LCNSS personnel have concentrated on three issues related to the new variant of CJD resulting from human exposure to meat products contaminated with bovine spongiform encephalopathy (BSE): 1) how to eliminate infectivity in potentially contaminated meat; 2) how to evaluate the potential of already infected individuals to transmit disease via blood or blood products; and 3) how to dispose of infected animal carcasses and carcass byproducts so as not to endanger the environment. 1. We have initiated studies of ultra-high pressure inactivation of TSE agents spiked into meat products, and have documented significant reduction of infectivity under conditions of temperature and pressure that are commercially practical, and are continuing to investigate optimal conditions for different products and different TSE strains (in particular, the strains that cause BSE and chronic wasting disease of deer and elk). 2. We have concluded a study in mice and have ongoing observations in monkeys on the occurrence of infectivity in the blood of animals infected with both classical and variant forms of CJD. Both studies suggest that variant CJD does not carry a greater risk of secondary blood transmissions than does classical CJD, which is now considered to represent a negligible risk. 3. Finally, we have just concluded a study in which highly infectious brain tissue was exposed to conditions simulating incineration (normal or starved air flow at 600?C and 100?C for 15 minutes), and have verified our earlier observation of the survival of a miniscule amount of infectivity in the ash residue of specimens heated at 600?C, and the total destruction of infectivity in the ash residue of speciments heated at 1000?C. More importantly, we have now shown that no infectivity escapes in the vented gas emissions at either temperature; thus, properly operated incinerators should pose no environmental risk.
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