Ten people were tested positive for the A/H1N1 influenza virus in Hong Kong on Friday, bringing the number of confirmed cases of the disease in the city to 73, local health authority said on Friday evening.

Among the 10 confirmed patients, three are local cases, including one student and two household members of the students from St. Paul's Convent School, where 12 students were confirmed to be infected with A/H1N1 flu on Wednesday and Thursday, classified as the first cluster of indigenous cases.

The first new local case involved a 13-year-old girl, who is the sister of a confirmed patient of the school. She developed cough and runny nose on Thursday evening. Her parents had already been put under directly observed chemoprophylaxis and medical surveillance.

The second local case is a 53-year-old man who is the father of a student of a confirmed case. He developed fever, cough, sore throat, myalgia and headache on June 11.

The third local case involved a 13-year-old girl studying in the school. She developed headache on June 7, sore throat and cough on June 9. Her family members are asymptomatic.

Other newly confirmed cases are all imported. The first imported case involved a 21-year-old woman who returned to Hong Kong from the Philippines by taking a flight of Cebu Pacific ( flight No. 5J110) on June 10, and sat in row 18 of the flight.

The second imported case involved a 49-year-old woman who returned to Hong Kong from Toronto on June 7.

The third and the forth imported cases involved two sisters aged eight and 15, who came to Hong Kong from the Philippines by taking a flight of Cathay Pacific (flight No. CX900) on June 11, and sat in row 51 of the flight.

The fifth imported case involved a 46-year-old man who returned to Hong Kong from the United States on June 5.

The sixth imported case involved a 26-year-old man who returned to Hong Kong from the United States on June 8.

The seventh imported case involved a 10-year-old girl who returned to Hong Kong from San Francisco by taking a flight of Singapore Airlines (flight No. SQ1) on June 11 and sat in row 50 of the flight.

Investigations into these cases are ongoing.

The Department of Health is now tracing passengers sitting in rows 16-20 of 5J110 arrived in Hong Kong on June 10, those sitting in rows 49-53 of CX900 arrived in Hong Kong on June 11 and, those sitting in rows 48-52 of SQ1 arrived in Hong Kong on June 11 and crew members who had served the affected section concerned as well as other close contact of the patients.

A spokesman for the Department of Health said on Friday the local authority started to adjust the current practice of tracing of flight passengers in connection with confirmed cases of A/H1N1 flu regarding to the latest developments of the disease in the community.

The spokesman said public health officers of the Center for Health Protection would contact passengers in the two rows in front and two rows behind of a confirmed patient to observe their health condition, instead of tracing flight passengers sitting three rows in front and three rows behind of a passenger of a confirmed case.

"Since human swine influenza has taken root in the community by this time and our Fight the Pandemic Campaign is now transiting from the containment to mitigation phase in gradual steps, the refinement of the contact tracing guidance can allow the health authority to be more focus in the control of the disease in the community," he said.

Apart from the existing control measures implemented at control points, the Department of Health's Port Health Office put up notices in all exit points to advise departure and transfer travelers not to travel if they have fever or influenza symptoms.

(Xinhua News Agency June 13, 2009)