Acute rheumatic fever and rheumatic heart disease on the Navajo reservation, 1962-77.

The occurrence of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) among Navajos was ascertained for the period from 1962 through 1977 by means of hospital discharge diagnoses and patients'' charts. The annualized attack rate for ARF was 12.4 per 100,000 population, with no clear evidence of an overall secular trend. The proportion of recurrences (19.6 percent) and clinical features were similar to those reported elsewhere, but no seasonal variation in attack rates was noted. Between 1962-71 and 1972-77, the age of RHD patients increased, suggesting few newly diagnosed cases and the aging of known patients. A streptococcal disease control program was instituted in many Navajo elementary schools before 1975. In the program, throat cultures were performed routinely for some asymptomatic children and for all symptomatic children. During the subsequent 3 years, ARF rates declined from 13.5 to 8.2 per 100,000 in areas covered by the program, while in the noncovered areas the rates showed little change-9.5 to 10.1 per 100,000.