Identification of infectious hypodermal and hematopoetic necrosis virus (IHHNV) in L. vannamei brood stocks in Boushehr Province, Iran

Objective: At least four viruses caused pandemics and have adversely affected the global penaeid shrimp farming industry, since 1980. Following of WSSD outbreak in Boushehr farms in 2004 that caused a huge economical loss, many approaches were taken to control and prevent the disease and restore production to industry. These approaches include: disinfection of infected ponds, use of SPF L. vannamei brood stocks, increase biosecurity operation, surveillance system of disease in hatcheries and farms. In this study, we controlled the biosecurity and health management in hatcheries and monitored WSSD, TSV, IHHNV and YHD. Method & Materials: Samples (pleopode) were taken from breeding brood stocks of two active hatcheries according to previous studies, with 2% surveillance and 95% confidence level, randomly. Samples were preserved in ethanol 70% and labeled base on OIE recommendations with complete history backgrounds to be sent to the shrimp disease diagnosis center. Totally, 285 peleopods were sampled that 140 were taken from one hatchery and 135 pleopods from the other one (140+135). DNA of samples were extracted by lysis buffer and processed with one step PCR base on the diagnostic kit of IQ2000 of farming intelligene tech corp. Results & Conclusion: IQ2000 kit can detect IHHNV in 3 levels quantitative of mild, moderate and sever. Negative results were seen, a 243bp band on electerophores gel, but positive samples showed 438bp and 644bp bands. In hatchery no. 2, 243bp band was appeared that means they were negative but in hatchery no.1 there were 438bp and 644bp bands that means they were positive. 80% of samples in hatchery no.1 were positive. A significant clinical sign was irregular growth of shrimps. The disease IHHNV and later its causative agent, IHHNV, was first describe as the cause of acute epizootic and mass morality(>90%) in L. stylirostris farmed but in L. vannamei was shown to be the cause of runt deformity (RDS), irregular reduced growth and cuticular deformities, rather than mortalities, were found to be the principle effect of nfection. Hence, the economic and production impacts of IHHNV in L. vannamie are due to reduced and irregular growth and small size shrimp at harvest and not to elevated mortality. By this study, we noted there were defects in hatcheries health management that we should improve it as soon as possible.

کلیدواژه ها:

IHHNV ، Brood stock ، PCR