The Laughing Death: A Rare Brain Disease

Laughing to death? Is that possible? As mind-boggling as the concept of laughing to death seems, the question holds some truth. “Laughing Death” is the nickname for a fatal neurodegenerative disease called Kuru. While the circumstances leading to the disease rarely apply today, the impact and spread of laughing death is a fascinating topic. Learn more about the human brain here.

The Laughing Death: A Rare Brain Disease
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Prion Diseases

Prion proteins are a normal finding on the surface of cells. They are involved in several biological processes such as cell signaling, protection against stress, and maintaining neuronal homeostasis. When a prion triggers normal proteins to fold abnormally, a transmissible spongiform encephalopathy or prion disease develops. These infectious agents differ from bacteria yet rapidly accumulate in the brain, hindering proper nervous system function.

What is Laughing Death?

Kuru, also nicknamed “laughing death,” is a transmissible prion disease. It earned its nickname because it causes fits of maniacal laughter and tremors. This rare, fatal disease is harbored in infected human brain tissue. The incubation period of laughing death is long. The disease remains dormant up to ten years after exposure before symptom onset. Transmission occurs through contact with infected brain tissue or open sores.

The History of Laughing Death

The laughing death originated in Papua, New Guinea in the 20th century.Zigasom, anAustralian doctor, discovered Kuru once it eradicated the entire Forbe tribe consisting of about 11,000 people. Experts suspect it spread rampant across the Forbe tribe because of the ritual ofcannibalism. Upon death, tribe membersbelieved they could inherit the wisdom and intellect of the personwho died if they consumed the brain as a funeral ritual. Women and children had a higher risk of contracting Kuru because they engaged in thecannibalisticrituals more frequently than men.

Symptoms of the Laughing Death     

While fits of uncontrollable laughter and tremors are the primary symptoms of laughing death, the disease affects all of the nervous system, which regulates numerous bodily functions.

Symptoms include:

  • Fits of laughter
  • Tremors
  • Fever
  • Dysphagia
  • Loss of coordination
  • Muscle twitching
  • Muscle weakness
  • Headache
  • Dementia
  • Fatigue
  • Cough
  • Runny nose
  • Lack of appetite
  • Abnormal gait
  • Joint pain
  • Mood and behavioral changes

The Stages of Laughing Death 

There are three stages of laughing death. The stages are categorized by the severity of symptoms which progressively worsen until death.

Preclinical or Asymptomatic Stage

The preclinical stage of Kuru is the asymptomatic stage. This is the incubation period. Although the person has been exposed to the laughing death, they do not present with symptoms. Signs of the disease may initiate five to fifty years following exposure. Ten to thirteen years is the most common.

Prodromal Period

The prodromal period follows the preclinical stage. It is a time span of several months in which individuals develop vague symptoms as a warning of impending disease. Research suggests common symptoms in the prodromal period are headaches and joint pain (Liberski, 2019). The joint pain is primarily in the legs, beginning with the knees and ankles. The pain eventually spreads to the elbows and wrists. Weight loss and abdominal pain are frequent complaints.

Clinical Stage One: Ambulant Stage

The clinical stage begins once someone with Kuru experiences symptoms. It is further divided into three distinct clinical stages. During the ambulant stage, the patient is still ambulant and able to move around. The ambulant stage is characterized by decrease muscle control. Walking becomes difficult, but not impossible, due to tremors, poor coordination, and an unsteady gait. The laughing death interferes with word pronunciation too, as individuals suffer fromdysarthria and lose control of the muscles needed for proper speech.

Clinical Stage Two: Sedentary Stage

The second clinical stage is the sedentary stage. Infected individuals can no longer walk without assistance. Studies show reflexes remain unaffected in the sedentary stage; however, ataxia and tremors impede movement. Fits of laughter arise. Patients often exhibit moodiness and depression with emotional and behavioral instability.

Clinical Stage Three: Terminal Stage

The terminal stage inevitably leads to death. Kuru is fatal three months to two years after the onset of the terminal stage. The progression of ataxia and tremors prevents the patient from even sitting up without support. While someone with Kuru is conscious and awake, they demonstrate no response to environmental stimuli. They cannot speak and areincontinent. Difficulty swallowing (i.e. dysphagia) results in malnutrition. Cause of death is typically from infected wounds, as ulcerated skin sores covering the body are prone to secondary infections.

Diagnosing the Laughing Death

Because of its rarity, the laughing death is not simple to diagnose. Medical professionals rely on a series of tests to rule out other diagnoses with similar symptoms. If kuru is suspected, physicians require a full medical history, a neurological exam, and blood tests to test for liver dysfunction and nutritional deficiencies.

The Laughing Death: A Rare Brain Disease
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An electroencephalogram (EEG) can measure brain activity consistent with various neurological diseases. Brain scans are occasionally helpful to identify the swiss cheese-like appearance of the brain in proton diseases. The only way to confirm Kuru is to perform a brain biopsy after the patient has died. Luckily, the disease is uncommon in today’s times when few participate incannibalism.

Treatment and Prognosis of Laughing Death

The prognosis for laughing death is poor. Outcomes always end in death. There is no known cure or effective treatment. Prevention is imperative. To prevent Kuru, people are encouraged not to consume infected brain tissue or partake incannibalism like the Forbe tribe inNew Guinea, as well as to avoid contact with the open wounds of those who are infected. Play free brain games here!


Liberski, P. P., Gajos, A., Sikorska, B., & Lindenbaum, S. (2019). Kuru, the First Human Prion Disease. Viruses11(3), 232.

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