Inactivation of BSE agent.

Although there are no data reported yet for inactivation of BSE agent it is reasonable in the interim, to draw upon existing data for other transmissible degenerative encephalopathies (TDE), much of which derives from experiments with the scrapie agent. Such studies suggest that no standard chemical or physical decontamination procedure will reliably inactivate the amount of scrapie/BSE infectivity present in worst-case situations but high concentrations of sodium hypochlorite or sodium hydroxide have been shown respectively to be completely effective or almost so. Regarding physical inactivation procedures, it is clear that some infectivity survives exposure to doses of UV and ionising radiations which represent "overkill" for conventional viruses. With dry heat, survival of infectivity is also remarkable, and it is only through autoclaving that apparently secure standards can be achieved for thermal inactivation; even so, autoclaving procedures need to be more rigorous than for conventional microorganisms, and can be compromised by prior chemical treatment of infected material.