Chlamydia pneumoniae infection in Thai children: serological diagnosis.

Recent Chlamydia pneumoniae infections were investigated in children with respiratory tract infections and in normal children. Four groups of sera were tested for C. pneumoniae antibody IgG and IgM serum fraction by the method of MIF test. A total of 7 cases of recent infection were detected, 3 of 116 with pneumonia, 3 of 123 with other respiratory tract infections, 1 of 263 normal school children and none in sera from cord blood. The cases with recent C. pneumoniae infection were as young as 24 days and 2 months old.