Streptococcal throat carriage in a population of nursery and primary school pupils in Benin City, Nigeria

Abstract

Background: Group A streptococcus (GAS) is a major cause of mortality in man. Regular disease surveillance can be achieved through evaluation of throat carriage. Objectives: To evaluate GAS throat carriage amongst nursery and primary schools pupils in Benin City, Nigeria. Method: This cross sectional study was carried out between September and November 2011. A multistage random sampling method was used to recruit the pupils. Throat swabs were obtained for microscopy and Lancefied grouping. Results: 426 pupils were recruited of which 363(85.2) were in primary and 63(14.8%) in nursery schools. The subjects were aged 2 to 15years and 203(47.7%) were males. Of the 426 pupils, 123 (28.9%) had positive throat swabs for β haemolytic streptococcus (βHS). None of the isolate was GAS. The isolates were groups C (50.4%), D (38.2%) and G (11.4%). Conclusion: Although βHS throat carriage rate in this study is high, there was no GAS isolate. This may suggest low prevalence of GAS related diseases in the community.

Streptococcal Throat Carriage among Primary School Children Living in Uyo, Southern Nigeria

“…The pattern of BHS isolates from the present study is consistent with that of recent Nigerian studies, which also reported GCS as the commonest BHS isolate in asymptomatic children. 9,18,20 These earlier reports had also noted a comparable absence of GAS in studies of BHS carriage. In contrast, an earlier study performed in Lagos in 1972 documented GGS as the commonest Lancefield group isolate.…”

“…41 Moreover, several authors have acknowledged wide variations in the prevalence rate of BHS carriage, even within localities in the same regional boundaries. 4,9,19 This variation may reflect differences in the burden of streptococcal diseases in various localities. The pattern of BHS isolates from the present study is consistent with that of recent Nigerian studies, which also reported GCS as the commonest BHS isolate in asymptomatic children.…”

“…22 It was however significantly lower than rates (20.9-28.9%) reported from earlier Nigerian studies. 9,18 The difference may be due to improved measures for control of respiratory infections, such as better hand hygiene and increased rates of exclusive breastfeeding in the country over the years. 41 Moreover, several authors have acknowledged wide variations in the prevalence rate of BHS carriage, even within localities in the same regional boundaries.…”

“…In Nigeria, in the last decade, three studies reported rates varying between 4 and 28.9% for streptococcal throat carriage in children. 9,18,20 Furthermore, these Nigerian studies have all demonstrated an absence of GAS in asymptomatic carriers despite purportedly high rates of rheumatic fever/rheumatic heart disease in the region. This increase in non-GAS BHS throat carriage has also been reflected in another African study, as well as studies from other parts of the world.…”

“…7,8 Active surveillance of BHS disease may thus be achieved by periodic evaluation of the prevalence of streptococcal throat carriage in a community. [8][9][10] Streptococcal throat infection may be complicated by early suppurative as well as medium and long-term non-suppurative sequelae such as acute rheumatic fever and poststreptococcal glomerulonephritis, with high morbidity and mortality. 11,12 Rheumatic heart disease affects over 15 million persons worldwide, causing about a quarter of a million deaths annually, with highest prevalence recorded in Sub-Saharan Africa.…”