Deer hunters flooded my inbox last week asking if I had heard the great news that Dr. Frank Bastian has developed a cure for chronic wasting disease.
The "news" is actually a couple of years old and illuminates Bastian's claims of having isolated the cause of chronic wasting disease, or CWD, a fatal neurologic disorder that destroys the central nervous systems of deer, elk and moose.
Chronic wasting disease is one of the diseases known collectively as transmissible spongiform encephalopathies, or TSEs, a group of rare degenerative brain disorders that can affect humans and animals. Their defining characteristic is misfolded proteins that destroy a victim's brain. These proteins are called "prions," a word coined by Nobel laureate Stanley Prusiner. Prion is short for "proteinaceous infectious particle."
Bastian, a professor of neuropathology at Louisiana State University, specializes in scrapie, a TSE that affects sheep.
I interviewed Bastian in 2002 for an article in North American Hunter in which he linked scrapie and chronic wasting disease with spiroplasma bacteria that were transmitted by hay mites. Prions, he insisted, did not cause scrapie or CWD, but were symptomatic of spiroplasma infection. In that 2002 article, Bastian also claimed to have eliminated scrapie in test animals with the antibiotic tetracycline.
Other highly credentialed critics also dispute prion orthodoxy, including Dr. Laura Manuelidis, professor of neuropathology in the Department of Surgery at Yale. She said the theory of prion (PrP) infectivity collapses under classical scientific scrutiny.
She said her rejection of the prion as the causative agent for CWD is essentially "Biology 101." The prion is non-nucleic and has no ability to encode the very different agent strains documented in human Creutzfeldt-Jakob disease, scrapie, epidemic "mad cow" disease and CWD.
"Proteins don't replicate," Manuelidis said. "PrP misfolds late in disease but does not manufacture millions of new copies of itself, unlike TSE infectious agents.
Agent replication was established in the 1940s, Manuelidis said.
"Where is the reproducible proof that PrP or any other protein itself can be infectious?" Manuelidis asked. "Thousands of experiments from various labs have not been able to reproduce any infectivity for recombinant PrP itself, as claimed by Prusiner's report in a publicized Science report."
Most importantly, highly infectious, virus-sized particles smaller than 20 nanometers with no detectable PrP have been demonstrated, Manuelidis said.
Conversely, all highly infectious "isolates" contain appreciable genomic-length nucleic acids, Manuelidis said. These are required for infection.
"Nuclease treatment destroys these nucleic acids and simultaneously destroys infectivity," Manuelidis said. "What is the specific sequence of that essential genome? No one knows, and few people have looked, but empirical evidence points to a protected viral genome of 0.5-3,000nt."
Public confusion arises partly from the misperception that one can transmit disease, Manuelidis said. Infectious agents cause disease.
"Abnormal PrP is an end-stage pathologic product, whereas the stealth infectious agent replicates a million-fold before pathologic PrP is detectable," Manuelidis said. "On the other hand, PrP is a good marker of TSE disease and is a required host protein for the effective replication of the agent. Host susceptibility to infection always rests on specific host proteins to support their replicative life cycle."
Much of the scientific community is so wholly invested in the theory of infectious prions that it ignores contradictory evidence.
"There is a great belief and investment in prions, and this has stymied anyone wanting to systematically investigate different alternatives," Manuelidis said.
In 2013, Manuelidis published a paper titled, Infectious particles, stress and induced prion amyloids -- a unifying perspective. She noted that certain TSEs have been controlled by modifying the environment. For example, a variant called "kuru" disappeared with the cessation of ritualistic cannibalism in a specific New Guinea tribe. It has not reappeared "spontaneously," violating a central tenet of the prion theory, Manuelidis said.
Epidemic mad cow disease was greatly reduced by removing contaminated feed in the form of protein cakes fortified with brain tissue harvested from scrapie-infected sheep.
"This is a classic infectious disease pattern, but many prion proponents seem to have little knowledge of classic infectious diseases, including their latent sequestration for years in myeloid cells and lymph nodes, which is also the hide-out place for TSE agents," Manuelidis said.
"They don't think in terms of those fundamental established principles. They ignore facts that do not fit their belief. Scientific truth, however, is not determined by popular vote or decree."
Sports on 02/24/2019
Print Headline: Yale professor refutes popular CWD theory