A Vienna hospital is searching for long-retired staff who might hold clues to a man's claim that he was deliberately infected with malaria when he was a psychiatric patient nearly half a century ago.

The case shed fresh light on an almost forgotten footnote in Viennese medical history - the use of malaria-induced fevers to treat some kinds of dementia, an approach once seen so promising that it won an Austrian neurologist a Nobel Prize in the 1920s.

Broadcaster ORF said Monday that "Wilhelm J.," aged 63, had come forward to complain that staff at the General Hospital in the city had injected him with malaria-infected blood in 1964, when he was 16 and had been diagnosed with "psychopathy."

He said he suspected he was not being treated but rather being punished for repeatedly running away from foster homes.

"I had fever up to 42 degrees" and for decades afterwards suffered outbreaks of fever and sweats, he told the radio.

Johannes Wancata, who now heads the hospital's psychiatric department, said records of the case had long been destroyed.

But he noted that inducing fever was once an accepted treatment for some forms of mental disorder before the advent of antibiotics, notably to cure syphilis, from the 1940s.

"We are trying to track down doctors and nurses who worked here in the 1960s - they all retired 10, 15 years ago or more - and ask them what they know about it," Wancata added. He would not speculate on whether other patients might also be affected.

"International scientific opinion was that that was absolutely an interesting approach 100 years ago, and there was even a Nobel Prize for this. But in the 1960s that was certainly no longer up to date," he said, expressing concern at the man's allegation that doctors may have had motives other than healing.

Julius Wagner-Jauregg of Vienna University won the Nobel Prize for Medicine in 1927 for, in the words of the awards committee, "malaria inoculation, which proved to be very successful in the case of dementia paralytica."

It was particularly used to treat the effects of advanced syphilis on the brain and the treatment lapsed as antibiotics were introduced to cure syphilis. However, other uses for malaria inoculation were also experimented with.

Brian Greenwood, a malaria expert at the London School of Hygiene and Tropical Medicine, said: "Malaria was also used more widely. Even fairly recently, in the last 20 years, it was used to treat certain autoimmune diseases in some countries.

"You've got a therapy that somebody has won the Nobel prize for, so you might well think it could work in something else."