Health authorities have confirmed that a viral haemorrhagic fever was the main reason behind the death of three people in Johannesburg. A fourth person did not die of the fever.

The type of virus and where it came from are still a mystery. This came out during a media briefing at the Morningside Medi-Clinic in Johannesburg this afternoon. Professor Guy Richards, from Wits University, says knowing the disease is a viral haemorrhagic fever, is a step forward in containing the disease.

Viral haemorrhagic fevers are a group of diseases that very often present with very similar manifestations -- most often it's related to an attack by the virus on the lining of the blood vessels.