The nature of the disease that has claimed the lives of at least three people in Johannesburg remained a mystery on Monday as health authorities sought to dispel public fears.

National health spokesperson Fidel Hadebe said the department was by late afternoon still awaiting blood culture results of samples taken from the deceased.

"(We) would like to call on South Africans not to panic... the department is monitoring the situation closely," he said.

"People with these symptoms who did not have contact with these cases do not need to be concerned. However, they may contact their doctor if they need reassurance."

Blood samples

Hadebe said blood samples of the three deceased were negative for any particular disease, including viral haemorrhagic fevers.

"The department is at this stage unable to link the death of the fourth patient (a general worker at the same clinic) to the initial three cases given the fact that she was admitted for an unrelated health condition and did not develop similar symptoms throughout her illness."

Further tests would be carried out to determine the cause of the worker's death.

The first death

The first casualty who succumbed to the unknown disease was a 36-year-old woman who was airlifted from Zambia to the Morningside Medi-Clinic in Sandton on 12 September.

She was treated for tick-bite fever and other potential infections but died two days later.

A Zambian paramedic who had accompanied her into the country died last week and a nurse at the Morningside Clinic and a cleaner died on Sunday.

Blood samples of three of the cases, excluding the cleaner, were negative for any particular disease.

The department was at this stage unable to link the death of the cleaner — who had worked in the ward — to the initial three cases.

"She was admitted for an unrelated health condition and did not develop similar symptoms throughout her illness," said Hadebe.

All health facilities were required to comply with universal infection control measures which include the washing of hands and the use of gloves, said Hadebe.

Contracted through bodily fluids

The illness could only be contracted through bodily fluids, therefore the department warned health workers to avoid direct contact with those suspected of having a communicable disease.

Hadebe said individuals who had been in close personal contact with the deceased were being monitored for flu-like symptoms and temperatures of above 38 degrees Celsius.

Isolation wards were ready and available in case there was a need.

The department said every hospital had isolation wards before and they were not just made available because of the outbreak of this unknown disease.

On Monday evening, Morningside Medi-Clinic said some members of the deceased nurse's family had been admitted to the hospital for purposes of observation and as an extra precaution.

Regional marketing manager Melinda Pelser said standard infection control precautions were being applied as a general rule to all patients admitted to the hospital.

A surveillance system was also in place to identify any "at risk" people.

"The hospital is not dealing with an outbreak, nor is it currently treating any patients with the unknown infectious disease that the Department of Health has reported on," said Pelser.

Have you travelled to Zambia recently?

She said anyone who had had contact with the deceased or had travelled to Zambia in the last month and was now experiencing high temperatures or flu-like symptoms should follow health department recommendations, and report either to Pretoria's Stephen Bantu Biko Academic hospital or the Charlotte Maxeke Johannesburg Academic hospital.

International intervention

Meanwhile, Zambian authorities and the World Health Organisation (WHO) said they had mounted investigations into the unknown disease.

Zambia's High Commissioner in Pretoria, Leslie Mbula, said reports from Zambia indicated that no other person in that country had contracted the "mysterious disease".

The Democratic Nursing Organisation of SA (Denosa) raised concerns about the outbreak, saying the department must address this "crisis" as a matter of urgency.

"(These deaths) underlines the extent of danger that is posed by the disease to both health workers and the general public," it said in a statement.

Further, the Congress of SA Trade Unions (Cosatu) expressed shock and said it was saddened by the "untimely" passing of two health professionals who treated the first victim.

"This unfortunate incident is an illustration of the life threatening risks to which health professionals such as doctors and nurses are exposed...," the federation said.

"While we are satisfied with Occupational Health and Safety mechanisms for all known highly contagious conditions the risk of exposure to new outbreaks cannot be understated."

Both Cosatu and Denosa conveyed their condolences to families of the victims.

Sapa