BSE/CJD

by Chris Bertram on January 3, 2004

Following up a link from “Iain Murray”:http://www.iainmurray.org/MT/archives/000559.html on mad cow disease and the threat it does or doesn’t pose to humans I came across “a column on the subject”:http://www.latimes.com/news/opinion/commentary/la-oe-milloy2jan02,1,1799702.story?coll=la-news-comment-opinions by Steven Milloy “an adjunct scholar at the Cato Institute” and proprietor of “JunkScience.Com”:http://www.junkscience.com/ in the LA Times. Molloy is sceptical of the prion theory and reports of the British experience that:

bq. Though laboratory testing seemed to indicate that BSE and variant CJD were similar, no one could determine with certainty whether and how the BSE epidemic was related to the “human mad cow” cases. There were no geographic areas in Britain with a significantly higher incidence of variant CJD cases, and there were no cases of variant CJD among apparently high-risk groups such as farmers, slaughterhouse workers and butchers.

Two minutes of googling found the report of the British government’s report into BSE and vCJD.

First “on the matter of geographical clustering”:http://www.bseinquiry.gov.uk/report/volume8/chapteb6.htm#561728 :

bq. The 1999 Annual Report of CJDSU draws attention to the geographical distribution of cases of vCJD (see Figure 5.1, in which the data have been further updated) and shows that if the UK is divided into ‘North’ and ‘South’ regions, the rate per million individuals aged between 16 and 54, is 2.57 for the ‘North’ region and 1.30 per million individuals for the ‘South’.

Perhaps Milloy wants to place some stress on “significantly highter”?

What about occupational links? The “British Government report again”:http://www.bseinquiry.gov.uk/report/volume8/chapteb6.htm#561728

bq. Among occupational groups exposed to BSE, farmers remain unusual in having such an excess over the incidence of CJD for the population as a whole. No cases of CJD have been reported amount veterinarians exposed to BSE. Four people in the meat industry (butchers, abattoirs, rendering plants, etc) have been reported to have vCJD.

Note that the excess for farmers is accounted for by additional but unexplained cases of _sporadic_ CJD (i.e. not vCJD). But what Molloy says about slaughterhouse workers and butchers “no cases” is directly contradicted by the Inquiry report.

I hasten to add that I have absolutely no expertise in this area but was struck my the apparent mismatch between what I read in the LA Times and my memory of the British outbreak.

Today’s London Times has “an article by John Collinge”:http://www.timesonline.co.uk/article/0,,482-949837,00.html , director of the Prion Unit at Britain’s Medical Research Council arguing that the threats to human health from the BSE/vCJD link may be great and that complacency on the basis of the small number of vCJD cases to date is misplaced.

{ 20 comments }

1

Keith M Ellis 01.03.04 at 11:28 am

I wish I could read that Times article. Is his argument the latency? But I thought that better slaughterhouse procedures would pretty much eliminate the threat. I mean, vCJD makes up a tiny fraction of CJD cases anyway.

I sure don’t worry about it. I’m confident that I’m much more likely to die from eating bacterial contaminated undercooked meat than I am of vCJD. And even more likely to die in an automobile crash. C’es la vie.

2

Chris Bertram 01.03.04 at 11:34 am

Sorry, perhaps that Times piece is inaccessible to those outside the UK. The $ paras:

bq. We are used to infectious disease epidemics, such as influenza or foot-and-mouth disease, that arise and decline over weeks and months. However, we know from the disease kuru, transmitted among the Fore people in Papua New Guinea during cannibalistic feasts with devastating effects, that human prion disease epidemics can span decades with incubation periods that can exceed 40 years, with an average of around 12 years. We also need to think about the effect of the so-called “species barrier”. When prions from one species infect another species, the incubation periods seen are typically very much longer. Average incubation periods of BSE prions in human beings of 30 years or more would not be surprising based on such comparisons.

Probably you’re right Keith that better slaughterhouse procedures will eliminate the threat. Of course that’s no comfort to those of us who consumed large quantities of British steak and kidney pies in the 1980s!

3

Kieran Healy 01.03.04 at 11:44 am

Just out of interest, here’s a little figure I just made that illustrates why complacency about small numbers of cases of a disease can be dangerous. Note that I’m not drawing strong analogies between HIV and vCJD here, just showing why small numbers of cases over a period of years doesn’t mean there’s nothing to worry about.

4

Tim Lambert 01.03.04 at 11:54 am

Milloy is a hack. You can read more about him here.

5

Nasi Lemak 01.03.04 at 12:28 pm

I’m sure I remember there being a very localised BSE hotspot (in Leicestershire?) with a public report into it. I’ll Google.

6

Nasi Lemak 01.03.04 at 12:30 pm

7

Motoke Kusanagi 01.03.04 at 12:30 pm

Here is the (disputed) article from the British Medicinal Journal to which Milloy refers. If the diseases are in fact related the epidemics of BSE in the 1980s and the later vCJD should develop in a similar way; so far that hasn’t happened. The BBC reported last year that in Britain 28 people died of vCJD in 2000, 20 in 2001 and 17 in 2002. In short, I’m skeptical.

Venters’ hypothesis that vCJD is a previously unrecognized disease was also supported by something I read about the (mis-)diagnosis of normal CJD; apparently the number of cases of CJD has grown significantly in the 1990s, simply because doctors are better at recognizing it. But I can’t find a link for that so maybe I dreamed it.

8

Ray 01.03.04 at 6:03 pm

So you have a difference of 1.3 per million and 2.6 per million. What that translates to, given Britain’s population of 60 million, is that you’re talking something in the area of 80 or so cases. Depending on how one draws one’s regions, it shouldn’t be too difficult to come up with a difference in occurrence rate. Reasonable people can differ on what is statistically significant in this case.

That said, it doesn’t really matter. People died from a mysterious and unexplained ailment. That’s reason enough for scrutiny, and statistically significant or not, one’s odds of finding the correct cause improve by honing in on correlating factors. It doesn’t prove anything, but it gives you a place to start looking.

9

Jim Henley 01.03.04 at 9:41 pm

Milloy is a hack. You can read more about him here.

Tim, that has to be one of the least impressive “debunkings” I’ve ever read.

It’s mostly a series of semantic games about the meaning of the word “science.” For example, it may be true that lawyers who try to get damage awards from cell phone manufacturers for post hoc brain cancers are not “doing science at all,” but they are making causal physical claims which require a theory behind them – that is to say, they are conjuring a scientific aura around their claims. That kind of conduct is certainly fair game. To complain that Milloy calls it “junk science” rather than, say, non-science or fake science is mere grumpery.

Much of the rest of it was taken up with “Why doesn’t Milloy write about this?” which is the sort of thing I’d expect from Glenn Reynolds talking about protestors.

Milloy may indeed be “a hack,” but you sure can’t tell it from the piece you cited. I’m somewhat surprised you seem so impressed with it.

10

back40 01.03.04 at 11:19 pm

Prions are interesting and may be part of normal protein functioning that goes wrong for several possible reasons such as old age or exposure to toxins of various sorts. The BSE scare has prompted a lot of work on a previously neglected area. There’s a fair amount of new and interesting research as well as an abundance of speculative writing.

11

degustibus 01.03.04 at 11:49 pm

oh well, then let’s put downer cattle back into the food supply.
(& Toxic waste is good for you too)

12

Zizka 01.04.04 at 1:22 am

Those of us who habitually eat our ancestors’ brains are even more worried than the rest of you. It seemed like the proper thing to do at the time. Who knew?

From what I’ve read, prion formation seems like self-catalysis, where a molecule of a certain compound, when added to a bath of components of the same compound, catalyzes the reproduction of more and more replicas of itself. Is there someone out there who actually knows chemistry and can tell me whether my hunch has any validity?

It’s very hard to get used to a whole new kind of cause of disease — neither a living creature nor a virus nor a toxin (as we usually use the word), but something else entirely. My etiological universe has been discombobulated.

13

clew 01.04.04 at 3:59 am

Zizka, a recent Economist has an article which not only describes prions much as you just did, but says that they may be part of memory, esp. long-term memory. (Not, I think, the same prions as the disease ones.)

14

back40 01.04.04 at 4:18 am

This MIT release discusses it clew. This BioMedNet article is also interesting. Protein folding variation is being recognized as a common mechanism, an elegant low energy method for quick state changes. But, things can go wrong…

15

Jim Miller 01.04.04 at 3:49 pm

Degustibus is no doubt trying to be funny when he (she?) says that “Toxic waste is good for you too”, but in fact there is some evidence that small amounts of some toxic substances can be good for living organisms.

The effect is called “hormesis” and has been shown in many experiments on a wide range of organisms. There’s some evidence that low levels of radiation are also beneficial.

And one amusing detail. One of the toxic substances thought to be helpful is arsenic. The right level for humans may be about 50 parts per million, the old “safe” level in the United States. By embarrassing the Bush administration into lowering it, the Democrats and media may actually have made us worse off.

Please note that I said “may”, since I understand that the scientific study of hormesis is still in its initial stages.

16

Zizka 01.04.04 at 6:04 pm

Some substances are never good and bad above a certain dosage. Asbestos, lead and mercury are examples, IIRC. Others are good in small doses and bad in large. This second list includes almost everything — salt, water, carbohydrates. “Toxic substance” is a shorthand term of uncertain definition (I suppose it is legally defined somewhere, and maybe medically, but the legal and medical definitions don’t govern everyday use.)

What Miller’s post tells us is that some toxic substances are not in the mercury-lead toxic category, but the other one (with zinc, table salt, etc.). Also granting that the research is pretty preliminary, I doubt that we need to change the way we think about pollution in general yet.

17

digamma 01.04.04 at 6:36 pm

Those of us who habitually eat our ancestors’ brains are even more worried than the rest of you. It seemed like the proper thing to do at the time. Who knew?

If zombie movies are to be believed (and certainly they are), the greater threat is our late ancestors’ eating OUR brains.

18

Tim Lambert 01.05.04 at 4:41 am

Jim, the difference between the Reynolds “why don’t they protest about X” argument and the critique of Milloy that I linked to, is that the protestors didn’t have a mission statement that implies they should be protesting about X. The only junk science that Milloy is critical of is that that does not suit his political agenda.

Milloy’s criticism of Levitt and Donohue’s abortion study could be also be applied to Lott’s MGLC study. You don’t even have to change any of the words. But he doesn’t criticize Lott’s work. In fact, he has articles praising Lott’s findings on his junk science site. I emailed him about this discrepency and his defence was that he didn’t write those articles. He is a hack.

19

Jon H 01.07.04 at 4:15 am

It occurs to me that the mad cow thing is precisely the sort of situation where Tech Central Station’s ownership could become an issue and call their coverage into question.

I know of one column they’ve run, which if I’m not mistaken was one saying that it wasn’t anything to worry about. I don’t know if they’ve covered it more.

It would be interesting to know if TCS’s owners, the lobbying firm, have the beef industry as a client.

20

Rod Dacombe 01.12.04 at 3:25 pm

I think that if Milloy had seen at first hand what vCJD does he’d be less concerned about hammering the beef industry

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