Marianne Køie

The life cycle ofContracaecum osculatum (Rudolphi, 1802) sensu stricto (Nematoda, Ascaridoidea, Anisakidae) in view of experimental infections

Hatched, ensheathed third-stage larvae ofContracaecum osculatum, 300–320 μm long, were shown to be infective to copepods, to nauplius larvae of {jtBalanus} and to small specimens of fishes (sticklebacks, 0-group eelpout). Other fishes such as gobies and small flatfishes became infected by ingesting infected crustaceans. Cod were infected by being given infected small fishes. In the crustacean paratenic hosts, little growth of the larvae occurred, if any. In the liver sinusoids of sticklebacks and gobies the length of most of the unencapsulated third-stage larvae had not even doubled within 6 months of infection. The fate of larvae (max. 2 mm long) given to cod via infected intermediate fish hosts was apparently decided by the size of the larvae only. Small larvae became encapsulated and eventually died in the liver and wall of the gastrointestinal tract. Larger larvae migrated to the liver parenchyma, where some grew to a length of as much as 10 mm. The growth of the larvae in sticklebacks was shown not to be affected by an increase in temperature (infected fish being transferred from 8° to 14° and 20°C), by the intensity of infection and, partly, by the age of infection (e.g some 2-week-old and 6-month-old larvea were of identical size). In the liver and mesentery of plaice the third-stage larvae developed via copepod paratenic hosts to infectivity (i.e. to more than 4 mm in length), showing that the life cycle may be completed with an optional paratenic invertebrate host and only one intermediate fish host. In combination with earlier results showing that the ensheathed third-stage larva (not the second stage) emerges from the egg and with literature data on the occurrence of larvae in fishes and the presence of fourth-stage larvae and adults predominantly in the stomach of grey seals, the life cycle ofC. osculatum is shown experimentally for the first time.

Parasites in European eel Anguilla Anguilla (L.) from Danish Freshwater, Brackishand Marine Localities

Abstract The parasite fauna of 370 specimens of European eel, Anguilla anguilla(L.), (35–55 cm long) caught in three lakes in Denmark, three brackish localities and in the western Kattegat, was examined. A total of 46 species of parasites were found, the highest number (27) was found in a lake, and the lowest (10) in the western Kattegat. Myxidium giardi and Myxobolus sp. were found at all seven localities. Pseudodactylogyrus anguillae, Diplostomum sp. metacercariae, Bothriocephalus clauiceps, Proteocephalus macrocephalus, Raphidascaris acus, Anguillicola crassus and Ergasilus gibbus were found in both freshwater and brackish localities. Podocotyle atomon, Deropristis inflate, Hemiurus communis, Brachyphallus crenatus, Derogenes varicus, Lecithaster gibbosus, Lecithochinum rufotnride and Cryptocotyle lingua metacercariae occurred in brackish or marine localities. Gyrodactylus spp., tetraphyllidean larvae and Hysterothylacium aduncum occurred in brackish localities. The freshwater dracunculoid nematodes Ph...

The redia, cercaria and early stages of Aporocotyle simplex Odhner, 1900 (Sanguinicolidae) -- a digenetic trematode which has a polychaete annelid as the only intermediate host.

Abstract An apharyngeate furcocercous cercaria which develops in the polychaete Artacama proboscidea Malmgren, 1865 (Annelida, Terebellidae), is shown experimentally to develop into Aporocotyle simplex Odhner, 1900 (Trematoda, Sanguinicolidae). A. simplex is a common blood fluke in Hippoglossoides platessoides (Fabricius), Limanda limanda (L.), and Pleuronectes platessa L. from Danish waters. About 7 % of A. proboscidea from Oresund were infested. At least two redial generations occur. More than 1000 rediae were found commonly in individual polychaetes. The rediae, which occur free in the coelomic cavity, castrate the host. The redia, cercaria and young specimens from fish are described. Both light microscopy and scanning electron microscopy were used. The cercaria has a cephalic organ with 6–9 circlets of spines. Similar spines are common on the anterior half of the body. Five pairs of penetration glands occur in the body, and one pyriform gland occurs entirely within the cephalic organ. The digestive sy...

Digenetic trematodes from Gadus morhua L. (Osteichthyes, Gadidae) from Danish and adjacent waters, with special reference to their life-histories

Abstract A total of 890 specimens of the Atlantic cod Gadus morhua L. (Osteichthyes, Gadidae) have been examined for infestations with digenetic trematodes. The cods were caught at 15 sampling stations in Danish and adjacent waters with salinities ranging from 8‰ (the Baltic off Bornholm) to 35‰ (the North Sea and the Atlantic Ocean off the Faroes), and from shallow water down to a depth of 230 m. 18 species (metacercariae and adults) were found. The following species were found in the alimentary tract: Prosorhynchus squamatus Odhner, 1905 (Bucephalidae), Podocotyle atomon (Rudolphi, 1802), P. reflexa (Creplin, 1825) (Opecoelidae), Lepidapedon elongatum (Lebour, 1908), L. rachion (Cobbold, 1858), Opechona bacillaris (Molin, 1859) (Lepocreadiidae), Stephanostomum pristis (Deslongchamps, 1824) (Acanthocolpidae), Derogenes varicus (Muller & 1784), Lecithaster gibbosus (Rudolphi, 1802), Brachyphallus crenatus (Rudolphi, 1802), Hemiurus communis Odhner, 1905, H. luehei Odhner, 1905, H. levinseni Odhner, 1905, ...

A NEW GENUS GADIMYXA WITH THREE NEW SPECIES (MYXOZOA, PARVICAPSULIDAE) PARASITIC IN MARINE FISH (GADIDAE) AND THE TWO-HOST LIFE CYCLE OF GADIMYXA ATLANTICA N. SP

The myxozoans Gadimyxa atlantica n. sp. and G. sphaerica n. sp., and G. arctica n. sp. (Myxozoa, Parvicapsulidae), are described from Gadus morhua L. and Arctogadus glacialis (Peters) (Gadidae), respectively. They develop coelozoic in bisporic plasmodia in the urinary systems. Two morphological forms of spores were found in all 3 species, i.e., wide and (sub)spherical forms. Both spore types are bilaterally symmetrical along the suture line. The wide spores, semicircular in frontal view and elliptical in apical view, have 2 spherical polar capsules, which open in the sutural or median plane mid on the flat side of the spore. Mean widths of the wide spores of G. atlantica, G. sphaerica, and G. arctica are 7.5, 10.0, and 10.0 μm, respectively. The older, more thick-walled, (sub)spherical spores with binucleate sporoplasm are 8.0, 5.3, and 7.3 μm in mean width, respectively. The mean diameters of the polar capsules of (sub)spherical spores are 2.4, 1.7, and 2.2 μm, respectively. The (sub)spherical forms of Gadimyxa are most similar to Ortholinea within the Ortholineidae, but they differ in the development of the spores and in the arrangement of the polar capsules. The polychaetes Spirorbis spp. (Spirorbidae) act as invertebrate hosts of G. atlantica. The previously described actinospores of the tetractinomyxon type develop to myxospores in Gadus morhua within 8 wk. This is the second known myxozoan 2-host life cycle in the marine environment. Phylogenetic analyses based on partial small subunit rDNA sequences places Gadimyxa spp. among Parvicapsula spp. in the Parvicapsulidae.

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

Abstract 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.

On the morphology and life-history of Opechona bacillaris (Molin, 1859) Looss, 1907 (Trematoda, Lepocreadiidae)

Abstract The life-cycle of the digenetic trematode Opechona bacillaris (Molin, 1859) Looss, 1907 (fam. Lepocreadiidae Nicoll, 1934, subfam. Lepocreadiinae Odhner, 1905) is described. It is shown experimentally that ophthalmotrichocercous cercariae which develop in the marine prosobranch Nassarius pygmaeus (Lamarck) penetrate the ctenophore, Pleurobrachia pileus, a chaetognath, Sagitta sp., and small medusae. Here they develop into the metacercaria of O. bacillaris, which previously has been described from a large number of planktonic invertebrates. The redia and cercaria of O. bacillaris are described. The cercaria and metacercaria are compared with immature O. bacillaris from a naturally infested lumpsucker, Cyclopterus lumpus, by means of the stereoscan electron microscope. The infestation percentage of the snail host population from the northern Oresund was determined at intervals over a period of nearly two years. During winter most infestations comprise only rediae, whereas during summer nearly all i...

Digenetic trematodes from Limanda limanda (L.) (Osteichthyes, Pleuronectidae) from Danish and adjacent waters, with special reference to their life-histories

Abstract A total of 650 specimens of the common dab, Limanda limanda (L.) (Osteichthyes, Pleuronectidae) were collected from twelve localities in Danish and adjacent waters - ranging from the Faroes to the Baltic - and examined for infestations with digenetic trematodes, of which 15 species were found. The following were found at two or more sampling stations: Steringophorus furciger (Olsson, 1868), Steringotrema pagelli (van Beneden, 1871), Monascus filiformis (Rudolphi, 1819) (Fellodistomidae), Podocotyle atomon (Rudolphi, 1802) (Opecoelidae), Zoogonoides viviparus (Olsson, 1868) (Zoogonidae), metacercaria of Stephanostomum baccatum (Nicoll, 1907), Neophasis lageniformis (Lebour, 1910) (Acanthocolpidae), Derogenes varicus (Muller, 1784), Lecithaster gibbosus (Rudolphi, 1802), Brachyphallus crenatus (Rudolphi, 1802), Hemiurus communis Odhner, 1905 (Hemiuridae), Aporocotyle simplex Odhner, 1900 (Sanguinicolidae), and the metacercaria of Cryptocotyle lingua (Creplin, 1825) (Heterophyidae). The metacercaria...

On the ultrastructure of the epidermis of the adult female of Kronborgia amphipodicola Christensen & Kanneworff, 1964 (turbellaria, neorhabdocoela)

Abstract The epidermis of Kronborgia amphipodicola, an internal parasite of ampeliscid amphipods, has been examined by means of transmission and scanning electron microscopes. The animal has been studied before and after building of the cocoon and spawning of the egg capsules. Characteristic features of the epidermis are long cilia, numerous clavate microvilli, and cytoplasmic extrusions. These contain small vesicles of unknown function. In addition large vacuoles and small rhabdite-like structures have been found in the cells. Various subepidermal gland cells penetrate the fibrillar basal lamina and the epidermal cells. The mechanism of food uptake is discussed and compared with that of other plathyhelminthes.

On the endoparasites of Buccinum undatum L. with special reference to the trematodes

Abstract In all 1375 Buccinum undatum from the Sound (Oresund) were collected during a one year period (May 1966–April 1967), and 325 Buccinum from the Gullmarfjord, Sweden, August 1967. Four species of larval trematodes were found in Buccinum from Oresund: Cercaria Neophasis lageniformis, C. Zoogonoides viviparus, C. buccini and a xiphidiocercaria of the genus Renicola, all in the digestive gland and in the gonad. An adult trematode, Steringophorus furciger, which occurs in the stomach, does not produce mature eggs in Buccinum, but attains the same size as in the true final hosts, various flatfishes. The vertebrate hosts of this trematode and Buccinum feed on the same diet, and Buccinum becomes, therefore, presumably infected by ingesting metacercariae with the food. The two last-mentioned trematodes have not previously been found in Buccinum. A turbellarian, Graffilla buccinicola, and two sporozoans, Merocystis kathae and Piridium sociabile, were also found. In eight cases two different species of cerca...