Isolation and Identification of the Infectious Haematopoietic Necrosis Virus (IHNV)-like Agent from Farmed Rainbow Trout (Oncorhynchus mykiss) from Iran

The isolation of viral causalive agenl or fry lrout morlality syndrome in farmed rainbow troul in Iran was discussed. Four hundred twcnty samples were eollected from six provinces for virological, serological and clectron microscopie examinations from October 2001 lill May 2002. No eylopathic elTeet (CPE) \Vas observed in the cell cultures excepl for EPC and BF-2 cclls in whieh signs of CPE appeared one day postinoculalion during lhe second and lhird passages or Iwo brooder ovarian fluids. I.:leclron microscopie examination revcaled the viral partieles measured 67-73 x 128-l82nm in lhe pelleted materials from the CPE positive in 81'-2 and EPC cell lines. Indirecl immunoflurccence antibody test \Vere positive lor sorne ot" smears obtained From kidney tissues of lhe larvae, the samples of ovarian lluids lhal showed CPE on EPC and BF-2 ccII lines as weil as CPE positive œil cultures. Using U.lS,\ eighl of ail sera samples lcslcd \Vere posilive \Vilh oPlieal dcnsil) rangcd (U 16-2.268 compared 10 0.06 f()r negali\'c conlrols.