Effect of temperature on the replication of striped jack nervous necrosis virus in kidney cell line of rainbow trout (RTK).

In the present study, striped jack nervous necrosis virus (SJNNV) was replicated at different temperatures i.e. 10, 15, 20 and 25°C in kidney cell line of rainbow trout (Oncorhynchus mykiss) to study the virion stability. Cells infected at sub optimal temperature (10 and 15°C) did not cause any significant CPE, but caused typical CPE of multiple vacuoles in the cytoplasm in the cells infected with SJNNV at optimum temperature 20 and 25°C. An expected band in the RT-PCR analysis confirmed the infection, with high viral load of 2.17×10⁸ and 3.08×10⁸ copy number/mL of cDNA was quantified in RTK at 20 and 25°C for SJNNV by qPCR. The TCID₅₀ value of SJNNV in infected RTK cell line gradually increased from low temperatures with maximum value at 25°C in course of infection. The capsid protein of SJNNV at different temperatures in RTK cell line was further confirmed by Western blot and quantified by iELISA. Results revealed that differences were found at different temperatures. The maximum OD value obtained with RTK cells infected was at 20 and 25°C. The results obtained from the present study revealed that the SJNNV possess the ability to cause infections to the fish species culturing in cold water attributes of the Indian aquaculture system, with proper screening and prophylactic measures this infection can be avoided.