Review on saprolegniasis in propagation and cultivation of cold water fish center emphasis on national and international investigation on prevention, control and treatment

Saprolegnia sp. is the most important pathogenic fungi in fish. Saprolegnia parasitica, S. diclina, S. ferax and S. hypogina are the most abundance of the fungi that caused saprolegniasis in fish and hatcheries.They have global distributions and their percences were reported from cold water fish farms of the world. It has been amazingly shown, 1 in 10 hatched salmon raised in fish farms die as a result of S. parasitica infection. Saprolegniasis caused mortality not only in cultivated cold water fish but also in wild cold water fish and the disease were killed up to 22% of wild salmon. Up till 2002, Saprolegnia infections in aquaculture were kept under control with malachite green, an organic dye that is very efficient at killing the pathogen. However, the use of malachite green has been banned worldwide due to its carcinogenic and toxicological effects and this has resulted in a dramatic re-emergence of Saprolegnia infections in aquaculture. The economical losses of Saprolegniasis are so high and many investigations were conducted on identification, virolence and predisposing factors, prevention and control of saprolegniasis in the world. This study has been focused on the last data about ofn physiological characteristic, identification methods, and pathogenicity of Saprolegnia sp., virulence parameters, predisposing factors, prevention and control of saprolegniasis