"It probably requires a lot of prions to cause a the disease."
There have been researchers who have been exposed and it and developed it pretty quickly. Canabalism isn't the only way, such as with wild deer.
"unless someone eats our brain and they produce more prions and someone east their brain and after a few rounds of cannibalism the concentration of prions is high and cause problems."
That's not really how it works. The prions will continue to replicate without the need for multiple rounds of cannibalism. There is no known safe limit of prions.
There have been researchers who have been exposed and it and developed it pretty quickly. Canabalism isn't the only way, such as with wild deer.
"unless someone eats our brain and they produce more prions and someone east their brain and after a few rounds of cannibalism the concentration of prions is high and cause problems."
That's not really how it works. The prions will continue to replicate without the need for multiple rounds of cannibalism. There is no known safe limit of prions.