Jude Hospital in Memphis, Tennessee, used reverse genetics to produce a vaccine against the H5N1 avian flu virus.

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The reported death toll gives the Middle East-based disease a case fatality rate of about 60%, similar to that of the feared H5N1 avian flu.

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His group will attempt to nail down exactly how many mutations - and which - are sufficient to make the H5N1 avian flu virus airborne, and whether these particular mutations can also make other bird flu viruses airborne.

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The authorities appear to have learned the lessons of previous deadly virus outbreaks such as the H5N1 avian flu and Sars (Severe Acute Respiratory Syndrome), and this time around have been quick to share information with the WHO.

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Flavonoids and flu: Two plant-based flavonoids disease-fighting compounds found in many foods significantly impaired the infectious activity of H5N1 avian-flu virus in laboratory experiments and may form the basis of future influenza treatments, a report in Antiviral Research says.

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For an advancing country, China is strangely vulnerable to infectious diseases, including the H5N1 variant of avian flu that has killed some 300 people.

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But the virus doesn't appear to notably sicken infected birds, unlike H5N1, another avian-flu virus that is deadly in birds and occasionally infects people.

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This is less deadly than the previous avian flu outbreak in China six years ago (that H5N1 bird flu virus killed more than 300 people after spreading from China to other countries in 2006).

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The World Health Organization says that most avian flu viruses do not infect humans and the majority of H5N1 cases have been associated with contact with infected poultry.

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