Queensland Chief Medical Officer Jeannette Young said the woman's fever had passed, but the 18-year-old would be tested a second time for the virus as per protocol.

The woman arrived in Australia from Guinea 12 days ago with her family under the humanitarian program and went straight into home quarantine with the group.

She developed a temperature on day 11 of that quarantine.

Dr Young said health authorities could not explain her fever.

"No idea at all, she has no other symptoms, but she has had a number of other tests done of course to look and see whether there is any other cause, but she is now afebrile [without fever], she has now got no fever, which is a really good sign," she said on Monday.

She will remain in hospital for the next few days and will be tested a second time on Wednesday.

Another three families, as well as the 18-year-old's family, remain under home quarantine. Nineteen people in total are being monitored.

"I am sure they are nervous, as is everyone," Dr Young said.

"But there is no need to be nervous, because we do know what we are doing and we do have the situation well managed."

Fever

The woman had had no known contact with people who were infected with the virus, according to Dr Young.

She came down with a fever in Brisbane mid-way through a voluntary 21-day home quarantine requested by Queensland Health after being contacted three days before she flew to Australia.

The woman, who is not a health care worker, had come to Brisbane with her family after flying in from Conakry, the capital city in Guinea.

"She didn't have any known contact with anyone who was sick with Ebola virus disease," Dr Young said on Sunday.

"But she did come from an area that had a reasonably large number of cases."

Family arrived under humanitarian program

Dr Young said the woman was moving to Australia with her family as part of the federal government's humanitarian refugee program.

The group included six children and three adults, including the 18-year-old woman.

"She is one of nine family members - in an extended family - and they all went into home quarantine when they arrived," Dr Young said.

Queensland Health had been advised the family was travelling to Brisbane three days before they flew from Conakry.

"So we had processes in place to meet them at the airport and to organise for them to go into home quarantine at that time," Dr Young said.

The woman developed the fever on Saturday night and was transferred by ambulance to the Royal Brisbane and Women's Hospital on Sunday after a health officer made a daily phone call to the family.

Dr Young said the ambulance officers who assisted the woman had worn full protective clothing.

She said no-one else in the family was unwell.

"They're all perfectly well and no-one else in that family has a fever," she said.

Family closely monitored

She said the remaining family members were being closely monitored, however they were not expected to be at risk as Ebola is thought to be contagious only when symptoms are evident.

Dr Young said the women's fever had abated, however that did not mean she was in the clear and testing would take place over the next three days to determine whether she had the Ebola virus.

She said the family's actions in minimising the potential for spreading the virus had been "highly responsible", ensuring that the risk of the disease spreading was low even if the woman tested positive for the Ebola virus.

Dr Young said there was no need to alert other passengers who were on the flight from Guinea to Brisbane.

"You need to have symptoms and be excreting the virus, in vomit, in faeces, in sweat or urine. And she doesn't have any symptoms, so she hasn't been excreting the virus," she said.

"So the other people in the house are quite safe. They have a risk of course.

"But they are also in home quarantine because of their risk from when they were in West Africa.

"But the risk from her is minimal and there is no risk to the community because she has not left the house or had any visitors in the time that she had been here."

She said the family had been in home isolation since arriving in Brisbane.

"There is no risk to the community at all because they haven't left the house .... in the time that they have been here," Dr Young said.

"I'm very confident that there is no risk to any member of the Queensland community."

Dr Young said the "risk of getting the Ebola virus disease in Australia is extraordinarily low".

"You do need direct contact with the secretions of someone who is sick [to catch the Ebola virus[," she said.

Case comes after nurse's quarantine period recently ended

Earlier this month, an Australian nurse who had been treating Ebola patients was isolated with a fever in Cairns.

Australian Red Cross aid worker Sue Ellen Kovack was admitted to a Cairns hospital after coming down with a low-grade fever soon after returning from treating victims in Sierra Leone.

The 57-year-old twice tested negative for the virus before she was released from hospital on October 13 to complete the 21-day incubation period for Ebola at home.

There are now four families in Queensland in home quarantine, Dr Young said.

The protocols

All travellers from countries where Ebola has been prevalent are assessed at both ends of their journey.

Australian immigration and customs officials notify Queensland Health authorities "if they believe the person is at any risk of having the infection or if they are unwell".

"So if they have any symptoms at all, we get notified and then the plan is the person is transported to the relevant hospital via ambulance," Dr Young said on Monday,

"So for the Gold Coast airport, that is the Gold Coast University Hospital, here in the Brisbane Airport, it is the Royal Brisbane and Women's Hospital, and in Cairns, it is the Cairns Hospital.

"So if they are unwell, or there is any suggestion they have been unwell, then they are transported to one of those three hospitals.

"If after talking to the person they think they have come into contact with someone who might have had Ebola, or if they have any concern at all, then they ring the human quarantine officer, who is a Queensland Health employee and talk through over the phone with them and then a decision will be made on whether they should be transported."

Queensland Health refines response

Dr Young said Queensland Health had changed its protocols slightly since an Australian aid worker recently returned from West Africa presented with a fever at the Cairns Hospital, earlier this month.

"We did make the decision that, if at all possible, we would prefer to move people immediately to their final point of care," she said.

"For instance, we'd like to move people to Brisbane, to the Royal Brisbane and Women's Hospital which is the designated hospital and that led to the change in protocol that any returning health care workers will home quarantine in Brisbane and indeed, these four families, a decision was made that they would all home quarantine in Brisbane, they wouldn't go elsewhere in the state.

"So that decision was made. And the same thing, we had a discussion yesterday with the Royal Brisbane and Women's Hospital when we were talking, would the lady be taken straight to the emergency department and then moved, or would she go elsewhere and the decision was made that she would immediately go to the infectious diseases ward rather than go through the emergency department.

"So that was a change in our protocol that we think makes sense and makes it easier to manage."

- Amy Remeikis, Tony Moore, and Ron Goodman