Thai health officials say a 14-year-old girl died of bird flu, raising the country's toll from the illness this year to 12.

A statement from the Public Health Ministry says lab results confirmed that the girl died from the lethal H5N1 strain of avian influenza last week.

The statement says the girl had been placed on a list of suspected cases of bird flu after suffering from flu-like symptoms for 11 days earlier this month.

Bird flu, which has also killed 20 people in Vietnam this year, is most commonly found in chickens. Health officials believe it is transmitted mainly through close contact with infected birds.