Today rheumatic fever is still the most common cause of heart disease in children and young adults in developing countries. This disease is typically associated with poverty, in particular with poor housing, overcrowding and inadequate medical care. Rheumatic fever has almost disappeared from economically developed countries; this trend has paralleled improvements in standards of living. However, the recent resurgence of rheumatic fever in middle-class families in the U. S. A. has re-emphasized the importance of this disease in the developed countries as well. Prevention and control of...