Conditions for the chemical and physical inactivation of the K. Fu strain of the agent of Creutzfeldt-Jakob disease

The unusual resistance of the 'unconventional viruses' to inactivation by the commonly used disinfectants has led to a high degree of apprehension regarding patients with any form of dementia. The rapid adaptation of a newly acquired isolate of the agent of Creutzfeldt-Jakob Disease (CJD) to mice made possible this large scale study of its heat and chemical stability. The agent showed a decrease in titer of approximately two logs following incubation at 80°C for 30 minutes with no additional loss at 80°C for up to 500 minutes. There was greater than a three log decrease in titer at 100°C for 30 minutes and temperatures of 115° and 130°C completely inactivated the agent. Treatment with sodium hypochlorite at three concentrations (0.33 per cent, 0.66 per cent and 1.31 per cent) showed inactivation of greater than 99 per cent at each. Crude agent preparations were not inactivated by sodium dodecylsulfate at detergent to protein ratios up to 4:1. These results suggest that those hospital supplies which resist autoclaving may be adequately disinfected by autoclaving for at least 30 minutes. Treatment of surfaces with solutions of sodium hypochlorite (household bleach) at concentrations of 15 to 25 per cent is also effective. Detergent treatment of contaminated surfaces or materials is inadequate for proper decontamination.