Can we eradicate rheumatic fever in the 21st century?
In the latter half of the 20th century, the clinical importance of variation in the virulence of strains of GAS has been clearly demonstrated. Although still obscure, the pathogenesis of ARF requires immunologically significant infection of the throat by virulent GAS strains. These strains contain large hyaluronate capsules and large M-protein molecules. The latter contain epitopes cross-reactive with host tissues, and also contain superantigenic toxic moieties. In areas where ARF has become rare, GAS pharyngitis continues to be common but is caused predominantly by GAS strains of relatively low virulence. These, however, may colonize the throat avidly and stubbornly. Molecularly distinct pyoderma strains may cause acute glomerulonephritis, but they are not rheumatogenic even though they may secondarily infect the throat. In developing countries with a very high incidence of rheumatic heart disease, identification of the prevalent rheumatogenic GAS strains and development of a multivalent vaccine against them is currently an interesting strategy. Pending vaccine development, intense primary and secondary penicillin prophylaxis should continue to be sharply focused on populations with the highest prevalence of RHD as such measures may often succeed in driving away the most virulent rheumatogenic clones of GAS from their midst.
Stollerman
G H
GH
Boston University, USA. gstollerman@valley.net
D006801:Humans; D012213:Rheumatic Fever / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology* / Q000517:prevention & control*; D013290:Streptococcal Infections / Q000175:diagnosis / Q000276:immunology / Q000517:prevention & control*; D013297:Streptococcus pyogenes / Q000302:isolation & purification; D014774:Virulence