A second person has died in China from a mystery virus that has stricken dozens and appeared in two other Asian countries, officials said late on Thursday.

The news comes as Thailand reported on Friday that a second Chinese national has been found to be infected of the mystery virus.

In China, local authorities said a 69-year-old man died on Wednesday in Wuhan, the central Chinese city believed to be the epicentre of the outbreak of the virus traced from the same family as the deadly SARS pathogen.

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The outbreak has caused alarm because of the link with SARS (Severe Acute Respiratory Syndrome), which killed 349 people in mainland China and another 299 in Hong Kong in 2002-2003.

At least 41 people have been hit with pneumonia linked to the new virus in China.

The Wuhan health commission said 12 people have recovered and were discharged from hospital while five people were in serious condition.

The man who died had become sick on December 31 and his condition worsened five days later, with pulmonary tuberculosis and multiple organ functions damaged, the commission said.

Three other cases were detected in Thailand and Japan with authorities in both countries saying the patients had visited Wuhan prior to their hospitalisations.

The second Chinese patient who was reported to be infected is a 74-year-old woman. She has been quarantined since her arrival in Thailand on Monday, Thailand's Public Health Ministry said on Friday.

Human-to-human transmission possible?

Last week, a 61-year-old man from Wuhan died from pneumonia which is suspected to be linked to the mysterious virus.

Authorities in Wuhan said a seafood market was the centre of the outbreak. It was closed on January 1.

No human-to-human transmission of the virus behind the Wuhan outbreak has been confirmed so far, but the health commission has said the possibility "cannot be excluded".

A World Health Organization (WHO) doctor also has said it would not be surprising if there was "some limited human-to-human transmission, especially among families who have close contact with one another".

The Wuhan health commission said on Wednesday that a man who had been diagnosed worked at Huanan Seafood Wholesale Market, but his wife had been diagnosed with the same illness despite reporting "no history of exposure" at the facility.

South Korean quarantine officials use thermal cameras to measure the temperatures of passengers from China at Incheon International Airport [File: Yonhap via EPA]

The woman diagnosed in Thailand had also not reported visiting the seafood market, the WHO said on Tuesday. She was reported to be in stable condition earlier this week.

The patient in Japan, who was released from hospital, had also not visited the market. Japanese officials said it was possible that the man had been in contact with a person infected with the virus while in Wuhan.

Coronaviruses are a large family of viruses that can lead to 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.

SARS originated in southern China in 2002 and infected more than 8,000 people in 37 countries before it was brought under control. Nearly 800 people died worldwide.

The latest outbreak comes ahead of the Lunar New Year holidays, when many of China's 1.4 billion people will be travelling to their home towns or abroad.

The Chinese government expects passengers to make 440 million trips via rail and another 79 million trips via aeroplanes.