Prospective study on streptococcal pharyngitis among a town population.

A one-year-round study on pharyngitis incidence among the general population of a town (24,300 inhabitants) was carried out. All patients, with pharyngitis who visited health centres were examined clinically and mcirobiologically. The overall pharyngitis incidence rate and the streptococcal pharyngitis incidence rate were, respectively, 8.3 and 3.9 cases per 100 population. Age-related incidence was highest in the group of 5-10 years, seasonal incidence was highest in autumn. Clinical diagnoses made preliminary to bacteriological examination were correct in only a half of the streptococcal pharyngitis cases. The accuracy of clinical diagnosis of streptococcal pharyngitis could, at best, be raised to 80% if fever of less than or equal to 38.0 degrees C and presence of exudate on tonsils should be considered significant criteria. A great majority of the streptococcal pharyngitis cases were caused by group A streptococci; the prevailing M types were 12, 1 and 3. Emphasis is laid on the necessity of performing microbiological examination of all pharyngitis cases in order to ensure etiological diagnosis and causal therapy. 15)