Credit: AP

Daniel Carleton Gajdusek, who won the 1976 Nobel Prize in Physiology or Medicine for his discovery of transmissible dementias, died on 12 December 2008 in a hotel in Tromsø, Norway. This isolated spot above the Arctic Circle was the winter refuge for American-born Gajdusek during the last 10 years of his life. He spent his summers mainly in Amsterdam. This migratory pattern, and his choice to spend winter in one of the darkest places on Earth, typified the eccentricity of the man.

Gajdusek was born in 1923 in Yonkers, New York, where his father had a butcher's shop. As an eight year old, he already seemed to know his destiny. He told me once that he inscribed the names of all the scientists in Paul de Kruif's book Microbe Hunters — which included giants such as Robert Koch and Louis Pasteur — on the staircase to his attic chemistry lab, leaving the last step blank for himself.

Gajdusek's mind was continuously attracted to the mysterious and exceptional, his rationale being that, to contribute to knowledge, you must find unexplained phenomena and observe them first-hand. From the early 1950s onwards, having trained as a research virologist, he recorded his scientific endeavours on film so that he could share his experiences as directly as possible with everybody.

In 1954, Gajdusek shot a documentary entitled Rabies in Man, which followed experiments at the Pasteur Institute of Iran in Tehran. The institute's director, Marcel Baltazard, had recently shown that almost a third of people who had suffered a rabid-dog bite to the head could not be saved by rabies vaccine. Baltazard considered this result disastrous. Gajdusek suggested that he should test anti-rabies antibodies (prepared from rabbit serum by Herald Cox in New York) in combination with the vaccine.

Baltazard agreed to this, and in August 1954 he began using the combination therapy in 18 patients who had sustained head wounds from rabid wolves. Gajdusek's documentary meticulously followed their progress during treatment. The study showed convincingly that addition of rabies antibodies to the vaccine can completely protect people from disease or death after exposure to rabies virus. This regimen has been the gold standard of care for the disease ever since.

Gajdusek's views on microbiology were shaped by the training in physical chemistry that he received from Linus Pauling, and by schooling in cell biology and virology from John Enders — both Nobel laureates. From 1955 to 1957, he also worked in Melbourne, Australia, with Frank Macfarlane Burnet, who received a Nobel prize in 1960 for his work on the recognition of 'self' by the immune system. His experiences in this vibrant field taught him to expect the unexpected, and prepared him for his greatest discovery.

In 1957, Gajdusek travelled to New Guinea upon hearing that Vincent Zigas, a district medical officer, had stumbled across a mysterious illness — kuru — in the Fore tribe of the Highlands. This turned out to be a neurological disease affecting women and children. It progressed swiftly from an initially unsteady gait to tremors and speech disorders, leading within months to complete incapacitation, and invariably to death. Gajdusek suspected from the beginning that the disease was caused by a form of ritual cannibalism in which only women and children participated.

In 1961, Gajdusek convinced Clarence Joseph Gibbs Jr, a specialist in insect-borne viruses, to lead a series of experiments designed to establish the concept of 'transmissible spongiform encephalopathies' (TSEs). Besides kuru, TSEs include neurodegenerative illnesses such as Creutzfeldt–Jakob disease (CJD) and 'mad cow' disease. Gajdusek and Gibbs reported the successful transmission of kuru to chimpanzees in 1966, of CJD to chimpanzees in 1968, and of scrapie (the sheep variant of TSE) to monkeys in 1972. In later years, CJD was categorized with Alzheimer's disease as an amyloidosis (diseases characterized by the deposition of insoluble proteins), but Gajdusek and co-workers showed in 1980 that Alzheimer's disease, unlike CJD, was not transmissible.

Gajdusek's work revealed the existence of a new kind of infectious agent, one that did not need a nucleic acid to replicate. Now called prions, these agents are misfolded proteins that can induce misfolding in other proteins. The initiation of misfolding falls in the twilight zone between normal and abnormal protein production, and is still not understood. The conspicuously unconventional Gajdusek had thus found a suitably eccentric infectious agent. The discovery won him a Nobel prize, and earned him the right to add his name to the staircase of the world's great microbe hunters.

Eccentricity was the source of Gajdusek's genius as a scientist, and of his notoriety late in life. In 1997, he was imprisoned on a child molestation charge involving one of the more than 50 Micronesian and Melanesian children he had adopted and brought to the United States. On his release in 1998 he moved to Europe, which he regarded as less puritanical than his home country.

Throughout his life, Gajdusek was a fervent reader of the world's literature and a prolific writer. He believed in a life of learning and in accurate documentation and reflection. An example of his acuity was his letter writing. When you wrote to him, you got your own letter back with an answer to each sentence scribbled between the lines.

Around two months before his death, I had dinner with him at the Academic Club of the University of Amsterdam, about a minute's walk from his university lodgings. It took us at least 20 minutes to get there, stopping every minute to rest because of his failing heart. This cumbersome trip did not stop him from talking all the way about his most recent interest: the physical evidence in the brain revealing a person's reading ability and the development of that skill. He kept yelling at me, while gasping for air, that before the age of six a child could achieve native fluency in at least six, if not ten, languages, if properly exposed. He must have had his own youth in mind: Gajdusek could read at least ten languages.

Gajdusek will be remembered for both his scientific contributions and his overwhelming presence. As Richard Rhodes observed in his book on TSEs, Deadly Feasts, Gajdusek was “A compulsive talker who spills ideas nonstop for hours — good talk, often brilliant talk and consummate story-telling, but more than some listeners can bear”.