2009-05-11 19:18:03 -

GENEVA (AP) - The number of swine flu infections in Europe could explode in much the same way it has in North America, a senior World Health Organization official said Monday.
Most instances of the disease _ which WHO says has reached 4,694 cases in 30 countries but other tallies put much higher _ have occurred in Mexico and the United States.
Most cases in Europe, Asia and South America are linked to travelers bringing the virus home with them, but there is a possibility the disease will become established there too, said WHO's flu chief Keiji Fukuda.
«Whether it will develop exactly as it did in the United States and in Canada and in Mexico is anybody's guess, but I think that the potential for it to be established either in Europe or in other places is there,» he said.
By late Monday the global body had been informed of 2,532 lab-confirmed cases in the United States, including three deaths, and 1,626 cases in Mexico, including 48 deaths.
Canada has 284 cases, while Costa Rica has eight cases, according to WHO. Both countries have recorded one death each.
In Europe, 14 countries have reported cases, with Spain (95) and Britain (47) having the most.
The virus has now been reported as far apart as Brazil, Israel, China, New Zealand and South Korea.
Fukuda told reporters in Geneva that the key feature WHO is looking for in deciding whether to raise its pandemic alert to the highest level _ indicating a worldwide outbreak _ is whether there are unexplained cases occurring outside North America.

«The threshold for community spread is when you begin to see people who are getting infected, who become cases, and it's just not clear where they're getting it from.
WHO has said the pandemic alert, currently at five, would be raised to six if sustained transmission appears to be taking place in more than one region
Infections within a single school or medical facility would be insufficient to trigger this alert, as such small-scale transmissions would be expected when a traveler carrying the disease returns home, Fukuda said.
«But if you look at the community spread occurring in the United States right now of this new H1N1 virus, in fact many of the cases cannot be traced anywhere.