Japan's number of confirmed swine flu cases soared to 93 at the weekend, officials said late Sunday, as senior health officials gathered in Geneva for talks on containing the spread of the virus.
Most of the infections were reported among high school and college students in and around the western cities of Kobe and Osaka, where authorities ordered more than 1,000 schools and kindergartens to stay shut on Monday.
"I don't know specifics about the cases but judging from confirmed cases the infection is likely to be spreading to hundreds of people," Japanese virologist Masato Tashiro told public broadcaster NHK.
"There must be a number of people who slipped through border controls (at airports) as their symptoms were quite light, passing the virus to other people before they knew it."
Tashiro was speaking from Geneva, where the World Health Organization (WHO) annual assembly will begin on Monday, with fears about the global outbreak of A(H1N1) influenza expected to dominate discussions.
Nearly 8,500 people in 39 countries have been infected with swine flu, according to the latest figures released by the WHO. Cases confirmed in Turkey, India, Hong Kong, Britain and Chile at the weekend have not been included in the tally.
More than 70 people have died from the virus -- all of them in the Americas and nearly all in Mexico, where the new strain of swine flu was first detected less than a month ago.
Hong Kong officials on Sunday confirmed the third case of swine flu in the city, a 23-year-old man who arrived from the United States a day ago.
Meanwhile 14 new cases were confirmed in Britain, 10 of them in London, pushing the total number of cases of the virus in the country over 100.
And a 32-year-old woman became Chile's first confirmed swine flu case Sunday, hours after returning to the country on a flight from the Dominican Republic via Panama, health officials said.
Acting WHO Assistant Director General Keiji Fukuda has said that studies indicated a "significant number of people" had been infected but their cases were either still to be detected or confirmed by laboratory tests.
A motion has even been put forth to shorten the talks in Switzerland from 10 to five days, so that senior officials are not away from their duties at home for so long.
Ahead of the WHO meeting, world governments failed to reach a final deal on the sharing of virus research material and vaccines in case of a global flu pandemic.
Mexican President Felipe Calderon said his country had given the WHO a sample of the virus on Saturday, along with statistical and clinical data on the evolution of the strain there.
Authorities in Mexico say that they are on the path to controlling the outbreak. The health ministry said in a statement that if the virus "is dealt with on time, usually it is curable."
Japan until Friday thought it had kept the virus at bay, after detecting four people who tested positive when they flew in from North America and immediately quarantining them along with about 50 fellow passengers.
But since the government Saturday confirmed the first domestic case, a 17-year-old male Kobe student who had not been overseas, the number of confirmed infections has risen quickly in Kobe and Osaka.
Late Sunday officials in Hyogo prefecture, which includes Kobe, told AFP 53 cases had been confirmed, while Osaka prefecture reported 36, raising the national toll to 93.
Prime Minister Taro Aso has urged the public to stay calm and take hygiene measures -- such as washing their hands often and gargling. He was due to convene a crisis meeting on the domestic outbreak early Monday.
Shigeru Omi, a former senior official at the World Health Organization, now head of the government's special swine flu task force, warned: "We believe that the infection is beginning to spread in the region."
The WHO said Saturday it was closely monitoring the situation in Japan.
It has not yet recommended travel restrictions to curb the spread of the virus but has advised anyone who is feeling unwell to postpone their trips.
(c) 2009 AFP
Explore further: Liberia works to contain Ebola, find source of new cases