Kuru - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Kuru is an incurable neurodegenerative disease (a type of disorder in which the cells of the nervous system do not function or get damaged permanently) in nature. This disease was first discovered by Dr. D. Carlton. It was considered to be one of the most significant discoveries of the 20th century in the field of medicine. It occurred during the period 1950 to 1960 among the Fore tribal people of New Guinea. The disease got its name “kuru” from the word “Kuria” or “Guria” (the local language of the Fore people of New Guinea). The meaning of the word “kuru” is to shake or tremble. The changes observed in the brain and nervous system of the people affected with kuru are similar to Creutzfeldt-Jakob disease (a disorder of the brain which causes memory loss and leads to death).

What Is Kuru?

Kuru is a dangerous disorder of the brain that is caused as a result of an infectious protein called prion found in the human brain tissues. It affects the cerebellum (the part which is in charge of coordination and balance) of the brain. It is even known by the name laughing sickness, as the patient experiences uncontrollable episodes of laughing. This was discovered in tribal people of the New Guinea region who practiced cannibalism (the ritual of one human being eating the flesh of another human). This disease was transmitted as the tribal people of that region ate the brains of dead people as a funeral ritual. It is a commonly contractible disease and can spread through contact with open wounds of an infected person. Similar diseases are seen in cows as bovine spongiform encephalopathy (incurable deadly disease of the nervous system seen in cattle) and scrapie (deadly disease affecting the nervous system of goats and sheep) in goats.

What Are the Causes of Kuru?

It was found in tribal people of New Guinea, who acquired it by eating the brains of dead people, which was considered to be a part of their funeral ritual. The Fore (tribal) people ate the body parts of their relatives after death. According to them, this custom was practiced to incorporate the body of the dead person into the body of the living relatives. By doing so, the tribal people believed that it would help to free the spirit of the dead person. In this ritual, women and children consume the brain, whereas men eat the muscles. Since the brain was the organ that contained the infectious protein, women and children were more affected by this disorder than men. The infective protein called a prion is responsible for causing this disease. Prions are not living organisms. They are proteins that multiply inside the brain and form clumps disturbing the normal processes of the brain.

What Are the Symptoms of Kuru?

• Loss of coordination (potential of an individual to use all the body parts to function efficiently).

• Difficulty walking.

• Trouble in holding things.

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• Shivering, which becomes uncontrollable.

• Sudden episodes of laughing or crying.

• The patient experiences difficulty swallowing.

• Severe pain in the arms and legs.

• Dementia (a condition in which a person’s memory and ability to think are affected, which in turn creates problems in day-to-day activities).

• Sudden mood changes.

• Limbs (arms and legs) become stiff.

• Difficulty in feeding oneself leads to malnutrition and starvation.

• Confused and unclear speech.

What Are the Stages of Kuru?

This disease has three stages:

• First Stage (Ambulant): In this stage, the person experiences a loss of control of his body movements. The patient feels difficulty in standing and sitting.

• Second Stage (Sedentary): In this stage, the person is almost unable to walk. Severe involuntary (action done without one’s own will) jerks occur throughout the body.

• Third Stage (Terminal): The patient becomes completely bedridden. Most people lose their ability to speak. They show signs of memory loss, and their thinking ability gets affected. The difficulty in swallowing leads to poor eating habits. As a result, malnutrition develops. In the later stages, people may get infected with pneumonia and can go into a coma. In most cases, people die within one or two years.

How to Diagnose Kuru?

This test cannot be diagnosed by any particular test. However, certain examinations can help in finding out this disease. They are:

• The doctor takes a detailed medical history of the patient to know about the symptoms.

• Blood tests check the levels of thyroid hormone and folic acid levels.

• Kidney function and liver tests (to eliminate the chance of other diseases which show the same symptoms).

• Electroencephalogram (EEG): This is done to check the electrical activity inside the brain.

• Magnetic Resonance Imaging (MRI): This can be done to check for any abnormalities in the brain. However, MRI does not provide any help in the definitive diagnosis of the disease.

What Are the Treatment Options for Kuru?

There are no known successful treatment options for kuru. The treatment focuses on relieving the symptoms. As it is a disease that was caused due to the consumption of the brains of dead people as a funeral ritual, the only way to prevent this disease was to stop this practice. Since this deadly disease started taking away the lives of people, the government and authorities took strict measures to stop the practice of cannibalism. The incubation period (the time span between the first infection and the appearance of symptoms) of this disease is between ten to fifty years. Due to this reason, cases have been reported even after cannibalism was stopped. However, according to the national institute of neurological disorders and stroke (NINDS), this disease has been wiped out completely.

Conclusion:

Although it is a deadly disease, it vanished as soon as the practice of cannibalism was put to an end. The discovery of kuru led Dr. D. Carlton Gajdusek (the person who first discovered this disease) to share the Nobel prize in medicine for “discoveries concerning new mechanisms for the origin and dissemination of infectious diseases.” The discovery of this disorder opened many new pathways in the field of human medicine and played an important role in finding out the ways of transmission of similar diseases from animals to human beings.