[Risk prevention of transmissible subacute spongiform encephalopathies]

The risk assessment of transmissible spongiform encephalopathies (TSEs or prion diseases) can be managed at three levels: 1. control of source material that could be potentially infected (biological products of human or animal origin, instruments in contact with these products); 2. control of the processes for the purification of biological products and instrument decontamination techniques; 3. evaluation of invasive medical or surgical acts. Highest infectivity is found in central nervous system. TSE agents do resist to almost all usual decontamination procedures. National recommended procedures include sodium hypochlorite 18,500 ppm or sodium hydroxide 1N for 1 hour and autoclaving at at least 134 degrees C for at least 18 min.