A Mshahi Moghadam - Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
F Ghazi Saeedi
A.R Saffarian
F Mehrdana

Objective: Streptococosis and yersiniosis are two important bacterial infections. In rainbow fishes which can cause a large amount of damages in aquaculture industry. Yersinia spp. are gram-negative bacteria which can cause infection with hemorrhagic spots on liver and visceral fat and superficial lesions. Streptococcus spp. are gram-positive bacteria which can cause infection with exophthalmia and dermal lesions. Method & Materials: Detection of these pathogens was performed on tissue samples (kidney, liver, spleen) and living fishes. Generally incidence of yersiniosis was lower in comparison with streptococcosis during these three years. Results & Conclusion: Statistics showed that variance of streptococosis in the year of 85 was much higher compare to years of 86 and 87. According to the statistics streptococosis and yersiniosis was not detected in the year of 86. According to the statistics, variance of yersiniosis was much higher in the year of 67 compared to two other years.

streptococosis, yersiniosis, rainbow fish, Mazandaran