Die Oligacanthorhynchidae sind eine Familie der Kratzwürmer mit obligatorischen Wirtswechsel, die als ausgewachsene Darmparasiten bei Landwirbeltieren und Vögeln parasitieren. Es handelt sich um große bis sehr große Arten mit Körperlängen von einigen Zentimetern bis zu 70 Zentimeter beim Riesenkratzer (Macracanthorhynchus hirudinaceus), der im Darm von Schweinen lebt und auch den Menschen befallen kann.
Die Oligacanthorhynchidae besitzen einen glatten oder auch quergefurchten Körper, der ventral eingebogen oder auch eingerollt sein kann. Der Rüssel (Proboscis) ist im Verhältnis zum Körper relativ klein und ei- bis kugelförmig. Er besitzt sechs oder sieben spiralig angelegte Hakenreihen aus jeweils fünf bis acht Haken, wobei die Haken an der Rüsselbasis besonders klein sind. Entsprechend dem kleinen Rüssel sind auch die Rüsselscheide und die Leminiski nur relativ kurz ausgebildet.
Die Weibchen besitzen wie alle Archiacanthocephala einen dorsalen und einen ventralen Ligamentsack im Pseudocoel, deren Wände sich im Gegensatz zu denen der Palaeacanthocephala nicht auflösen. Bei den besonders großen Arten der Oligacanthorhynchidae finden sich Protonephridien, wodurch sie sich von allen anderen Kratzwürmer unterscheiden. Die acht Zementdrüsen der Männchen sind paarig angeordnet und kompakt gebaut.
Die Eier sind oval mit einer dicken, mehrlagigen Eischale und besitzen eine Oberfläche mit deutlicher Struktur.
Die Oligacanthorhynchidae haben vollständigen terrestrischen Lebenszyklus, sie sind also nicht von wasserlebenden Zwischenwirten abhängig. Die Endwirte sind vor allem Vögel und Säugetiere, als Zwischenwirte kommen Insekten und Myriapoda in Frage. So stellen beispielsweise die Larven von verschiedenen Blatthornkäfern, vor allem Mai-, Juni- oder Rosenkäfer die Zwischenwirte des Riesenkratzers dar, der die Macracanthorhynchose des Schweines auslöst.
Die Oligacanthorhynchidae sind eine Familie der Kratzwürmer mit obligatorischen Wirtswechsel, die als ausgewachsene Darmparasiten bei Landwirbeltieren und Vögeln parasitieren. Es handelt sich um große bis sehr große Arten mit Körperlängen von einigen Zentimetern bis zu 70 Zentimeter beim Riesenkratzer (Macracanthorhynchus hirudinaceus), der im Darm von Schweinen lebt und auch den Menschen befallen kann.
Oligacanthorhynchida is an order containing a single parasitic worm family, Oligacanthorhynchidae,[1] that attach themselves to the intestinal wall of terrestrial vertebrates.
Oligacanthorhynchida contains twelve genera and numerous species.[4][5][a]
The genus Cucullanorhynchus Amin, Ha and Heckmann, 2008 is named for the anterior hood.[6] It was described in 2008 based on samples collected from the intestines of mammals between 1998 and 2004 in Vietnam.[6]
C. constrictruncatus is the only species in the genus Cucullanorhynchus. It has been found in the intestine of the leopard (Panthera pardus) in Vietnam. The trunk has an anterior hood in both sexes and a posterior constriction in females. The species name derives from this constriction near the posterior end of females.[6]
The genus Heptamegacanthus Spencer-Jones, 1990 contains 1 species.
H. niekerki is a parasite of the giant golden mole (Chrysospalax trevelyani) found in South-East Africa.[7]
The genus Macracanthorhynchus Travassos, 1917 contains many species.
M. hirudinaceus is a parasite which lives in the intestines of pigs and other suids, and very occasionally in humans or dogs. It causes enteritis, gastritis or peritonitis. Its life cycle includes beetles of the genus Melolontha as intermediate hosts. This species has many synonyms which include: Echinorhynchus gigas (Block, 1782), Macracanthorhynchus gigas (Block, 1782),[8] Echinorhynchus hirundinacea (Palas, 1781), Gigantorhynchus hirundinaceus (Pallas, 1781), Gigantorhynchus gigas (Block, 1782),[9] Hormorhynchus gigas (Block, 1782), Taenia haeruca (Pallas, 1776), and Taenia hirundinaceus (Pallas, 1781)[10] The complete mitochondrial genome of M. hirudinaceus has been sequenced.[11] The eggs have 4 membranes are 98 um long and have an elongation ratio of 1.85.[12]
The eggs have 3 membranes are 94 um long and have an elongation ratio of 1.66.[12] It parasitizes the raccoon (Procyon lotor) in the United States.[3]
The genus Multisentis Smales, 1997 contains 1 species.
The genus Neoncicola Schmidt, 1972 contains several species.
N. artibei was found infesting the great fruit-eating bat (Artibeus lituratus) in Paraguay.[13]
The genus Nephridiacanthus Meyer, 1931 contains several species.
N. major has been found infesting the long-eared hedgehog (Hemiechinus auritus) and the southern white-breasted hedgehog (Erinaceus concolor) in Iran, Germany, Morocco, central Asia, Egypt, Bulgaria, Tajikistan, Lebanon, Sicily, Italy, Nigeria, Turkey and Mongolia. Phylogenetic analysis has been done on the small subunit ribosomal DNA and cytochrome c genes, and have determined that it belongs to the family Oligacanthorhynchidae.[3]
The genus Oligacanthorhynchus Travassos, 1915 contains numerous species. The trunk is cylindrical and smooth or irregularly ringed. The proboscis is generally globular being somewhat longer than it is wide and has stout hooks in left handed spiral rows, with their point obliquely cut and their root produced forwards. The proboscis receptacle consists of a thick inner wall i inserted into inside of proboscis which is shrinks along the ventral side, and a thinner outer wall inserted at base of neck. A series of intercommunicating spaces branching from two median main vessels and numerous longitudinal and circular anastomoses in the hypodermis form the lacunar system. Protonephridia are present. The lemnisci are filiform with a central canal and numerous nuclei. In the far posterior of the male, there are testes and eight cement glands used to temporarily close the posterior end of the female after copulation.[14][15][16] The eggs are almost spherical with shells that are radially striated. Hosts include birds with snakes being the intermediate hosts.[16]
O. carinii was found infesting the southern three-banded armadillo (Tolypeutes matacus) in Paraguay.[13]
The eggs are 58 um long and have an elongation ratio of 1.45.[12]
O. ricinoides was found inside the body cavity of 0.68% of the African five-lined skink (Trachylepis quinquetaeniata reported as Mabuya quinquetaeniata) sampled in the Qena Governorate, Egypt. The worm is cylindrical and white. The wall of the body consists of a thin cuticle over a syncytical hypodermis. The proboscis is cylindrical and contains recurved sclerotized hooks. The trunk measures 1.9–3.1 mm long by 0.56–0.77 mm wide in the female and 1.9–2.99 mm. in length and 0.58–0.98 mm in width in the much smaller male. A series of intercommunicating spaces branching from two median main vessels and numerous longitudinal and circular anastomoses in the hypodermis form the lacunar system. The proboscis receptacle is inserted in the inner side of proboscis. The lemnisci are filiform with a central canal and numerous nuclei. The testes are located in the mid-region of the body and each measure 0.14–0.15 mm long by 0.10–0.11 mm wide.[16]
The genus Oncicola Travassos, 1916 contains many species.
O. canis was found infesting the Red fox (Vulpes vulpes) in Iran.[17]
The complete mitochondrial genome of O. luehei has been sequenced.[18]
O. schacheri is named after the collector of the samples Dr. John F. Schacher. It was found in the small intestines of around 20% of foxes (Vulpes vulpes, palestina subspecies) and juveniles were also found in the mesentaries of a badger (Meles meles) and are considered incidental hosts. All samples were collected in Lebanon.[19] There is no marked sexual dimorphism apart from a small size difference: males were between 30.0 and 39.0 mm long and females were 39.0 to 44.0 mm long. There are twelve regularly alternative longitudinal rows of 3 hooks each. The hooks vary in size between 95 and 210 microns.[19]
South American species that is common in captive primates.[19]
This species was described by a sample infecting the intestine of the ocelot (Leopardus pardalis) in Venezuela, where it gets its name. It differs from other species of the genus mainly by its longer lemnisci which have six nuclei.[20] There is no sexual dimorphism, with males ranging in length from 13.5 to 14.4 mm (without proboscis) and 2 mm maximum width and females ranging in length from 15 to 16 mm (also without proboscis) with a maximum width of 1.9 to 2.2 mm.[20]
Cystacanths of O. venezuelensis are present in the hemocoel of Caribbean termites (Nasutitermes acajutlae) from St. Thomas and St. John islands in the U.S. Virgin Islands as an intermediate host. Cystacanths were present in Other intermediate hosts including in subcutaneous nodules of lizards (Anolis cristatellus and Anolis stratulus), in the greater omentum of small Indian mongooses (Urva auropunctata), and embedded in mesenteries of pearly-eyed thrashers (Margarops fuscatus). The host from the U.S Virgin Islands is yet to be determined.[21]
The genus Pachysentis Meyer, 1931 contains ten species.[22] Generally, they look identical to Oncicola apart from the number of hooks on the proboscis. Species of Oncicola have 36 or less hooks whereas species of Pachysentis have more. Specifically, the proboscis is not quite spherical and contains 42 to 102 hooks arranged into 12 longitudinal rows 3 to 12 hooks each. The rows may be regularly or irregularly alternating and straight or crooked. Hooks have tips with or without barbs, and the larger hooks with complex manubria and roots with the remaining spines being rootless. The trunk is fairly wide relative to the length with the anterior half usually wider than the posterior half. The testes are in tandem with at least one located before the middle of the worm. There are eight cement glands compactly arranged each with single giant nucleus used to temporarily close the posterior end of the female after copulation.[14][15] The eggs have a sculptured outer membrane. Hosts include Brazilian or Egyptian carnivores.[16] Species can be distinguished based on the number and arrangements of proboscis hooks, whether these hooks are barbed, the arrangement of the cement glands, host, and the length of lemnisci.[2]
Paraprosthenorchis Amin, Ha and Heckmann, 2008 have a trunk over 200 mm long, ornate proboscis with three non-barbed hooks in each of 16 rows. They have simple hook roots without manubria, and a large oblong horizontally posterior hook base. There are about 35 festoons. Protonephridia are gill-like and capsular. Gonopore is terminal. The primary host are Manidae in Vietnam with ants and termites as intermediate hosts. This genus is named for its nearest oligacanthorhynchid genus, Prosthenorchis.[6]
P. ornatus has been found in the intestine of the Chinese pangolin (Manis pentadactyla) collected from the Hanoi Zoological Park, Vietnam. The anterior trunk has many small festoons and proboscis hooks are inserted in elevated papillae separated by beady, near hexagonal, ornate grids. The species is named for its uniquely ornate proboscis.[6]
Prosthenorchis Travassos, 1915 have a trunk up to 50 mm long, a proboscis that is not ornate with three barbed hooks in each of 12 rows. They have complex hook roots with large manubria, and a small discoid posterior hook base. There are up to 23 festoons. Gonopore is subterminal. The primary host are primates in South America and Felidae in Africa with cockroaches and beetles as intermediate hosts.[6]
The genus Tchadorhynchus Troncy, 1970 was erected as the single species contained within differs from related Oligacanthorhynchidae genera by morphological features of bot the adult and embryo as well as the group of hosts, hyenas, the worms parasitize.[24]
T. quentini was found parasitizing the striped hyena (Hyaena hyaena) and the spotted hyena (Crocuta crocuta)in Chad.[24]
Oligacanthorhynchidae species parasitize mammals with insect and lizard intermediate hosts.
The leopard is a host of Cucullanorhynchus constrictruncatus
Oncicola schacheri was found parasitizing the Palestinian subspecies of the red fox
The Chinese pangolin is a host of Paraprosthenorchis ornatus
Oligacanthorhynchida is an order containing a single parasitic worm family, Oligacanthorhynchidae, that attach themselves to the intestinal wall of terrestrial vertebrates.
Les Oligacanthorhynchidae sont une famille de vers à tête épineuse (acanthocéphales), de la classe des Archiacanthocephala et de l'ordre des Oligacanthorhynchida. Cette famille a été créée par Southwell et Macfie en 1925.
À l’état adulte ce sont des parasites du tube digestif des mammifères et des oiseaux terrestres.
Les embryophores, disséminés dans le milieu extérieur par les selles, sont ingérés par des insectes terrestres (surtout des larves) qui sont les hôtes intermédiaires. L’hôte définitif s’infeste soit directement en dévorant l’hôte intermédiaire, soit indirectement en mangeant les reptiles, oiseaux ou mammifères (plus rarement les amphibiens) qui peuvent être des hôtes d’attente pour les juvéniles. D’autres mammifères et oiseaux peuvent servir d’hôtes accidentels. Dans leur intestin, les juvéniles se fixent, grandissent mais n’atteignent pas la maturité sexuelle.
Taille du corps généralement grande à très grande.
Tronc cylindrique en coupe, parfois aplati latéralement, avec rides transversales à disposition anarchique, très fortement accusées chez les spécimens conservés, se superposant parfois à une pseudo-métamérisation régulière. Extrémités antérieure et postérieure du tronc souvent arquées ventralement, parfois enroulées. Vaisseaux principaux du système lacunaire dorsal et ventral, unis par des anastomoses transversales à disposition pseudo-métamérique.
Proboscis ne se rétractant jamais en doigt de gant, court, ovoïde ou sphéroïde, portant six spires de quatre à huit crochets, les antérieurs étant plus volumineux, souvent terminés en « pointe de flèche » et possédant des racines bien développées, symétriques ou non par rapport au plan médian, perpendiculaires à l’axe de la lame du crochet. Réceptacle du proboscis inséré soit à l’intérieur du proboscis, soit à sa base, au niveau de son union avec le cou, présentant toujours une assise longitudinale externe mince et une assise circulaire interne épaisse surtout dorsalement, avec fente ventrale d’où sortent les muscles rétracteurs du proboscis et du réceptacle. Lemnisci filiformes ou rubanés, contenant quelques noyaux géants sphéroïdaux en nombre spécifiquement défini. Protonéphridies annexées au tractus génital et manquant dans les genres les plus évolués. Organes mâles occupant la totalité ou presque la totalité de la moitié postérieure du tronc. Testicules ovoïdes, plus ou moins allongés. Glandes cémentaires au nombre de huit, disposées plus ou moins régulièrement en quatre paires superposées, drainées chacune par un canal distinct, possédant chacune un seul noyau géant sphéroïde, parfois amœboide et même pouvant être amitotiquement fragmenté. Embryophores en ovale large, à coque externe granuleuse ou vermiculée[2].
Cette famille comporte douze genres composés des espèces suivantes[3] :
Les Oligacanthorhynchidae sont une famille de vers à tête épineuse (acanthocéphales), de la classe des Archiacanthocephala et de l'ordre des Oligacanthorhynchida. Cette famille a été créée par Southwell et Macfie en 1925.
À l’état adulte ce sont des parasites du tube digestif des mammifères et des oiseaux terrestres.