The latest human bird-flu case in Shenzhen was particularly worrying, the Secretary for Health, Welfare and Food warned yesterday. 'We have a suspicion, but we have not confirmed it yet, that the virus might have become more virulent and more widespread than we had expected,' said York Chow Yat-ngok, speaking on the first day of the latest ban on imports of live poultry from Guangdong. 'If that is the case, the risk of humans being infected is higher than before.' He said this meant there might be more cases of bird flu in the winter, the season when the virus tended to strike. Dr Chow said he was particularly concerned about the Shenzhen case because the victim had no previously known prolonged contact with poultry. Dr Chow also pointed out that the case had occurred in a city, as had happened in Shanghai and Guangzhou, the previous two cases. Usually, outbreaks occurred in remote areas or on farms. Liufu Qirong, animal husbandry officer and vice-director of Guangdong's agriculture department, said that the latest bird-flu victim had not visited a market. 'Shenzhen's agriculture bureau sent people to investigate before the case was reported to the provincial agriculture department, and they found that the man had not been near markets,' he said. Shenzhen Health Bureau chief Jiang Hanping said the man remained in critical condition. A team of Hong Kong public health and veterinary experts yesterday visited the victim's home and a market that the patient's wife had visited. The woman and other family members had tested negative for the virus. Meanwhile, Steven Wong Wai-chuen, chairman of the Hong Kong Poultry Wholesalers' and Retailers' Association, said the city had only 200,000 to 300,000 live chickens left locally, enough to meet demand for about 10 days. The ban has caused the wholesale price of chicken at Cheung Sha Wan market to jump from $12 to $22 a catty. About 20 representatives of poultry farms and the wholesaling and transportation trade met with Agriculture, Fisheries and Conservation officials to discuss the ban and the way forward. The chairman of the Hong Kong Live Poultry Wholesalers' Association, Tsui Ming-tuen, has asked the government for a long-term solution for the industry, such as raising the compensation to be paid out under the voluntary surrender scheme.