Several cities in eastern China have suspended trading in live poultry in an effort to contain the problem.
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The city government said that road checks were being stepped up to prevent live poultry from being trucked into Shanghai.
On Saturday the eastern city of Nanjing banned live poultry trade and closed markets, according to the official Xinhua news agency.
Eastern Chinese cities have been closing live poultry markets and taking other precautions to limit the spread of the new virus.
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Beijing and major eastern Chinese cities have closed live poultry markets and are taking other precautions to limit the spread of the new virus.
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Authorities have halted live poultry trade in cities where cases have been reported, and slaughtered fowl in markets where the virus has been detected.
On Saturday International Consolidated Airlines Groupthe eastern city of Nanjing banned live poultry trade and closed markets, according to the official Xinhua news agency.
Eastern Chinese cities have been closing live poultry markets and taking other measures to try to contain the disease which has killed six to date.
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They have threatened to release live poultry on to the streets.
Cities in eastern China where H7N9 first appeared have been closing live poultry markets and taking other precautions to limit the spread of the new virus.
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Such markets were the source of the first known outbreak in Hong Kong in 1997 when 20% of the chickens in live poultry markets were infected.
Hong Kong officials say they are ready to halt live poultry imports or cull birds if needed, as Shanghai has already done, to prevent a mass outbreak.
Cantonese cooking places a high premium on fresh ingredients, but in recent years, the government has clamped down on the live poultry trade through a buyout program.
Live poultry markets in Shanghai that were shut on April 6 in a move to control the spread of the flu will remain closed, the newspaper said.
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Eastern Chinese cities where most H7N9 cases have been concentrated have closed live poultry markets and are taking other precautions to limit the spread of the new virus.
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The closure of live poultry markets in Beijing will put new pressure on an industry how to handle chickens ready to be sold but that have no buyers.
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Eastern Chinese cities where most H7N9 cases have been concentrated have also closed live poultry markets and taking other precautions to limit the spread of the new virus.
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The rate of new cases has slowed since Shanghai's live poultry markets were closed on April 6, said Anne Kelso, director of the World Health Organization's Collaborating Centre for Influenza in Melbourne.
The virus has been detected in live poultry in several food markets where human cases have been found, leading officials to think people are most likely contracting the virus through direct contact with infected fowl.
The primary risk factor for human infection appears to be direct or indirect exposure to infected live or dead poultry or contaminated environments.
The trading of live birds - how poultry is traditionally sold in China - has also been halted at a market in the Zhejiang city of Hangzhou, after the virus was detected in quail being sold there.
Live bird markets are the traditional way that poultry is sold in China.
The authorities in Shanghai, where four deaths were recorded, have closed three poultry markets and banned the import of all live birds into the city.
Pigeon is a common type of poultry in Chinese cuisine and the birds are sold live in markets around the country.
Wang Sumin, 61, used to buy live chickens twice a month and slaughter them at home but has stopped purchasing poultry altogether.
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