Anine-year-old South African child with HIV has surprised experts by showing no symptoms of the virus having had just one year of treatment followed by eight and a half years with no drugs.

This has given hope to the 37 million people worldwide infected with the virus that causes AIDS.

However, the case is extremely rare and does not suggest a simple path to a cure, experts say.

HIV patients typically have to keep taking antiretroviral (ART) drugs permanently to stop the virus from developing into AIDS. However, this child has no signs of the disease. The child was part of a clinical trial in which researchers were investigating the effect of treating HIV-positive babies in the first few weeks of life, and then stopping and starting the ART medicines while checking whether their HIV was being controlled.

The case was revealed Monday at an AIDS conference in Paris.

"It's a case that raises more questions than it necessarily answers," said Linda-Gail Bekker, president of the International AIDS Society, which is holding the conference in Paris this week.

"It does raise the interesting notion that maybe treatment isn't for life," she said, adding that "it's clearly a rare phenomenon."

Researchers believe that intensive treatment soon after infection could enable long-term remission of the disease. 

Treatment with ART started when the child was almost nine weeks old but was interrupted at 40 weeks when the virus had been suppressed, and the child was monitored regularly for any signs of relapse.