Are Young People More Susceptible to Mad Cow (vCJD)?

[livius drusus]

Now that Roland has told us about prions (http://www.freethought-forum.com/forum/article.php?a=11), I find this BBC article (http://news.bbc.co.uk/1/hi/health/3549396.stm) even more interesting.

"We found that exposure alone could not explain the young age of vCJD cases as seen in the UK," said Pierre-Yves Boelle, one of those involved in the study.

The researchers say more studies are needed to find out why young people may be more susceptible to the disease.

But they suggested that changes in the intestine when children are growing could be one reason.

"One possible explanation for the difference in susceptibility could be that the permeability of the intestinal barrier changes with age," they said.

Do you have thoughts on the issue, Ro? How about the rest of you scienticians out there?

[Roland98]

First thought--damn, how it ticks me off when they don't reference the journal it was published in. I have to go and track down the original paper via PubMed, and of course it takes several days to weeks to actually be referenced on there. And I hate believing what reporters summarize, because many times, they are simply dumbasses. [/rant]


But any-hoo, it's interesting stuff just from the BBC overview. There are a lot of diseases that disproportionately affect one age group. Most of these focus on the young and old, as they are groups that are most likely to have compromised immune systems, but others affect younger age groups. For example, take your typical childhood diseases--measles, chickenpox, mumps, etc. Generally annoying for a child, can be fatal, but rarely so. Take those and give them to an adult who's never contracted them before, and they are far more likely to develop severe complications from the infection. Why? No one is sure. It's often written off to something involving the immune system, though exactly what it would be is unclear.

However, prions aren't immunogenic (since they are a derivative of normal host proteins, they don't invoke an immune response). Additionally, no one is 100% sure how the prions move from the intestine, presumably through the bloodstream, and then to the brain (where they cause damage). So the idea that there may be something different in the intestine is intriguing.

[Roland98]

One more thing--there's CJD, and then there's vCJD (just to confuse y'all). They have the same symptoms, but the difference is in the way they're contracted. CJD is an internal mutation--for whatever reason, the person's own protein starts misfolding spontaneously (as far as we know). vCJD ("variant" CJD) is what's known as "mad cow," and develops after exposure to the prion from an external source (whether by eating contaminated meat, surgical operations with affected instruments, tissue transplants, etc.) CJD generally is only seen in older folks, somewhat akin to Alzheimer's; vCJD, as mentioned, can affect other age groups (and as they said, is more common in the young).

[livius drusus]

Thanks for the clarification on vCJD, Ro. I went ahead and changed the thread title to reflect my new decrease in ignorance.

First thought--damn, how it ticks me off when they don't reference the journal it was published in. I have to go and track down the original paper via PubMed, and of course it takes several days to weeks to actually be referenced on there. And I hate believing what reporters summarize, because many times, they are simply dumbasses. [/rant]

I feel your pain, although I usually don't attempt to read medical studies due to my acres of undecreased ignorance. Let me see if I can at least find a journal reference to help you along.

I found Estimation of Epidemic Size and Incubation Time Based on Age Characteristics of vCJD in the United Kingdom (http://www.sciencemag.org/cgi/content/short/294/5547/1726) in Science Magazine, but I only have the limited access so all I can see is the abstract and citations. How's your French?

But any-hoo, it's interesting stuff just from the BBC overview. There are a lot of diseases that disproportionately affect one age group. Most of these focus on the young and old, as they are groups that are most likely to have compromised immune systems, but others affect younger age groups. For example, take your typical childhood diseases--measles, chickenpox, mumps, etc. Generally annoying for a child, can be fatal, but rarely so. Take those and give them to an adult who's never contracted them before, and they are far more likely to develop severe complications from the infection. Why? No one is sure. It's often written off to something involving the immune system, though exactly what it would be is unclear.

Y'all don't know? Sheeit. People have been threatening me with the chickenpox I never got ever since I turned 20. I had no idea the adult onset childhood diseases were still so mysterious.

However, prions aren't immunogenic (since they are a derivative of normal host proteins, they don't invoke an immune response). Additionally, no one is 100% sure how the prions move from the intestine, presumably through the bloodstream, and then to the brain (where they cause damage). So the idea that there may be something different in the intestine is intriguing.

The permeability of the intestine seems like it would make a difference, assuming that's the path the little prion buggers take to get into the bloodstream, that is. It really is intriguing, even to the ignant layman such as myself.

[Roland98]

Thanks for the clarification on vCJD, Ro. I went ahead and changed the thread title to reflect my new decrease in ignorance.

Heh. You didn't have to do that; I was just clarifying a bit.

I feel your pain, although I usually don't attempt to read medical studies due to my acres of undecreased ignorance. Let me see if I can at least find a journal reference to help you along.

I found Estimation of Epidemic Size and Incubation Time Based on Age Characteristics of vCJD in the United Kingdom (http://www.sciencemag.org/cgi/content/short/294/5547/1726) in Science Magazine, but I only have the limited access so all I can see is the abstract and citations. How's your French?

That's a 2001 paper, so that wouldn't be it. That's the thing with media articles; often the university will release the details of the paper to the press before it's released to the public, so many times the news stories hit the popular press before the actual journal articles are out for the rest of us. Occasionally they'll at least be good enough to say, "in this week's Nature magazine" or something like that.

Y'all don't know? Sheeit. People have been threatening me with the chickenpox I never got ever since I turned 20. I had no idea the adult onset childhood diseases were still so mysterious.

Nope. The one that comes up most often is simply a more vigorous immune response in adults. As I mentioned in the "for dummies" article, a lot of what we see as far as symptoms from infection are due to the immune response--fever, shock, swelling etc. So if the immune response is too vigorous, it may do more damage than good. I'll probably do an article on the 1918 flu at some point; that's a classic example. Highest mortality rates were in adolescents and young adults, ~age 15-35.

And of course, what may cause higher mortality with one organism may not hold with another one, so it often has to be taken on a case-by-case basis.

The permeability of the intestine seems like it would make a difference, assuming that's the path the little prion buggers take to get into the bloodstream, that is. It really is intriguing, even to the ignant layman such as myself.

Yeah. I'd imagine it'll be on Medline in a few days, or if it's in one of the journals I receive eTOCs for, I'll link it in here and add anything interesting the BBC didn't mention.

[Dingfod]

Maybe us old folks brains are too mushy and all and prions only like fresh pink brains.

See how simple it can be. Shit, who needs them advanced degrees and shit?


Warren

[JoeP]

First thought--damn, how it ticks me off when they don't reference the journal it was published in. The BBC's web news has been seriously dumbed-down. Their articles are formulaic and simplistic. However, they're still less sensational and glitzy than CNN's (ref the lone ranger's comments in luna's fuck america thread which I can't be bothered to dig out the url for, since after all I am commenting on people not providing references).

[Roland98]

Maybe us old folks brains are too mushy and all and prions only like fresh pink brains.

See how simple it can be. Shit, who needs them advanced degrees and shit?


Warren

I think you're thinking about zombies, not prions. :wink:

[Roland98]

The BBC's web news has been seriously dumbed-down. Their articles are formulaic and simplistic. However, they're still less sensational and glitzy than CNN's (ref the lone ranger's comments in luna's fuck america thread which I can't be bothered to dig out the url for, since after all I am commenting on people not providing references).

No, I very well recognize that. And though the BBC admittedly isn't the worst offender, it's still annoying. I can't recall the paper, but someone sent me an article on Streptococcus not too long ago, where the journalist called it a virus (it's a bacterium). Just amazing the things that slip through the cracks.

[Roland98]

Alrighty, found it. It's here (http://www.biomedcentral.com/1471-2334/4/26/abstract) in BMC Infectious Diseases, which means that even those of you who don't work at a swanky university should have access. Really, though, it doesn't add much. I was hoping they'd elaborate a bit more on the intestinal changes or other possibilities, but they don't have more than a sentence or two.

[Dingfod]

I think you're thinking about zombies, not prions. :wink:Oh. I guess. I supposed that came from those advanced degrees and shit. Stuff I ain't got.


Warren

[Scotty]

Actually, it is all absorbed through the lips. Everybody knows that younger people have bigger lips, except Mick Jager possibly.

Collagen injections actually slow the prions in their tracks.

-Scott (not a Dr. and I don't play one on TV)

[WinAce]

Mad cow? As long as I don't taunt those walking steaks in Oregon, I don't think I need worry... :P

[JoeP]

Just amazing the things that slip through the cracks.
Now I'm confused. Do these viruses, bacteria and prions slip through cracks? I thought it was mostly mucus membranes like the digestive system and the airways.

[Roland98]

Now I'm confused. Do these viruses, bacteria and prions slip through cracks? I thought it was mostly mucus membranes like the digestive system and the airways.

:) I was referring to the reporter's use of "virus" instead of "bacterium" in the one article. But actually, some organisms can wiggle their way between the tight junctions between cells. Of course, I'm blanking on any specific ones right now that invade this way, damn it. :glare:

[JoeP]

What about the navel? Is that permeable? See, obsessed. :innocent:

[Dingfod]

Mad cow? As long as I don't taunt those walking steaks in Oregon, I don't think I need worry... :PWomen really don't like it when you call them a cow, even if they do look good enough to eat. :wink:


Warren

[Roland98]

What about the navel? Is that permeable? See, obsessed. :innocent:

:) No, no more so than any other area of the body.

[WinAce]

Women really don't like it when you call them a cow, even if they do look good enough to eat. :wink:

The last time I called any human woman that was years ago, and in hindsight, I could have handled that a lot better. This time, I was referring to literal cows. One of them, if not mad, is apparently grumpy for some reason, so I'll have to watch it. That includes making 0 ill-advised comments about eating them. :D

[Beth]

The last time I called any human woman that was years ago, and in hindsight, I could have handled that a lot better. This time, I was referring to literal cows. One of them, if not mad, is apparently grumpy for some reason, so I'll have to watch it. That includes making 0 ill-advised comments about eating them. :DI nursed both my kids. My oldest, my son, had it in his mind I was a Mommy cow and called me that. We had a pasture behind us with grazing cattle.