A teenager who was in isolation in an Australian hospital has tested negative for Ebola after she developed a fever following arrival from Guinea, the authorities said Monday. The 18-year-old, who arrived in Australia 12 days ago with eight relatives, had been under home quarantine in Brisbane before she developed a raised temperature and was placed in isolation at the Royal Brisbane and Women's Hospital on Sunday. Queensland Chief Health Officer Jeannette Young announced the negative results and told reporters "she now has no fever, which is a really good sign". "She of course was very relieved to be given the information," Young said, adding that the teenage girl would remain in hospital and undergo a second test for the deadly virus on Wednesday. "She understands that a second test needs to be done. But given that her fever has resolved at this time, and she's got no other symptoms, she's feeling well." Young would not specify the teenager's nationality, but said she was moving to Australia permanently under a humanitarian visa programme with her family. There were three other families that had arrived in Queensland from Guinea, Liberia and Sierra Leone, where the vast majority of Ebola cases have occurred. All were in home quarantine and being monitored by health officials, Young added. "They've all come from sites in West Africa that have had, you know, significant numbers of transmission of Ebola virus disease," Young said. "So they're at an increased risk so that's why we've asked each of them to go into home quarantine." The girl, whose name was not released, was the 12th person tested for Ebola in Australia, Health Minister Peter Dutton said. "This would bring to 12 the number of people who have been tested -- all of whom have been negative -- and we have in place the systems you would expect in the developed world," Dutton told the Australian Broadcasting Corporation. The number of Ebola infections has surpassed 10,000 and the death toll neared 5,000 worldwide, mainly in the three West African nations. There have been no confirmed Ebola cases in Australia.