A newly discovered form of HIV may have spread around the world, scientists fear.
And they warn that current treatments and experimental vaccines will prove ineffective against the latest strain of the deadly virus.
The new AIDS threat was first detected in blood samples taken from a patient in Cyprus who died in 1998.
But members of a medical team in Seoul, South Korea, say they have detected the same form in a 33-year-old woman with AIDS who died in 1997.
Seoul National University said the HIV samples collected from the blood of the woman had a totally different gene structure than the usual form of HIV.
But it was the same as the samples taken from the patient in Cyprus.
The South Korean scientists, along with U.S. researchers, will give details of their discovery at a conference in Chicago this week.