Beijing - Authorities in Shanghai closed all poultry markets on Friday and began culling birds at a major wholesale market, after the death toll from the H7N9 strain of bird flu rose to six, reports said.
All birds from the Huhuai wholesale farm product market in the city's Songjiang district were to be killed to prevent the spread of the disease, after the H7N9 virus was found in pigeons at the site, state media quoted Shanghai authorities and the Agriculture Ministry as saying.
A 64-year-old farmer died on Friday in Huzhou city in Zhejiang province, which borders Shanghai, while two people died from the virus in Shanghai on Thursday.
China has reported 14 confirmed infections with H7N9 in Shanghai, Zhejiang and neighbouring Jiangsu, including six deaths.
It is the first country to report the new strain of bird flu in humans.
There has been no confirmed human-to-human transmission of the virus, but one patient in Shanghai developed flu-like symptoms after contact with a bird flu victim, and has been quarantined, the official Xinhua news agency said.
Concern over under reporting
Health officials warned that poultry farmers and traders, butchers and meat processors were among the groups most at risk of infection.
Concern over possible under reporting of infections was raised after two sons of an 87-year-old Shanghai man who died of H7N9 were both treated for severe pneumonia, from which one of them died.
"Retrospective testing of recently reported cases with severe respiratory infection may uncover additional cases that were previously unrecognised," the World Health Organisation said Thursday.
A 14-year-old Thai tourist who died from severe pneumonia on Thursday in the south-western Chinese province of Yunnan tested negative for the virus, the agency quoted health officials as saying.
Health authorities nationwide have ordered medical staff to strengthen monitoring and prepare isolation units for possible new infections with H7N9 avian influenza.