Kuru:(yeah I know it's wiki) is a very rare, incurable and fatal neurodegenerative disorder that was formerly common among the Fore people of Papua New Guinea. Kuru is a form of transmissible spongiform encephalopathy caused by the transmission of abnormally folded proteins, which leads to symptoms such as tremors and loss of coordination from neurodegeneration. The term kuru derives from the Fore word kuria or guria, due to the body tremors that are a classic symptom of the disease. Kúru itself means "trembling". It is also known as the "laughing sickness" due to the pathologic bursts of laughter which are a symptom of the disease. It is now widely accepted that kuru was transmitted among members of the Fore tribe of Papua New Guinea via funerary cannibalism. Deceased family members were traditionally cooked and eaten, which was thought to help free the spirit of the dead.Wikipedia

"Laughing sickness..." Suddenly those odd bursts of laughter make sense