Mad Cow caused by 'garbage' on the brain: Ingram

By ALEX MCCUAIG, medicinehatnews.com (the entire piece is displayed here because the link to the Medicine Hat News is not working consistently)

The history of prion causing diseases such as mad cow (bovine spongiform encephalopathy, BSE) chronic wasting disease (CWD) and its human counterpart Creutzfeldt - Jakob disease (CJD) is varied and poorly understood.

Science journalist Jay Ingram was in Medicine Hat Wednesday to discuss the history and what research is currently out there in connection with these diseases and the agent which causes them.
"There was a human prion disease discovered in Papau-New Guinea in the 50s that was spread by cannibalism," Ingram said during an interview with the News earlier this week.

"It's a fantastic medical detective story but it also has lessons for mad cow diseases as that was triggered by rendering dead animals with the disease and feeding it to others."

Ingram explains the prion spreads disease not like other agents as it's a protein molecule rather than a bacteria or virus. But unlike the millions of prions that are found in mammalian brain tissue, the disease carrying prions are "misfolded."

"If normal prions sitting on your brain cells come into contact with misfolded prions then they get recruited to misfold," he said.

This leads to accumulations of what Ingram termed "garbage" on the brain which it's believed causes diseases such as mad cow.

As for the life cycle for these prions, it depends on the variant, said Ingram.

Scrapie, the variant which affects sheep, and CWD, which infects deer, can exist in soil for at least a decade. He added it's not definitively know how long the BSE triggering prion can remain active.
CWD poses one of the biggest issues in tracking infected animals as it's almost impossible to find which deer have CWD before they are able to spread the prion which has a two or three year incubation period.

"If (the deer) are killed and consumed by a predator, then you will never know they were there but they will have been leaving prions all over the place," said Ingram. Adding that CWD potentially could have an effect on farmed elk and, if the infected deer migrate far enough to the north, see caribou herds put at risk.

While Ingram said research appears to concluded CWD won't transfer between those species, it's far from complete and could potentially put humans who rely on caribou at risk to contracting the disease.

The continued study of prion diseases is important, said Ingram, to unlocking the answers of how other degenerative neurological conditions such as Parkinson's, Lou Gehrig's and Alzheimer's are caused.

"Some of the mechanisms in the spread of destruction in those three diseases are similar. They involve little deposits of misfolded proteins.

"It looks like that mechanism can spread to adjacent cells," said Ingram. "There is enough similarities to think the better we understand the prion diseases the more likely it is we might find a crucial connection, a way to interrupt that process, something that would lend itself to the treatment of these other diseases."