The Shanghai Animal Disease Prevention and Control Center tested 34 samples from pig carcases and reported finding no traces of bird flu, state media reported. Many city residents, however, remain skeptical.
This week, Vietnam enacted a ban on all poultry products from China, stepping up border controls, while Taiwan put officials on alert and set up a monitoring group as a precaution against an epidemic-level outbreak.
Some experts have deemed China a higher risk for bird flu given the sheer size of its poultry industry and its use of production methods that put farmers in closer proximity to their chickens.
In their media and public-health response, Chinese authorities have been haunted by the specter of past medical crises, most notably the SARS outbreak of 2002 and 2003, when official censorship and tight control of information worsened matters. But Zhong Nanshan, director of the Chinese Medical Association, told Chinese media it is considered very unlikely that this bird flu strain will turn into a problem on the scale of SARS.