Protective effect of low-concentration chlorine dioxide gas against influenza A virus infection

Abstract

Influenza virus infection is one of the major causes of human morbidity and mortality. Between humans, this virus spreads mostly via aerosols excreted from the respiratory system. Current means of prevention of influenza virus infection are not entirely satisfactory because of their limited efficacy. Safe and effective preventive measures against pandemic influenza are greatly needed. We demonstrate that infection of mice induced by aerosols of influenza A virus was prevented by chlorine dioxide (ClO2) gas at an extremely low concentration (below the long-term permissible exposure level to humans, namely 0.1 p.p.m.). Mice in semi-closed cages were exposed to aerosols of influenza A virus (1 LD50) and ClO2 gas (0.03 p.p.m.) simultaneously for 15 min. Three days after exposure, pulmonary virus titre (TCID50) was 102.6±1.5 in five mice treated with ClO2, whilst it was 106.7±0.2 in five mice that had not been treated (P=0.003). Cumulative mortality after 16 days was 0/10 mice treated with ClO2 and 7/10 mice that had not been treated (P=0.002). In in vitro experiments, ClO2 denatured viral envelope proteins (haemagglutinin and neuraminidase) that are indispensable for infectivity of the virus, and abolished infectivity. Taken together, we conclude that ClO2 gas is effective at preventing aerosol-induced influenza virus infection in mice by denaturing viral envelope proteins at a concentration well below the permissible exposure level to humans. ClO2 gas could therefore be useful as a preventive means against influenza in places of human activity without necessitating evacuation.

Chlorine Dioxide is a Better Disinfectant than Sodium Hypochlorite against Multi-Drug Resistant <i>Staphylococcus aureus</i>, <i>Pseudomonas aeruginosa</i>, and <i>Acinetobacter baumannii</i>

“…However, the use of NaClO brings several disadvantages including its irritating and toxic effects and efficacy in a limited pH range. In contrast, ClO 2 is an efficient disinfectant and is less toxic, less irritant, effective in a wide pH range, can be used as both liquid and gas (16), and produces fewer trihalomethane compounds (12). It has been demonstrated that the mode of action of ClO 2 is via protein denaturation and involves the covalent oxidative modification of tryptophan and tyrosine residues (6).…”

Inactivation of Airborne Bacteria and Viruses Using Extremely Low Concentrations of Chlorine Dioxide Gas

“…This result indicates that ClO 2 can inactivate both gram-positive (S. aureus) and gram-negative (E. coli) bacteria. Ogata and Shibata [17] also demonstrated that low-concentration ClO 2 gas (0.03 ppm) can protect mice against influenza virus infection, which suggests that this gas could also be used to control viral infections. This finding also suggests that ClO 2 can inactivate viruses with envelopes, such as influenza virus.…”

Generation and Measurement of Chlorine Dioxide Gas at Extremely Low Concentrations in a Living Room: Implications for Preventing Airborne Microbial Infectious Diseases

“…Ogata et al also demonstrated in other experiments that this level of ClO 2 gas had no adverse effects on rats [25,26] . In fact, in the mouse experiment described above [24] , all of the mice subjected to the experiment appeared very healthy during and after exposure to 30 ppb ClO 2 gas.…”

“…Ogata and Shibata [24] recently reported that very lowconcentration ClO 2 gas prevented infections of the influenza virus in a mouse infection model. The concentration of the gas used in this experiment was as low as 30 parts per billion (ppb, volume/volume).…”

“…Based on the data of using low-concentration ClO 2 gas to prevent the spread of airborne infectious diseases [24] , ClO 2 gas generating devices are commercially available in some countries; these include a large machine-type device for offices and a small table-top canister for houses. However, there are always controversies over whether the extremely low concentration of ClO 2 gas is actually delivered as expected from these devices because the concentrations to be measured are extremely small.…”