World Health Organization likely to declare swine flu a pandemic

The World Health Organization is likely to raise its alert for the new influenza strain to the highest level and declare a pandemic, its head indicated in an interview published on Monday.

"Level six does not mean, in any way, that we are facing the end of the world. It is important to make this clear because (otherwise) when we announce level six it will cause an unnecessary panic," Margaret Chan, WHO Director General told Spanish newspaper El Pais.

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"Flu viruses are very unpredictable, very deceptive.... We should not be overconfident. One must not give H1N1 the opportunity to mix with other viruses. That is why we are on alert," she told the newspaper.

Chan warned against over-confidence following a stabilization in the number of new cases of H1N1 because the southern hemisphere was about to enter winter when flu cases naturally spike.

"We have to be very careful. No one can predict what is going to happen when countries in the south have flu peaks and this new one arrives - which it is going to do, without a doubt."

"It is true that the number (of cases in people who have not been to Mexico) is small but because of that I would say that we have not seen the full situation or the whole picture of what is happening. The situation is evolving and the virus is changing."

She said it was too early to predict what proportion of the population would catch the new influenza strain after the European Union predicted 40 percent of the population would become infected.

The World Health Organization said on Monday that its laboratories have identified a total of 985 H1N1 flu infections in 20 countries, including El Salvador and Colombia, and said there have been 25 confirmed deaths in Mexico.

The WHO's toll lags national reports about the virus but is considered more scientifically secure. Its figures about Mexico - considered the epicenter of the outbreak -- have been rising in recent days because of lab results on previously collected samples coming in, not because of new infections reported.