Variation in Group A Streptococci and the Prevalence of Rheumatic Fever: A Half-Century Vigil

This editorial reviews a current report of the disappearance of recurrent rheumatic fever in a Chilean cohort followed prospectively in which antibiotic prophylaxis was discontinued, although sporadic outbreaks of rheumatic fever continued to be observed in neighboring communities with similar racial, ethnic, and socioeconomic characteristics. Observations of the past 50 years are cited to support an explanation that changes in the attack rate of rheumatic fever can be explained not only by the relative frequency of group A streptococcal infections and their appropriate treatment but, in addition, by quantitative and qualitative differences in strain virulence properties that determine whether group A streptococci are rheumatogenic.

In this issue of Annals, Berrios and colleagues [1] report a prospective study conducted in Chile in which prophylaxis for rheumatic fever recurrences was discontinued and close medical surveillance was maintained. The subsequent rheumatic recurrence rate was only 0.7 per 100 patient-years. Moreover, no recurrences were observed during an outbreak of 52 cases of acute rheumatic fever in the study area in 1986.

How can one explain focal outbreaks of acute rheumatic fever or dramatic changes in rheumatic fever recurrence rates in populations that differ little or not at all in racial, ethnic, or socioeconomic circumstances? Is the explanation simply the relative frequency of group A streptococcal infection and its appropriate treatment or are there, in addition, marked differences among group A streptococcal strains that make some strains far more rheumatogenic than others? Those of us who have pondered these issues for several decades recall most vividly that acute rheumatic fever was one of the greatest plagues of the first half of this century. As a freshman medical student in 1941, I learned that acute rheumatic fever killed more school children in the United States than all other diseases combined. Moreover, survivors afflicted with rheumatic heart …