More than 90 cases of swine flu have been confirmed in Japan although none of the A/H1N1 cases are critical.

日本已经发现超过90例猪流感案例，尽管没有发现致命的A型H1N1。

The first four swine flu cases in Japan were people returned from Canada

The figures have been rising rapidly; the first case in someone who had not been abroad - a 17-year-old student in Kobe（神户） - was reported only on Saturday.

Nearly all those affected¹ are students in the Hyogo and Osaka（大阪） prefectures in western Japan.

Just four cases had been confirmed in Japan as of Friday - people who had returned from Canada.

They were kept in quarantine（隔离，封锁交通） and all international passengers have been scanned for raised temperatures as they arrive in the country.

The government has shut down schools and cancelled public events in cities where the flu has been reported.

"We must be careful, but with quick treatment patients can recover," said Prime Minister Taro² Aso.

"We must respond calmly and appropriately."

Even in the sporting arena³ steps have been taken to reduce the potential for infection.

At a national sumo wrestling（相扑运动） competition in Tokyo on Sunday officials sprayed（喷雾，扫射） disinfectant（消毒剂） on the hands of every spectator as they arrived.

The outbreak has caused alarm in Japan, which with its aging population is exceptionally anxious about flu, the BBC's Roland Buerk in Tokyo says.

People routinely wear face masks on public transport to prevent the spread of coughs and colds.