcribed spacer (ITS-2) was amplified and sequenced. Based on the sequence differences, a PCR-based restriction fragment length polymorphism method was established for the unequivocal delineation of the four species. Phylogenetic analysis showed that H. aduncum clustered with P. decipiens, whereas A. simplex was not closely related to these according to the nucleotide sequences of all rDNA.

Abdominal Cavity↗
PubMed2004

Helminth parasites of Girardinichthys multiradiatus (Pisces: Goodeidae) in the upper Lerma River sub-basin, Mexico.

Thirteen helminth species were recorded during a helminthological examination of 754 Girardinichthys multiradiatus (Meek) (Pisces: Goodeidae) collected from 20 localities in the upper Lerma River sub-basin on the highland plateau of Mexico. The study constitutes a complete and extensive inventory of the helminth parasites of this freshwater fish species across its entire current geographic distribution. The collected species included one adult trematode, three metacercariae, one monogenean, one adult cestode, three metacestodes, three nematode larvae and one cystacanth. The records of the metacercariae of Tylodelphys sp. and Ochetosoma brevicaecum, the larvae of the nematodes Contracaecum sp. and Falcaustra sp. and the cystacanth of Polymorphus brevis are all new records for G. multiradiatus. The metacercariae of Tylodelphys sp. were the most widespread and prevalent species in the sample, being collected from 15 of the 20 sampling localities, with a prevalence of 3.2-72.2%. The data indicate the helminth parasite community of G. multiradiatus to be relatively poor when compared with the helminth communities of freshwater fish from other parts of Mexico. This community is subject to colonization by generalist helminth species, mostly transported by birds. A further component of this community consists of helminth species that have been introduced anthropogenically.

Acanthocephala↗
PubMed2005

Field studies on endoparasites of Thoroughbred foals on seven farms in central Kentucky in 2004.

Fecal samples (n=1,584) for a parasite study were collected from Thoroughbred foals (n=349), 28 to 330 days old, on seven farms in central Kentucky during 49 monthly trips from May to October, November, or December 2004. The main purpose was to determine possible drug resistance of ascarids, also of strongyles, to ivermectin (IVM) and other commercially available compounds [fenbendazole, moxidectin (MOX), oxibendazole (OBZ), and pyrantel pamoate]. In addition, interest was on prevalence of foal parasites. Qualitative data were obtained by recording presence or absence of ascarid and strongyle eggs in feces from 7 to 25 days after treatment of some of the foals. None of the compounds completely eliminated ascarid eggs in feces of all foals posttreatment. Activity on ascarids was significantly the highest for OBZ and lowest for IVM. Activity on strongyles was significantly higher for IVM and MOX than for the other compounds. Prevalence (mean percentage of foals infected) was recorded for eggs of Parascaris equorum (39%), of strongyles (32%), and of Strongyloides westeri (2%) and oocysts of Eimeria leuckarti (28%) in feces of foals. One or more foals had infections of P. equorum on six farms (86%), strongyles on seven farms (100%), S. westeri on two farms (29%), and E. leuckarti on six farms (86%). The oldest foal infected with E. leuckarti was 301 days of age. Comparison was made on the prevalence of parasites in foals on five of the same farms in the 2004 study, which were part of a similar 14-farm project in 2003 (Lyons and Tolliver in Parasitol Res (2004) 92:400-404).

Animals↗
PubMed2006

Prevalence of large endoparasites at necropsy in horses infected with Population B small strongyles in a herd established in Kentucky in 1966.

Two closed horse herds (Old Lot 4 and Field 24), infected since 1966 with Population B small strongyles resistant to thiabendazole (TBZ) and phenothiazine (PTZ), were terminated in February, March, and May, 2005. At necropsy, only the large endoparasites were identified and counted. The number of horses on pasture was 14 (239 days of age to 23 years old) for Old Lot 4 and two (3 to 20 years old) for Field 24. The time of the last antiparasitic treatment, relative to the year (2005) of necropsy, was 26 years for Old Lot 4 and 9 years for Field 24 horses. Gasterophilus intestinalis third instars (three to 113 specimens/horse) were found in all 16 horses and second instars (one to two) in two horses. Gasterophilus nasalis third instars (one to three) were recovered from five horses. Parascaris equorum infections (23 to 144) were in four horses (239 days to 4 years old). Strongylus vulgaris were present in the large intestine (one to 155) of 13 horses from 239 days to 23 years old and in the cranial mesenteric artery (two to 79) in 10 horses from 239 days to 23 years old. Strongylus edentatus were in the large intestine (two to 101) of 12 horses, ranging in age from 2.5 to 23 years old and in the ventral abdominal wall (one to 53) of six horses from 239 days to 21 years old. Specimens (seven to 872) of Anoplocephala perfoliata were in all horses. Oxyuris equi (one to 129) were recovered from seven horses (330 days to 23 years old). Thelazia lacrymalis (one to 85) infected the eyes of five horses (317 days to 11 years old).

Animals↗