By Pascal Fletcher
MEXICO CITY (Reuters) - Mexico's flu outbreak appeared to be easing with a fall in serious cases, the government said, but world health officials warned the unpredictable virus could still become a pandemic.
"Each day there are fewer serious cases and the mortality has been decreasing," Health Minister Jose Angel Cordova told a news conference in Mexico City, where millions were heeding government advice to stay at home.
Of the more than 100 suspected deaths from the new H1N1 virus that have emerged in Mexico, 19 had been confirmed, Cordova said. Mexico had already scaled back from its original estimate of 176 suspected deaths.
However, new cases of the mongrel virus, which mixes swine, avian and human flu strains, were still being tracked across the world. Colombia became the latest country to report a confirmed case of the disease, which has now been found in 19 countries.
In Geneva, the World Health Organisation said the H1N1 influenza had not spread in a sustained way outside North America, as required before the pandemic alert 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 on Saturday.
In Canada, health officials said a traveller carried the virus from Mexico to Canada and infected his family and a herd of swine.
The Canadian Food Inspection Agency said the herd had been quarantined and the safety of the food supply was not affected. But the U.N. Food and Agriculture Organisation said the Canadian case was a reason for concern and confirmed the need for increased surveillance of pig farms.
Few countries are ready to take chances with the new virus, widely dubbed swine flu.
Action by Chinese authorities to hold Mexicans in hotels and other places, irrespective of whether they were ill or not, sparked a diplomatic row with Mexico.
In Hong Kong, police quarantined a hotel for one week after a Mexican guest was found to have the virus and Mexicans also were being confined in Beijing, Shanghai and elsewhere.
Mexican Foreign Minister Patricia Espinosa criticized China, saying Mexican citizens who showed no signs of illness at all were being "isolated, under unacceptable conditions."
Hong Kong is under Chinese control but has its own government. The authorities in Hong Kong have confined about 300 guests and staff in the hotel. China said its steps were justified and lawful.
Asia's trade and tourism could be hit by the flu outbreak but lessons from the SARS epidemic in 2003 would boost efforts to counter the effects, Jong-Wha Lee, the acting chief economist at the Asian Development Bank, said on Sunday.
"I think Asia has been well prepared because the region has good experience in countering SARS," Lee said on the Indonesian island of Bali where the ADB was holding its annual meeting.
SARS, or severe acute respiratory syndrome, killed more than 800 people around the world in 2003. It first appeared in southern China in late 2002 and began spreading in February 2003.
FEWER PATIENTS WITH FEVERS
Mexican authorities said earlier they believed the situation with the new flu outbreak was stabilizing as fewer patients with severe symptoms were checking into hospitals.
The WHO said its laboratories had identified a total of 787 H1N1 flu infections in 17 countries, including one case in Ireland, and said there were 19 confirmed deaths in Mexico.
The WHO's toll lags national reports about the virus but is considered more scientifically secure.
The United States, the second hardest-hit nation, has confirmed 160 cases in 21 states.
But public hospitals in Mexico have noted a steady drop in patients turning up with fevers, suggesting the infection rate may be declining as people use hand gel and avoid crowds. The streets of Mexico City were largely empty on Sunday.
U.S. officials said they were encouraged by the developments in Mexico but added it was too early to relax.
Almost all infections outside Mexico have been mild. The only death in another country has been a Mexican toddler who was taken to the United States before he became ill.
President Barack Obama said the United States was responding to the new flu strain, closing some schools temporarily and distributing antiviral drug supplies as needed.
British Health Secretary Alan Johnson on Sunday said the spread of the new flu strain has been contained in Britain but there will be more confirmed cases.
Scientists are still trying to assess how the new virus behaves and compares to regular seasonal flu strains, which kill between 250,000 and 500,000 globally every year.
WHO hiked its alert level to 5 from 3 last week -- the last step before a pandemic -- due to the flu's spread and the threat it could target poor and disease-prone communities.
(Additional reporting by Cyntia Barrera, Louise Egan, Jason Lange, Alistair Bell, Esteban Israel and Anahi Rama in Mexico City, Tan Ee Lyn in Hong Kong, Laura MacInnis in Geneva, Silvia Aloisi in Rome, Allan Dowd in Vancouver and Yoo Choonsik in Nusa Dua; Writing by Pascal Fletcher and Maggie Fox; Editing by Bill Trott)
