Pig Brain Mist and PIN

There are two write ups on this one; the secondary source is "Austin pork plant investigation zeroes in on pig brains" and the primary source is "Investigation of Progressive Inflammatory Neuropathy Among Swine Slaughterhouse Workers".

The Minnesota Department of Health and the Centers for Disease Control have given an update on the disease down in Austin, Minnesota. The Star Tribune nails down the idea that has been floating in my head since I first heard about this.

Pigs and humans are such biologically similar mammals that researchers are trying to find ways to use pig organs to replace diseased human organs. So it's not surprising that if the immune system creates cells to attack proteins from pig neural tissue, those immune cells might also attack human neural tissue as well, experts said.

If the body is attacking an influx of nervous tissue from pig brains, it isn't much of a leap for that same attack to be wrongly redirected to the body's own nervous tissue. Our bodies are very good at attacking invading infections, but unfortunately when that system turns back on the body things go badly. See lupus, MS and Chrohn's.

I don't think that we evolved to be able to deal with liquefied and aerosolized brains. Touch them, eat them yes; inhale them, no. So it doesn't surprise me that things might go wrong. I wonder who came up with the idea of using air to remove the brain anyhow? Bet they feel pretty bad right now.

The experts have decided upon a name for the cluster of symptoms, progressive inflammatory neuropathy or PIN for short. They looked at other large slaughter plants in the US and found two more that were using pressurized air to blow the brains out.

To date, no cases of PIN have been identified in association with workers at the Nebraska plant. However, several workers at the Indiana plant have been preliminarily identified with neurologic illnesses and similar histories of exposure to head-processing activities at that slaughterhouse. Further assessments of these patients, and additional measures to identify other workers with illness, are being conducted in Indiana. As a result of this investigation, all three plants have stopped using compressed air to extract brain material.

The health officials are also looking to talk to anyone who has worked at the Austin plant since the air pressure system was installed a decade ago. The problem is that the job has a high turn over rate, with many of the workers being immigrants. In December of 2006 a different meat packing plant in another small Minnesota town was raided by Immigration and Customs Enforcement and took away hundreds of workers. So finding everyone that worked at the Austin plant over the past decade is impossible from the start. Which means there is a chance that there is someone out there who might never figure out why their limbs stop working and go weak.

Revere over at Effect Measure has a post about this too. Revere is a public health scientist and credits the medical specialist who was seeing several of the patients. A very good post from a blogger I really like.

Maybe not CIDP, but still bad

Pork-plant ailment a mystery again

The Department of Health has backed off from the initial diagnosis of CIDP. That said they do have another case, bringing the total up to 12 people.

Key to differentiating the condition from CIDP is a characteristic of CIDP involving an interruption or blockage of the electrical signaling in and between nerves, Lachance said. Tests now show that none of the 11 workers has that problem, he said.

They do have damage to the nerve system caused by their immune systems, he said. But at this point it can be categorized generically only as an inflammatory response that is damaging the nerve sheaths, he said.

What I said before about the myelin sheath and Schwann cells being the target of the immune reaction is still true. My speculation about a connection to the Guillain-Barre syndrome and the 1976 swine flu vaccine is out the window though.

There is no doubt in my mind that this still has something to do with the fact that they were literally blowing the pigs brains out. What I would call aerosolized biological tissue, Norwegianity is calling "Brain Mist."

When solids are aerosolized they are able to get into places they normally wouldn't, such as the lungs. From there they can get into the blood stream and then strange things can happen.

Scratchtasia

Not exactly accurate, but good at getting one point across; some things should not be aerosolized.

More on the CIPD in Austin

I read most of this from the Dead Tree Edition of the Star Tribune, but it has been reposted by the fine folks at MSNBC so we don't have to run into the subscription problem.The question at Austin pork plant: Why?

There isn't much here that I didn't already know or figure out on my own but there were a few bits that caught my attention.

CIDP is the chronic form of another disease, Guillain-Barré; syndrome, which develops much more rapidly and has a number of known triggers. It first received public attention in 1976 when linked to the swine flu vaccine.

That seems interesting to me. Could there be a connection between the swine flu and what happened here?

Symptoms first emerged around the same time the plant began using the high-powered air system. Some health experts think exposure to blood and pulverized tissue might have caused the autoimmune response.

But the compressed-air system almost certainly is not the problem, said mechanical engineer Frank Moskowitz, a compressed-air expert based in Phoenix. "Compressed air itself absolutely cannot introduce anything bad," he said. He said pressurization kills any living organism in the air.

Well that maybe true, but I doubt anyone was actually thinking that this was do to physical pressure from blasts of air. But the fact that the compressed air system and the disease are temporally linked means to me that there was something about blowing biological tissue into the air that is the key here.

Gross job leads to rare disease

Pork plant employees contract neurological illness

Between December last year and July of this year 11 workers at a pork processing plant in Austin, MN have been victims of a strange set of symptoms. Numbness and tingling in their hands. At first I'm sure they thought it was some repetitive stress, but the Health Department is saying that it is Chronic Inflammatory Demyelinating Polyneuropathy.

Department investigators have been poring over the cases since then. So far they say they have determined that the workers experienced an inflammatory response to some kind of trigger. But they haven't identified the trigger yet. It could be an infectious agent within the plant, or even a chemical exposure.

Well, lets look at what CIDP is. Whats happening is that something, the Health Department doesn't know what, is triggering an immune response that is targeting the myelin sheath that is wrapped around the dendrite of the nerve cell.



The Schwann cells make up the myelin sheath, the gaps between them are nodes of Ranvier. This set up allows the electrochemical impulse to travel down the axon more efficiently than an unmyelinated axon. Human neurons need this myelination, when those Schwann cells are damaged, the message from the nerve cell doesn't travel as it should, leading to the weakness, numbness and tingling. See Wikipedia.

So the next question is what would make the immune system target the Schwan cells that create the myelin sheath? The Health Department doesn't know right now. Since all the workers suffering were using compressed air to remove the brain from the pig heads, most people are going to think of a prion disease. But this is not much like prion diseases that tend to attack the central nervous system rather that the peripheral. Plus, there are not any known prion diseases in pigs. That isn't to say it isn't possible that there is a mad pig disease, just that we have no documentation of anything that would fit that description.

I'm going to reference the Star Tribune now, since its physical newspaper thats in front of me, but I don't like to use their online stuff since they require registration after a few clicks.

Anyway, the paper says that the workers are different ages, ethnicities, and genders. This means that it really is something at work and probably not the water. Add to that the fact that no one not working with the brains has come down with this. So there is something about either the brains or the way they were removing the brains.

"We've already given some of our employees a face mask, and discontinued some operations that could be potential. Again, we have no idea of the cause," said Wadding. "But we do want to take every precautionary step that the Department of Health recommends, and that we see that could possibly contribute to this."

The Strib dead tree edition also says the company is no longer using compressed air, and is now giving out safety goggles, disposable sleeves and towels for showers. You mean that the workers were using compressed air, shooting brain matter all over, and they didn't have goggles, face masks, or sleeves? Besides the immediate eeww factor, I don't think its a good idea to be aerosolizing raw biological tissue at all, much less without eye protection.

However, there is still a chance that the root cause of this CIDP is chemical rather than biological. I don't know enough about how one cleans a pork slaughtering plant to speculate on the cleaning agents. Might they have used a different chemical for cleaning the debraining room? Might the compressed air lines have been cleaned by some nasty chemical?

On top of all this, the plant has a strange history. The plant was spun off from Hormell in 1989. According to my father, whom I don't think counts as a scholarly reference, this lead to a strike because the spin off meant it was suddenly a non-union shop. Anyone who wasn't four at the time, as I was, want to confirm that? Maybe its my pro-union bias, but I worry about safe working conditions at non-union companies.

I hope the workers get better.

EDIT: It seems that CIPD has been ruled out, see more here.