Japan's health ministry confirmed the country's first case of the new coronavirus - known as the Wuhan pneumonia - ahead of the busy Lunar New Year travel period.
Health authorities in Wuhan in central China have diagnosed 41 people with the coronavirus, known as 2019-nCoV, including one who has died.
Japan’s confirmation of the second infection outside China, following a case in Thailand, came just days before the busy Lunar New Year, which is a peak period for Chinese tourists travelling abroad, placing officials across Asia on high alert.
The man, a Chinese national in his 30s who lives in Kanagawa Prefecture south of Tokyo, visited Wuhan and began to experience symptoms including fever and fatigue as well as difficulty breathing around January 3, Wuhan officials said.
He returned to Japan three days later and was admitted to hospital on January 10. His condition was reported to local health authorities but he was released after five days, displaying no further signs of infection.
Japan’s National Institute of Infectious Diseases (NIID) on Wednesday confirmed the man had contracted the coronavirus. The man told Japanese health authorities he did not visit the now-closed Huanan seafood market identified as the source of the infection.
The Chinese woman diagnosed in Thailand earlier this week also did not visit the market, raising fears she may have contracted the virus at another location in Wuhan, although the World Health Organisation on Tuesday said there was “no evidence” of human-to-human transmission.
In Japan, the case has fuelled concerns about a repeat of the 2003 outbreak of severe acute respiratory syndrome (Sars), which killed 774 people in 37 countries, including more than 600 in mainland China and Hong Kong. However, authorities have said the new virus is unlikely to lead to such a deadly outbreak.
In 2019, some 723,600 mainland Chinese visited Japan – that figure was expected to rise this year. Health officials throughout Asia have also expanded precautions to coincide with the peak travel period around Lunar New Year.
“The ministry has instructed quarantine officials at points of entry to be more vigilant for people who display signs of infection as they arrive and to improve their surveillance of passengers,” the health ministry official said.
“We are stepping up quarantine procedures and instructing people who are coming into Japan from China to declare themselves if they have any symptoms associated with the illness and to immediately undergo a medical exam if they feel unwell.”
Japan Airlines has introduced its own measures aboard aircraft arriving in Japan from other parts of Asia.
“Our head office is attempting to gather as much information as possible on the illness, although at the moment the details remain quite unclear,” spokesman Mark Morimoto said.
“We have started issuing announcements on our flights for anyone who feels unwell to contact quarantine officers as soon as possible. We’re being very proactive in this situation and making sure those announcements are repeated very frequently.”
Elsewhere in Asia, health officials have been stockpiling protective gear, preparing isolation beds and even boarding trains to individually screen passengers to contain the virus.
Vietnam’s Ministry of Health on Thursday confirmed two Chinese visitors from Wuhan were placed in isolation after arriving in Da Nang on Tuesday with fever-like symptoms.