Tuesday, March 25, 2008

Stupid mad cow disease...

For whatever reason, I'm now going to ramble on about this Sentinel article about Mad Cow disease and groups demanding more testing for it.

Actually, I'm not sure this article was even written by the S&E staff, and it's not a terrible article. So my complaint is more with people who freak out about Mad Cow disease than anything else. Meh.

By pure coincidence, it happens that this past weekend I watched a terrible and annoying movie called Mad Cowgirl that had Mad Cow disease as part of its theme. Do not under any circumstances watch this movie! It will make you want to never eat beef again just so you won't have to be reminded of this stupid movie!

Anyway, one of the (many, many) problems with the movie was that Mad Cow disease is just not anything anyone should be scared of.

Mad Cow disease is more technically known as Bovine Spongiform Encephalopathy, or BSE. It's a pretty nasty degenerative brain disease. For cows. Humans don't get BSE, because humans are not bovines (myself excluded, of course).

Unfortunately for humans, there's pretty strong evidence for a causal relationship between BSE and Variant Creutzfeldt-Jakob Disease (vCJD). vCJD is also a nasty degenerative brain disease, but it occurs in humans. Don't get it.

But don't worry either, because you won't. You're probably more likely to choke to death on your toothpaste.

There have been three cows found in the US with BSE. That's it, ever. Yes, the article's headline is correct when it suggests that if you don't test for BSE you won't find it, but chances are you're not going to find much of anything even if you were to test every single cow.

Let's look at some numbers...
Today, about 40,000 -- or 0.1 percent -- of the 37 million U.S. cows slaughtered each year are tested, a number that consumer groups say is too low, especially when compared to testing programs in other countries.


...two mad cow cases found from tests of the brain tissue of 787,000 cows between 2004 and 2006 -- dimmed fears that the disease had a foothold in the country.
As well they should.

Now, the Consumers Union is complaining that testing 0.1% (or 1 in a thousand) of the cows is too low. Maybe it is. But the incidence of BSE among the cows tested is only about 0.00025% (or 1 in 400 thousand)!

In other words, if that percentage held up uniformly (which is admittedly unlikely) and we tested all 37 million cows at an astronomical cost, we might find 94 cows with BSE. Most of which would be sickly and dying and shouldn't find their way to market anyway (which is a separate issue, but I'm going to assume most cows with BSE aren't going to be food).

You almost certainly have more cows getting struck by lightning (the rate is 1 in 280,000 among humans, and we don't spend all day in a field) or getting abducted for crazy alien cattle mutilations than getting Mad Cow disease.

The CDC information for travelers says this about human risk of acquiring vCJD from eating beef:
A rough estimate of this risk for the UK in the recent past, for example, was about 1 case per 10 billion servings.
Incidentally, the UK has by far the highest rate of BSE in the world. Still, you could eat three servings of beef a day there, every day, for more than nine million years before you'd really need to worry.

So seriously, don't worry about Mad Cow disease. Also, don't watch crappy movies that make you rant about boring things.

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