Mexico's flu outbreak appeared to be stabilizing on Saturday, as officials said hospitals were seeing fewer new cases of people with symptoms from the new swine flu virus and cut the estimated death toll from the outbreak.
"It would still be imprudent to say that we're past the worst of it but I do think ... we are in a stage of stabilization," Mexican Health Minister Jose Angel Cordova told reporters.
Costa Rica, Italy, and Ireland confirmed cases of the virus, which has now been found in 18 countries.
In Geneva, the World Health Organization said H1N1 influenza had not spread in a sustained way outside North America, as would be required before the pandemic alert level is raised to its highest level. But it said that would probably happen soon.
"I would still propose that a pandemic is imminent because we are seeing the disease spread," Michael Ryan, WHO director of Global Alert and Response, told a briefing.
Mexico on Saturday lifted its confirmed death toll by three to 19, and reported 454 infected patients. The number of suspected deaths has been cut from as many as 176 to 101.
'More like a regular seasonal flu' - US experts
Officials at the US Centers for Disease Control and Prevention (CDC) organisation believe that the Mexican outbreak may not be as severe as it first seemed.
What has been seen of the virus as it spreads globally, they say, suggests that it is acting more like a regular seasonal flu than anything more frightening,
Genetic analysis from several countries shows the virus has not mutated, so the people in Mexico are not being made ill by a virus that is somehow more virulent, according to the CDC.
It notes that the cases reported around the world - mostly among people who have travelled in Mexico - have been mild, and most people have recovered with little or no treatment.
Not to be compared with 1918 pandemic
Experts have been struggling to explain why there have been so many deaths in Mexico and not elsewhere, but the CDC report suggests a simple explanation - that there are many cases in Mexico, most are mild, and just the bad ones have been seen so far.
There have been references in the media to the influenza pandemic that killed perhaps as many as 50 million people worldwide in 1918, but the CDC says it's not seeing the markers for virulence that were seen then.
Virus reaches Asia: hotel sealed off
Hong Kong on Saturday confirmed Asia's first case of swine flu, prompting authorities to seal off the hotel where the 25-year-old man who contracted the flu had been staying.
The man, from Mexico, arrived on a China Eastern flight on Thursday afternoon after a stopover in Shanghai. China has since suspended flights from Mexico.
At least 200 guests and 100 staff members have been told they may have to stay inside for a week.
Hong Kong was badly hit by the SARS virus in 2003 and has had many episodes of H5N1 bird flu for more than a decade.
South Korea has reported its first case of swine flu, as have France and Denmark.
Mexico plea for 'fair treatment'
Mexican Foreign Minister Patricia Espinosa criticised five nations - China, Peru, Argentina, Cuba and Ecuador - which have cut flights to Mexico.
"We're surprised by the adoption of unjustified measures," she said.
She also urged Mexicans to avoid travel to China, accusing the government of placing a number of Mexican citizens in unnecessary quarantine in three Chinese cities.
Mexico has also - together with the US and Canada - appealed to those countries which had banned pork products.
Decisions should be made based on scientific evidence and not create "unnecessary trade restrictions", a joint statement from the three countries' agriculture ministers said.
The WHO has also cautioned against flu-linked restrictions on pig products.