Correspondence

Rheumatic Heart Disease in Developing Countries

N Engl J Med 2007; 357:2089November 15, 2007

Article

To the Editor:

In his Perspective article on rheumatic heart disease in developing countries, Carapetis (Aug. 2 issue)1 correctly notes the important contribution of improved living conditions to the decline in the incidence of acute rheumatic fever over recent decades in wealthy countries. However, he does not acknowledge the contribution of the very substantial decrease in the prevalence of highly rheumatogenic emm types of group A streptococci as causative agents of acute pharyngitis.

Our surveillance studies of pediatric pharyngitis group A isolates in the United States and Canada from 2000 through 2005 showed a striking disappearance of emm types 14, 18, 19, and 29 or a marked decrease of emm types 3, 5, and 6. These have been the most important rheumatogenic types from the 1960s (when rheumatic fever was prevalent) to the present decade (when rheumatic fever is quite rare).2 The basis for this marked decline in circulating rheumatogenic types is not clear, but it is very likely to be independent of the changes in living conditions.

Stanford T. Shulman, M.D.
Northwestern University Feinberg School of Medicine, Chicago, IL 60611
sshulman@northwestern.edu

2 References

1. 1

   Carapetis JR. Rheumatic heart disease in developing countries. N Engl J Med 2007;357:439-441
   Full Text | Web of Science | Medline

2. 2

   Shulman ST, Stollerman G, Beall B, Dale JB, Tanz RR. Temporal changes in streptococcal M protein types and the near-disappearance of acute rheumatic fever in the United States. Clin Infect Dis 2006;42:441-447
   CrossRef | Web of Science | Medline

Author/Editor Response

It may well be that changes in the virulence of circulating group A streptococci have accounted for much of the decline in the incidence of rheumatic fever since the late 1960s in the United States. However, approximately 95% of the reduction in the rate of death due to rheumatic fever during the 20th century in the United States occurred before 1960,1 probably because of reduced group A streptococcal transmission resulting from an improved housing infrastructure.

I agree with the concept of “rheumatogenic” group A streptococci, but studies in areas where rheumatic fever is common have not shown associations with classic rheumatogenic emm types.2,3 In these settings, rheumatogenic strains, regardless of the emm type, are probably always circulating — hence the endemic rather than epidemic disease pattern.4 In populations in which dozens of streptococcal strains are present at any one time,5 dramatic reductions in overall transmission rates will be necessary before we can expect to see a waning of particular rheumatogenic strains.

Jonathan R. Carapetis, Ph.D.
Menzies School of Health Research, Casuarina, NT 0811, Australia
jonathan.carapetis@menzies.edu.au

5 References

1. 1

   Gordis L. The virtual disappearance of rheumatic fever in the United States: lessons in the rise and fall of disease: T. Duckett Jones Memorial Lecture. Circulation 1985;72:1155-1162
   CrossRef | Web of Science | Medline

2. 2

   Martin DR, Voss LM, Walker SJ, Lennon D. Acute rheumatic fever in Auckland, New Zealand: spectrum of associated group A streptococci different from expected. Pediatr Infect Dis J 1994;13:264-269
   CrossRef | Web of Science | Medline

3. 3

   Pruksakorn S, Sittisombut N, Phornphutkul C, Pruksachatkunakorn C, Good MF, Brandt E. Epidemiological analysis of non-M-typeable group A Streptococcus isolates from a Thai population in northern Thailand. J Clin Microbiol 2000;38:1250-1254
   Web of Science | Medline

4. 4

   Carapetis JR, Currie BJ, Kaplan EL. Epidemiology and prevention of group A streptococcal infections: acute respiratory tract infections, skin infections, and their sequelae at the close of the twentieth century. Clin Infect Dis 1999;28:205-210
   CrossRef | Web of Science | Medline

5. 5

   McDonald MI, Towers RJ, Andrews RM, et al. The dynamic nature of group A streptococcal epidemiology in tropical communities with high rates of rheumatic heart disease. Epidemiol Infect (in press).
   

Citing Articles (1)

Citing Articles

1. 1

   Tsung O. Cheng. (2009) How much of the recent decline in rheumatic heart disease in China can be explained by changes in cardiovascular risk factors?. International Journal of Cardiology 132:3, 300-302
   CrossRef