Experimental infections of Atlantic salmon Salmo salar with Spironucleus barkhanus

Abstract

Atlantic salmon Salmo salar L. (Salmonidae) were experimentally infected with Spironucleus barkhanus (Diplomonadida: Hexamitidae). Parasites were found in the blood 1 to 8 wk after infection, after which they disappeared from the blood and were found mainly in the internal organs (e.g. spleen and liver), eye socket or muscles. Mortality (38 out of 40 infected fish) occurred when fish had lesions in internal organs and/or on the body surface. Uninfected fish cohabiting with infected fish became infected after 4 wk, indicating direct transmission. There was no difference in susceptibility to spironucleosis between 3 different families of Atlantic salmon. All families developed the disease with a similar pattern of parasitaemia in the blood, similar clinical signs and gross pathology, and with very high mortality (29 out of 30). Clinical signs of systemic spironucleosis may include anemia, skin blisters, muscle ulcerations or unilateral exophthalmia. Gross pathologies include hemorrhaging of internal organs, splenomegaly or deformed (globulated) spleen, or granulomatous lesions in the spleen and liver.

Pathogenesis of mixed infection by Spironucleus sp. and Citrobacter freundii in freshwater angelfish Pterophyllum scalare

“…Similar clinical signs were observed for cyprinids infected with C. freundii [14]. These changes are normally associated to bacterial infection, however, Spironucleus affects the fish head and causes lip tumors and bleeding [30], which can extend up to the eyes due to the structures being within close approximation morphologically for this fish species [31]. described granulomatous liver, numerous melano-macrophage centers in the spleen and inflammation of the intestine in fish infected by S. vortens.…”

Economic costs of protistan and metazoan parasites to global mariculture

“…60% of the stock had lesions. A total of 4 fish farms were affected - Mo et al (1990); Poppe et al (1992); Poppe and Mo (1993) Fish mortality occurs in both the blood and tissue phases of the disease - Guo and Woo (2004) An increased rate of mortality was recorded in *1-year old salmon stocked in 8 m diameter concrete tanks. No details relating to the pattern or magnitude of loss are provided -Ferguson et al (1987) Trichodina sp.…”

Changes in the interbranchial lymphoid tissue of Atlantic salmon (Salmo salar) affected by amoebic gill disease

“…Enlargement of the spleen (splenomegaly) was reported in parasitic infections, such as a diplomonad flagellate, Spironucleus barkhanus (Hexamitidae) in Atlantic salmon [32] and a haematozoic endoparasite, Trypanoplasma borreli in common carp (C. carpio L.) [33]. Splenomegaly was attributed either to proliferation of lymphocytes and granulocytes in carp [10,11], or retention of erythrocytes in rainbow trout and Atlantic salmon [34].…”