TOKYO - Japan has confirmed its first three cases of swine flu, a quarantine official said Saturday.
The patients were among about 390 passengers who arrived in Tokyo's Narita International Airport on a flight from Detroit the previous day, an airport quarantine official said on condition of anonymity, citing department rules.
The three have been identified as two high school students and a teacher who had visited Canada on a school trip.
They were quarantined after showing such flu symptoms as a cough and fever, and tested positive in a primary test on board, the official at the Narita Airport Quarantine said. They are recovering at a hospital near the airport.
The teenage male students and the teacher in his 40s travelled to Ontario last month with about 30 other students, and returned to Tokyo via Detroit on a Northwest Airlines flight, public broadcaster NHK said.
The teacher and the students participated in various programs hosted by a local high school in Oakville, Ont., since April 24, NHK and Kyodo News agency reported. It was not immediately known if they were exposed to any swine flu cases during the trip to the Toronto suburb.
They tested positive for the influenza A virus, and later confirmed positive for the swine flu H1N1 strain in a DNA test at the National Institute of Infectious Diseases.
Airport quarantine officials were also examining other passengers who were seated near the patients as a precautionary measure, the official said.
Andrew Morrison, a spokesman for the Ontario Ministry of Health, said Ontario and federal health officials were investigating whether the three people were infected while in Canada.
The three people were the first confirmed cases of swine flu after dozens of suspected cases earlier had all turned out to be seasonal influenza patients in secondary tests.
Earlier this month, a six-year-old Japanese boy living in Chicago was confirmed as a swine flu patient, becoming the first Japanese national to have been infected with the flu.
