A second US patient has been diagnosed with coronavirus as more potential cases are monitored across 22 different states and two students are under quarantine.
The latest case is a Chicago woman who returned from Wuhan, the epicentre of China's outbreak, with the infection. Sixty-three other people are being monitored in the city.
Potential cases are being monitored across 22 different states, including the first patient in Washington state and the new case.
Officials said the Chicago patient, a woman in her 60s who visited China in late December and fell ill last week, is currently doing well and is in stable condition. She remains isolated in a hospital as a precaution.
The potential patient in Texas was announced on Thursday, with local health officials saying the student had come down with a cough and congestion after travelling to the Chinese port city of Wuhan — the epicentre of the breakout that has now crossed the Pacific Ocean. The student in Tennessee was also placed in isolation as they await testing results.
The new potential cases come shortly after a man in his 30s was diagnosed with the virus in Seattle on Monday, and another 43 people have been identified as having come into contact with him in some form or another during his trip from China to the United States. He was the first confirmed case in the US, as well as the first outside of Asia.
In response to the growing outbreak, the Centres for Disease Control and Prevention rose its travel advisory to a level 3 on Thursday, recommending people avoid travel to Wuhan except when essential. The State Department, meanwhile, has kept its travel advisory at a level 2, urging caution if travelling to the affected areas of China.
The issue has received some response from Donald Trump, who claimed on Tuesday, after the first case was reported, that the US has “it totally under control. It’s just one person coming in from China. It’s going to be just fine.” White House spokesman Hogan Gidley on Thursday told reporters that the US has "taken all the precautions necessary".
On Friday, the Chinese National Health Commission reported a spike in both the number of cases and the death toll from the virus, which is in the family of viruses that have caused past global outbreaks including Sars and the 2015 Mers outbreak.
The number of infections had jumped by 200 people to 830 cases of the virus between Thursday and Friday, while the death toll spiked by more than half a dozen in a 24-hour period to 25.
The first 17 deaths in China — where the health commission reportedly has tightly controlled news about the magnitude of the outbreak, leading to some criticism — were mostly older men, and many had underlying health problems when they contracted the disease. All of those deaths have occurred since December in Hubei Province, which includes the city of Wuhan and is hundreds of miles inland west of Shanghai.
The virus is novel, meaning health officials have never encountered this particular strain of it before. Officials believe that it came from animals, and many of those who were first infected were said to have worked or frequently shopped at the Huanan seafood wholesale market in the centre of Wuhan, where live and freshly slaughtered animals were also sold.
As the virus spread over the week, the issue has sparked concern worldwide, though the World Health Organisation (WHO) has so far declined to classify it as a global health emergency, saying it is “too early” for that designation.
“Make no mistake. This is an emergency in China, but it has not yet become a global health emergency,” Tedros Adhanom Ghebreyesus, the director-general of WHO, said on Thursday.
“WHO’s risk assessment is that the outbreak is a very high risk in China, and a high risk regionally and globally,” he continued.
In addition to the US, patients have tested positive for the virus in Thailand, South Korea, Singapore and Vietnam.
While there have been no confirmed cases of the virus in the United Kingdom or Europe, health officials are on high alert, with 14 people having been tested in the UK for suspected cases. Five of those have been confirmed negative, and nine are still awaiting results, Public Health England said. It is unclear where the patients were being treated.
The UK government has meanwhile called a government contingencies meeting to discuss the growing threat, after the medical director for Public Health England said it is “highly likely” that a case would make it onto British soil.