Journalists with facemasks work at the high school where the confirmed A/H1N1 patient studies in Kobe city, Japan, on May 16, 2009. Japan's first domestic case of A/H1N1 flu was confirmed on Saturday. The patient is a 17-year-old male high school student in Kobe city, who has no records of overseas travel, according to the Ministry of Health, Labor and Welfare. (Xinhua)   A notification to reinforce prevention of A/H1N1 flu is seen at a local hospital in Kobe city, Japan, on May 16, 2009. Japan's first domestic case of A/H1N1 flu was confirmed on Saturday. The patient is a 17-year-old male high school student in Kobe city, who has no records of overseas travel, according to the Ministry of Health, Labor and Welfare. (Xinhua)

Nine students from a high school in Osaka Prefecture were confirmed to have been infected with the H1N1 strain of influenza A, the health ministry said Sunday, bringing the total number of infections in Japan to 21.

The nine had no record of overseas travel. The confirmation follows the discovery of Japan's first eight domestic cases of the new flu in the neighboring Kobe, Hyogo Prefecture, on Saturday.

Japan found the first four cases of infection on travelers who returned from North America.

The nine in Osaka Prefecture are from the Kansai Okura Senior High School in the city of Ibaraki. About 110 students at the high school have shown symptoms of influenza since around Monday, according to the school.

The health ministry said the patients are recovering at local hospitals.

The Japanese government on Saturday shifted the stage of its new-flu action program from "a period of overseas outbreak" to "an early period of domestic outbreak" and called for companies and schools in the areas concerned to allow individuals to avoid commuting during rush hours.

The Kyodo News quoted Tashiro, a member of the World Health Organization's emergency committee, as saying that several hundred people in Japan already may have been infected with the H1N1 strain of influenza A.

(Xinhua News Agency May 17, 2009)