Laboratory tests results on the influenza A H5N1 virus found in a 33-year-old man and his nine-year-old son show that the virus genes were purely avian in origin.

A spokesman for the Department of Health said that further analyses of the test results were underway and would take a few days to complete.

The son recovered and was discharged after treatment at Princess Margaret Hospital. The man died on February 17. Both had recently returned from Fujian province.

Secretary for Health, Welfare & Food Yeoh Eng-kiong said officials are studying the feasibility of vaccinating imported live poultry to reduce the bird-flu risk.

Dr Yeoh noted that Beijing authorities' response to the bird-flu cases was quick. But the Bureau will further improve the reporting mechanism between Hong Kong and the Mainland on outbreaks of infectious diseases.

However, he added, Hong Kong relied on Beijing to co-ordinate information from different cities and provinces which have different surveillance and reporting mechanisms so the new system would have to be workable for them. 

Dr Yeoh clarified that, in the absence of human genes in the virus, the risk of human-to-human transmission will be low.

Meanwhile, Deputy Director of Food & Environmental Hygiene SP Mak said they would introduce an additional "Rest Day" on the 10th of each month from March to prevent the outbreak of bird flu.

The decision was made after discussion with live poultry retailers during a meeting last week. The Department will  accede to their request to start cleaning at noon on that day, enabling them to operate in the morning.

Dr Yeoh added that they would consider allowing for more flexibility when implementing "Rest Days" to minimise the impact on live poultry wholesalers and retailers.