Study of streptococcosis in rainbow trout farm in Hamedan Province

Objective: Streptococcusis is a systemic bacterial disease that is caused by streptococcus iniae. This disease has typical symptoms and usually has high rate of mortality which has caused high economic damages to some species of rainbow trout. It was first reported in rainbow trout in Mazandaran Province in 2000. This disease is often observed during summer time when temperature is at maximum level but it could also be observed in the end of summer and autumn. Unfortunately, this disease is observed throughout the whole year due to variety of weather. Most cold-water fish aquaculture farms are infected in Iran. In this study, the infection with streptococcus in aquaculture farms producing cold-water fish in Hamedan Province was surveyed in 2007. Method & Materials: 140 fish from Hamedan Province aquaculture farms were sampled and culture from their livers and kidneys were prepared in TSB and Blood agar media. Moreover the water of the pools was tested for temperature, pH, and the amount of soluble oxygen Results & Conclusion: After 24 to 48 hours following the culture of the sample, standard methods of streptococcus identification were used and no streptococcus bacteria were isolated in the samples. Therefore, it is necessary to study other factors such as pathogenic agents having similar clinical symptoms, the quality of the consumed food as well as other environmental and managerial factors.