DAO 33:43-49 (1998)  -  doi:10.3354/dao033043

Pathology of Piscinoodinium sp. (Protozoa: Dinoflagellida), parasites of the ornamental freshwater catfishes Corydoras spp. and Brochis splendens (Pisces: Callichthyidae)

E. Ferraz*, C. Sommerville

Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, UK
*Address for correspondence: Instituto Nacional de Pesquisas da Amazonia, CPBA, Caixa Postal 478, CEP 69.083-000 Manaus, AM, Brazil. E-mail:

Piscinoodinium sp.(Protozoa, Dinoflagellida) was commonly found on routine smears of samples of Brochis splendens and Corydoras spp. imported into Britain from South America, and on samples of the same group of fish examined at the exporters' holding facilities in Brazil. Infected fish had trophonts of different sizes on the gills and skin. In histological sections of the skin, the trophonts were found to be attached within depressions of different depths or enclosed by hyperplastic epithelial cells. Such enclosed trophonts have not previously been reported. Since some of the enclosed trophonts were dead, it was thought that enclosure was a result of the deep penetration of the trophont and the host defence mechanism. On the gills the Piscinoodinium infection was commonly associated with epithelial hypertrophy, focal and diffuse hyperplasia, oedema of the respiratory epithelium and lamellar fusion. The presence of this protozoan on different species of fish from the same shipment suggests that the infection was acquired before export. The source of infection and the stages of the export process which expose the fish to the highest risk of infection are discussed.

Protozoa · Piscinoodinium · Skin pathology · Freshwater ornamental fish

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