Cryptosporidium scophthalmi n. sp. (Apicomplexa: Cryptosporidiidae) from cultured turbot Scophthalmus maximus. Light and electron microscope description and histopathological study

Diseases of Aquatic Organisms

Palenzuela¹  A. Sitjà-Bobadilla¹  S. Vázquez¹  P. Alvarez-Pellitero¹  M. I. Quiroga¹  M. J. Redondo¹  F. Padrós¹  J. M. Nieto¹  O.¹ 

关键词: Cryptosporidium scophthalmi n. sp.;    Coccidia;    Ultrastructure;    Histopathology;    Teleostei;    Aquaculture;   

DOI  :  10.3354/dao062133

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Cryptosporidium scophthalmi n. sp. is described from the turbot Scophthalmus maximus L., sampled from different farms on the coast of NW Spain. The parasite was found mainly in the intestinal epithelium and very seldom in thestomach. Oocysts were almost spherical, with 4 naked sporozoites and a residuum, and measured 3.7–5.03 × 3.03–4.69 µm (mean 4.44 × 3.91) (shape index 1.05–1.34, mean 1.14). Sporulation was endogenous, as fully sporulatedoocysts were found within the intestinal epithelium, lumen and faeces. Merogonial and gamogonial stages were in the typical extracytoplasmic position, whereas sporogonial stages were deep within the epithelium. Oocysts and other stages of C.scophthalmi comply with most of the diagnostic features of the genus Cryptosporidium, but differ from all hitherto described species. Ultrastructural features, including the characteristic feeding organelle, were mainly comparable with those ofother Cryptosporidium species. Mitochondria were frequently observed in sporozoites. Infection prevalence was very variable, and juvenile fish were most frequently and intensively parasitised. External clinical signs were not detected, althoughsome fish showed intestinal distension at necropsy. The marked histopathological damage occurring in severe infection includes distension of epithelial cells by large vacuoles, containing clusters of oocysts, and can lead to sloughing of epithelial cellremnants and oocysts or even detachment of intestinal mucosa. An inflammatory reaction involving leucocyte infiltration was sometimes observed.

【 授权许可】

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