Identification of H5N1 mutation warning signs was taking too long and the next human-flu pandemic could be upon us before we knew, the expert said.

Assoc Prof Prasert Auewarakul monitors the H5N1 virus and viral pathogenesis in humans at Siriraj Hospital medical school.

He said detecting changes in the highly pathogenic virus and heading off a global pandemic had to be achieved in days, not weeks.

"We should be able to do it in days, not weeks," he said adding that in a worst-case scenario the disease could change so suddenly it could be too late.

In some cases the incomplete collection of virus samples had made mutation detection more difficult.

Not all confirmed human cases of flu were analysed for mutations, he said, and this meant it remained inconclusive if the disease had changed to an "alarming level" or not.

"So far, as far as we've seen, there has not been any significant changes."

However, he warned there were "some changes in the virus which we're closely monitoring". These changes were in the virus receptor binding sites.

Monitoring virus receptor binding sites was the best way scientists could keep track of changes.

Prasert is working on a flu vaccine with the National Centre for Genetic Engineering and Biotechnology (Biotec).

Prasert said Biotec would extend its vaccine development to cover a new strain of the virus detected in Nakhon Phanom.

An outbreak in Nakhon Phanom last month exhibited a strain never seen in Thailand and most closely related to one circulating in southern China.

Genetic analyses showed the mutated strain was typical of influenza-A viruses but that did not make it any more dangerous to people.

"The strain is not an issue. How to get a vaccine produced in sufficient volume is," he said.

At present Thailand was capable of producing a bird-flu vaccine in limited amounts at the lab level.In a related development, the Cabinet was told yesterday that human flu was spreading rapidly. Ministers say people should protect themselves with flu shots.

Arthit Khwankhom

The Nation