HONG KONG, June 2 (Xinhua) -- Three people were tested positive for the A/H1N1 virus in Hong Kong on Tuesday, taking the number of confirmed cases of the disease in the city to 26, local health authorities announced here.

    The first case involved an eight-year-old boy living in Puerto Rico. The boy, accompanied by his family members and friends left Puerto Rico on May 28 for New York where they took a flight of Cathay Pacific (Flight no. CX831) to Hong Kong on May 29.

    The boy had onset of sore throat and cough on the evening of May 30. The symptoms subsided after taking over-the-counter medications.

    He developed fever on June 1 and consulted a private doctor, then he was referred to North District Hospital by ambulance for isolation.

    The second case involved a 19-year-old man studying in San Francisco. He returned to Hong Kong on May 30 from San Francisco by taking a flight of Singapore Airlines (flight no. SQ1)

    He developed shortness of breath and headache on the morning of May 31 and had onset of fever in the afternoon. Then he was taken to Kwong Wah Hospital by ambulance on June 1 for isolation.

    The third case involved a 20-year-old man studying in New York. He returned to Hong Kong on May 28 by taking a flight of Cathay Pacific (flight no. CX889).

    He developed fever, headache and cough on the evening of June 1. Accompanied by two sisters, he took a taxi to the United Christian Hospital. He was admitted for isolation.

    A spokesman of Food and Health Department of the Hong Kong Special Administrative Region (HKSAR) government said that the laboratory analysis on respiratory sample taken from the three patients yielded positive results for human A/H1N1 influenza on Tuesday.

    All three people's family contacts are asymptomatic.

    The spokesman said that as the three patients had onset of symptoms more than 12 hours after arriving in Hong Kong, the Center for Health Protection would not trace the passengers of the flights concerned.

    The Department is now tracing the close contact of the three patients and investigations into the three cases are ongoing.