The clinical presentation of Kuru includes the following:
- Early in the disease the infected person has headaches with pain in the joints of the arms and legs.
- Several weeks later this is followed by muscular twitching, tremors, and loss of muscle coordination (ataxia), which causes difficulty in walking. Typically the twitching and tremors disappear during sleep but seem to become worse if the infected individual becomes stressed or anxious. Eventually the twitching, tremors, and ataxia become so severe that an upright position is difficult to maintain without support.
- As the disease progresses, swallowing becomes difficult accompanied with slurred speech as well as urinary and fecal incontinence.
- Infected individuals also have the bizarre tendency of laughing and/or crying for no apparent reason.