The Department of Health has confirmed four imported human swine flu cases involving a 27-year-old woman, a 33-year-old man, a 39-year-old man, and a 15-year-old girl, bringing the tally to 45.

The 27-year-old woman, who travelled with a friend to the US and Canada from May 28 to June 6, returned to Hong Kong on June 7 on flight AC007.

She took an airport bus to her home in Kwong Fuk Estate, Tai Po and developed a runny nose and cough in the morning of June 8. She took a taxi to Alice Ho Miu Ling Nethersole Hospital and was admitted for isolation.

The 33-year-old went to Phuket with a friend from June 4 to 8 and returned to Hong Kong on flight KA213 on June 8 at about 10.30pm. He failed the temperature check at the airport and was taken to Princess Margaret Hospital by ambulance.

The 39-year-old man, who lives in Melbourne, travelled with his family to Hong Kong on June 8 at about 3.30pm on flight CX134. He failed the temperature check and was sent to Princess Margaret Hospital by ambulance.

The 15-year-old girl, who studies in San Francisco, flew in with an elder sister and a younger brother on flight CX873 on the morning of June 7.

As her brother was confirmed to have been infected with the virus upon arriving in Hong Kong on June 7, she was put under medical surveillance and took Tamiflu at Lei Yue Mun Park & Holiday Village on the same day.