Further studies on rheumatic fever epidemiology

It is generally agreed that rheumatic fever is more prevalent in temperate than in tropical zones. It has also been stated that the salutary effect of the tropics on rheumatic patients may be due to the lower incidence of upper respiratory infections in regions enjoying a tropical climate. The present study confirms the rarity of rheumatic disease in the tropical zones of Mexico, but also shows that the rate of streptococcus carriers is as high in the tropics as in temperate regions. It also gives data showing that antistreptolysin titers are higher in the sera from persons inhabiting the tropics, thus pointing to the greater prevalence of streptococcal infections in tropical zones. The above considerations suggest that the tropical climate affects the response of the host before the rheumatogenic agent.