"That's always of course possible...as long as there are poultry outbreaks, people will be exposed to the virus. You can expect that people might get infected," WHO's China head, Henk Bekedam, told reporters in Beijing.

    "On the other hand, I would like to stress...the current virus is not easily transmittable to humans. We don't expect a large number of cases."

    Other cases of H5N1 crossing from birds into humans in China were also being investigated on Thursday.

    In northeastern Liaoning province, a poultry farmer who had contracted pneumonia after coming into contact with dead chickens was being investigated despite initially testing negative for the virus and making a recovery.

    Confirmation of human infections and fatalities in the world's most populous nation has raised the stakes for Chinese and global health authorities in battling the virus.

    More than 60 people have already died of the H5N1 strain in Southeast Asia since 2003, with most of the deaths in Vietnam, Thailand and Indonesia.

    Although human-to-human transmission has not yet been proved, scientists warn that continued contact between infected birds and humans might result in the virus mutating into a form that could be easily passed on between people.

    WHO praises China containment measures

    China has the world's biggest poultry industry, with billion of chickens existing in cramped conditions and close to humans, especially in rural areas.

    Adding to the danger is that three of the world's major bird migratory routes pass through China. Migratory birds are regarded as the main carriers of the virus around the world.

    In Liaoning, the scene of four of the outbreaks, farmers have also been banned from raising their chickens outdoors in an attempt to stop them coming into contact with migratory birds.

    In the capital Beijing, all live poultry and bird markets were shut down early this month.

    China has also ordered the country's whole poultry stock of 1.4 billion to be vaccinated as the expense of central and local governments.

    Bekedam praised the Chinese government's containment measures as "almost textbook".

    In an effort to reassure the nation, Premier Wen Jiabao said China would defeat the bird flu just as it overcame the Severe Acute Respiratory Syndrome crisis more than two years ago.

    China is stepping up efforts in studying the efficiency of traditional Chinese medicine to help prevent or control human cases of bird flu, Xinhua news agency said.

    The State Administration of Traditional Chinese Medicine has launched a working group to supervise and coordinate the study, according to the agency.

    
    (Source: China Daily/AP)