The effect of ultraviolet irradiation, heat, pH, ozone, salinity and chemical disinfectants on the infectivity of white spot syndrome baculovirus

The virucidal effects of ultraviolet (UV) irradiation, heat, pH, ozone, salinity and some chemical disinfectants on white spot syndrome baculovirus (WSBV) were investigated by infectivity assay using juvenile black tiger prawn, Penaeus monodon. WSBV became completely non-infectious after 60 min UV irradiation (9 x 10(5) mu W s/cm(2)). WSBV was rendered non-infectious by 55 degrees C and 70 degrees C heat treatment within 90 min and 5 min, respectively. WSBV was also completely inactivated by high acidity, pH 1 for 10 min, pH 3 for 1 h and by high alkalinity, pH 12 for 10 min at RT (25 degrees C). The effective concentration for ozone to reduce WSBVs infectivity to zero was 0.5 mu g/ml as a total residual oxidant for 10 min at RT. WSBV was inactivated by contact for 10 min at RT with a final concentration of 100 ppm of sodium hypochlorite and povidone iodine and 75 ppm of benzalkonium chloride. Sodium chloride in concentrations ranging from 0-10% had no virucidal effect on the infectivity of WSBV. (C) 1998 Published by Elsevier Science B.V. All rights reserved.