Medical Forum / General / General / February 2008
CJD - what is a food chain?
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FCS - 26 Jan 2008 19:45 GMT Well, hope this doesn't get written off as SPAM.
There has been some fudging in the press over the matters related to CJD, or Creuzfeld-Jacob Disease over the years.
What has been established is that BSE is contracted by cattle fed on remains of cattle, particularly the CNS and other aspects of offal.
What has also been established is that CJD can be contracted by humans eating human remains, particularly the CNS and Brain.
Part of the dispute over whether or not we should be able to go out and buy T-Bone steaks has been whether or not there is any real link between BSE and CJD.
Whilst I am not disputing there is, recent media reports of remote parties on Canadian pig farms in the rural backwoods near Vancouver featuring snuff-while-you-wait type cabaret acts, from which the human remains were fed to pigs would seem to offer a reasonable indicator of whether 2nd degree exposure to prions via the food chain is responsible for any CJD cases.
The guy's business records will show where he sold his pigs to, the stuff will have been in the food chain at least a decade, maybe more, by now, and if there is any positive correlating blip in CJD with a distinct link to Canada may help explain how the cases of CJD in long-term vegetarians arose.
Then again it may not as I gather it can be the height of adolescent wit to palm meat products on vegetarians. I'm thinking more in terms of meat by-products used in the manufacture of foodstuffs generally considered suitable for vegetarians.
Now before people think I'm a scaremongering creep with a sinister mind, there are ways in which human remains can quite accidentally get into the food chain where free- ranging animals are concerned--someone dying quite a normal death in a remote area and their body not being found, for example. So, no, I shan't be suggesting the rewording of food packaging with warnings such as "may contain traces from nuts".
But it will be interesting to see if there is any Canadian blip as far as total knowledge of the conditions go and this goes double as the authorities should have a fair idea of the timescales involved by now.
G DAEB COPYRIGHT (C) 2008 SIPSTON --
Bob - 28 Jan 2008 05:06 GMT >Well, hope this doesn't get written off as SPAM. > [quoted text clipped - 20 lines] >exposure to prions via the food chain is responsible for any >CJD cases. You are suggesting that the disease might be transmitted by pigs eating humans and then humans eating those pigs?
I suppose that might be conceivable. But do either of those acts involve eating the high risk parts (mainly CNS as you note)?
Further, the incidence of CJD is humans is so low that the probability of a pig getting it from eating some human material seems quite low. (Hm, is this common -- for a pig to eat human material?) And, to my knowledge, CJD (and such diseases) are rare -- or even unknown -- in pigs.
bob
bae@cs.toronto.no-uce.edu - 30 Jan 2008 00:28 GMT >You are suggesting that the disease might be transmitted by pigs >eating humans and then humans eating those pigs? [quoted text clipped - 7 lines] >knowledge, CJD (and such diseases) are rare -- or even unknown -- in >pigs. The original poster is referring to a serial killer who fed parts of the bodies of some of his victims to his pigs. Now that the murderer has been caught, tried and imprisoned it's not likely to occur again.
AFAIK, nCJD has never been recorded in Canada, and with the usual background level of sporadic CJD of 1 per million, it's not likely that any of these victims had the disease, assuming that sporadic CJD is communicable at all.
Bob - 30 Jan 2008 03:48 GMT >The original poster is referring to a serial killer who fed parts of >the bodies of some of his victims to his pigs. Now that the murderer >has been caught, tried and imprisoned it's not likely to occur again. Thanks. I was wondering.
>AFAIK, nCJD has never been recorded in Canada, and with the usual >background level of sporadic CJD of 1 per million, it's not likely >that any of these victims had the disease, assuming that sporadic >CJD is communicable at all. Hm, isn't the iatrogenic CJD (that transmitted by medical intervention) presumably from a case of sporadic CJD?
bob
bae@cs.toronto.no-uce.edu - 30 Jan 2008 06:18 GMT >>AFAIK, nCJD has never been recorded in Canada, and with the usual >>background level of sporadic CJD of 1 per million, it's not likely [quoted text clipped - 3 lines] >Hm, isn't the iatrogenic CJD (that transmitted by medical >intervention) presumably from a case of sporadic CJD? Good point, I'd forgotten that case. CJD has been transmitted through dura mater grafts, IIRC, and via tools used in brain surgery.
While none of these prion diseases are known to be transmitted through blood transfusions, the blood banks up here now ask whether you have any close relatives with CJD, have had a dura mater graft, or have spent n amount of time in the UK or France since 1980. Better safe than sorry.
Bob - 02 Feb 2008 02:10 GMT >While none of these prion diseases are known to be transmitted through >blood transfusions, the blood banks up here now ask whether you have any >close relatives with CJD, have had a dura mater graft, or have spent >n amount of time in the UK or France since 1980. Better safe than >sorry. Yep.
There is some reason to be concerned about blood. There are recent findings of prions in blood. I've listed below a few refs I just happen to have.
The first of them (the Soto paper) says that there are now reports that vCJD can be transmitted human-human by blood transfusion -- with two refs to Lancet in 2004 (363:417, 364:527), reporting three such cases. They also note experimental blood transmission of BSE in sheep. (Their main interest is using blood for diagnosis, making use of the high sensitivity of the amplification assay they developed.)
1) Presymptomatic Detection of Prions in Blood Paula Saa, Joaquin Castilla, and Claudio Soto 2) Prion-Induced Amyloid Heart Disease with High Blood Infectivity in Transgenic Mice Matthew J. Trifilo, Toshitaka Yajima, Yusu Gu, Nancy Dalton, Kirk L. Peterson, Richard E. Race, Kimberly Meade-White, John L. Portis, Eliezer Masliah, Kirk U. Knowlton, Bruce Chesebro, and Michael B. A. Oldstone Science 313:92 & 94, 7/7/06. News.
Efficient detection of PrPSc (263K) in human plasma Ryo Fujita, Takeru Urayama, Akimasa Ohmizu, Mikihiro Yunoki, Shoutaro Tsuji, Kazuyoshi Ikuta Biologicals 34:187-189, 9/06. PDF. blood.
Infectious Prions in the Saliva and Blood of Deer with Chronic Wasting Disease Candace K. Mathiason, Jenny G. Powers, Sallie J. Dahmes, David A. Osborn, Karl V. Miller, Robert J. Warren, Gary L. Mason, Sheila A. Hays, Jeanette Hayes-Klug, Davis M. Seelig, Margaret A. Wild, Lisa L. Wolfe, Terry R. Spraker, Michael W. Miller, Christina J. Sigurdson, Glenn C. Telling, and Edward A. Hoover Science 314:133, 10/6/06.
I'm sure that at least the abstracts, and possibly the articles in Science, are freely available online. But if you would like a copy of any you can't access, feel free to email me privately, at bbruner at berkeley dot edu.
bob
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