NEW : Authorities slaughter market birds in Shanghai after H7N9 found in pigeons . Poultry markets in Shanghai will close starting Saturday . Fourteen human cases of H7N9 have been reported in eastern China so far . The virus is believed to be spread by the same bird flu that caused a deadly outbreak last year at China's poultry farms, which killed more than 100 people and infected thousands more.
NEW : Authorities slaughter market birds in Shanghai after H7N9 found in pigeons . Poultry markets in Shanghai will close starting Saturday . Fourteen human cases of H7N9 have been reported in eastern China so far . No cases of human-to-human transmission virus have been confirmed .