Virus identified - nurse ill
12/10/2008 21:50 - (SA)
Johannesburg - The mystery viral haemorrhagic fever which killed three people in South Africa has been provisionally identified as an arenavirus, the National Institute for Communicable Diseases and the Department of Health said on Sunday.
"The causative agent of the disease... may be a rodent-borne arenavirus related to the Lassa fever virus of West Africa," NICD's Dr Lucille Blumberg told reporters at the Charlotte Maxeke Johannesburg Academic Hospital.
She said tests done by the NICD and the Centres for Disease Control in Atlanta, US, indicated that the disease seemed to be a kind of an arenavirus.
The World Health Organisation has also been providing technical assistance in identifying the virus.
Arenaviruses cause chronic infections in multimammate mice - a kind of wild mouse - who excrete the virus in their urine which can then contaminate human food or house dust.
Viruses similar to the Lassa fever virus have been found in rodents in Africa, but other than in West Africa have not been found to cause diseases in humans.
More tests needed
She said there was no indication that arenaviruses which could cause disease in humans were present in South African rodents.
Blumberg said further tests still needed to be done.
"It needs to be determined whether it is a previously unrecognised member of the arenaviruses and what its distribution is," she said.
The NICD's Robert Swanepoel said there were viruses of this family in southern Africa, but that this could be an undiscovered kind.
"Not every country has been thoroughly searched," he said.
He said the kind of rodents that carried the virus were not generally found in urban areas.
"They are out there, but are attracted [to human dwellings] if there is inadequate waste disposal."
Crops and animal feed also sometimes attracted them, he said.
He said the effects of the various viruses could range from causing mild fevers to being lethal.
There were only three cases to go on for the kind of arenavirus now discovered, but "it looks like it is very lethal", he said.
Head of the NICD's Special Pathogens Unit, Dr Janusz T Paweska, said the arenavirus diagnosis came about after a number of tests.
Biopsies conducted on the last two victims where infected tissues, skin, liver and muscles were tested were critically important in being able to make a diagnosis.
A blood sample obtained in Zambia from the first victim also confirmed test results.
He said doctors were now waiting for the virus to grow in cell culture to conduct further tests to identify what strain it was.
Lived on smallholding
Gauteng Health MEC Brian Hlongwa said the first victim of the virus was 36-year-old Cecilia van Deventer, who was airlifted from Zambia to the Morningside Medi-Clinic in Sandton on September 12 in a critical condition.
She is known to have lived on a smallholding on the outskirts of Lusaka where she kept three horses and other animals, although the exact point of contamination has never been discovered.
She fell ill on September 8 and was treated in three different hospitals in Lusaka. Once in South Africa she was treated for tick-bite fever and other potential infections, but died two days later.
She was not tested for viral haemorrhagic fever.
On September 27 a Zambian paramedic who had accompanied her to South Africa was admitted to the hospital with similar flu-like symptoms, fever and a skin rash. In his case, viral haemorrhagic fever was queried.
He developed diarrhoea, severe headaches, nausea and vomiting and although he initially seemed to respond to treatment, died on October 2 at the clinic.
A third victim of the virus was a nurse from Morningside Medi-Clinic who had attended to Van Deventer.
She became ill with fever 18 days after Van Deventer was admitted to the hospital and consulted a general practitioner, receiving intravenous therapy.
She was then referred to Robinson Hospital in Randfontein and later transferred due to a bedding shortage to Sir Albert Clinic. Here she was treated for a suspected case of meningitis.
Her condition deteriorated and she died last Sunday.
A fourth person, a contract cleaner working at Morningside Medi-Clinic, Maria Mokubung, 37, died in Charlotte Maxeke.
Two people in isolation
Earlier this week the Health Department said her death was not related to viral haemorrhagic fever.
On Sunday, Blumberg said a female nurse and a male paramedic were currently in isolation after they had had contact with the deceased.
The paramedic had contact with Van Deventer and after developing flu-like symptoms and a fever was admitted to Flora Clinic. He was subsequently transferred to Morningside Medi-Clinic and diagnosed with kidney stones.
On Sunday Blumberg said it was "less likely" he had the virus.
The second person in isolation is a nurse who had contact with the paramedic that died. She has developed symptoms similar to the three deceased and is receiving anti-viral medication called ribavirin.
Nurse's condition 'highly suspect'
The Department of Health said she was presently stable.
Asked whether she could have contracted the virus, Blumberg said her condition was "highly suspect".
She said she could not say how her condition was likely to progress.
This week three other people who had been hospitalised after contact with the deceased were discharged.
On Friday morning the 11-year-old son of the nursing sister who had died and his 23-year-old nanny were discharged.
A cleaning supervisor at Morningside Medi-Clinic who had been admitted to the Chris Hani Baragwanath Hospital on Monday with symptoms of viral haemorrhagic fever was also released.
151 people still being tracked
On Sunday, Hlongwa said the cleaning supervisor was currently "well".
All three continued to be monitored as part of the disease surveillance system currently tracking 151 people who had had contact with the deceased.
Blumberg said arenaviruses could cause a disease that spreads from human to human through contact fluid.
In hospital settings, special precautions were needed when nursing patients.
People in contact with those who had contracted the virus must be monitored for 21 days following their last contact with the patient.
Their body temperature was monitored and those who developed fever or illness were admitted to an isolation ward in the hospital.
Blumberg said there was a drug which showed promising results in treating patients if their illness was recognised early.
Those who have been in contact with patients but are well, do not spread infection.
On Sunday, Hlongwa said the diagnosis of the virus was a step forward.
"We are now a step further because we know specifically what we are dealing with."
However, it was still vital to conduct more tests to find out what kind of arenavirus it was, he said.
Health Department director-general Thami Mseleku cautioned South Africans not to now fear that every mouse that came their way contained the virus.
Since the virus first broke out, medical officials have been at pains to emphasise that the general public was not at risk as only people who had been in direct contact with the bodily fluids of a person who had a confirmed case of the virus could be infected.