This was written as a response to this article. I put a fair amount of time into it, so I figured it would be worth re-posting here.
What a load of pseudoscientific garbage. Before I start addressing specific errors and spin, I’d like to suggest that anyone interested in this topic read Richard Rhodes’s Deadly Feasts, in which the real science regarding BSE and vCJD is described in painstaking detail. That said, on with the show…
BSE is not contagious and cows cannot give it to each other or other animals just by living together. Nor can they give it to people. There’s never been a single case.
Just because cows can’t get BSE directly from each other doesn’t mean they can’t get it from a common source. If everyone living around a certain water source seemed to get river blindness, would you want to live there? After all, river blindness isn’t directly contagious so, according to this author, you’d be perfectly safe. Nonsense. A huge number of diseases and parasites, including some well-known ones such as malaria, do not infect members of the same species directly but do infect them nonetheless by jumping from one species to another.
BSE is an bovine-specific example of a Transmissible Spongiform Encephalopathy (TSE) which has many species-specific names but is really the same underlying prion/protein disease, and it is notoriously capable of jumping between species. Nervous-system tissue from deer or elk infected with Chronic Wasting Disease has been conclusively shown to trigger BSE in cows. A similar experiment with the squirrel form of TSE has shown similar results. BSE is generally considered to have arrived in cows in the UK from sheep (in which scrapie is endemic) either directly or via pigs.
The problem with BSE is not intra-species infection, but infection from a common source, and that common source still exists in the US beef herd.
Since 1997 the Food and Drug Administration (FDA) has prohibited the use of most mammalian protein in animal feeds given to all ruminants — conventional and organic.
That’s hardly meaningful when the FDA does hardly anything to enforce the ban and the industry itself does even less. Cases of mammalian protein being found in beef-cow feed, even though it’s nominally illegal, are so common that I don’t even need to cite them. Just Google.
It appears to have a genetic component 5 to 10% of the time, with a small percentage iatrogenic
If five to ten percent have a genetic component and a few percent are iatrogenic, what about the other ninety percent? The answer can be found in one of the author’s very own citations.
The epidemic of bovine spongiform encephalopathy in the United Kingdom, which began in 1986 and has affected nearly 200,000 cattle, is waning to a conclusion, but leaves in its wake an outbreak of human Creutzfeldt-Jakob disease
Note that they don’t call it a “possible outbreak” or a “theorized outbreak”; they’re pretty unequivocal that it’s a real outbreak. Their reasoning can best be explained by reference to the following quote:
Then, from May to October 1995, the CJD Surveillance Unit was notified of three cases of CJD in patients 16, 19, and 29 years of age (23,24). On neuropathologic examination, all three patients had amyloid plaques, which was unexpected in view of their occurrence in only 5%-10% of sporadic cases of CJD.
The reference to amyloid plaques is significant, because they are a distinguishing feature of variant CJD which is believed to be associated with BSE contamination. Some cases of CJD occur spontaneously – “sporadically” in the article – but that doesn’t mean all cases. It’s similar to the situation with cancer; some cases are of unknown origin, but there are many known risk factors and many of those lead to characteristic forms of cancer. In the case of CJD, the appearance of amyloid plaques is strongly suggestive – in the scientific meaning of that phrase – of infectious origin.
To sum up, then, the author commits the following egregious errors, which are too serious to be considered merely accidental:
- Addressing only direct intra-species infection, ignoring the possibility of infection from a common source even though such infection is the dominant pattern for hundreds of diseases.
- Pretending that something never happens just because one of the most toothless regulatory agencies in the US government has declared it illegal, despite overwhelming that its illegality is widely ignored.
- Conflating vCJD with generic CJD, presenting findings about one as though they were about the other and ignoring the possibility that spontaneous and infectious origins can coexist.
If Szwarc’s article sounds like beef-industry PR that shouldn’t come as a surprise. Szwarc is a columnist for Tech Central Station, with a decidedly laissez-faire anti-government pro-food-industry bent; here’s another example of her “everything’s OK” style having to do with oysters, and a quick search on the site turns up plenty of others. Tech Central Station is a notorious front for the DCI group, a Washington lobbying firm. Personally I believe that such blatant industry propaganda has no place on a forum supposedly devoted to factual debate.
It might be worth noting that there’s another author at TCS named Iain Murray. After a bit of head-scratching I remembered that there’s also an Iain Murray who is the most frequent poster over at The Edge of England’s Sword. Same person, or just a coincidence? I have no idea; if anyone can shed any light on the matter I’d appreciate it.