Study on Streptococcosis and Lactococcosis Outbreaks in Rainbow Trout Farms in Fars and Lorestan Provinces

Strepococcosis and lactococcosis are economically important zoonotic diseases in aquaculture industry particularly in farmed rainbow trout. The annual loss due to the disease is tens millions USD. Because of the disease occurrence in farmed rainbow trout in Iran، this study was aimed to identify 20 risk factors in 38 trout farm in Fars (16 farms) and Lorestan (22 farms) provinces. Infected fish were sampled for the confirmation of the disease occurrence by bacteriological and molecular methods. The obtained results showed that there was a closed correlation between the presence of the risk factors (90%) and clinical signs (100%) of the disease. Also، bacteriological and molecular diagnosis methods، confirmed that the disease occurrence in 30 trout farms (15 fish farms in Lorestan and 15 fish farms in Fars) were involved in clinical farm of diseases. The results of this study also showed that the number of fish farms infected with Lactococcus garvieae was higher than Streptococcus iniae. Also، presence of both risk factors and clinical signs of the disease were significant in the trout farms of Fars and Lorestan provinces.