The first US case of the coronavirus that originated in China has been confirmed by American health officials.
The viral pneumonia, which has no cure, has been dubbed 'Wuhan virus' as it originated at the seafood market in the city of Wuhan in central Hubei province in China.
It is from the same family of coronaviruses that causes Severe Acute Respiratory Syndrome (SARS) - which saw a significant outbreak in 2002-2003.
US officials today confirmed that an American citizen - who is in his 30s - is in a good condition in a hospital after returning from Wuhan in the middle of last week.
The case was detected in the state of Washington.
Nearly 300 people are known to have been infected by the virus in China, leading to fears of an international pandemic during the Lunar New Year travel rush.
Meanwhile, the mayor of Wuhan city has announced a sixth death in the region.
It comes after authorities confirmed that the viral pneumonia can spread through human contact.
15 medical staff have caught it, prompting airports around the world - including in Australia and the US - to step up screening of travellers arriving from China.
The US Centers for Disease Control and Prevention (CDC) last week said that screening of travellers from Wuhan was being carried out San Francisco, New York JFK and Los Angeles airports.
That is now being extended to Atlanta and Chicago.
In a statement today, the CDC said the situation regarding the so-called "2019-nCoV" is still unclear.
The organisation said: "While severe illness, including illness resulting in several deaths, has been reported in China, other patients have had milder illness and been discharged.
"Symptoms associated with this virus have included fever, cough and trouble breathing.
"The confirmation that some limited person-to-person spread with this virus is occurring in Asia raises the level of concern about this virus, but CDC continues to believe the risk of 2019-nCoV to the American public at large remains low at this time."