WHO warns on Shanghai Sars
A team of WHO experts is touring hospitals in Shanghai The World Health Organisation has said there are likely to be more cases of Sars in China's second city of Shanghai than officially reported.
A WHO expert said there were likely to be "tens" of cases in Shanghai, rather than the two cases officially reported.
A team from the WHO is currently investigating the spread of the disease in the city, and has extended its visit by an extra day to complete a tour of civilian and military hospitals and meet disease control experts.
Shanghai's inhabitants have long been wondering how China's business hub could have so few cases while numbers have skyrocketed elsewhere, BBC correspondent Francis Markus says.
Dr Wolfgang Preiser, a member of the WHO team in Shanghai, said the disparity between actual and official figures may have arisen because China's classification system is too narrow.
At the moment, to be confirmed as a Sars sufferer, a person must either have had contact with a Sars patient or have been in a region classed as a Sars epidemic area.
But with the disease rapidly spreading, this definition is inadequate, Dr Preiser told the BBC.
Either the epidemic area needed to be expanded - perhaps to encompass the whole of China - or the criteria needed to be altered, health experts said.
But Dr Preiser also said the situation in Shanghai was nowhere near as bad as in Beijing, because the authorities had acted much faster to monitor and prevent the disease.
In contrast to its criticism of China's general handling of the disease, the WHO has praised Shanghai for its efforts to contain Sars.
Many people now wear protective masks in the city, and the authorities have taken measures to disinfect public areas.
Shanghai has also urged migrant workers not to return home, and asked companies to stop hiring staff from affected areas.