title: Infectivity studies of both ash and air emissions from simulated incineration of scrapie-contaminated tissues.
abstract: We investigated the effectiveness of 15 min exposures to 600 and 1000 degrees C in continuous flow normal and starved-air incineration-like conditions to inactivate samples of pooled brain macerates from hamsters infected with the 263K strain of hamster-adapted scrapie with an infectivity titer in excess of 10(9) mean lethal doses (LD50) per g. Bioassays of the ash, outflow tubing residues, and vented emissions from heating 1 g of tissue samples yielded a total of two transmissions among 21 inoculated animals from the ash of a single specimen burned in normal air at 600 degrees C. No other ash, residue, or emission from samples heated at either 600 or 1000 degrees C, under either normal or starved-air conditions, transmitted disease. We conclude that at temperatures approaching 1000 degrees C under the air conditions and combustion times used in these experiments, contaminated tissues can be completely inactivated, with no release of infectivity into the environment from emissions. The extent to which this result can be realized in actual incinerators and other combustion devices will depend on equipment design and operating conditions during the heating process.
authors.affiliation: Laboratory of CNS Studies, National Institute of Neurological Disorders and Stroke, and Div. of Environmental Protection, Office of Research Facilities Development and Operations, NIH, US Dept. of HHS, Bethesda, MD 20892, USA. paulwbrown@comcast.net
authors.forename: Paul
authors.initials: P
authors.lastname: Brown
authors.forename: Edward H
authors.initials: EH
authors.lastname: Rau
authors.forename: Paul
authors.initials: P
authors.lastname: Lemieux
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Johnson
authors.forename: Alfred E
authors.initials: AE
authors.lastname: Bacote
authors.forename: D Carleton
authors.initials: DC
authors.lastname: Gajdusek
mesh_terms: D000393:Air Pollutants; D000818:Animals; D001921:Brain / Q000378:metabolism; D006224:Cricetinae; D006358:Hot Temperature; D017745:Incineration / Q000379:methods*; D018620:PrPSc Proteins / Q000472:pathogenicity*; D012608:Scrapie / Q000635:transmission*; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D018620:PrPSc Proteins