Myxobolus cuneus n. sp. (Myxosporea) infecting the connective tissue of Piaractus mesopotamicus (Pisces: Characidae) in Brazil: histopathology and ultrastructure

Parasite

and N.S. Cordeiro²  S. Arana³  E.A. Adriano¹ 

[1] Centro de Pesquisa e Gestão de Recursos Pesqueiros Continentais-CEPTA/IBAMA, Rod. SP 201, Km 6,5, Caixa Postal 64, CEP 13630-970 Pirassununga, SP, Brasil/Centro Universitário da Fundação de Ensino Octávio Bastos-UNIFEOB, São João da Boa Vista, SP, Brasil;Departamento de Parasitologia, Instituto de Biologia, Universidade Estadual de Campinas-UNICAMP,Caixa postal 6109,CEP 13083-970, Campinas, Campinas, SP,Brasil;Departamento de Histologia e Embriologia, instituto de Biologia, Universidade Estadual de Campinas-UNICAMP,Caixa postal 6109,CEP 13083-970, Campinas, SP,Brasil

关键词: ultrastructure;    histology;    connective tissue;    Characidae;    Piaractus mesopotamicus;    Myxobolus cuneus n. sp.;    Myxosporea;   

Others  :  808711
DOI  :  doi:10.1051/parasite/2006132137

 received in 2005-05-31, accepted in 2006-01-17,  发布年份 2006

【 摘 要 】

The characteristics of Myxobolus cuneus n. sp. and its relationship to the host Piaractus mesopotamicus are described based on light and electron microscopy and histological observations. Polysporic plasmodia measuring 20 μm to 2.1 mm in size were found in 63.3 % of the P. mesopotamicus examined. The parasite was found in the gall bladder, urinary bladder, gills, spleen, fins, head surface, liver and heart. Generative cells and disporoblastic pansporoblasts occurred along the periphery of the plasmodia, and mature spores were found in the internal region. The mature spores had a pear shaped body in frontal view, with a total length of 10.0 ± 0.6 μm and a width of 5.1 ± 0.3 μm (mean ± SD). The spore wall was smooth with sutural folds. The polar capsules were elongated, were pear shaped, and equal in size (length 5.7 ± 03 μm; width 1.7 ± 0.2 μm), with the anterior ends close to each other. The polar filaments were tightly coiled in 8-9 turns perpendicular to the axis of the capsule. The plasmodia were always found in connective tissue (wall of the arterioles of the gill filaments, serous capsule of the gall bladder, middle layer and subepithelial connective tissue of the urinary bladder, connective tissue between the rays of the fins, subcutaneous tissue of the head surface and fibrous capsule spleen). The parasite caused important damage in the gills, where development occurred in the wall of gill filament arterioles; a mild macrophage infiltrate was also observed. In advanced developmental stages, the plasmodia caused deformation of the arteriole structure, with a reduction and, in some cases, obstruction of the lumen. The parasite was found throughout the period studied and its prevalence was unaffected by host size, season or water properties.

【 授权许可】

   
© PRINCEPS Editions, Paris, 2006