Inactivation of Enteric Adenovirus and Feline Calicivirus by Chlorine Dioxide

Abstract
Chlorine dioxide (ClO2) inactivation experiments were conducted with adenovirus type 40 (AD40) and feline calicivirus (FCV). Experiments were carried out in buffered, disinfectant demand-free water under high- and low-pH and -temperature conditions. Ct values (the concentration of ClO2 multiplied by contact time with the virus) were calculated directly from bench-scale experiments and from application of the efficiency factor Hom (EFH) model. AD40 Ct ranges for 4-log inactivation (Ct99.99%) at 5°C were >0.77 to 0.80 to 0.49 to Ct99.99% ranges were >4.20 to Ct values and inactivation curves demonstrated that the EFH model described bench-scale experiment data very well. Observed bench-scale Ct99.99% ranges and EFH model Ct99.99% values demonstrated that FCV is more resistant to ClO2 than AD40 for the conditions studied. U.S. Environmental Protection Agency guidance manual Ct99.99% values are higher than Ct99.99% values calculated from bench-scale experiments and from EFH model application.