A screening programme on the Tongan island of Vava'u has treated hundreds of children for rheumatic heart disease over the last few months.
Dr Toakase Fakakovikaetau says between four and five percent of Tongan have have been found to have rheumatic heart disease - the highest confirmed rate in the world.
The Vava'u screenings are the latest in a nationwide programme that has seen thousands of children screened.
Dr Fakakovikaetau says early detection is important as in its early stages the disease can be treated very cheaply with penicillin.
"The problem with rheumatic heart disease is that the kids will be having rheumatic heart disease and recurrence of rheumatic fever. And the heart will continue to be damaged and they will hardly have any symptoms until their heart is really damaged."
Dr Fakakovikaetau was recently presented with the United States Louise Lown Heart Hero Award for her work in treating rheumatic heart disease in Tonga.