Mystery fever kills 3
The World Health Organization says the ailment appears to be a form of hemorrhagic fever.
It says tests have proved negative for Ebola, Lassa fever, Rift Valley fever, Marburg fever and other main types of hemorrhagic fever.
WHO spokesman Gregory Hartl says the first death on Sept. 13 was a tour guide who had fallen ill in Zambia before being evacuated to South Africa. Two further deaths on Sept. 30 and Oct. 4 involved a paramedic and a nurse who treated the woman.