By Louise Egan and Luis Rojas Mena
MEXICO CITY (Reuters) - Mexico announced on Sunday that its swine flu epidemic had passed the worst and experts said the new H1N1 virus might be no more severe than normal flu, although it could still impact on world health.
Mexican Health Minister Jose Angel Cordova said the flu was easing but warned that it was too early for Mexico -- the epicentre of an outbreak that has spread to 19 countries -- to let down its guard.
The mayor of Mexico City, Marcelo Ebrard, said the capital of 20 million inhabitants was likely to resume normal activities on Thursday, observing certain health precautions, after a five-day partial shutdown to limit the virus' spread.
Cordova said the H1N1 flu outbreak appeared to have peaked in Mexico between April 23 and 28 and fewer people had gone to hospitals with serious flu symptoms in the past few days.
"The evolution of the epidemic is now in its phase of descent," he told a news conference in Mexico City, where millions of people heeded government advice to stay at home.
After days of alarm that had kept streets eerily quiet, the atmosphere in Mexico City appeared more relaxed on Sunday, with some people venturing out on bikes or running. Many no longer wore the surgical masks that have been almost obligatory in the city in the last week as residents feared infection.
But millions of Catholics stayed away from churches, watching Sunday mass on television instead.
Mexican authorities have scaled back their estimate of deaths from the flu strain to over 100, down from 176. Only 19 deaths in Mexico are confirmed as being caused by the new flu.
But new cases of the virus, which mixes swine, avian and human flu strains, still were being tracked across the world, keeping alive fears of the threat of a pandemic.
The World Health Organisation said its laboratories had identified a total of 898 H1N1 flu infections in 18 countries, including one case in Italy. Its toll lags national reports but is considered more scientifically secure.
"ENCOURAGING SIGNS"
The flu has spread to 30 U.S. states and infected 226 people, the U.S. Centres for Disease Control and Prevention said. It appears to be hitting mostly younger people, with very few cases reported in those over 50 years old.
CDC acting director Richard Besser said there were "encouraging signs" that the new strain was not more severe than what would be seen during normal seasonal flu.
But he still expected the virus to have a "significant impact" on people's health. "We're not out of the woods," Besser told "Fox News Sunday."
The U.S. government said it hoped to have a vaccine ready for the new flu strain by the autumn.
In Britain, Health Secretary Alan Johnson said the spread of the new flu strain had been contained there.
A World Health Organisation spokesman said in Geneva its emergency committee had no meeting scheduled to review its global alert for the H1N1 flu, which it set last week to 5, one notch below pandemic level.
Health officials and scientists from around the world have been focussing on how the new mutated, mongrel flu strain may be passed between animals and humans.
The WHO said flu surveillance should be increased in both humans and animals now that the latest H1N1 strain was found to have infected pigs in Canada.
Canadian health officials said a traveller carried the virus from Mexico to Canada and infected his family and a pig herd.
SOME STILL WARY
Mexico has seen a stabilization of serious cases in the past few days, bringing some relief to its population, millions of whom have stayed indoors in line with a government order for non-essential businesses to remain closed through Wednesday.
"We've been indoors since Friday. So now we've come out to enjoy some fresh air," cyclist Silvia Rodriguez told Reuters, relaxing on the grass of a central park in Mexico City.
Others were more wary. "I'm not totally convinced that the worst is over," said Juan Antonio Hernandez, 48, a caretaker.
A Mexican Embassy official in China said Chinese authorities were quarantining more than 50 Mexican business people and tourists after some showed flu symptoms.
Asia's trade and tourism could be hit by the latest flu outbreak but lessons learned from the SARS epidemic in 2003 would boost efforts to counter the effects. SARS, or severe acute respiratory syndrome, killed more than 800 people around the world in 2003 after first appearing in southern China.
(Additional reporting by Maggie Fox in Washington, Daniel Trotta, Anahi Rama, Jason Lange, Louise Egan, Pascal Fletcher and Esteban Israel in Mexico City, Tan Ee Lyn in Hong Kong, Laura MacInnis in Geneva)
