BANGKOK (Reuters) – A Chinese woman has been quarantined in Thailand with a mystery strain of coronavirus, authorities said on Monday, the first time it has been detected outside China.

Thai authorities are stepping up monitoring at airports ahead of the Lunar New Year holiday, beginning on Jan. 25, when hundreds of thousands of Chinese tourists are expected to visit.

A 61-year-old man died from pneumonia, a symptom of the disease, in the central Chinese city of Wuhan after an outbreak of the yet to be identified virus.

In total, 41 cases of pneumonia have been reported in China, which preliminary lab tests cited by Chinese state media show could be from a new type of coronavirus.

Coronaviruses are a large family of viruses that can cause infections ranging from the common cold to SARS. Some of the virus types cause less serious disease, while some like the one that causes MERS, are far more severe.

The Wuhan Municipal Health Commission said on Monday seven of the 41 had been discharged and six were in a serious condition.

The Thai Health Ministry said on Monday that of 12 passengers quarantined since Jan. 3, lab results show that a 61-year-old Chinese woman carried a strain of the coronavirus.

The woman, who was quarantined on Wednesday, had received treatment and was well enough to return home, the ministry said.

“Being able to identify a patient shows that there is efficiency in our monitoring system. We are confident that we can manage the situation,” Public Health Minister Anutin Charnvirakul told reporters.

Officials in China and Thailand are working with the World Health Organization.

The Chinese outbreak appeared to be linked to a single seafood market in Wuhan and had not so far spread beyond there, the WHO said.

“The possibility of cases being identified in other countries was not unexpected, and reinforces why WHO calls for on-going active monitoring and preparedness in other countries,” its statement said.

WHO Director-General Tedros Adhanom Ghebreyesus will consult with international experts to assess the public health risks of outbreaks and decide whether an emergency meeting is needed, it said.

(Reporting by Panarat Thepgumpanat and Chayut Setboonsarng; Additional reporting by Stephanie Nebehay and by Vincent Lee; Editing by Nick Macfie and Alison Williams)