Histopathological studies of experimental Aeromonas hydrophila infection in blue tilapia, Oreochromis aureus .

Blue tilapia, Oreochromis aureus , was experimentally infected with Aeromonas hydrophila , a bacterium that damages the gills, liver, and intestine, resulting in histopathological changes in the infected organs. Our histopathological study showed an aggregation of hemocytes with cell necrosis in gills; a massive aggregation of hemocytes and pyknotic nuclei in the hepatopancreas; and a lower rate of hemocyte aggregation in the digestive system of the infected fish.