Access
This article is part of Nature's premium content.
Published online 1 July 2008 | Nature | doi:10.1038/news.2008.926
News
Prions' great escape
Disease-causing proteins can evade sewage treatment procedures.
Prions, the infective particles behind diseases such as bovine spongiform encephalopathy (BSE), can breach standard sewage treatment methods, new research shows.
The discovery raises the possibility that the rogue proteins, which are infamously hard to detect, can jump one of the most important barriers that safeguard human health.
To read this story in full you will need to login or make a payment (see right).
Comments
Reader comments are usually moderated after posting. If you find something offensive or inappropriate, you can speed this process by clicking 'Report this comment' (or, if that doesn't work for you, email webadmin@nature.com). For more controversial topics, we reserve the right to moderate before comments are published.
It would make sense to look at manure lagoons from cattle operations or fields amended with manure as a field test for whether prions are present, considering the minimal treatment that manure undergoes prior to field application.
This doesn't surprise me at all, since I remember a talk by one of the older researchers in the field from more than 10 years ago, that he had put one prion containing tissue (as far as I remember, a whole mouse or hamster or similar) into the soil of his garden - and, about a year later, took some earth from this area, autoclaved it at normal temperatures (which should leave remaining prions infectious) - and could transfer the disease from garden soil by infecting animal brains. This result appeared even scary to him, but in some way he expected it, too. Considering the extremely high resistance to temperature and other things, it appears to be reasonable to beleive that prions will remain infectious over decades even with millions of living bacteria surrounding them in gardens and other soil. Therefore, anywhere where prion diseases appear, special care should be taken: laboratories with animal models and infectious prions but also pathology and neuropathology rooms with Creutzfeld-Jacobs' disease, and of course all the fields where ever Mad-cow disease occurred.
I guess it couldn't hurt to take a batch of infective prions, use them as the sole carbon/nitrogen source on a petri dish, and see which (dominant) sludge bacteria are able to break 'em down with good efficiency. add these bacteria back to your sample/sludge and see if persistence of prions drops. let bacteria do the work. it makes life so much easier.
The fact that meat producers have the potential to contaminate waterways with prions that resist waste-treatment procedures adds to other potential catatrophes the industry is already known for. The salmonella that are believed to have been transmitted by tomatoes obviously did not begin in the tomato patch, since salmonella are intestinal bacteria. Like the E. coli that nearly turned the spinach industry belly-up in 2006 and were eventually traced to a livestock operation in San Benito County, California, salmonella are propagated by animal agriculture. Meanwhile, the methane produced by animal agriculture is reportedly a leading contributor to global climate change, and the loss of grains, thanks in part to meat producers, contributes to the world food crisis. There was a time when all we could say about the meat industry is that it contributed to heart attacks, colon cancer, and high blood pressure. These scientific findings should lead to major public policy changes, to encourage healthful plant-based diets. We've been too patient with the risks of the meat industry.