Thursday, May 03, 2012

Mad Cow: A Case Of Spontaneous Generation

Ronald's comment about "spontaneous generation" of worms on onions reminded me of the cause given for the latest incident of mad cow:
"Experts [from USDA] said the case was "atypical" - meaning it was a rare occurrence in which a cow contracts the disease spontaneously, rather than through the feed supply."
- Mad Cow Disease Found In California; No Human Threat Seen, Reuters, 25 April 2012
So, it was a case of spontaneous generation.

Why then is CNN reporting this morning:
"Two farms have been quarantined by the U.S. Department of Agriculture as the agency continues to investigate last month's discovery of mad cow disease at a California dairy farm. ... Determining if the cow became sick from feed is an area where investigators are focusing close attention."
- USDA Quarantines 2 Farms In Mad Cow Investigation, CNN, 3 May 2012
The cow did not become sick from feed. It couldn't because feed does not contain animal parts. This was a rare case of spontaneous generation.
________
Photo of dairy cows feeding on April 25, 2012, near Hanford, California, where the mad cow was found at a rendering plant, from Reuters.

26 comments:

Bix said...

That CNN article also said:

Unlike most other meat-borne illnesses, such as those caused by E. coli bacteria, cooking does not kill the infectious agent that causes mad cow disease.

Dr. Mel said...

Spontaneous generation--

Dr. Mel said...

The word "snort" (as in derision) was cut from the end of my remark by your widget. The snort remains though. Or, perhaps the "mad cow" was taken up by aliens & then returned to us, complete w/ disease.

caulfieldkid said...

Bix,

I understand what you're saying, and it is humorous (if not ludicrous). However, it did make me think about CWD in deer. They aren't sure how it spreads, but it's not from eating animal matter that much is sure. I wonder if there isn't a similar mechanism for MCD that is being willfully ignored.

shaun

Bix said...

Aliens! omg... I don't know what to say. I know people believe in them.

Bix said...

The word "spontaneous" to me is a red flag. I don't believe things happen spontaneously. There is a reason for things happening, even if we don't understand what it is.

Cancer doesn't occur spontaneously, it is a result of interaction between genes and the environment. Mad cow doesn't occur spontaneously, it is an interaction between genes and environment.

I don't know much about prions, but I recall reading that they are a particular conformation of a protein that was "induced" to change shape by neighboring proteins. I'm guessing that induction is chemical or molecular or otherwise over my head. But there is a reason, even though I don't understand it.

Yes, deer ... I would not feel comfortable eating one that was taken in sport around here. No siree bob. Mad deer notwithstanding there is unfettered and flagrant use of pesticides and herbicides and other chemicals for keeping grass golf-course perfect. And the deer use peoples' chemicalized yards as salad bowls.

Bix said...

And, omg, "taken in sport." I can't go there.

Shreela said...

Bix, you haven't heard/read about Mark Purdey's organophosphate theory? I'd love to see a movie of how Mr. Purdey came up with his theories, but Monsanto and Big Beef might have issues with a movie of Mark Purdey's theories being made.

Bix said...

No, Shreela, I haven't. Let me go see...

Well, how about that. It's a line of research that, you'd think, would be seized upon. I wonder what the hold up is.

One thing this article in Wikipedia says is that mad cow encephalopathies are linked to Parkinson's and Alzheimers. It's not the first time I read that they show up as dementia. In fact, even this pretty mainstream CNN article says:

"In people, symptoms of the disease include psychiatric and behavioral changes, movement deficits, memory disturbances and cognitive impairments."

caulfieldkid said...

To clarify: I think the idea that MCD was "spontaneous" is ludicrous.

shaun

Laurie Endicott Thomas said...

It could be spontaneous. Prion diseases result from a misfolded protein. This protein (prion-related protein, PrP) is in the body naturally. Similar versions are found in other mammals. Some individuals have a mutation that makes their PrP to be prone to spontaneous misfolding. The misfolded configuration is stable, and it also tends to cause other PrP molecules to assume the misfolded configuration, which is why prion diseases are partly hereditary and partly communicable.

Laurie Endicott Thomas said...
This comment has been removed by the author.
Bix said...

Oh, yes, shaun, I did think that was what you were saying. I was just rambling... :)

Bix said...

Well, Laurie, that was my point. Or maybe we're making the same point. That the prion protein does not fold spontaneously, but folds (or misfolds) based on chemical properties. Although, I realize protein folding is generally termed "spontaneous" in that it doesn't require ATP.

There are lots of reasons why proteins fold the way they do ... their sequence of amino acids (in turn based on DNA), where the charges (and so attractions and repulsions) exist along the chain, hydrogen bonding, the medium the protein finds itself in (hydrophobic or hydrophilic, the pH), and others, as I recall.

To term something "spontaneous" is to, in my mind, lessen the impetus for delineating cause.

Laurie Endicott Thomas said...

By "spontaneous" misfolding, I mean transformation from the PrP(superscript c) conformation to the PrP(superscript Sc) conformation (infectious prion) in the absence of any PRP in the PrP(superscript Sc) conformation to serve as a template. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC478560/?tool=pubmed

The sequence of amino acids in each variant of the PrP protein determines how susceptible it is to misfolding, which explains why some individuals get prion diseases without having been exposed to prions and why some individuals are resistant to prion diseases despite having been exposed to prions.

ribbie said...

I think those mad cows need therapy. They have something to say but no one is really listening.

Bix said...

Oh boy. If cows could talk.

Laurie Endicott Thomas said...

Temple Grandin listens to them.

Dr. Mel said...

Temple Grandin does indeed listen. Good woman. And doc.

Anonymous said...

Don't know how you handle the snide comments, Bix.

For the know-it-all, the word spontaneous was used for political reasons. They wanted not to alarm the public which would result in an outcry for more testing.

Dr. JeffM

Anonymous said...

http://www.cattlenetwork.com/cattle-news/latest/Temple-Grandin-enters-New-York-Times-meat-eating-contest--150229685.html

The New York Times recently announced an essay contest, asking readers to sum-up why eating meat is ethical in 600 words or less. A panel of vegetarian and vegan judges then selected the top six entries.

Dr. Temple Grandin, animal welfare expert and professor of animal welfare at Colorado State University, also submitted an essay into the contest. Despite her expertise on the issue, her essay was no among the finalists selected.

"I have a final reason why I think eating meat is ethnical. My metabolism requires animal protein, and I get lightheaded and unable to concentrate if I go on a vegan diet."

Bix said...

I had seen her essay on James McWilliams' site.

In the last paragraph Grandin says a reason why she thinks eating meat is ethical is because, "my metabolism requires animal protein." Does that mean if a person's metabolism doesn't require animal protein, eating meat is unethical?

Laurie Endicott Thomas said...

Dr. Grandin is an authority on animal behavior and animal welfare, not human nutrition.

Bix said...

Well, Dr. Grandin may think it's ethical to eat animals, but I think supporting the present livestock industry by purchasing and consuming their output - dairy, eggs, fish, cows, pigs, chickens - is one of the most ethically compromising actions we perform. I think ethics can inform food choice.

Bix said...

http://fanaticcook.blogspot.com/2011/01/ethics-of-dairy-consumption.html

Claudia said...

ribbie is right, no one is listening to the cows. They're mad! It's nice and all to say Temple grandin listens but she doesn't really. Cows are saying please feed me these things I don't want to eat to fatten me so you can eat me? Pigs are saying please cut my tail off an castrate me!! Please keep me in a pen so i can't root around and please take my babies from me? Chickens are saying they don't know what the sun looks like! If someone is listening to the animals its going in one ear and out other.