H1N1 flu tally 4,379 in 29 countries - W.H.O.

* 4,379 people infected with H1N1 flu in 29 countries

* Big increase in confirmed cases in United States

* First death reported in Costa Rica



ZURICH, May 10 (Reuters) - H1N1 flu has infected 4,379 people in 29 countries, the World Health Organisation (WHO) said on Sunday, increasing its count by almost a thousand in a day.

The WHO tally tends to lag national reports but is considered more definitive.

The U.N. agency said Mexico has reported 1,626 confirmed cases, up from 1,364 on Saturday, and repeated that 45 people have died there from the new flu strain that is a genetic mixture of swine, bird and human viruses.

The Mexican government has said the worst is over and eased restrictions on commercial and public activity in the country that has been at the epicentre of the outbreak.

The WHO's latest flu tally increased the number of confirmed infections in the United States to 2,254 from 1,639 reported on Saturday, while the number of reported deaths remained at two.

U.S. officials on Saturday said a man died from the new flu in Washington state last week, bringing the toll in the United States to three.

WHO increased the number of infections in Canada to 280, from 242, and repeated one person had died there.

It said one person had also died in Costa Rica, which had eight confirmed cases.

European countries with cases confirmed in WHO laboratories include Spain (93), Britain (39), Germany (11), Italy (9), France (12), Portugal (1), Ireland (1), Netherlands (3), Austria (1), Denmark (1), Sweden (1), Switzerland (1) and Poland (1).

The WHO also confirmed the following infections in the rest of the world: Israel (7), New Zealand (7), Brazil (6), Japan (4), Panama (3). South Korea (3), El Salvador (2), Hong Kong, China (1), Guatemala (1), Colombia (1) Argentina (1) and Australia (1).

Evidence that the disease, popularly known as swine flu, has taken hold in communities outside the Americas would prompt WHO Director-General Margaret Chan to declare a full pandemic.

Chan raised the global pandemic alert level last week to 5 out of 6 in response to the spread of H1N1 flu. Phase 5 means a pandemic is imminent.

The WHO also repeated its guidance that international travel should not be restricted as a result of the outbreak.