Study the occurrence of Aeromonas hydrophila septicemia in Carassius gibelio of Shazde River of Babolsar

Shazde River is one of the rivers in Mazandaran province in Babolsar which end to the Caspian Sea. In the past, this river was one of the valuable rivers in terms of fish diversity and their migration, but today due to pollutants entering the river, migratory and resident fish have declined dramatically.The present study investigated the bacterial infection of the fishes (Carassius gibelio) in Shazde River .To the aim the fishes were transferred to the laboratory. After bacterial culture, gram staining and biochemical test Aeromonas hydrophila was identified. In the histopathological study of skin and muscle destruction of epithelium, melanomacrophages aggregation, infiltration of inflammatory cells, edema, hyperemia and muscular fibers degeneration, in liver melanomacrophages aggregation, infiltration of inflammatory cells, increase of sinusoidal spaces, vacuolar degeneration, bile ducts hyperplasia and fibrosis, in kidney infiltration of inflammatory cells, vacuolar degeneration, edema, hyperemia, destruction of urinary tubules and fibrosis were observed. A. hydrophila is one of the opportunistic bacterium that becomes a pathogenic in stressful condition such as decrease of water quality. It is also a zoonosis bacterium that transferred to human via contaminant water and aquatic animals that cause severe abdominal pain, nausea, vomiting, and watery to bloody diarrhea. Therefore, preventing the entry of pollutants and wastewater into the rivers, besides the necessity of conservation of the aquatic ecosystem, is very important for the protection of human health.