RE:QuestionA type of rare amoeba infection was again in the news this week:
https://www.nytimes.com/aponline/2018/12/07/us/ap-us-brain-eating-amoeba-neti-pot.html
But, just look up amoeba on wikipedia:
https://en.wikipedia.org/wiki/Amoeba
The offending amaeba that can enter the nasal cavity in these recent news cases and get to the brain is, I believe, Naegleria fowleri. This amoeba is ubiquitous in non-chlorinated water and tap water should not be used to rinse the sinuses. This is not an infection one might ever get from a scope or a surgical instrument, at least in normal uses, as these should be rinsed only with sterile water, not tap water or be terminally sterilized.
Amoebas are single cell organisms that can cause many types of infection, including in the brain or in the eye (cornea - Acanthamoeba) from tap water, though these infections are rare, and in the cornea are often associated with using tap water with contact lenses or with using contaminated CL rinsing solutions.
Regarding sterilizing or killing amoeba, the VP4 effectively does this, as these organisms and their relatvely difficult to kill cysts are usually eliminated through most terminal sterilization processes, though there may be issues with competing low temperature sterilizers not being able to effectively sterilize long narrow lumens or difficult to access areas such as around duodenoscope elevator mechanisms. Again, this should never be a serious practical issue regarding Naegleria fowleri. It should, however, be noted that only some HLD disinfection systems are effective in eliminating many amoeba, and that those HLD systems using gluteraldehyde-type liquid disinfectants have been found NOT effective. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2916629/
BSE, mad cow disease, or Creutzfeld-Jacob disease are types of transmissible spongiform encephalopathies due to prions, which are a type of unfolded protein that can cause other proteins to become unfolded. These are nasty incurable neurodegenerative diseases once acquired. See wikipedia again: https://en.wikipedia.org/wiki/Creutzfeldt–Jakob_disease
As noted earlier this year following testing in Europe where prion disease is more prevalent (from eating contaminated beef esp. in UK in decades past) and a bigger issue than in N. America (https://www.newswire.ca/news-releases/tso3-details-results-of-prion-inactivation-studies-680917881.html ), the VP4 can sterilize or eliminate prions. I believe some other H2O2 sterilizers might be able to do this as well (personal communication), though heat or regular steam sterilization is importantly not effective against prions.