Pathology and morphology of Ichthyophonus hoferi in naturally infected fishes off the Swedish west coast

Diseases of Aquatic Organisms

Hassan Rahimian¹ 

关键词: Ichthyophonus hoferi;    Morphology;    Pathology;    Herring;    Sprat;    Flounder;    North East Atlantic;   

DOI  :  10.3354/dao034109

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: The pathology and morphology of Ichthyophonus hoferi was studied in naturally infected Atlantic herring Clupea harengus, in sprat Sprattus sprattus, and in flounder Pleuronectes flesus from the west coast of Sweden.The pathogen was found in all organs examined, with the intensity of infection varying in different organs of the different fish species. Two main phases in the life of infecting parasites were identified, 'active' and 'passive', the latter being able toswitch to active. The active phase of the infection in herring was usually accompanied by a lean and slender appearance of the body, a drastic decrease in intestinal fat, emaciation of the somatic muscles, swelling of the visceral organs, poor quality offlesh texture and a distinctive off-odour. The most characteristic macroscopic sign of ichthyophonosis in herring and flounder was the occurrence of creamy white nodules on the heart. The infection causes a chronic systemic granulomatous inflammation. Thenature of the granulomatous inflammation was host- and tissue-dependent. The pathogenicity of the parasite in its active form and the side effects of host defence cells were also reflected in dramatic tissue damage and loss of structure and function ofthe infected organs. Three kinds of spores were identified: 'un-developing spore', 'developing spore' and 'plasmodio-spore'. The formation and spread of 'plasmodia', from plasmodio-spores, as a secondary infection agent is documented. Transmissionelectron microscopy revealed I. hoferi to be multinucleated, containing different organelles and structures. These included a cell wall, an undulating cell membrane, a thin paramural endoplasm, an endoplasmic reticulum, polymorphic but usuallyspherical mitochondria with short tubulo-vesicular cristae, dictyosomes with plate-like cristernae, large electron-dense lipid droplets and electron-lucid vacuoles, probably containing glycogen.

【 授权许可】

Unknown