Ž . Aquaculture 166 1998 1–17 The effect of ultraviolet irradiation, heat, pH, ozone, salinity and chemical disinfectants on the infectivity of white spot syndrome baculovirus Poh-Shing Chang ) , Li-Jing Chen, Yu-Chi Wang Department of Aquaculture, National Kaohsiung Institute of Marine Technology, Kaohsiung, Taiwan Accepted 5 October 1997 Abstract Ž . The virucidal effects of ultraviolet UV irradiation, heat, pH, ozone, salinity and some Ž . chemical disinfectants on white spot syndrome baculovirus WSBV were investigated by infectivity assay using juvenile black tiger prawn, Penaeus monodon. WSBV became completely Ž 5 2 . non-infectious after 60 min UV irradiation 9 =10 mWsrcm . WSBV was rendered non-infec- tious by 558C and 708C 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 Ž . 12 for 10 min at RT 258C . The effective concentration for ozone to reduce WSBVs infectivity to zero was 0.5 mgrml 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. q 1998 Published by Elsevier Science B.V. All rights reserved. Keywords: WSBV; Infectivity; Penaeus monodon; Ultraviolet; pH; Ozone; Heat; Chemical disinfectants 1. Introduction Ž . White spot syndrome WSS , a shrimp disease responsible for mass mortalities, was Ž first reported in 1992 in Penaeus japonicus cultured in northeastern Taiwan Dr. S.N. ) Corresponding author. Tel.: q886-7-361-7141 ext 2704; fax: q886-7-365-2915; e-mail: pschang@mail.nkimt.edu.tw 0044-8486r98r$19.00 q 1998 Published by Elsevier Science B.V. All rights reserved. Ž . PII S0044-8486 97 00238-X