How Do You Get Kuru And Why Did It Disappear? The Reason

Kuru is a fatal brain disease that spread among the Fore people of Papua New Guinea through a specific practice: eating the brains and other tissues of people who had died. It belongs to a group of conditions called transmissible spongiform encephalopathies, or TSEs, caused not by a virus or bacteria but by misfolded proteins called prions. The disease largely disappeared after the Fore stopped mortuary feasting in the late 1950s and early 1960s, though a small number of cases appeared decades later because of the unusually long incubation period.

What Causes Kuru?

Kuru is caused by prions — infectious proteins that accumulate in the brain and destroy nerve tissue. A prion is a normal protein that has folded into an abnormal shape. When it enters the body, it can trigger healthy proteins to misfold the same way, setting off a chain reaction that kills brain cells and leaves the tissue full of tiny holes, giving it a sponge-like appearance.

Prions are not living organisms. They contain no genetic material. That makes them unlike viruses or bacteria, and it also makes them extraordinarily hard to destroy. Standard cooking does not eliminate them. Neither do many of the usual methods used to sterilize medical equipment.

In the case of kuru, the prions were transmitted when people consumed the tissues of deceased relatives as part of a mourning ritual. The brain and spinal cord carried the highest concentration of infectious material, but other organs could transmit it too.

How Did the Fore People Get Kuru?

The Fore practiced what researchers call mortuary feasting or ritual cannibalism. When a person died, family members prepared and consumed parts of the body as an act of respect and grief. The brain was typically eaten by women and children, while men often ate other parts.

This practice explains a striking pattern in who got sick. Kuru affected women and children far more often than adult men. That was not because women were more susceptible biologically — it was because they were more likely to eat the brain tissue where prion concentration was highest.

The first recorded cases appeared in the early 20th century, though the disease may have existed before that. It spread slowly through families and villages over generations. At its peak in the mid-1950s, kuru was killing more people in some Fore communities than any other cause. It was the leading cause of death among women in certain villages.

What Are the Symptoms of Kuru?

Kuru means “to shake” or “to tremble” in the Fore language, and that name captures its most visible feature. The disease attacks the brain and nervous system, and symptoms worsen over months until the person dies.

Early symptoms include:

• Tremors and shaking, especially in the arms and legs
• Difficulty walking and unsteady balance
• Problems with coordination
• Slurred speech
• Emotional instability and inappropriate laughter

As the disease progresses, people lose the ability to walk, speak, and swallow. They become unable to care for themselves. In the final stage, they are bedridden and typically die from complications such as pneumonia or starvation. The whole course usually lasts between 3 and 24 months from the first symptoms, though some cases have lasted longer.

Kuru is always fatal. There is no treatment and no cure.

Why Did Kuru Disappear?

Kuru disappeared because the practice that spread it stopped. In the late 1950s and early 1960s, Australian authorities and missionaries working in the region discouraged and eventually ended mortuary feasting among the Fore. Once people stopped consuming human tissue, new infections essentially stopped.

The decline was not immediate. Because prions incubate slowly, people who had been exposed years or even decades earlier continued to develop the disease long after the practice ended.

This is where kuru becomes scientifically remarkable. The incubation period for kuru can be extremely long — in some cases more than 50 years. Researchers documented cases in people who were exposed during childhood in the 1950s but did not develop symptoms until the 2000s. That is one of the longest incubation periods known for any infectious disease.

By the 1970s, new cases had dropped sharply. A handful of cases continued to appear into the 2000s, but the disease is now considered essentially gone. No new cases have been reported in recent years.

How Is Kuru Related to Other Prion Diseases?

Kuru is one of several diseases caused by prions. Others include Creutzfeldt-Jakob disease (CJD), variant CJD (linked to eating beef from cattle with bovine spongiform encephalopathy, or “mad cow disease”), and a few rare genetic conditions.

The study of kuru helped scientists understand prion diseases broadly. Research on the Fore and on kuru patients led to key discoveries about how prions work and how they can be transmitted. The scientist Carleton Gajdusek received a Nobel Prize in 1976 for his work showing that kuru was an infectious disease with a long incubation period. Stanley Prusiner later received a Nobel Prize in 1997 for discovering prions as a new class of infectious agent.

Kuru also raised important questions about cannibalism and disease. Some researchers have suggested that the Fore may have developed genetic resistance to prions over generations of exposure. Studies have identified a genetic variant that appears to offer protection against prion diseases, though this remains an active area of research.

Is Kuru Still a Risk Today?

No. Kuru is not a current public health risk. The practice that transmitted it no longer occurs, and no new cases have been reported in years. You cannot get kuru from casual contact with someone who has it, and it does not spread through air, water, or food in any normal sense.

The only theoretical risk would be if someone consumed infected human tissue. That is not a concern in any modern context. Prion diseases in general remain rare, and kuru specifically is a disease of the past.

However, prion diseases as a category are still studied because of their unique biology. They are not fully understood, and there is no treatment for any of them. Research continues into how prions spread and how they might be stopped.

What Does Kuru Teach Us About Disease?

Kuru is a case study in how disease can be shaped by cultural practice. The Fore did not get kuru because of genetics or environment. They got it because of a specific behavior that happened to transmit an infectious agent.

It is also a lesson in how long a disease can linger. Even after the practice stopped, kuru persisted for decades because of the slow incubation of prions. That is unusual. Most infectious diseases show symptoms within days or weeks. Prion diseases can take years or decades.

Finally, kuru shows how science can solve a mystery. Researchers did not initially know what caused it. Some thought it was genetic. Others thought it was a slow virus. It took years of careful work to identify prions as the cause. That work changed how we think about infectious disease.

How Do You Get Kuru And Why Did It Disappear?

You get kuru by consuming the brain or other nervous system tissue of a person who had the disease. The infectious agent is a prion — a misfolded protein that triggers a chain reaction in the brain. It is not a virus or bacteria, and it does not spread through normal contact.

Kuru disappeared because the Fore stopped mortuary feasting. Once the practice ended, new infections stopped. The disease lingered for decades because of its long incubation period, but it is now essentially gone.