By Alistair Bell
MEXICO CITY (Reuters) - Mexico voiced hope on Friday it might be getting control of an outbreak of a new flu strain that has killed up to 176 people there, shut down large parts of the country and raised fears of a global epidemic.
The U.S. Centers for Disease Control and Prevention said Mexico's outbreak of the new H1N1 swine flu virus may not be as severe as it looked at first, citing many mild cases that were not immediately noticed.
Worldwide, 13 countries have confirmed cases. Almost all infections outside Mexico have been mild, and only a handful of patients have required hospital treatment.
In Mexico, many offices and businesses were closed for a five-day break to help slow the spread of the disease. The capital's mayor, Marcelo Ebrard, said emergency campaigns against the virus were bringing results.
"Individuals and families have been taking these measures very seriously and as a result we have had timely and early detection of cases of respiratory illnesses that could be of this type. This has led us to a situation where the numbers are getting better every day," he said.
"I'm not saying we should let our guard down ... I'm telling you so you know where we stand."
Mexican public hospitals that treat roughly half the country admitted just 46 patients with severe flu symptoms on Thursday, down from 212 patients on April 20.
The latest countries to report new infections were Denmark and Hong Kong -- where authorities sealed off a hotel where a 25-year-old Mexican visitor had been staying. He became the first verified case in Asia.
The United States, the country with the largest number of confirmed cases outside Mexico, reported 141 cases across 19 states.
The CDC said in a new report on Friday it had confirmed 84 out of up to 176 deaths in Mexico blamed on the H1N1 strain. Only one person has died outside Mexico: a toddler from Mexico who travelled to the United States.
U.S. President Barack Obama said he was pleased with progress in fighting the virus.
"I think that those who have been on top of this have done an extraordinary job. I'm optimistic that we're going to be able to manage this effectively but we still have more work to do," he told reporters after a Cabinet meeting.
A WHO vaccine expert said there was no doubt that it would be possible to make a successful vaccine against the virus in a reasonably short period.
MEXICO WINDS DOWN
Much of Mexico shut down until next Wednesday to help battle the outbreak. Many government offices, car plants, factories and offices are letting employees stay home on a presidential order, extending a long weekend that starts with a public holiday on Friday.
Many stayed in the capital rather than go to the beach at Acapulco, as is traditional.
Residents felt a bit easier that the death toll appeared to be stabilizing after a week of people wearing face masks, avoiding public gatherings and washing hands frequently.
"When they announced the virus it was a blow. We are going to keep taking precautions but I feel a little less worried now even though there is still uncertainty," said Jessica Santiago, 29, an optometrist walking her dog beside the deserted Chapultepec Park.
Experts have been struggling to explain why so many deaths have occurred in Mexico and nowhere else. On Friday, the CDC suggested a simple explanation: there are many cases in Mexico, most are mild, and just the bad ones have been seen so far.
"To date, case-finding in Mexico has focussed on patients seeking care in hospitals," the report said. "A large number of undetected cases of illness might exist in persons seeking care in primary-care settings or not seeking care at all."
Scientists hope to get a clearer picture as data comes in from special test kits that the CDC sent to Mexico to measure the extent of the illness. Even normal flu can be deadly, with seasonal influenza killing an estimated 250,000 to 500,000 people globally every year.
The World Health Organisation said on Friday no meeting of its emergency committee was scheduled, meaning there was no immediate likelihood of its level 5 alert being raised to a full 'phase 6' pandemic alert.
The WHO has said it would call the new virus strain Influenza A (H1N1), not "swine flu," since is no evidence that pigs have the virus or can transmit it to humans. Pork producers had said consumers were shunning their product.
Most global markets have shrugged off flu fears as traders focussed on hopes that a deep U.S. recession may be nearing an end.
(Additional reporting by Jason Lange, Helen Popper, Lewis Krauskopf, Karen Jacobs, Maggie Fox, Donny Kwok, editing by Jackie Frank)
