What is Laughing Death

QUESTION: I don't know how you come up with all the information, but I think
this one may test you just a bit. It is a disease called "the laughing death"
and I became aware of it while serving in our Armed Forces. With just this as
a clue, what can you tell me about this condition?
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ANSWER: Obviously, if I couldn't come up with an answer, I just would not
include your question in the column. Honestly, it has taken a bit of looking
to find out the information about a disease called "kuru" which only occurs in
the Fore tribe of the Papua region in eastern New Guinea. The best guess as
to its cause is that it results from a viral infection by a "slow" or
retrovirus that causes wide spread changes in the brain, and may have an
incubation period as long as 30 years. Other theories that cited toxic or
nutritional factors as the cause seem improbable. It occurs most frequently
in children and adult women, who suffer involuntary trembling and jerking
(ataxia) of the leg muscles, incoordination then spreading to the arms,
slurred speech, incontinence, and finally they are incapable of making sounds
or swallowing. As a degenerative disease of the central nervous system, it
causes about 70% of the female deaths in this tribe, and may be due in part to
the ritual cannibalism practiced by the women and children. There is no known
cure, and the affliction has never been identified outside of this area,
although it can be transmitted to chimpanzees. The incidence of the disease
has declined with the cessation of cannibalistic rituals. The term "laughing
death" is not commonly used, and possibly refers to the state of dementia that
may occur shortly before death.