Evaluation of the Use of Sea Water as a Diluent for an Accelerated Hydrogen Peroxide Disinfectant for Inactivation of Avian Influenza Virus: A Surrogate for Infectious Salmon Anemia Virus.

Introduction: Use of sea water as a diluent for disinfectants has been of practical interest for control of aquaculture disease outbreaks in sea where fresh water is limited. This study evaluated the use of natural sea water (NSW), artificial sea water (ASW), or standard hard water (SHW) as a diluent for preparation of accelerated hydrogen peroxide (AHP) solutions against an avian influenza virus, a surrogate for the infectious salmon anemia virus. Methods: AHP solutions containing 0.18%, 0.35%, or 0.44% (w/w) of hydrogen peroxide (H₂O₂), corresponding to 1/40, 1/20, and 1/16 dilutions of the disinfectant concentrate, were evaluated at -20°C, 4°C, and 21°C. Results: When NSW was used as the diluent, a 0.35% H₂O₂ concentration was required to inactivate ∼6 log₁₀ virus at 21°C in a 5-min contact time. When temperature dropped to 4°C, 0.44% H₂O₂ in NSW was required to obtain a similar inactivation within a 5-min contact time. At -20°C, supplemented with antifreeze agents, the 0.44% H₂O₂ in NSW solutions produced complete inactivation of 5.4 log₁₀ virus within a 10-min contact time. In comparison, lower H₂O₂ concentrations and/or shorter contact times were needed to inactivate equal amounts of the virus at the same temperature when using SHW or ASW as a diluent to prepare disinfection solutions. Conclusion: The results suggested that NSW could be used as a diluent in disinfection solutions for virus inactivation as long as disinfectant concentrations and/or contact times are properly increased.