Effect of chemical and physical treatments on the inactivation of striped jack nervous necrosis virus (SJNNV)

Abstract

The effects of some chemical disinfectants, organic solvents, hydrogen ions, heat, ultraviolet (UV) irradiation and ozone on the inactivation of striped jack nervous necrosis virus (SJNNV) were investigated. SJNNV was inactivated by contact with a final concentration of 50 ppm of sodium hypochlorite, calcium hypochlorite, benzalkonium chloride and iodine for 10 min at 20 °C. Cresol concentrations of more than 10 000 ppm were required to inactivate SJNNV, and no inactivation of SJNNV by formalin was detected at any concentration tested. The effective concentrations of ethanol and methanol were 60% and 50%, respectively, but SJNNV was resistant to ether and chloroform. SJNNV was inactivated by high alkalinity, pH 12 for 10 min at 20 °C, and also inactivated by heat treatment at 60 °C for 30 min. Inactivation of SJNNV by UV irradiation was observed at an intensity of 410 μW cm −2 for 244 s. Ozone at 0.1 μg ml −1 as a total residual oxidant was required to inactivate SJNNV for 2.5 min. Washing fertilized eggs and the treatment of sea water with ozone decreased the rate of occurrence of VNN.