BEIJING, June 11 -- Four people tested positive for the A/H1N1 influenza virus in Hong Kong on Tuesday, bringing the number of confirmed cases to 45, health authorities said.

    All of the 45 cases are imported cases.

    The first of the four cases involved a 27-year-old woman who traveled to the United States and Canada and returned to Hong Kong on June 7.

    The second case was a 33-year-old man who visited Thailand and returned to Hong Kong on June 8.

    The third case involved a 39-year-old man living in Australia, who flew to Hong Kong on June 8.

    The fourth case involved a 15-year-old girl studying in the United States who flew into Hong Kong on June 7.

    The Department of Health is tracking passengers on those flights, as well as crew members and others who had close contact with the latest four cases.

    Xinhua News Agency correspondents reporting from Hong Kong. (XHTV)