Three cases of the deadly coronavirus have been confirmed in New South Wales, bringing the total nationwide to four.
NSW Health confirmed three men - aged 43, 45 and 53 - are being treated in Westmead Hospital in Sydney and are in isolation.
Victorian Health Minister Jenny Mikakos said that a case of the respiratory condition had been confirmed in a man who last week returned from China, where the city of Wuhan is considered the epicentre of the virus.
The man was in Australia for six days before being diagnosed.
The news comes as the death toll from the virus rises to 41 in China, where more than 1200 cases have been reported. Millions are in lockdown in China, with roads and schools closed and public transport cancelled. Many Chinese New Year celebrations have been called off.
One doctor is believed among the dead there.
In Australia, NSW Health Minister Brad Hazzard said 18 people across the state have now been assessed for the virus after samples were sent to a "world-leading" laboratory in Victoria, with 12 patients being "excluded" and three being confirmed on Saturday.
"I'd like to thank each of these three people because they have been exemplary in the way that they presented themselves (to health services)," Hazzard told reporters tonight.
All three men arrived on flights from China - one on January 6, one on January 19 and the other is being checked by authorities.
The Victorian case was the first confirmed case in Australia of "about a dozen" being investigated nationwide, an estimate put forward by Queensland's Chief Health Officer Dr Jeannette Young on Saturday.
"It's an evolving number," she told reporters at a press conference on Saturday afternoon.
"We will be treating them as if they're confirmed cases, as a precaution.
"We still don't understand the transmissibility of this virus," Ms Young explained, noting that treatment is symptomatic.
"If you develop fever, coughs or shortness of breath, you should ring ahead to your GP, discuss it and your GP will refer you to the emergency department."
Queensland Health shared some good news in an update on Saturday night.
"Five people being assessed in Queensland for the Wuhan coronavirus have tested negative to the disease," the department said.
Dr Young said one more person was being tested but their results will be available on Sunday.
She said they were taking "all precautions possible" and had stepped up their response with the State Health Emergency Coordination Centre. Public hospital emergency departments across Queensland will be instructed to waive testing fees for foreign nationals suspected of carrying coronavirus.
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The man with a confirmed diagnosis in Victoria is a Chinese national aged in his 50s. He is in a stable condition at the Monash Medical Centre in Clayton, in Melbourne's southeast.
The man flew in from Guangzhou in China to Melbourne about 9am on January 19 on China Southern Airlines flight CZ321.
Ms Mikakos said there was no cause for alarm for the community, as the patient was isolated and there were no other suspected cases.
Victoria's acting chief health officer, Dr Angie Bone, said the man was being cared for in a negative pressure isolation room for a "type of pneumonia", which is expected with this kind of coronavirus.
"China has been very helpful in sharing the genome sequence with us so we have a very good test and we can be absolutely categorical about whether this is the situation or not, and that is the situation in this case."
The man had been staying with family and had not been out and about so the risk to the broader community was minimised, she added.
Australia's chief medical officer Professor Brendan Murphy said it was important for people arriving from Wuhan, and those in close contact with them, to monitor for symptoms including fever, cough, sore throat, vomiting and difficulty breathing.
Australia is the 11th country to have a confirmed case across the globe, authorities said.
China reports over 1280 virus cases
China's National Health Commission has reported the number of people infected with a new virus has risen to 1287 with 41 deaths.
The commission said the latest tally comes from 29 provinces across China, including 237 patients in serious condition.
All 41 deaths have been in China, including 39 in Hubei province, the epicenter of the outbreak, one in Hebei and one in Heilongjiang.
Meanwhile, France announced that three people had fallen ill with the virus — the disease's first appearance in Europe.
And the United States reported its second case, involving a Chicago woman in her 60s who was hospitalized in isolation after returning from China.
The outbreak cast a pall over Lunar New Year, the country's biggest, most festive holiday, which falls this week.
Authorities in Beijing and other cities canceled many public celebrations and other events.
On Wall Street, stocks slumped amid fears over the widening crisis, with the Dow Jones Industrial Average losing 170 points and the S&P 500 posting its worst day in three months. Health care companies suffered losses, along with financial institutions, airlines and other tourism and travel industry businesses.
Transportation was shut down in Wuhan, the city of 11 million where the outbreak originated, and in at least 12 other cities in central China's Hubei province, encompassing a population bigger than that of New York, London, Paris and Moscow combined.
Hospitals in Wuhan grappled with a flood of patients and a lack of supplies. Videos circulating online showed throngs of frantic people in masks lined up for examinations, and some complained that family members had been turned away at hospitals that were at capacity.
Authorities in Wuhan and elsewhere put out calls for medicine, disinfection equipment, masks, goggles, gowns and other protective gear. Wuhan officials said they are rapidly constructing a new hospital to deal with the crisis, to be completed February 3. It will be modelled on a SARS hospital that was built in Beijing in just six days during the SARS outbreak.
The seriousness of the crisis was still an open question.The new virus comes from a large family of what are known as coronaviruses, some causing nothing worse than a cold. But it is not clear just how lethal this coronavirus is, or even whether it is as dangerous as ordinary flu, which kills tens of thousands of people every year in the US alone. Scientists say it is also not clear if it spreads as easily as SARS, its genetic cousin, which also originated in China and killed about 800 people in 2002-03.
The rapid increase in reported deaths and illnesses does not necessarily mean the crisis is getting worse. It could instead reflect better monitoring and reporting of the newly discovered virus, which can cause cold- and flu-like symptoms, including cough, fever and shortness of breath, but can worsen to pneumonia.
"It's still too early to draw conclusions about how severe the virus is because at the beginning of any outbreak you would focus more on the severe cases," said Tarik Jasarevic, a spokesman for the World Health Organization in Geneva. "And then maybe we are missing some mild cases because people will just be a little bit sick and will not have it tested. And they will recover."
In France, Health Minister Agnes Buzyn said that two infected patients had traveled in China and that France should brace for more such cases. A third case was announced in a statement from her ministry about three hours later.
"We see how difficult it is in today's world to close the frontiers. In reality, it's not possible," she said. Buzyn said authorities are seeking to reach anyone who might have come in contact with the patients: "It's important to control the fire as quickly as possible."
In the US, the latest person confirmed to have the disease was reported to be doing well. The US Centers for Disease Control and Prevention likewise said it is expecting more Americans to be diagnosed with the virus.
Still, "CDC believes that the immediate risk to the American public continues to be low at this time, but the situation continues to evolve rapidly," said the agency's Dr Nancy Messonnier.
With Chinese authorities afraid that public gatherings will hasten the spread of the virus, the outbreak put a damper on Lunar New Year. Temples locked their doors, Beijing's Forbidden City, Shanghai Disneyland and other major tourist destinations closed, and people canceled restaurant reservations ahead of the holiday, normally a time of family reunions, sightseeing trips, fireworks displays and other festivities in the country of 1.4 billion people.
Wuhan's usually bustling streets, malls and other public spaces were unnervingly quiet and masks were mandatory in public. Shoppers emptied store shelves, stocking up for what could be an extended period of isolation. Karaoke bars, movie theaters and internet cafes around the region were shut down.While most of the deaths have been older patients, a 36-year-old man in Hubei died on Thursday.
The vast majority of cases have been in and around Wuhan or involved people who visited the city or had personal connections to those infected. About two dozen cases in all have been confirmed outside mainland China, nearly all of them in Asia: Hong Kong, Macao, South Korea, Japan, Singapore, Thailand, Taiwan, Vietnam and Nepal.
Recalling the government's initial cover-up of SARS, many Chinese are suspicious of the case numbers reported by officials. Authorities have promised transparency. China's cabinet, the State Council, announced it will be collecting information on government departments that have failed in their response to the outbreak, including "delays, concealment and under-reporting of the epidemic."