The incubation period of Chlamydia pneumoniae is about 2–4
weeks. The disease is usually mild but may be prolonged. The
common symptoms are fever and cough. Crackles are usually
revealed on chest examination. The only reservoir for Chlamydia
pneumoniae is human beings. The signs and symptoms are seen
in prodromal phase. Sputum is scanty and pulmonary infltration
is minimal. About 9% of mortality is seen with Chlamydia
pneumoniae infections.