DAO 56:155-161 (2003)  -  doi:10.3354/dao056155

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

Erik Sterud1,*, Trygve Poppe2, Geir Bornø3

1National Veterinary Institute, PO Box 8156 Dep., 0033 Oslo, Norway
2Norwegian School of Veterinary Science, PO Box 8146 Dep., 0033 Oslo, Norway
3National Veterinary Institute, 9480 Harstad, Norway

ABSTRACT: 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. Intracellular infection with Spironucleus spp. has never previously been reported. The prevalence of infection and mortality in the affected farm was low. In contrast to systemic spironucleosis in farmed Atlantic salmon, and despite huge numbers of flagellates in the vasculature, the tissues of the organs were remarkably unaffected. The relatively few gross and histopathological lesions may indicate that Arctic char are more tolerant to this parasite than Atlantic salmon.


KEY WORDS: Arctic char · Diplomonadida · Hexamitids · Pathology · Salvelinus alpinus ยท Spironucleus barkhanus


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