Trichodinids are ciliated protozoa that are widely known as one of the main groups
of fish parasites. The genus Trichodina presents the greatest species diversity. However,
records of Paratrichodina species are scarce, and little is known about their pathogenicity in
hosts. The present study provides new records of Paratrichodina africana Kazubski and El-
Tantawy (1986) in Nile tilapia from South America and descriptions of pathological changes
and seasonality. A total of 304 farmed fish were examined. From gill scraping, parasites
were identified using Klein’s nitrate impregnation method. Gill samples were fixed for
histopathological analysis. Small trichodinid found in this study have a prominent blade
apophysis and narrow central part and blade shape that corresponds to the characteristics
of P. africana Kazubski and El-Tantawy (1986). Gill lesions were proportional to parasite
intensity, in which the gill tissue was compromised in heavy infestation. Proliferative disturbances
were found, including epithelial hyperplasia, desquamation, and mononuclear
and eosinophilic infiltrate that culminated in necrosis. We did not observe a seasonality
effect on the occurrence of P. africana. This ciliated protozoan causes compromised respiratory
capacity that leads to severe gill lesions and currently is an important pathogen that
afflicts intensive tilapia cultures in Brazil.
Trichodinids are ciliated protozoa that are widely known as one of the main groupsof fish parasites. The genus Trichodina presents the greatest species diversity. However,records of Paratrichodina species are scarce, and little is known about their pathogenicity inhosts. The present study provides new records of Paratrichodina africana Kazubski and El-Tantawy (1986) in Nile tilapia from South America and descriptions of pathological changesand seasonality. A total of 304 farmed fish were examined. From gill scraping, parasiteswere identified using Klein’s nitrate impregnation method. Gill samples were fixed forhistopathological analysis. Small trichodinid found in this study have a prominent bladeapophysis and narrow central part and blade shape that corresponds to the characteristicsof P. africana Kazubski and El-Tantawy (1986). Gill lesions were proportional to parasiteintensity, in which the gill tissue was compromised in heavy infestation. Proliferative disturbanceswere found, including epithelial hyperplasia, desquamation, and mononuclearand eosinophilic infiltrate that culminated in necrosis. We did not observe a seasonalityeffect on the occurrence of P. africana. This ciliated protozoan causes compromised respiratorycapacity that leads to severe gill lesions and currently is an important pathogen thatafflicts intensive tilapia cultures in Brazil.
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