Effect of chlorine dioxide on avian influenza A (H7N9) virus

• Scientific question H7N9 virus is highly pathogenic transmitted by droplets, aerosol, or direct or indirect contact. For controlling H7N9 disease, it is important to select effective disinfectants using to decontaminate poultry farm markets, items used by patients, or their surrounding environment. • Evidence before this study Chlorine dioxide (ClO 2 ) is a globally recognized microbicide disinfectant, and it is new-generation, safe, efficient, broad-spectrum, and powerful, with strong oxidizing activity. It disrupts bacterial cell walls and damages viral capsid proteins and viral RNA • New findings In the study, an aqueous solution of ClO 2 at 126 µg/mL for 15 seconds was effective given that no surviving virus was detected with the hemagglutination test. ClO 2 gas at >5 µL/mL sustained for 1 h inactivated the virus effectively • Significance of the study Our findings reveal that ClO 2 , as a gas or an aqueous solution at a certain concentration, is effective in inactivating the H7N9 influenza virus, and can be applied for decontamination and disinfection of environments. Avian influenza remains a threat to human wellbeing. Hypochlorite derivatives are commonly used as disinfectants to prevent the spread of the disease. The World Health Organization (WHO) has listed chlorine dioxide (ClO 2 ) as an A1-level, safe, and efficient disinfectant. In this study, we tested the efficacy of ClO 2 , in aqueous solution and gas forms, against avian influenza A (H7N9) virus. The virus suspension was mixed with ClO 2 aqueous solutions of various concentrations and for various time intervals. Aliquots of the mixture were then serially diluted, and the 50% tissue culture infective dose (TCID 50 ) was measured with a hemagglutination test on MDCK cells. ClO 2 gas produced from generators was introduced in a chamber containing the virus suspension in a Petri dish. The infective activity of the surviving virus was measured by the hemagglutination test. An aqueous solution of ClO 2 at 126 µg/mL for 15 s was effective given that no surviving virus was detected with the hemagglutination test. ClO 2 gas at >5 µL/L sustained for 1 h inactivated the virus effectively, while at 2.5 µL/L for 1 h, it only partially inactivated the virus. ClO 2 as gas or aqueous solution at a certain concentration is effective in inactivating the H7N9 virus, and can be applied for the decontamination and disinfection of environments.