By Se Young Lee

BEIJING (Reuters) – The U.S. State Department warned Americans in China about an outbreak of pneumonia in the central city of Wuhan believed to be caused by a new strain of coronavirus, which has killed one person.

The outbreak comes ahead of the Lunar New Year holiday in late January, when many of China’s 1.4 billion people will be travelling to their home towns or abroad. The World Health Organization and Chinese authorities are taking steps to ensure the disease does not spread further.

Thai health authorities said on Wednesday they were stepping up monitoring of passengers arriving at airports with infrared thermal scanners ahead of the holiday, when 800,000 Chinese tourists are expected to visit the country.

Memories remain fresh in Asia of a 2002-2003 outbreak of SARS, or Severe Acute Respiratory Syndrome (SARS), which emerged in China and killed nearly 800 people worldwide.

WHO has said there may have been limited human-to-human transmission of the new coronavirus in China within families.

And authorities in Wuhan confirmed on Wednesday that a married couple were among 41 people diagnosed with pneumonia believed to be caused by the new virus. There were no new cases or deaths at the end of Tuesday, the city’s health authority said. The Wuhan Municipal Health Commission did not say in the statement whether the couple represented an instance of human-to-human transmission. But it said the husband, who worked at a seafood market suspected of being at the epicentre of the outbreak, was the first to fall ill and that his wife did not have any exposure to the market.

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Some of the other people diagnosed also denied visiting the market, the commission said.

The authorities in Wuhan also confirmed that a Chinese woman quarantined in Thailand, the first case of the mystery strain of coronavirus to be detected outside of China, had come from Wuhan.

The State Department’s notice referred to an alert by the U.S. Centers for Disease Control and Prevention urging citizens in China travelling to Wuhan to avoid contact with animals, animal markets or animal products, among other precautions.

It also asked citizens those who had visited Wuhan and feel sick to seek medical care.

The Wuhan health commission said in another statement issued late Wednesday that 7 of the 41 pneumonia patients have been released. The statement also said that 450 of the 763 people put under observation due to their close contact with known patients have been released.

(Reporting by Se Young Lee; Editing by Simon Cameron-Moore and Alex Richardson)