Austrodiplostomum compactum em peixes do rio Paraná, São Paulo, Brasil

Abstract

Austrodiplostomum compactum (Digenea, Diplostomidae) Lutz,1928 is a trematode that causes ophtalmic and tissue lesions in a variety of fish species. The aim of this study was to evaluate the parasitism index of A. compactum in fishes captured in Paraná river, Presidente Epitácio, São Paulo, Brazil, and the relation of these index with weather and water quality. Monthly, specimen of Plagioscion squamosissimus, Geophagus surinamensis, Hoplias malabaricus and Cichla sp. were captured. All individuals captures were individually examined. Muscle, organs, cavities and ocular globe were macroscopically evaluated. Recovered parasites were stained and identified under optic microscopy. Influence of climate (temperature and rainfall) and water quality (temperature, oxigen level, pH e alcalinity) on the prevalence was investigated. All the recovered parasites were restricted to ocular globe fishes. A. compactum was observed in 93.3%, 66.6%, 52.1%, 46.1%, respectively, of P. squamosissimus, H. malabaricus, Cichla sp. and G. surinamensis. Prevalence of H. malabaricus and Cichla sp. was higher in autumn, whereas G. surinamensis was higher in winter than in the other seasons. Regarding P. squamosissimus, it was observed a prevalence of 100% and recovery of the parasite in the whole year. Parasite recovery was directly proportional to the high temperature and rainfall regimen. Based on the results it is possible to admit that the river Paraná fish of commercial value are susceptible to infection by A. compactum.