Chinese mainland health authorities yesterday were still seeking some of the 147 passengers who were on a Tokyo-Beijing flight with a Chinese man declared to be the mainland's first confirmed case of swine flu.

Meanwhile, Taiwan yesterday cleared a woman and her baby of the disease after saying earlier they had contracted the H1N1 virus.

The confirmed carrier, a 30-year-old man surnamed Bao who had been a student in the United States, took Northwest Airlines flight NW029 to Beijing at 1:30am on Saturday after transferring in Tokyo from St Louis, Missouri, and St Paul, Minnesota.

He then flew from Beijing to Chengdu on Sichuan Airlines flight 3U8882 the same day, the Ministry of Health said on Sunday.

Deng Ying, chief of the Beijing Center for Disease Control and Prevention, said the passengers list contained 75 foreign nationals and 72 Chinese citizens.

As of 2pm yesterday, the municipal health department had contacted 121 of the 147 people on flight NW029, and were still looking for the others, including 24 foreign nationals.

Deng said Bao stayed for more than nine hours at the Xinhanglu Hotel in Beijing before he flew to Sichuan. All 103 people at the hotel, including nine foreign nationals, were told to remain under week-long observation. None has shown fever symptoms.

Deng said the municipal health department had also informed other localities to seek 10 other people who took a van from the hotel to the airport with Bao.

Sun Hao, spokesman for Beijing's emergency response liaison office, said the passengers on Bao's flight from the US included foreign nationals who had checked into hotels in Beijing.

The health department was "persuading them to take quarantine measures" while passengers holding Chinese citizenship were forced to undergo week-long observation in designated medical centers.

According to the Sichuan Health Department, which reported the case to the Ministry of Health on Sunday, 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.

The health ministry said yesterday morning that he tested positive for the virus. He was being treated last night at the Chengdu Infectious Disease Hospital.

All the crew members of the Sichuan flight were under quarantine. The Sichuan Provincial Center for Disease Control and Prevention said yesterday afternoon that it had contacted and quarantined 128 out of the 150 passengers aboard the flight from Beijing to Chengdu.

With assistance from police, the Sichuan Provincial Center for Disease Control and Prevention is looking for the remaining passengers. Guangdong Province has also joined the manhunt as some passengers were reported to be going on to south China.

Also yesterday, tests on two people earlier thought to have been the first to be suffering from influenza A in Taiwan have shown they did not have the virus after all, according to the island's health department.

Health chief Yeh Ching-chuan said earlier that a 32-year-old mother and her baby from Taipei most probably had the virus after returning from the US six days ago.

"After carrying out a series of tests, we have confirmed that the mother and daughter who returned from the United States do not have influenza A," the Department of Health said in a brief statement.

Chinese leaders, including President Hu Jintao and Premier Wen Jiabao, yesterday called for enhanced vigilance and strict steps against swine flu after the mainland reported its first case.

(Xinhua News Agency May 12, 2009)