Three people were tested positive for the A/H1N1 virus in Hong Kong on Saturday, taking the total number of confirmed cases of the disease in the city to 23, a spokesman for the Department of Health (DH) said Saturday.

All of the 23 cases are imported cases, the spokesman said.

The first case involved a 21-year-old man. He stayed in the United States from May 15 to 27 and returned to Hong Kong on May 28 from New York by taking a flight of Continental Airlines, whose flight number is CO099. He wore a face mask during the flight and sat in row 23.

The patient took Airport Express to Tsing Yi where he took a taxi to his home in Cheung Hang Estate, Kwai Tsing. He had onset of headache in the middle of the flight and developed fever and sore throat after arriving home, but he stayed at home during that night.

He consulted a private doctor on the morning of May 29. The doctor referred him to Princess Margaret Hospital (PMH) by ambulance.

His family members are asymptomatic, the spokesman said.

The second case involved an eight-year-old boy living in the United States. The boy, accompanied with three family members, arrived in Hong Kong on May 30 from San Francisco by taking a flight of Singapore Airlines, whose flight number is SQ1.

The boy developed fever, cough, runny nose and malaise during the flight. He sat in row 39 of the flight. He was intercepted by Port Health Office and was transferred to PMH by ambulance for isolation.

His mother stayed with him in Hong Kong while his father and sister had gone to the mainland Saturday morning. They were asymptomatic.

The third case involve a 19-year-old woman studying in the United States. She returned to Hong Kong from New York on the evening of May 28.

She and her mother took an airport bus to Wan Tsui Estate in Eastern District.

On May 29, she went to the China Travel Agency in Shau Kei Wan and to Immigration Department in Wan Chai to apply for some documents.

She had onset of fever, cough and sore throat in the afternoon. Her mother took her to the Accident and Emergency Department of Pamela Youde Nethersole Eastern Hospital by minibus and was admitted for isolation. She wore a face mask on the journey.

Her family contacts are asymptomatic.

As she had onset of symptoms more than 12 hours after she arrived Hong Kong, CHP would not trace the flight passengers, the spokesman said.

Laboratory analysis on respiratory sample taken from the three patients yielded positive results for A/H1N1 influenza Saturday.

The Department of Health is now tracing passengers sitting in rows 20-26 of CO099 which arrived in Hong Kong on May 28 and those sitting in rows 36-42 of SQ1 which arrived in Hong Kong on May 30, and crew members of the flights concerned who had served the affected section of the cabin concerned as well as other close contact of the three patients.

Passengers who had traveled on the two concerned flights are urged to call the DH's Center for Health Protection hotline 21251111.

The spokesman also urged the taxi driver who took the 21-year- old male patient from Tsing Yi to Cheung Hang Estate on May 28 to call the hotline.

Meanwhile, the spokesman called on members of the public to advise their children, relatives or friends coming to Hong Kong from abroad to defer their trips if they developed symptoms such as fever, cough or sore throat.

(Xinhua News Agency May 31, 2009)