1990. {At low ppm for only a few seconds} The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4 degrees C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10(5)-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate at neutral pH, and the sensitivities to chlorine dioxide were similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity.

(2010). Chlorine dioxide (ClO2) has a strong antiviral effect, and can disinfect the surface of object and the air in space. In recent study on interaction between ClO2 and protein, ClO2 oxidatively modified tyrosine and tryptophan residues, and the pro-tein was structurally denatured. Since hemagglutinin and neuraminidase of influenza virus A/H1N1 were inactivated by the reaction with ClO2, it is likely that denaturation of the proteins caused inactivation of the virus. A low concentration (0.03 ppm) of ClO2 gas, where people can stay for a long period of time without any harmful effect, prevented the death of mice (0 of 10 mice versus 7 of 10 in controls) caused by infection of influenza virus delivered as aerosol. We review current information based on the efficiency of ClO2 solution and gas, and also discuss the application of ClO2 against influenza pandemics outbreak.

****!!!!****!!!! 2008. {As a relevant additional finding, this study indicates also that chlorine dioxide was not effective as a nebulization treatment for flu under the test conditions} "A virus was prevented by chlorine dioxide gas at an extremely low concentration (below the long-term permissible exposure level to humans, namely 0.1 ppm). Mice in semi-closed cages were exposed to aerosols of influenza A virus (1 LD(50)) and 0.03 ppm ClO2 gas simultaneously for 15 min. Three days after exposure, pulmonary virus titre (TCID(50)) was 10(2.6+/-1.5) in five mice treated with ClO(2), whilst it was 10(6.7+/-0.2) in five mice that had not been treated). Cumulative mortality after 16 days was 0/10 mice treated with ClO(2) and 7/10 mice that had not been treated." "ClO2 gas inactivated the virus before it entered the lungs, but that it lacked the ability to inactivate viruses thathad already entered the lungs and established infection" "In in vitro experiments, ClO(2) denatured viral envelope proteins (haemagglutinin and neuraminidase) that are indispensable for infectivity of the virus, and abolished infectivity." "When the diameter of the aerosolis in the range 1–10 micrometers, as in the present experiment, equilibrium is reached within 1 min. We also found that Henry’s equilibrium gas constant k regarding the ClO2–water equilibrium, namely k in the above equation, was 3.9 x 10-5 mol 1-1 Pa-1" "This suggests further that theinfluenza A virus is inactivated at 0.12 micromolar ClO2 in water [Note: Molar concentration is measured as the ratio of the amount of substance in moles to the total volume of the solution]" "Taken together, we conclude that ClO(2) 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. ClO(2) gas could therefore be useful as a preventive means against influenza in places of human activity without necessitating evacuation."

****!!!!****!!!!**** {Taiko} "Can be applied to any space that can be in a closed state or an open state... Can be supplied at a concentration at which the animal can survive but the suspended microorganisms are inactivated. Therefore, the present invention can be applied to a space where an animal exists. More specifically, the present invention can be applied to living spaces (eg, residences, offices), medical institutions (eg, hospital waiting rooms, examination rooms, treatment rooms, operating rooms, anterior rooms, hospital rooms), research institutions, disaster medical facilities (eg, disaster containers, tents), public facilities (eg, stations, airports, schools), vehicles... When the chlorine dioxide gas concentration in the space is set to 0.00001 ppm to 0.01 ppm, there is no problem even if chlorine dioxide gas is continuously supplied. When the chlorine dioxide gas concentration in the space is 0.01 ppm to 0.1 ppm, the time for supplying the chlorine dioxide gas into the space is preferably 10 minutes to 480 minutes, and 15 minutes to 90 minutes. More preferably, it is more preferably 15 minutes to 60 minutes. When the chlorine dioxide gas concentration in the space is 0.1 ppm to 0.3 ppm, the time for supplying the chlorine dioxide gas into the space is preferably 0.5 minutes to 480 minutes, preferably 1 minute to 60 minutes is more preferable, and 2 minutes to 15 minutes is even more preferable."

******!!!!****!!!!****!!!*** 2012. {Note: Click "Download full text" and wait. Full text file will download to your computer} "More than half of the ClO2 gas decomposed indoors." Gaseous ClO2 is chemically dissociated by light with wavelengths between 350 nm and 475 nm. They reported that the dominant (96%) dissociation products were ClO and O (atomic oxygen). It is important to take into account whether these dissociation products are toxic to humans. Judging from the short lifetime of O (39 ns), the toxic effect of this chemical, if ever present, would be negligible... High air temperatures and light irradiation accelerated the decrease of ClO2 gas concentration; the latter had the greatest influence. A quicker decay of concentration and greater value of the reaction rate constant of ClO2 were found under irradiated conditions, especially when a UV lamp was used... ClO2 gas concentration was significantly reduced when an evaporative humidifier was employed due to adsorption and a chemical reaction between the gas and the filter in the humidifier. The results obtained from these experiments can be used to predict the indoor concentration of ClO2 gas" "it was concluded that indoor humidity does not affect the reaction of the ClO2 gas" "an aquarium... filled with 10 L(2.64 gal) water was set in the room" "indoor ClO2 gas levels were lower in the room where water was present because the gas dissolved in water" "Ogata and Shibata (2008) reported that ****!! ClO2 gas concentration in virus aerosols is theoretically 0.12 µM when the aerosols are in equilibrium with 0.03 ppm ClO2 gas !!****, based on their revealed Henry’s equilibrium gas constant k = 3.9 × 10−5 mol 1−1 Pa−1. The present experiment showed higher concentrations of ClO2 in the water"