Chlamydia Infection and Pneumonia

A wide spectrum of human diseases can result from chlamydial infections. Psittacosis is an infectious disease of avians caused by Chlamydia psittaci that can manifest in severe systemic disease in humans.' Chlamydia trachornatis infections are the leading cause of sexually transmitted genital tract disease, the only cause of classic trachoma, and also result in perinatal infant pneumonia and conjunctivitis acquired from the infected mother during childbirth.2 Chlamydiapneurnonb causes a variety of acute respiratory illnesses, including pharyngitis, sinusitis, bronchitis, and pneumonia, and has been associated with chronic cardiopulmonary diseases including adult-onset asthma3 and atheroscler~sis.~ Although C. psittaci, C. trachomatis, and C. pneurnoniae each have been associated with a distinct array of human diseases, pneumonia is common to all three. Pneumonias caused by each species have both unique and shared features and consideration of these differences and similarities may provide insight into mechanisms of these chlamydia1 diseases. For this reason, the current chapter examines the epidemiology, pathogenesis, clinical symptoms, and immune response to chlamydia1 pneumonias.