Rheumatic fever and streptococcal infections in an isolated population group in eastern Siberia

During a two-week expedition, the prevalence of rheumatic heart disease (RHD) and the prevalence of group A streptococcal infections was investigated in a group of Yakut families of about 600 persons. In the 478 examined persons no clear-cut RHD was identified, but possible participation of rheumatic etiology in heart changes was not excluded in one adult. Group A streptococci were grown from pharyngeal swabs from 13.3% of the 202 persons examined, in the absence of any overt streptococcal disease in the settlement at the time of screening. Streptococci of at least six M-types were present among the population. Titres of antistreptolysin 0 greater than or equal to 250 u. and of antideoxyribonuclease-B greater than or equal to 1200 u. were found in 21% and 18%, respectively, of the 205 examined individuals. The bacteriological and serological data combined suggested a rather high streptococcal transmission rate in the settlement in the recent past, the pattern of which was reminiscent of the pattern of streptococcus spread in heavily interconnected population groups of the moderate climate. Possible reasons for the absence of definite RHD are discussed.