Chlamydial infections have a growing significance for children and ado
lescents. In addition to biological and diagnostic aspects of chlamydi
al diseases this paper will deal with infections caused by Chlamydia t
rachomatis and Chlamydia psittaci. A detailed discussion of Chlamydia
pneumoniae is included too. The incidence of infection within the gene
ral population is high. The initial contact with Chlamydia pneumoniae
occurs most commonly in individuals between five to fifteen years of a
ge. The symptoms of the initial or subsequent infections may range fro
m that of a viral infection to a pneumonia episode.