Comparison of Chlorine and Ozone as Virucidal Agents of Poliomyelitis Virus. ∗

Abstract

Conclusions and Summary

1. Gaseous chlorine and hypochlorite in residual amounts of 0.5 ppm failed to inactivate a 1:1000 dilution of Le strain of poliomyelitis virus after an exposure of 90 minutes but inactivated the virus by 180 minutes. These results compare favorably with those of Kempf and Soule in working with the MV strain of virus. 2. Ozone in residual amounts not exceeding 0.45 ppm, inactivated a 1:1000 dilution of Le virus in 2 minutes and a 1:100 dilution of the same virus in 45 minutes. A 1:10 dilution of MV virus was not inactivated in 30 minutes and a 1:10 dilution of Le virus was not inactivated in 45 minutes. The extra amount of brain material in the lower dilutions constitutes an excess of organic matter which probably accounts for the longer time necessary for inactivation of virus at these dilutions.

It is observed from these results that an identical dilution of the same strain and pool of poliomyelitis virus when exposed to chlorine in residual amounts ranging from 0.5-1.0 ppm and to ozone in residual amounts between 0.05-0.45 ppm under the same controlled experimental conditions was inactivated almost immediately by ozone, i.e., within 2 minutes, while an interval ranging between 1^1/2 hours and 3 hours was required for inactivation by chlorine.

Thompson¹² in a recent review of the significance of the findings concerning the occurrence of poliomyelitis virus in intestinal contents and sewage and of its inactivation by current water purification procedures suggests either “superchlorination” or that “ozone treatment might be effective.”

The germicidal effects of ozone have been noted in the past but recent quantitative determinations have not been reported and its effect on viruses has not been observed.