Scientists find new strain of HIV

The new strain is thought to have been transmitted from Cameroonian gorillas

A new strain of the HIV virus has been discovered in a 62-year-old woman from Cameroon, West Africa.

Only three strains of the virus that causes Aids were previously known, all from chimpanzees.

But the new form of HIV, discovered by researchers from the University of Rouen in France, appears to be closer to a strain found in wild gorillas.

The team think it came from gorilla-to-human transmission - but the patient said she had no contact with apes.

The woman had moved from Paris to near the Cameroonian capital of Yaounde, but insists she never ate wild bush-meat or encountered simians.

Despite remaining untreated she currently shows no signs of developing full-blown Aids.

Jean-Christophe Plantier, who led the scientists, said the finding "highlights the continuing need to watch closely for the emergence for new HIV variants, particularly in western-central Africa".

Could be spreading

The first HIV virus is thought to have originated in the region before crossing to humans, possibly by infected blood splashing into the wound of a hunter.

It is not known how widespread the new strain may already be - but researchers said it could already be spreading in Cameroon or elsewhere in the world.

The virus replicates itself rapidly in the human body, indicating that it is already adapted to human cells.

Although the most likely reason for the new strain's emergence is gorilla-to-human transmission, Mr Plantier's team could not rule out the possibility that it started in chimpanzees before moving to gorillas.