Kuru, a transmissible spongiform encephalopathy, is a disease of the nervous system that causes physiological and neurological effects which ultimately lead to death.
In the first (ambulant) stage, the infected individual may exhibit unsteady stance and gait, decreased muscle control, tremors, difficulty pronouncing words (dysarthria), and titubation. This stage is named the ambulant because the individual is still able to walk around despite symptoms.[12]
In the second (sedentary) stage, the infected individual is incapable of walking without support and suffers ataxia and severe tremors. Furthermore, the individual shows signs of emotional instability and depression, yet exhibits uncontrolled and sporadic laughter. Despite the other neurological symptoms, tendon reflexes are still intact at this stage of the disease.[12]
In the third and final (terminal) stage, the infected individual's existing symptoms, like ataxia, progress to the point where they are no longer capable of sitting without support