Understanding Kuru : Causes, Symptoms, and Prevention of the Rare Nervous System Disease

Kuru is a fatal and rare disease of the nervous system, which occurred primarily during the 1950s and 1960s among a tribe known as the Fore people in the highlands of New Guinea ⁽¹⁾. These Fore people got this disease through the act of cannibalism on corpses of their relatives when performing the last funeral rites.⁽¹⁾

Kuru is a form of spongiform encephalopathy,⁽²⁾ which is a category of diseases characterized by degeneration of brain tissue and the healthy tissue gets replaced with clusters of cysts giving the brain of the patient an appearance of sponge.

The symptoms of this disease consist of loss of coordination, muscle twitching, involuntary movements, dementia, difficulty in walking, difficulty in eating, mood and behavioral changes.⁽¹⁾ Difficulty in eating causes malnutrition.

The meaning of kuru is “trembling or shivering.”⁽¹⁾

Kuru belongs to a group of diseases called prion diseases also known as transmissible spongiform encephalopathies (TSEs).⁽³⁾ The cerebellum is primarily affected in this disease which is a part of the brain which is responsible for balance and coordination.

Kuru is not caused by viruses, bacteria, or fungi. Prions are the abnormal and infectious proteins which cause kuru. Prions do not reproduce as they are not living organisms. They are misshapen, inanimate proteins, which can multiply in the brain resulting in clumps that interfere with the normal brain processes.

Some of the other degenerative diseases caused by prions are Gerstmann-Sträussler-Scheinker, Creutzfeldt-Jakob, disease and fatal familial insomnia. Kuru and these spongiform diseases create holes which look like sponge in the brain and this is life threatening.

There is no known cure for Kuru and this disease is often fatal within a year of contracting it.⁽⁴⁾

Symptoms of Kuru resemble some of the more well known neurological disorders, such as stroke or Parkinson’s disease and these are: poor coordination; difficulty walking; difficulty swallowing; dementia; slurred speech; muscle tremors and twitching; behavioral changes; moodiness; inability to hold objects and random, compulsive crying or laughing.⁽¹⁾

This disease is commonly preceded by joint pain and headaches. As these are common symptoms, they are often dismissed as signs that there is a more serious disease occurring in the body. There are three stages in which Kuru occurs:⁽⁴⁾

First Stage of Kuru: In this stage, there is some loss of bodily control and the patient has difficulty in maintaining posture and balancing.

Second Stage of Kuru: This is also known as the sedentary stage, as the patient is not able to walk. There are also significant involuntary jerks and movements along with body tremors.

Third Stage of Kuru: This last stage of the disease sees the patient being bedridden and incontinent. The patient also is unable to speak and can also exhibit signs of dementia or have behavior changes which make them look as if they do not care about their health. Malnutrition and starvation is seen in this third stage and this occurs due to the patient experiencing difficulty in eating and swallowing. All these secondary symptoms can cause death of the patient within a year. Many patients die from pneumonia in the end.

Kuru is contracted by consuming an infected brain or coming into contact with open sores or wounds of a person having it. Kuru was seen primarily in a tribe of people known as the Fore people of New Guinea where they consumed brains of dead relatives during funeral rituals.⁽⁶⁾ Children and women were mainly infected as they were the chief participants in these rites.

This practice of cannibalism has been discouraged by the New Guinea government. However, there are still cases seen due to the long incubation period of this disease, however it is rare.

The doctor performs a neurological exam on the patient, which also includes neurological function, medical history, blood tests (folic acid level, thyroid) and kidney and liver function tests are also done to exclude other causes of the symptoms.

Electro-diagnostic tests, such as electroencephalogram (EEG) are also done to assess the electrical activity in the brain of the patient. MRI scan can also be done; however, it cannot help with definitive diagnosis.

As of now, there is no known successful treatment for Kuru. The cause of this disease, which are Prions, is very difficult to destroy. Brains that have prions continue to remain infectious even when they are preserved in formaldehyde for many years. The treatment of kuru consists of supportive therapies, such as pain killers for managing pain and physical therapy to help with movements and mobility.

This is an exceptionally rare disease and can be contracted by eating infected brain tissue or when coming in touch with sores that have kuru prions. Government has discouraged this practice of cannibalism to prevent this disease.

According to NINDS, kuru has almost completely disappeared.⁽⁵⁾

The incubation period of Kuru can be quite lengthy as much as 30 years. There have been cases reported many years after this cannibalism practice has stopped.

Kuru is rarely diagnosed these days. Symptoms resembling those of Kuru can be a sign of another acute spongiform disease or neurological disorder.

The prognosis of this disease is poor with death being the end. Patients suffering from Kuru need assistance or help with moving, standing and slowly lose the ability to eat and swallow because of these symptoms.

Kuru has no cure and the patient can get into a coma about six to 12 months after experiencing the initial symptoms. This is a life threatening disease and can be prevented by avoiding exposure.

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Also Read:

• What is Kuru & How is it Treated? | Symptoms, Causes, Diagnosis and Prevention of Kuru