Rheumatic fever - is it still a problem?

The incidence of rheumatic fever has declined in industrialized countries s ince the 1950s and now has an annual incidence of around 0.5 cases per 100, 000 children of school age. In developing countries it remains an endemic d isease with annual incidences ranging from 100 to 200 per 100,000 school-ag ed children and is a major cause of cardiovascular mortality. Interest in t he pathogenesis of rheumatic fever was rekindled by outbreaks in the USA (1 985-1987) and the rare cases still seen in industrialized countries. The cu rrent concept is that the disease results from the host's poorly adapted au toimmune response to group A beta-haemolytic streptococci. The risk of deve loping rheumatic fever following untreated tonsillopharyngitis is 1% in the civilian population. Knowledge of virulence factors has been greatly enric hed by progress in molecular biology. One of the key elements is protein M, a surface protein on the bacterial wall which carries specific epitopes. S everal serotypes which lead to rheumatic fever have been recognized among m ore than 80 identified serotypes. However, the reason why specific strains within a given serotype have increased rheumatogenic virulence remains unkn own. The causal strain adheres to the oral and pharyngeal cells and then re leases its degradation products. These products present antigenic determina nts which cross-react with certain human tissues, particularly in cardiac v alve tissue and myocardium. Diagnosis is now difficult owing to the low inc idence. Late diagnosis can have serious consequences and acute rheumatic fe ver is a therapeutic emergency requiring immediate antibiotic and anti-infl ammatory treatment. In most of Europe there is tacit agreement that all cas es of pharyngitis and tonsillitis should be treated with antibiotics withou t identification of the causal agent despite the fact that only about 20% o f the cases are caused by group A beta-haemolytic streptococci, and could l ead to rheumatic fever.