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Published on: March 10, 2015
Resistance of the ME7 scrapie agent to peracetic acid
1AFRC & MRC Neuropathogenesis Unit, Institute for Animal Health, Edinburgh, UK.
Abstract:
Mouse brain infected with the ME7 strain of scrapie agent was exposed for 24 h to a range of concentrations of PAA, either as fragments of intact brain or as supernates of homogenised brain. Two % PAA inactivated the infectivity in intact tissue but not in a supernate. None of the concentrations tested (up to 19%) was effective with supernates, and this was considered to result from the protection afforded by aggregation of infectivity-containing particles.
Insights
Peroxyacetic acid (PAA) inactivated scrapie infectivity in intact mouse brains. However, PAA was ineffective against homogenized brain supernates, likely due to particle aggregation protecting the infectious agent.
Area of Science:
- Neuroscience
- Infectious Diseases
- Biochemistry
Background:
- Scrapie is a transmissible spongiform encephalopathy affecting the brain.
- Understanding agents that can inactivate prion infectivity is crucial for disease control.
- Peroxyacetic acid (PAA) is a potent oxidizing agent with antimicrobial properties.
Purpose of the Study:
- To investigate the efficacy of peroxyacetic acid (PAA) in inactivating the scrapie agent in mouse brain tissue.
- To determine if PAA's effectiveness is influenced by the physical state of the brain tissue (intact vs. homogenized).
Main Methods:
- Infection of mouse brains with the ME7 strain of scrapie agent.
- Exposure of intact brain fragments and homogenized brain supernates to varying concentrations of PAA for 24 hours.
- Assessment of scrapie infectivity following PAA treatment.
Main Results:
- A 2% concentration of PAA effectively inactivated scrapie infectivity in intact brain tissue.
- PAA showed no significant inactivation of infectivity in homogenized brain supernates, even at concentrations up to 19%.
- The reduced efficacy in supernates is hypothesized to be due to the aggregation of infectivity-containing particles, shielding them from PAA.
Conclusions:
- Peroxyacetic acid (PAA) can inactivate scrapie infectivity in intact brain tissue.
- The physical state of the brain tissue significantly impacts PAA's efficacy, with homogenization reducing its effectiveness.
- Particle aggregation in homogenized samples likely protects the scrapie agent from PAA inactivation, highlighting challenges in decontaminating prion diseases.
