Beijing health authorities are seeking 143 passengers who were on a Tokyo-Beijing flight with a Chinese man who has become the mainland's first confirmed case of A/H1N1 flu, a government spokesman said on Monday.

The suspected carrier took Northwest Airlines flight NW029 to Beijing on May 9, after making a transfer in Tokyo from St. Paul, Minnesota in the United States.

He then flew from Beijing to Chengdu on Sichuan Airlines flight3U8882 the same day, the Ministry of Health said on Sunday.

Sun Hao, spokesman for Beijing's emergency response liaison office, said the health department had reached about 120 of the 143 passengers from NW029. None had shown fever symptoms.

He said that among the passengers, there were some foreign nationals who had checked into several hotels in Beijing. The health department was "persuading them to take quarantine measures."

He didn't specify the exact number of people or what hotels they were staying at, although the Beijing News quoted a source assaying there were about 70 foreigners aboard the flight.

Sun said that the health department was trying to quarantine all the passengers at the Guomenlu Hotel near the airport, which was used to quarantine people in an earlier flu case involving a Mexican national who ended up in Hong Kong.

The passengers were found to be residents of 14 districts and neighboring counties in Beijing.

The case, the first in the mainland so far, involved a 30-year-old man surnamed Bao.

According to the Sichuan health department, which reported the case to the health ministry Sunday afternoon, Bao was in the Sichuan People's Hospital with a fever and was "initially diagnosed as a suspected A/H1N1 influenza case" based on his symptoms and laboratory tests. And the Ministry of Health said Monday morning he tested positive for the A/H1N1 influenza. He is now at the Chengdu Infectious Disease Hospital.

The Sichuan health department also said Monday morning that more than 130 of the 150 passengers aboard the flight from Beijingto Chengdu with Bao had been put under quarantine.

(Xinhua News Agency May 11, 2009)