The World Health Organization has called an emergency meeting of experts on Thursday to discuss the spreading H1N1 flu outbreak, in a sign the U.N. agency may be poised to declare a pandemic.

A patient with symptoms of the influenza A H1N1 virus 

stands next to a stadium gate where he is being treated, 
in Colon City, May 28, 2009. Panama's health department 
announced that the total number of people infected 
had risen to 107. REUTERS/Alberto Lowe 

WHO Director-General Margaret Chan, who consulted health officials in affected countries on Wednesday, was drawing up her own evaluation ahead of the meeting set to begin at midday (1000 GMT), a spokesman said.

She is looking for some detailed epidemiological explanation for what is going on, WHO spokesman Dick Thompson told Reuters. She is making her own assessment based on information gathered today and running it by the Emergency Committee tomorrow.

Thompson declined to say whether the WHO would declare a full-blown pandemic after the closed-door talks, saying he did not want to prejudge the experts' recommendations.

Chan had sought further information from some countries to clarify news reports that they were detecting sustained transmission of the new virus in the community, and not just imported cases, he said.

WHO spokesman Gregory Hartl said the expert committee would consult on the state of the outbreak. The strain, which emerged in April in Mexico and the United States, has spread widely in places including Australia, Britain, Chile and Japan.

The agency said on Tuesday it was on the verge of declaring the first influenza pandemic in more than 40 years, but wanted to ensure countries were well prepared to prevent a panic over the disease, widely known as swine flu.

Chan, a former health director in Hong Kong, has previously consulted the group of international experts before raising the alert level.

Confirmed community spread in a second region beyond North America would trigger moving to phase 6 -- signifying a full-blown pandemic -- from the current phase 5 on the WHO's 6-level pandemic alert scale.


There have been 27,737 cases reported in 74 countries to date, including 141 deaths, according to the WHO's latest tally.

Keiji Fukuda, acting WHO assistant director-general, told reporters late on Tuesday that a move to phase 6 would reflect the geographic spread of the new disease.

It does not mean that the severity of the situation has increased or that people are getting seriously sick at higher numbers or higher rates than they are right now, he said.

One of the critical issues is that we do not want people to 'over-panic' if they hear that we are in a pandemic situation, Fukuda told reporters at the time.

The WHO wants to avoid causing undue alarm over a virus that has been largely mild in most countries, while warning it could still mutate into a more virulent form. 

Members such as Britain have called on the WHO to revise its scale to reflect severity in future.

The WHO and its 193 member states were working hard to prepare for a pandemic, for instance developing vaccines and building up supplies of anti-viral drugs, Fukuda said.

Drug makers are on track to have a vaccine against the new strain ready for the northern hemisphere autumn after receiving seed virus samples, company officials said.