Characterization and infectivity evaluation of Vibrio harveyi causing white patch disease among captive reared seahorses, hippocampus kuda

Pathogenic bacterium was isolated from infected parts of the captive reared seahorse. During the present investigation, high mortality with symptoms such as external white patches on the body and anorexic conditions were noted among laboratory-cultured seahorses, Hippocampus kuda. Bacteria isolated from internal organs of infected fish were biochemical homogenized and identified as Vibrio harvei. In infectivity studies with Tilapia, Oreochromis mossambicus, symptoms such as tail rot and erythemia were noted apart from the white skin. The lethal dose for Tilapia with average body weight of 8.8g was 8 × 106 cells/fish, while for seahorse with an average body weight of 6.2 g, it was 4×104 cells/fish