MEXICO CITY - Mexico began shutting down parts of its economy on Thursday to slow the spread of a new flu strain as officials urged increased worldwide precautions against an imminent pandemic.

The World Health Organization (WHO) said it would remain for now at its current alert level -- one notch below full pandemic -- and it would no longer refer to the H1N1 virus as swine flu in a nod to beleaguered meat producers.

New confirmed flu cases were reported in the United States, Latin America and in Europe. U.S. officials said new infections were occurring, although only a handful of people outside Mexico have required hospital treatment.

In Mexico, the worst hit country with up to 176 deaths, President Felipe Calderon told government offices and private businesses not crucial to the economy to stop work beginning on Friday to avoid further spreading a virus that is striking across age and class lines.

There is no safer place than your own home to avoid being infected with the flu virus, Calderon said in his first televised address since the outbreak started.

In Mexico City, where the virus has already brought public life to a standstill, some were skeptical.

Closing businesses is not right and not fair. What are we going to live on? Air? said Andres Garcia, who works in a tailor shop in the old colonial center of the capital.

With its tourism industry savaged, shoppers staying home and exports to the U.S. in steep decline, Mexico could find itself in the longest, deepest recession it has seen in years, according to analysts.

Global markets were taking the flu news in their stride, and Wall Street opened stronger on hopes that the U.S. recession is easing, although it later slid as auto giant Chrysler filed for bankruptcy.

The International Monetary Fund's chief economist Olivier Blanchard said fallout from the outbreak could be quite dramatic in some countries, particularly in the tourism sector. But he said it was too early to predict the full impact on a global economy already deep in recession.

The information that we have at this stage is it is a relatively minor (economic) event, Blanchard said.

Previous studies at the World Bank have said a severe flu pandemic which triggers a clampdown on trade could cost the global economy trillions of dollars.

The World Bank itself said operations were running normally at its Washington D.C. headquarters, where one staff member had a preliminary flu diagnosis after returning from Mexico.

UNANSWERED QUESTIONS

The WHO and flu experts say they do not yet know enough about this new strain to say how deadly it actually is, how far it might spread and how long any potential pandemic may last.

Flu epidemics generally last a few weeks or months in any single community, and can pass around the world in one or two waves over 18 months to two years before fading out.

U.S. officials have reported 109 confirmed swine flu infections in 11 states and the only death recorded outside of Mexico -- a Mexican toddler visiting Texas.

U.S. Health and Human Services Secretary Kathleen Sebelius told a public webcast there were still many unanswered questions. We know what happens year in, year out with seasonal flu. What we don't know is if this is going to be more virulent or milder, she said.

Worldwide, 12 countries have reported cases of the H1N1 strain, with the Netherlands the latest to join the list. It said a three year-old who had recently returned from Mexico had contracted the virus.

Switzerland also confirmed its first case on Thursday in a man returning from Mexico. Peru reported what appeared to be the first case in Latin America outside Mexico, also in someone who had been to the country.

Mexico Medicine Chrysler Down