Re: Prions not destroyed by incineration?

["Jon Campbell" <jon@cqs.com>]

Please read www.cqs.com/madcow.htm
(This is slightly off-topic for dioxin-l)
Regards
Jon Campbell
-----Original Message-----
From: Mike Ewall <catalyst@envirolink.org>
To: Multiple recipients of list DIOXIN-L <dioxin-l@essential.org>
Date: Tuesday, January 26, 1999 3:41 AM
Subject: Prions not destroyed by incineration?


>>Also has anyone any data on dioxin emissions from a BSE/cattle incinerator
>>anywhere in the world?  As cattle, as a food, are a major source of our
>>bodies dioxin contamination, surely these chemicals must be released into
>>the environment when cattle, with BSE or not, are disposed of by
>>incineration?
>
>I can't speak to the dioxin issues in BSE/cattle incinerators, but I was
>just checking out http://mad-cow.org/ (a very comprehensive website on the
>topic) and the fact that prions are hard to destroy, even in incinerators
>is quite disturbing.  Below are a few of the notable issues that I found
>through that website's search engine.
>
>Mike
>------
>
>http://cyber-dyne.com/~tom/biol_tse.html#res
>Resistance of the agent to destruction
>
>Chemical disinfectants (e.g. domestic bleach), weak acids, DNAase, RNAase,
>proteinases (including those found in the animal gut), ultraviolet light,
>ionising radiation, heat (cooking tempertures), and chemicals that react
>with DNA (psoralins/UV light, hydroxylamine, zinc ions), all have little
>effect on the infectivity of the agent. High temperature autoclaving (135
>degrees centegrade for 18 minutes) decreases the infectivity dramatically,
>as does the use of 1M NaOH, but neither will fully destroy the agent, as it
>has been found to remain infective after 360 degrees C for 1 hour or even
>after incineration. Internment of infective tissue in the soil for three
>years did not destroy the agent. Some phenols and proteases will decrease
>the infectivity of the agent but not to an adequate degree to be of value
>in disinfection.
>
>http://cyber-dyne.com/~tom/well_apr14.html
>Making the picture even bleaker is the resiliency of prions. They are not
>destroyed by the usual means used to kill infectious agents. They are
>resistant even to boiling at temperatures as high as 250 degrees Celsius
>(well over 400 degrees Fahrenheit).  They are also resistant to ionizing
>radiation.
>
>
>http://cyber-dyne.com/~tom/current_UK_news.html
>Yesterday, the realisation that people who harbour the new variant may be
>capable of passing on the infection through operations fuelled calls for
>new rules on disposal of surgical instruments , since the prion protein
>survives standard sterilising processes. Prof Liam Donaldson, the
>Government's Chief Medical Officer, said: "We are looking at the
>possibility of disposable instruments but in any field it is the matter of
>balancing different sorts of risk.
>
>This raised the prospect of using disposable instruments wherever possible
>because "there is no means of sterilising surgical instruments adequately
>against prions ".
>
>
>http://cyber-dyne.com/~tom/May97_news.html
>Prions don't need to be soluble to leach into the water table. My point is
>again that we simply don't know what the level of risk is.  The phrase used
>about nv-CJD is that the most likely hypothesis is "exposure to the BSE
>agent". Nobody said by what medium.
>
>
>http://cyber-dyne.com/~tom/blood_supply.html
>Although organ tissue carries the greatest risk, animal studies do suggest
>that meat itself can transmit prion-related diseases. However, we cannot
>exclude the possibility that milk could also carry disease-inducing prions.
>
>Eating the flesh of other animals (besides cows) or drinking their milk may
>not be safe either. These other animals may also be affected with a
>prion-related diseases. As we have already mentioned, sheep as well as
>goats can become infected with such illnesses. Even if some of these
>illnesses do not seem to be easily transmitted to humans (because of what
>is often called, "the species barrier"), the possibility exists that
>different strains of prions could present more danger.
>