A large-scale global outbreak of flu is likely given the current conditions, warned Zhong Nanshan, an academician with the Chinese Academy of Engineering who rose to prominence during the SARS outbreak.

"But we can't pin down a specific time for the outbreak, " Zhong was quoted as saying in an Information Times report on Wednesday.

According to the report, Zhong said that a global flu outbreak generally takes place every 20 to 50 years. The last worldwide flu outbreak took place more than 20 years ago.

"It's bird flu that renders the current situation so serious," said Zhong, fearing a mutated flu virus might present a more dangerous threat.

"To date, we still can't tell whether bird flu viruses can join human flu viruses to create viruses that could live easier inside humans," he said.

"It would be more terrible if one contracts both human and bird flu at the same time," he said.

"If there develops viruses that can be transmitted from human to human, I'm afraid that could pose a catastrophic disaster for human beings," Zhong said.

He recommended that people get inoculated against the flu during the September-October period, immediately before flu season typically breaks out.

The old, the very young, patients and medical workers, and anyone who might be particularly vulnerable to infection, are strongly advised to take precautions as early as possible, Zhong added.

According to Zhong, flu viruses mutate almost every year. This year, the strains are the H1N1 and H3N2, and the Shanghai viruses.

Mutation means the antibodies created before to tackle older strains would be useless against newer strains, he said.

(Xinhua News Agency September 15, 2005)