Prospective study of pharyngitis: clinical diagnosis and microbiological profile.
A prospective study of pharyngitis was carried out in the general population of twenty-two thousand in a small country town, over a period of ten weeks in the fall of 1984. It has been confirmed that, as in the past clinical diagnosis "streptococcal" and "nonstreptococcal" pharyngitis without microbiological examination is still highly inaccurate. From the clinical and microbiological parameters, the incidence in the period of follow-up was calculated as 7.2 and 12.0 cases per 100 population per year for streptococcal and nonstreptococcal pharyngitis, respectively. These data document the health importance of this disease which is frequently underestimated. The M (by M or OF antigens) typability accounted for 62% of group A strains isolated, the prevailing types being M 1 and M 12. Comparison of M and OF typability of field strains immediately after isolation and three weeks later proved the superiority of an early typing. The accurate identification of prevailing types is essential for the prospect of streptococcal vaccine. In streptococcal pharyngitis cases treated with penicillin, the increase of antistreptolysin O and antideoxyribonuclease B titres was recorded in very few instances during a three week period after the onset of the disease. The examination of patients with nonstreptococcal pharyngitis aimed at detecting the role of some viruses or of M. pneumoniae proved that the etiology by these agents was practically nil in the cases concerned at this particular period of time. This finding suggests focusing interest on a possible role of other pathogens. The morbidity rates of pharyngitis, and the clinical as well as the microbiological data resulting from the study make it urgent to pay further attention to this infection and to attempt to elucidate the missing points in the etiology and diagnosis of this disease which belongs to the bacterial infections most frequently seen in man in economically developed countries.