Hepatic steatosis associated with microsporidiosis in teleost fishes from Marajó Island, Brazil.

A total of 40 specimens of the teleost fish Gobioides grahamae Palmer & Wheeler, 1955 were obtained from the municipality of Salvaterra on Marajo Island in the Brazilian state of Para. Their livers were removed and processed for light microscopy. Overall, 90% of the specimens presented some degree of steatosis of the liver, which was invariably associated with the presence of Microsporidium sp. The present study confirms the occurrence of steatosis in G. grahamae associated with parasitic infections by Microsporidium. The findings indicate that the condition of otherwise healthy fishes in their natural environment may be affected negatively by parasites.