The fall and rise of rheumatic fever in the United States: a commentary.

After a documented decline in the incidence of acute rheumatic fever in the United States during the past three decades, an apparent resurgence has occurred in the mid-1980s. Although standards of living have continued to improve with concomitant decrease in crowding and easier accessibility to medical care, the precise reasons for the decline remain unexplained. Furthermore, the decline has occurred even though there is no epidemiologic evidence to suggest any reduction in the incidence of group A streptococcal pharyngitis. Just as the decline remains unexplained, so also does the "resurgence". Of considerable interest are the facts that the preceding pharyngitis has been mild in the majority of cases, the incidence of documented carditis has been high (over 90% in one series), and the rheumatic fever has been concentrated in middle class families with ready access to medical care. Even more intriguing has been the appearance of very mucoid strains of group A streptococci at the same time. While this simultaneous appearance suggests "rheumatogenicity", this has not been substantiated; no "rheumatogenic factor" has yet been isolated from these strains. This outbreak, although small in comparison with the number of cases occurring in many of the developing countries of the world, has important implications for those countries. Unless and until the pathogenesis of rheumatic fever is fully understood, methods of control will not be optimal.