HONG KONG, July 9 (Xinhua) -- The Secretary for Food and Health of Hong Kong York Chow Wednesday announced the scale down of the response level for avian influenza from "serious" to "alert".

    After the detection of H5N1 avian influenza in environmental samples collected from poultry stalls in Po On Road Market, Sham Shui Po, on June 7, the government had raised the response level to "serious".

    With more environmental samples from three other retail markets found to have the virus on June 11, live chicken trading in Hong Kong was suspended for 21 days.

    The government implemented a ban on overnight stocking of live poultry in retail outlets when live chicken sales resumed on July 2 to reduce the risk of avian flu outbreaks.

    The measure has been put into place for a week and market operations have been generally smooth, environmental hygiene with improved.

    The Agriculture, Fisheries and Conservation Department of the government has collected samples from chicken farms, the wholesale market and retail outlets and tested them for H5N1 virus. All results were negative.

    "The government has decided to scale down the response level after assessing the present risk posed by avian influenza, taking into account the above factors," Chow said.

    He appealed to the public to remain vigilant and pay attention to personal and environmental hygiene in order to prevent avian flu.