Where does that come from? A regular column that examines the history and origins of a particular medical topic.

New Guinea, the second largest island in the world after Greenland, is, of course, Australia's near neighbour, with which we have close ties. Despite their proximity the social and cultural background of each nation is quite different. It was these differences that made a mysterious chapter in modern medical history particularly baffling to Australian researchers.

It was only as recently as 1936 that the eastern highlands of New Guinea were first explored and Fore Indians first seen. They were of short stature, lived in mainly agricultural communities and feared sorcery and ghosts. Men slept in a central lodge and the women and children in smaller peripheral huts.

In 1949 Papua New Guinea became Trust Territories of Australia, with, among other things, the establishment of patrol posts in Fore Territory. In December 1953 a patrol officer, JR MacArthur, observed 'an unusual occurrence', as official jargon has it. A small girl sitting by the fire was shaking violently and jerking her head from side to side. He was told that she was a victim of sorcery and would die. The syndrome was locally called kuru, which meant shaking, a name also for the curse itself, which condemned its victims to a sure death.

To inflict the curse, it was said, a journeyman sorcerer cursed a piece of the victim's hair or clothing, then buried it. As it rotted the victim's health languished. A bemused MacArthur thought the bizarre effect psychological, though it had come close to wiping out some villages.

The victim was usually a woman and the onset of the condition insidious. The gait was affected first, followed by tremor and purposeless movements. Sufferers became mentally disturbed and usually withdrew into the bush. Kinsfolk tried to identify the magician through secret methods, and if the suspicion was strong enough he was waylaid and killed.

The victim then moved back to her hut. Weakness became profound, the voice gave out and eventually walking and even sitting upright became impossible. It took about two years to die a miserable death from a completely baffling disease.

Scientific explanation sought
In 1955 a government medical officer, Dr Vincent Zigas, discounted the sorcery theory and concluded a hitherto unidentified organic lesion was occurring in epidemic proportions. Specimens sent to the prestigious Walter and Eliza Hall Institute in Melbourne gave no clue as to the diagnosis.

An American doctor, Daniel Carleton Gajdusek, working under the great immunologist Sir Macfarlane Burnet at the Hall Institute, was prompted to try to unravel the mystery, with no official backing or resources, apart from encouragement from Burnet.

Gajdusek's early diagnosis of a meningo-encephalitis, an inflammation of the brain and its lining, returned negative tests. No toxic substance in common use could be implicated, nor could a dietary deficiency.

Gajdusek established that the current epidemic was fairly recent and within a circumscribed area where the Fore people had made contact with their neighbours. As no white person had ever contracted kuru, Gajdusek postulated that it was genetic in origin.

By now the malady had so depleted the female population that the men began to move away to find partners. The Australian administration reasoned that if kuru was genetically spread it could burgeon, so they placed the Fore Indians in quarantine.

In 1959 a letter from veterinary scientist William Hadlow appeared in the British medical journal Lancet. In it he drew attention to the similarity between Gajdusek's description of kuru and the sheep's brain disease scrapie. The symptoms were similar, but lab tests with kuru already carried out on animals had been found negative. But these tests had been sustained only for a few weeks. It was known that if the brain cells of a scrapie-infected sheep were injected into a healthy animal it took some years to develop the condition.

The puzzle solved
In the summer of 1962, Gajdusek succeeded in having more kuru specimens flown to America where they were injected into chimpanzees. By late 1965 the first chimpanzees fell ill, displaying all the stigmata of the disease.

It was now obvious the malady could not be genetic and further examination located a virus with an incredibly long incubation period, a so-called `slow' virus that affected the brain.

But why was it contracted only by the Fore, and why mainly by women?

Two anthropologists, Robert and Shirley Glasse, provided the last pieces in the diagnostic jigsaw. They found that the first case of kuru had occurred in the early twentieth century, coinciding with the onset of cannibalism among the Fore.

While cannibalism had been usual among other tribes in PNG, it was unknown to the Fore. While visiting the Kamano peoples in 1915 the Fore saw it for the first time and made it part of their own funeral ceremonials. The whole of a dead relative's body was consumed in a ritualistic manner, which clearly set out who got what. For instance, the mother's brother's wife had first claim to the brain.

Two last features emerged. Firstly, all bodies were consumed, infected or fit, and germs were rarely destroyed during preparation. Secondly, the men left the women and children the lions' share of the feast.

As the incubation period for the slow virus is between two and 20 years, the victims had contracted the disease before they ever had contact with white men. With the cessation of cannibalism, kuru has died out.

In 1976 Carleton Gajdusek was awarded the Nobel Prize for medicine for his research into the viral brain infection.

ACSM #38