Etiology of acute lower respiratory tract infections in children in a rural community in The Gambia

Approximately 500 children younger than 5 years old resident in 7 villages in a rural area of the Gambia were monitored closely for 1 year for episodes of acute lower respiratory tract infection (ALRI). Each episode was investigated with antigen detection techniques and antibody assays as well as culture for bacteria and viruses. A pathogen was identified in 76 (34.2%) of 222 cases with clinical signs of ALRI and in 34 (42%) of the 81 cases who, in addition, had radiologic evidence of ALRI. Evidence of infection with a bacterial pathogen, most commonly Streptococcus pneumoniae or Haemophilus influenzae, was obtained in 32 (14.4%) cases with clinical signs of ALRI (23.5% of those with radiologically proved pneumonia). Viral agents were cultured from 42 (19%) of 221 cases but also from 14 (14.6%) of 96 controls some of whom had minor symptoms of upper respiratory tract infection. In the absence of an outbreak of respiratory syncytial virus the viral agents recovered most often were influenza A and adenoviruses.