Re: more frozens, CJD, known cases

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From:"R.Wadley" <>
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	Dear Glynn & LuAnn,

	I'm sorry but I'm digging my heels here.  OK, as stated below advanced
cases of CJD can be detected by clinical signs & various scans.  But what
about those cases without symptoms, CJD can lie dormant for decades without
any symptoms, are you suggesting these cases are non-infectious?

	What about the "mad cow" scare in the UK?  Surely the entire population
(with the possible exception of vegetarians & vegans) has been exposed to a
degree of risk of prion infection.  By Glynn's guidelines cryostats are now
obselete in the UK, no patient could possibly considered 100% free from
possible prion infection.  The last reports I read said it would be 20 or
30 years before the full effect to public health in the UK is known.

	I have to say that this debate has become too centred on CJD, & I don't
disagree with any of the guidelines to which I have been referred.  But,
the point I have been arguing is why a discrimination against a known
infectious sample, but an apparent 'devil may care' attitude to an unknown
sample.  A cryostat has the same need of disinfection following sectioning
of an unknown infectious sample as it does after a known infectious sample.

	I do think it is a shame that through no fault of their own a person can
contract CJD, & then find that hospitals consider them such a risk that
they have difficulty getting surgical procedures performed, or tissue
samples appropriately examined.  I would hate to get a letter saying that I
was suspected of having CJD (or other infectious disease), therefore my
melanoma, bowel cancer, whatever, would not be treated because of a risk to
hospital staff.  What a way to die!

	Surely we must have appropriate OH&S guidelines that protect both the
technician/scientist & the patients right to appropriate
diagnosis/treatment.  This may mean that patients have to travell to the
sort of biohazard facility where absolute containment is available, (I
really hope it doesn't come to that).  Perhaps what we are arguing here is
that a routine diagnostic laboratory should not be expected to perform
techniques on samples that should be referred to more appropriate facilities.



At 08:44 03/16/2000 -0600, you wrote:
>Responding to the message of 
>from Gayle Callis <>:
>We are all at risk for those "unknown" cases which pop in unexpectedly and
>the reason for Universal Precautions.  CJD patients exhibit some very
>symptoms which would prompt a clinician to suspect CJD and awareness is much 
>more acute these days. MRI's show distinctive changes in the brain which
>also be consistant with CJD.  In our facility the combination of symptoms
>other tests (MRI,CAT scans) would make a specimen suspect and it would
then be 
>treated as possible CJD. As stated, we can't help the occassional case
which may
>pop through (it's yet to happen to me, knock on wood), but with the
awareness of
>the prion protein diseases and attention to the clinical picture, it is less 
>likely to go undetected now than before.  Most hospitals and neurosurgeons
>NOT perform biopsies on possible CJD cases because of the decontamination 
>problems in the OR suite and with surgical instruments. This has been a
>source of transmission.  Contrary to Gayle's comment, there is NO sure or
>way to decontaminate a cryostat  (or microtome for that matter) when working 
>with Prions.  NOTHING is 100% effective in deactivating the prion protein. 

R. Wadley, B.App.Sc. M.L.S, Grad.Dip.Sc.MM
Laboratory Manager
Cellular Analysis Facility
School of Microbiology & Immunology
UNSW, New South Wales, Australia, 2052
Ph (BH) 	+61 (2) 9385 3517
Ph (AH)	+61 (2) 9555 1239
Fax 	+61 (2) 9385 1591

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