beta-Hemolytic streptococcal throat carriage and tonsillopharyngitis: a cross-sectional prevalence study in Gabon, Central Africa.

BACKGROUND: Group A streptococcus (GAS) and possibly other beta-hemolytic streptococci (BHS) account for a considerable morbidity and mortality burden in African populations; however, disproportionately little is known about the epidemiology of BHS in sub-Saharan Africa. This study assessed the prevalence of GAS, group G streptococcus (GGS) and group C streptococcus (GCS) carriage and tonsillopharyngitis in a Central African population. METHODS: A prospective cross-sectional study was performed to assess the prevalence of and risk factors for BHS carrier status and tonsillopharyngitis in children and adults in Gabon. RESULTS: The overall BHS carrier prevalence was 135/1,005 (13.4%); carrier prevalence of GAS, GGS, and GCS was 58/1,005 (5.8%), 50/1,005 (5.0%), and 32/1,005 (3.2%), respectively. Streptococcal carriage was associated with school and pre-school age (adjusted OR 2.65, 95% CI 1.62-4.36, p = 0.0001 and 1.90, 95% CI 1.14-3.17, p = 0.0141, respectively). Participants residing in urban areas were less likely carriers (OR 0.52, p = 0.0001). The point-prevalence of BHS-positive tonsillopharyngitis was 1.0% (9/1,014) and 15.0% (6/40) in school children with sore throat. CONCLUSIONS: Non-GAS exceeded GAS throat carriage and tonsillopharyngitis suggesting a yet underestimated role of non-GAS streptococci in BHS diseases.