The condition of a nursing sister being treated for viral haemorrhagic fever in the Morningside Medi-Clinic has become serious as the disease progresses, Medi-Clinic's Northern Region marketing manager Melinda Pelser said on Friday.

"Antiviral treatment continues."

A tour operator from Zambia, a paramedic who accompanied her to South Africa for treatment, and a health worker who came into contact with her, have died since 14 September.

Six people, including the two people who were discharged earlier this week, had been admitted and discharged under the clinic's monitoring protocol.

"Monitoring continues of everyone on our contact list of 94 people who had close contact with any of the people who developed the disease.

"This monitoring is carried out at home or at work, and the results are telephoned in to Morningside Medi-Clinic.

"Anyone who shows a change in temperature is brought into the hospital for increased temperature monitoring as part of this conservative monitoring protocol," Pelser said.

Sapa