Phylogenetic analysis of the SSU rRNA gene from the piscine diplomonad Spironucleus torosus (Diplomonadida: Hexamitinae).

Previous studies have recorded Spironucleus torosus Poynton et Morrison, 1990 from several species of gadoid fishes, including the only freshwater gadoid, the burbot Lota lota (L.). Two morphologically different isolates of S.

Severe mortality in wild Atlantic salmon Salmo salar due to proliferative kidney disease (PKD) caused by Tetracapsuloides bryosalmonae (myxozoa).

Extensive mortality in Atlantic salmon fry was reported in the River Aelva from 2002 to 2004. Dead fish were collected in late summer 2006, and live fish were sampled by electrofishing in September the same year. At autopsy and in histological sections, the fish kidneys were found to be pale and considerably enlarged.

Ultrastructure and molecular diagnosis of Spironucleus salmonis (Diplomonadida) from rainbow trout Oncorhynchus mykiss in Germany.

Diplomonad flagellates infect a wide range of fish hosts in aquaculture and in the wild in North America, Asia and Europe. Intestinal diplomonad infection in juvenile farmed trout can be associated with morbidity and mortality, and in Germany, diplomonads in trout are commonly reported, and yet are poorly characterised. We therefore undertook a comprehensive study of diplomonads from German rainbow trout Oncorhynchus mykiss, using scanning and transmission electron microscopy, and sequencing of the small subunit (ssu) rRNA gene.

Isolation of a novel fish thymidylate kinase gene, upregulated in Atlantic salmon (Salmo salar L.) following infection with the monogenean parasite Gyrodactylus salaris.

Analysis of differential gene expression in salmon (Salmo salar) blood following infection with the monogenean parasite Gyrodactylus salaris, resulted in the isolation of a thymidylate kinase gene not previously described from fish and which showed similarity to an LPS-inducible thymidylate kinase gene isolated from mouse macrophages. This salmon TYKi-like gene may play a role in an innate generalised response to pathogen infection as it was upregulated in salmon following infection with the parasite, and also in response to injection with the immunostimulants LPS and Poly I:C, used to emulate bacterial and viral infections, respectively. The possible role of this gene in the biosynthesis of mitochondrial DNA in activated macrophages, in response to G.

Phylogeny of spironucleus (eopharyngia: diplomonadida: hexamitinae).

Diplomonad flagellates from the genera Spironucleus and Hexamita (Hexamitinae) inhabit the digestive tract of a variety of animal hosts, some as important pathogens, and others as commensals. Species descriptions of many diplomonads have been based on light microscopy only, causing many taxa to be misidentified. Presently, electron microscopy is considered the appropriate tool for description of diplomonads.

The marine pathogenic genotype of Spironucleus barkhanus from farmed salmonids redescribed as Spironucleus salmonicida n. sp.

There are two genotypes of the diplomonad Spironucleus barkhanus. Based on sequence data from the small subunit ribosomal RNA gene the conspecificity of these two genotypes has been questioned. Therefore, we have sampled Spironucleus from 27 fish, representing 14 populations, five species, and four genera.

Identification of genetic markers associated with Gyrodactylus salaris resistance in Atlantic salmon Salmo salar.

Gyrodactylus salaris Malmberg, 1957 is a freshwater monogenean ectoparasite of salmonids, first recorded in Norway in 1975 and responsible for extensive epizootics in wild Atlantic salmon Salmo salar L. The susceptibility of different populations of Atlantic salmon to G. salaris infection differs markedly, with fish from the Baltic being characterised as relatively resistant whereas those from Norway or Scotland are known to be (extremely) susceptible.

SSU rRNA gene sequence reveals two genotypes of Spironucleus barkhanus (Diplomonadida) from farmed and wild Arctic charr Salvelinus alpinus.

Spironucleus barkhanus isolated from the blood of Arctic charr Salvelinus alpinus from a marine fish farm were genetically compared with S. barkhanus isolated from the gall bladder of wild Arctic charr. The wild Arctic charr were caught in the lake used as the water source for the hatchery from which the farmed fish originated.

Intracellular infection with Spironucleus barkhanus (Diplomonadida: Hexamitidae) in farmed Arctic char Salvelinus alpinus.

A case of intracellular systemic infection with the diplomonad flagellate Spironucleus barkhanus in farmed Arctic char Salvelinus alpinus is described. The parasites were widely disseminated throughout the vasculature and in most organs. Aggregates of the parasites were seen within well-defined structures regarded as host cells in capillaries and sinusoids of the liver, spleen and head kidney.

Infection by Parvicapsula sp. (Myxozoa) is associated with mortality in sea-caged Atlantic salmon Salmo salar in northern Norway.

In March 2002, 3 seawater farms in northern Norway experienced high mortality among Atlantic salmon postsmolts. A myxosporean parasite assigned to the genus Parvicapsula was detected in the pseudobranchs of diseased fish, and extensive destruction of this organ was observed. The parasite was also found in the gills, liver and kidney of some fish.

Spironucleus vortens (Diplomonadida) in the Ide, Leuciscus idus (L.) (Cyprinidae): a warm water hexamitid flagellate found in northern Europe.

The hexamitid flagellate Spironucleus vortens, previously reported from Pterophyllum scalare from Florida, was found in the intestine of Leuciscus idus in Norway. The flagellate was cultivated and studied by scanning and transmission electron microscopy. Identification was based on a suite of ultrastructural features unique for S.

Parasites of wild sea bass Dicentrarchus labrax from Norway.

Thirteen wild sea bass from the Oslo fjord in south-eastern Norway were examined for parasites. Nineteen species were found, comprising 5 protozoans, 1 monogenean, 8 digeneans, 1 cestode, 2 nematodes and 2 crustaceans. Based on the similarity to the parasitic fauna of Mediterranean sea bass, it is predicted that sea bass farmers in Northern Europe will experience the same parasite problems as sea bass farmers in warmer regions.