The first suspected case of swine flu has been detected in Japan, the Japanese Health, Labor and Welfare Ministry said late Thursday night.

The patient, a 17-year-old high school student in Yokohama, is subjected to further examination to determine whether he is infected with the new type of influenza, the ministry said.

The patient, who had been on a school trip in Canada's British Columbia Province on April 10-25, suffered from a fever and cough and underwent a medical checkup Thursday at a Yokohama municipal hospital.

According to the municipal government of Yokohama, he has already been hospitalized and his symptoms are not serious. And none of his family members has any flu-like symptoms.

Three new cases of swine flu infection were reported Wednesday in Canada's British Columbia and Ontario, bringing to 19 the total cases of the new influenza infection.

Meanwhile, it has been confirmed that the female Japanese passenger, who was tested positive for influenza in a preliminary examination after arriving at Japan's Narita international airport, was not infected with swine flu virus.