Kuru aka Mad Cow Disease aka Jacob Krutchfelds Disease is all the same.
It comes not from bone marrow, but the nerve tissue of infected creatures. Most associate it with the brain, which is the biggest nerve of course, but other nerves also are infected and their injestion causes the disease.
On a note, a person can have it but it is dormant like any other disease, and well if they end up on the platter the people who eat the infected tissues have a chance of getting it, but it developing well that is part of the question how it affects some and not others.
They also have the theory that if the meat is cooked to a specific temperature then the disease is killed, much like cooking pork or chicken.
So, if you ever find yourself in New Guinea or the South Seas and are the guest of honor....not that guest of honor
Make sure you ask for your WELL DONE!