Mainland health officials believe the Shenzhen-based Hong Kong man infected with H9N2 bird flu is likely to have contracted the virus at a market that he visited every day. But the live poultry stall at the wet market near where the 86-year-old patient lived was open again yesterday after briefly closing for disinfection. He Hianfeng of the Centre for Disease Control and Prevention of Guangdong said yesterday that the man visited the market every day although he did not come into contact with live poultry. The man was in a stable condition yesterday under isolation in Princess Margaret Hospital. An infectious diseases expert warned, meanwhile, that without more stringent controls on mainland chickens, more Hongkongers were likely to be infected with the H9N2, H7N9 and H10N8 bird flu strains. "Three different strains of bird flu appear to be spreading from birds to humans this year. It shows that the virus has been very active," University of Hong Kong microbiologist Professor Yuen Kwok-yung said. "Since there is a large number of live poultry on the mainland, the chance of cross-infection will increase too, and there may be a higher chance of it spreading to humans." Fifty-one medical staff at North District Hospital, where the man sought help after crossing the border, and an officer who handled the man on his entry at Lo Wu control point remained under medical surveillance. But the Hong Kong Centre for Health Protection said his home contacts in Shenzhen had not displayed any symptoms so far. One hospital staff member developed a cough and sore throat, the centre's spokesman said. Influenza A viruses including H9N2 can infect humans from contaminated environments since they can persist on inanimate surfaces for 12 hours to two days, according to a research paper by Yuen and his team. "Visits to wet markets without direct contact with poultry have been shown to be an independent risk factor for acquiring avian influenza A," they wrote, adding that many H9N2 infections might have been overlooked due to the relatively mild symptoms in patients with normal immunity. The paper, published in the Journal of Infection in 2011, said the virus had adapted to land-based poultry in Southeast Asia and had also been detected in pigs in the region.
