Rheumatic fever is a delayed sequel to throat infection by a group A streptococcus. More than one third of affected children develop carditis, followed many years later – especially in the case of recurrent rheumatic infections – by progressive and permanent valvular lesions, known as rheumatic heart disease. 2 Rheumatic heart disease is now largely restricted to developing countries and most of the reduction in its incidence in wealthy countries is attributable to better living conditions with consequent reductions in the transmission of group A streptococci. Nevertheless, with the decline in rheumatic fever in industrialized countries and the emphasis on diseases such as malaria and HIV in developing countries, there has been a parallel reduction in research into this still prevalent and important condition. 3 Rheumatic heart disease remains an obvious public health burden across the developing world causing more than 200 000 deaths a year. 4 An exaggerated immune response to specific bacterial epitopes in a susceptible host is thought to be the basis of the disease. 5 Rheumatic heart disease usually results from the cumulative damage from recurrent episodes of acute rheumatic fever. It has been reported that after a first episode of carditis, cardiac ausculta tion becomes unremarkable in one-third of children but even these children may progress to significant rheumatic valve disease in later life, as confirmed by echocardiography. 6 Thus early detection of “subclini cal” rheumatic valve disease is vital, as it presents an opportunity for case detection at a time when prophylactic penicillin – to prevent recurrent episodes – can prevent progression to important valve disease in young adult life. Early detection of rheumatic heart disease in school children is traditionally done by listening for murmurs by stethoscope, followed by echocardiographic confir mation only in suspected cases. Recently, we did systematic echocardiographic screening in schools in Cambodia and Mozambique, to assess whether early case detection could be improved by using portable ultrasound. 7 We achieved a case detection rate by echocardiography approximately 10-fold that achieved by clinical examination only. Such screening thus makes it possible to identify children at risk of developing severe rheumatic valve disease for whom secondary prevention with penicillin prophylaxis may be effective. Acute rheumatic fever episodes can be prevented by antibiotic treatment of group A streptococcal throat infections, a strategy known as primary prophy