Nematodes from some Norwegian marine fishes
TL;DR: More than 260 specimens of fish, belonging to 64 species, have been searched for nematode parasites and 9 species of fish were found to be free of nematodes.
Abstract: The present paper deals with nematode parasites from some Norwegian marine fishes. The major part of the material was collected personally from fishes caught in the fjords near Bergen and Tromso; the minor part of the material was obtained from the zoological museums in Oslo and Bergen and from other sources. 260 specimens of fish, belonging to 64 species, have been searched for nematode parasites. 9 species of fish were found to be free of nematodes.
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TL;DR: Examples in which anisakid nematodes recognized genetically at the species level in definitive and intermediate/paratenic hosts from various geographical areas of the Boreal and Austral regions and their infection levels have been used as biological indicators of fish stocks and food-web integrity in areas at high versus low levels of habitat disturbance are presented.
Abstract: The application of molecular systematics to the anisakid nematodes of the genera Anisakis, Pseudoterranova and Contracaecum, parasites of aquatic organisms, over the last two decades, has advanced the understanding of their systematics, taxonomy, ecology and phylogeny substantially Here the results of this effort on this group of species from the early genetic works to the current status of their revised taxonomy, ecology and evolutionary aspects are reviewed for each of three parasitic groups It has been shown that many anisakid morphospecies of Anisakis, Contracaecum and Pseudoterranova include a certain number of sibling species Molecular genetic markers provided a rapid, precise means to screen and identify several species that serve as definitive and intermediate and or/paratenic hosts of the so far genetically characterized species Patterns of differential distribution of anisakid nematodes in various definitive and intermediate hosts are presented Differences in the life history of related species can be due both to differential host-parasite co-adaptation and co-evolution, and/or to interspecific competition, that can reduce the range of potential hosts in sympatric conditions Phylogenetic hypotheses attempted for anisakid nematodes and the possible evolutionary scenarios that have been proposed inferred from molecular data, also with respect to the phylogeny of their hosts are presented for the parasite-host associations Anisakis-cetaceans and Contracaecum-pinnipeds, showing that codivergence and host-switching events could have accompanied the evolution of these groups of parasites Finally, examples in which anisakid nematodes recognized genetically at the species level in definitive and intermediate/paratenic hosts from various geographical areas of the Boreal and Austral regions and their infection levels have been used as biological indicators of fish stocks and food-web integrity in areas at high versus low levels of habitat disturbance (pollution, overfishing, by-catch) are presented
402 citations
Cites background from "Nematodes from some Norwegian marin..."
...Morphological features such as the length of the ventriculus and presence/absence of caudal spine were proposed for the recognition of larval stages of Anisakis, but these are too inconsistent and inaccurate for use at the specific level (Berland, 1961; Shiraki, 1974)....
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TL;DR: While euphausiids appear to be important crustacean hosts of Anisakis at least in offshore areas, further is required to show other crustaceans to be significant, possibly in inshore waters.
Abstract: Publisher Summary This chapter reviews the literature on Anisakis, including use of the nematode as a biological tag in applied fishery science. The genetic diagnosis of Anisakis is presented as: three lips, each bearing a bilobed anterior projection, which carries the single dentigerous ridge; interlabia absent; excretory gland with duct opening between ventrolateral lips; oesophagus with anterior muscular portion (preventriculus) and posterior ventriculus, the latter being oblong and sometimes sigmoid or as broad as long; no oesophageal appendix or intestinal caecum; vulva in middle or first third of body; spicules of male unequal; preanal papillae numerous; postanal papillae including a group of three or four pairs set close to the tip of the tail on the ventral side. While euphausiids appear to be important crustacean hosts of Anisakis at least in offshore areas, further is required to show other crustaceans to be significant, possibly in inshore waters. Further investigation may show squid to be of greater significance in the transmission of Anisakis to final hosts than the literature indicates, bearing in mind the importance of squid in the diet of many cetacean species. Several aspects of development remain obscure. In view of the taxonomic importance of the “excretory system” in ascaridoid nematodes, its physiological functions are poorly understood; Anisakis may prove to be a useful experimental model for investigation of these functions. With regard to accidental infection of man with Anisakis, further study might be made of a possible allergic predisposition to severe gastrointestinal reaction.
289 citations
TL;DR: Preliminary data for reconstruction of a possible co-evolutionary scenario between cetacean hosts and their Anisakis endoparasites suggests that cospeciation and host-switching events may have accompanied the evolution of this group of parasites.
Abstract: Advances in the taxonomy and ecological aspects concerning geographical distribution and hosts of the so far genetically recognised nine taxa of the nematodes belonging to genus Anisakis (i.e. A. pegreffii, A. simplex s.s., A. simplex C, A. typica, A. ziphidarum, Anisakis sp., A. physeteris, A. brevispiculata and A. paggiae) are here summarized. Genetic differentiation and phylogenetic relationships inferred from allozyme (20 enzyme-loci) and mitochondrial (sequences of cox-2 gene) markers, are revised and compared. The two genetic analyses are congruent in depicting their phylogenetic relationships. Two main clusters are showed to exist in the obtained trees, one encompassing the species A. pegreffii, A. simplex s.s., A. simplex C, A. typica, A. ziphidarum and Anisakis sp.; while, the second including A. physeteris, A. brevispiculata and A. paggiae. The existence of two clades is also supported by their morphological differentiation in adult and larval morphology. Comparison of phylogenetic relationships among Anisakis spp. with those currently available for their cetacean definitive hosts suggests parallelism between host and parasite phylogenetic tree topologies. Preliminary data for reconstruction of a possible co-evolutionary scenario between cetacean hosts and their Anisakis endoparasites suggests that cospeciation and host-switching events may have accompanied the evolution of this group of parasites. Finally, genetic/molecular markers for the identification of the so far genetically recognized taxa of Anisakis at any life-stage and both sexes were given also in relation to human anisakiosis is discussed.
202 citations
Cites background or methods from "Nematodes from some Norwegian marin..."
...Today, the existence of two main clades is clearly shown, by genetic studies, in the genus Anisakis: one encompassing the species showing the larval stage indicated as Anisakis Type I (sensu Berland, 1961), and a second sharing the larval morphology Anisakis Type II (sensu Berland, 1961)....
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...…species has traditionally relied on adult (According to Davey’s revision, these included length and shape of ventriculus, length and shape of male spicules, and arrangements of male caudal papillae), and larval morphology (length of ventriculus, presence/absence of caudal spine) (Berland, 1961)....
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...ANISAKIS SPP. INCLUDED IN CLADE 2 Three species of Anisakis share so far, at larval stage, the morphology known as Type II (sensu Berland, 1961)....
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TL;DR: Gravid Hysterothylacium aduncum from the intestine of eelpout, Zoarces viviparus, were used as the source of eggs for study and the two first moults occurred in the egg.
Abstract: Gravid Hysterothylacium aduncum from the intestine of eelpout, Zoarces viviparus, were used as the source of eggs for study. The two first moults occurred in the egg, which does not normally hatch ...
198 citations
01 Jan 1993
TL;DR: During the 1950s, Ishikura noticed in the fishing town of Iwanai, Hokkaido, an intestinal disease that frequently occurred in winter with clinical and histopathologic characteristics different from those of ordinary ileitis terminalis.
Abstract: During the 1950s, Ishikura noticed in the fishing town of Iwanai, Hokkaido, an intestinal disease that frequently occurred in winter with clinical and histopathologic characteristics different from those of ordinary ileitis terminalis. He reported eight such cases, which occurred within a 2-month period in 1955, as acute ileitis terminalis showing peculiar pathologic features (1). By 1959, thirty cases of this disease had been reported (2). Ishikura, Kikuchi, and their coworkers considered the lesion peculiar because this regional enteritis (or terminal ileitis) caused severe allergic tissue reaction with extensive eosinophilic infiltration. On histologic examination, cross sections of a nematode-like worm were sometimes found, and the specimens were sent to parasitologists for identification. The parasitologists regarded these structures as roundworm larvae, not realizing that they were Anisakis larvae. Meanwhile Otsuru et al. (3), based on a description by Beaver (4), warned that visceral larva migrans might occur in Japan.
186 citations
References
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TL;DR: Y Yorke and Maplestone's book is actually a boiled-down library and museum combined, and makes possible an enormous amount of work in the far corners of the World which otherwise could not have been attempted, and will be the means of saving countless hours of tedious work for every investigator who interests himself in any phase of the study of nematodes which Evolves determination of genera.
Abstract: The study of parasitic nematodes has proceeded at an extremely rapid rate in recent years, and it has become increasingly difficult for investigators, particularly those who are interested in systematic phases of the subject (and every parasitologist is and must be to a greater or less extent), to keep abreast of the current literature. What constituted single genera fifty years ago, with no more species than one could count ?n his fingers, may now be split into as many genera ^ there were formerly species, and the number of described species has increased many fold. As Dr. Stiles Points out in his foreword, the present tendency is to seek knowledge for the sake of the good it will do rather than for the sake of knowledge itself, and it is because ?f this changed viewpoint that nematology has so Sreatly expanded. Except in a few of the largest library centres of the world, only a fraction of the hterature is ever available, and the worker who is far Removed from these centres is greatly restricted in his field and hopelessly handicapped in much research which he might otherwise profitably pursue. Yorke and Maplestone's book is actually a boiled-down library and museum combined, and makes possible an enormous amount of work in the far corners of the World which otherwise could not have been attempted, and it will be the means of saving countless hours of tedious work for every investigator who interests himself in any phase of the study of nematodes which Evolves determination of genera. The book makes it Possible for anyone with a knowldge of nematode Morphology to place correctly any species of nematode which he may come upon in its proper genus, if it belong to any genus described up to the middle of 1925. The book contains clear and carefully worked out keys to all the superfamilies, families, and genera of Parasitic nematodes, the best available description of the genera, the name and synonyms of the type species, and a list of such species as can, with a reasonable degree of certainty, be ascribed to each genus. Of Iriestimable value are the drawings which illustrate the essential characteristics of each genus. In most cases these are drawings of the type species, but in a few
900 citations
Book•
01 Jan 1922
102 citations
TL;DR: A synopsis of the families and genera of Nematoda can be found in this paper, where the authors present a taxonomy of the genera and families of these animals.
Abstract: A synopsis of the families and genera of Nematoda , A synopsis of the families and genera of Nematoda , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
57 citations
TL;DR: The great French helminthologist, Dujardin, appears to have been the first to suggest a grouping of the genus “ Ascaris ” according to the structure of the alimentary canal.
Abstract: The great French helminthologist, Dujardin, appears to have been the first to suggest a grouping of the genus “ Ascaris ” according to the structure of the alimentary canal. As is, unhappily, only too well known to modern helminthologists, little attention was paid to internal structures by the earlier workers, whose numerous descriptions and classifications were based almost entirely upon external characters. It is now recognized that a natural system must be based on a survey of the whole structure of the animal, both external and internal, and a re-examination of many of the older species becomes extremely important.
55 citations