The Oconee Enterprise, July 28, 2016:
Dr. David Lewis
Neuroscientists studying eight middle-aged patients who died from Creutzfeldt–Jakob disease, which is caused by infectious proteins called prions, discovered half of them had early onset Alzheimer’s disease. Alzheimer’s disease, therefore, may also be caused by prions. If true, it could be spread by dirty surgical instruments. Other scientists have already demonstrated Alzheimer’s disease may be caused by an infectious agent. Laboratory animals injected with brain matter from people who have died with Alzheimer’s disease appear to develop the disease.
Although prions act like viruses, they possess the alarming ability to survive all known chemical and heat sterilization methods. Potentially, sporadic transmission of Alzheimer’s disease could occur with difficult-to-clean dental and medical devices used to perform invasive procedures. This includes, for example, flexible endoscopes used for taking biopsies during colonoscopies, dental handpieces used to drill and polish teeth, and bone cutters used to saw through bone.
Because prions survive sterilization, disposable covers and single-use devices are recommended whenever possible. The European Society of Gastrointestinal Endoscopy, for example, recommends disposable accessories be used during colonoscopies and other endoscopic procedures. Manufacturers, however, are slow to catch on. Olympus Corporation, which manufactures most flexible endoscopes used in the United States, still makes internal channels that are too small for brushing out blood and bits of tissue. The FDA should require that all contaminated internal and external surfaces in such devices be accessible to brushing.
Prions are also transmitted by contaminated food products. For example, bovine spongiform encephalopathy, also called mad cow disease, is transmitted to humans by hamburger meat and other food products containing nerve tissue. Recently, scientists in Texas and Colorado demonstrated that plants take up prions from soil contaminated with urine and feces from prion-infected animals. Hamsters feeding on the contaminated plants became infected.
Brain-wasting prions, once rare, are rapidly becoming endemic in domestic and wild animal populations. This includes scrapie in sheep and goats, and chronic wasting disease in deer, elk, and moose. And Alzheimer’s disease appears to be on the rise in humans. Perhaps this shouldn’t be surprising since prions can be spread to grazing animals by plants growing in soil contaminated with animal wastes; and municipalities are spreading treated sewage sludges, aka biosolids, on farmland. According to the University of Arizona’s Water Quality Center, prions in sewage sludge are destroyed at temperatures ranging from 37 to 60 degrees Centigrade. Research everywhere else, however, demonstrates that autoclaving prions at 121 to 132 degrees Centigrade is ineffective. The Water Quality Center is funded by EPA, leading biosolids companies, and wastewater industry associations to support land application of biosolids. Perhaps this explains the discrepancy.
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David Lewis, Ph.D.
Former U.S. EPA Research Microbiologist
David Lewis is an internationally recognized research microbiologist whose work on public health and environmental issues, as a senior-level Research Microbiologist in EPA’s Office of Research & Development and member of the Graduate Faculty of the University of Georgia, has been reported in numerous news articles and documentaries from TIME magazine and Reader’s Digest to National Geographic.