Nastaran Shahbazian

The importance of rainbow trout (Onchorhynchus mykiss) in Iran aquaculture industry on one hand, and increasing the mortality of this fish due to outbreaks of infectious diseases, on the other hand, indicate the requirement for more profound understanding the rainbow trout immune system and access to laboratory tools for definitive diagnosis of its diseases. One of the most important defense mechanisms of vertebrates including fish is the production of immunoglobulin against microbial pathogens. In rainbow trout, dominant immunoglobulin in serum is immunoglobulin M (IgM). The purpose of this study was the cloning and expression of the constant region of rainbow trout IgM heavy chain (μ chain) gene in Escherichia coli. Therefore, RNA of the targeted gene was extracted from spleen and head kidney of rainbow trout and the constant region of μ chain was amplified by RT-PCR. The amplified fragment was ligated to pMALc2x vector and transferred to DH5α strain of E. coli. Recombinant vector...

During a fish disease outbreaks in 2015-2016 suspected to viral hemorrhagic septicemia virus (VHSV), moribund rainbow trout fries were obtained from fish farms. Samples of kidney, heart and spleen tissues were taken [X1] for examination. The full coding region of the G gene was amplified by RT-PCR reaction. Genotyping was carried out by phylogenetic analysis with reference sequences of four VHS genogroup. A phylogenetic tree was constructed with the maximum likelihood method and the Kumara 2- parameter substitution model by using MEGA software version 6.06. A maximum likelihood phylogenetic analysis reveals that all the Iranian VHS   strains belonged to clade Ia-2 of genotype Ia. The intra- sequence comparison of Iranian VHS strains ranged from 99.1% to 100% (average was 99.55%). In this study, two strains (Chaharmahal and Bakhtiari (1) and Chaharmahal and Bakhtiari (3) showed 100% identity but 0.1% differences with Isfahan strain. The Iranian strains belonging to European genogroup...

Viral haemorrhagic septicaemia (VHS) is one of the most important viral diseases in rainbow trout that has caused great losses to the Iranian rainbow trout aquaculture industry in few recent years. In the early autumn of 2015, in order to identify the possible causes of loss, farmed fish were sampled from the epicenter where massive mortalities and economic losses had occurred. Three samples were collected from relevant tissues (i.e. liver, kidney, spleen, heart, and brain) of the rainbow trout with clinical signs of VHS disease. The samples were stored in 70% ethanol, Eagle’s minimum essential medium (EMEM) and 10% formalin to perform RT-PCR, cell-culture and histopathology examinations, respectively. A virus was isolated using fish cell lines inoculated with a homogenate of the internal organs. Sequencing analysis of truncated N gene confirmed the existence of VHS virus. RT-PCR and histopathology tests indicated the suitability and simplicity of the test as a paraclinical diagnost...