Countries around the Asia-Pacific and beyond are stepping up their defences against a new coronavirus that emerged in the central Chinese city of Wuhan in December and is now known to have infected at least 440 people on the mainland as well as a handful of others overseas.

Cases of what is currently being called 2019-nCOV have now been confirmed in South Korea, Japan, Thailand, Taiwan, Macau and the United States.

"Given travel patterns and increased testing, more cases of 2019-nCOV should be expected in other parts of China and possibly other countries in coming days," a spokesman for the World Health Organization (WHO) told Al Jazeera in a statement.

"WHO encourages all countries to continue preparedness activities."

In Asia, which was hit hard in the 2002-03 outbreak of severe acute respiratory syndrome, or SARS, which also started in China, authorities are taking no chances.

Measures, including thermal screening, have been introduced at airports in an attempt to limit the spread of the virus, with checks targeted at passengers coming from Wuhan.

"It's a matter for each country to look at the frequency of travel from Wuhan and adjust to that," Raina Macintyre, who heads the Biosecurity Programme at the Kirby Institute at the University of New South Wales, told Al Jazeera.

Direct flights between China and the rest of the world have expanded rapidly over the past 20 years, with Wuhan's 11 million people now able to fly direct to destinations in Europe and the US as well as cities closer to home, like Seoul, Bangkok, Kuala Lumpur and Singapore.

SARS lessons

The southeast Asian city-state was hit hard after an unassuming traveller from Hong Kong brought the SARS virus to the island in 2003.

The threat caused widespread public panic, prompting school closures and inflicting economic damage to business and tourism. People rushed to buy face masks or remained indoors. Some 238 people were infected and 33 died. The WHO says SARS killed about 800 people globally.

Singapore has close ties with mainland China and Changi Airport is one of the world's busiest for international traffic. Wuhan is just four and a half hours away on a daily direct flight.

After initially screening only passengers from Wuhan, Singaporean health authorities this week began screening all inbound passengers from China, issuing them health advisory notices.

The Ministry of Health and the National Centre for Infectious Diseases are also distributing clinical guidance about the disease to infectious disease specialists, doctors in hospital emergency departments and hospital laboratories.

Hsu Li Yang, an associate professor at the National University of Singapore's Saw Swee Hock School of Public Health, told Al Jazeera that while Singapore was vulnerable to such outbreaks, the country was better prepared than it was during SARS.

"The healthcare system and hospitals are far better prepared today, with improved surveillance systems, medication and equipment [including masks] stockpiles, and a state-of-the-art 330-bed facility in the National Centre for Infectious Diseases that was built precisely to avoid a repeat of the SARS debacle," he said.

"A whole of government approach to crisis management has also been developed post-SARS."

Airports across the region, including Kuala Lumpur, have introduced thermal screening for international arrivals [Ahmad Yusni/EPA]

The coming Lunar New Year holiday looms large in the minds of many decision-makers. It is one of the biggest holidays in the region, not only in China and nations with large populations of ethnic Chinese, but also in countries such as Koreas and Vietnam. Many people take the chance to meet up with family and go on holiday.

Curbing infections

The WHO has already advised people to ensure they wash their hands thoroughly and regularly, cover their nose and mouth if coughing or sneezing and avoid people who appear to have a cold or flu.

In many parts of Asia, people have begun wearing surgical masks.

Taiwan, a self-governing territory, imposed checks on passengers arriving from Wuhan when the outbreak was first announced on December 31, and reported its first confirmed case on January 21 when a Taiwanese woman in her 50s was placed in quarantine after she arrived by plane from Wuhan showing symptoms of the virus, the Taiwan Center for Disease Control (CDC) said.

So far, the CDC says more than 4,300 passengers have been screened, but it expects the risks to rise as tens of thousands of Taiwanese travel abroad during the Lunar New Year, and mainland Chinese head around the country or overseas.

Dual Taiwanese-Australian national Kathy Cheng told Al Jazeera that while she thought Taiwan was taking the Wuhan virus seriously, she was still concerned about travelling with her two-year-old daughter next week.

"I feel pretty confident the Center for Disease Control at the airport is pretty thorough and efficient, but since we are travelling to Australia after Lunar New Year, I am a little bit worried because in a big international airport you never know who you come in contact with," she said.

Taiwan was also badly affected during the SARS outbreak, recording more than 300 cases. Government figures show there were at least 73 SARS-linked deaths in 2003.

WHO to meet

Another complication for Taiwan is that while it follows all WHO protocols, the island has not been a member of the global health agency since the 1970s when the territory was replaced by the People's Republic of China at the United Nations.

People wear face masks at a Taipei Metro station as the island confirmed its first case of the new coronavirus that emerged in Wuhan in December [David Chang/EPA]

The WHO is due to hold an emergency session on the virus on Wednesday as scientists work to try and identify the virus and where it came from.

"Much remains to be understood about 2019-nCoV," the spokesman said. "Not enough is known to draw definitive conclusions about how it is transmitted, clinical features of the disease, its severity, the extent to which it has spread or its source."

China has already shared the genetic code of the Wuhan virus, and promised to take all measures necessary to prevent its further spread. Whatever it turns out to be, people beyond its borders are not taking any chances.

Reporting by Manar al-Adam in Kuala Lumpur, Tom Benner in Singapore and Erin Hale in Taipei.