Chlamydia is a pathogenic microorganism, small in size and a pathogenic bacteria, chlamydia is much smaller than bacteria, slightly larger than viruses, it is the biggest difference with bacteria is that it can not reproduce in the outside world, mainly parasitic in the cells, different chlamydia can cause different diseases in humans, such as invasion of the eyes, genitourinary system, respiratory tract, nervous system and so on. 1. Chlamydia infection in the lungs usually enters the respiratory tract by inhalation and causes the patient to develop. Chlamydia pneumonia is a type of pneumonia, atypical pneumonia, mainly invades the interstitial lung, so it is easy to appear some manifestations of interstitial pneumonia. 2, chlamydia invasion of the eye can cause trachoma, the clinical manifestations of the eye redness, pain, foreign body sensation, the appearance of purulent discharge, treatment requires the active application of antibiotics for treatment. 3, chlamydia can also infect the genitourinary system, appearing female leucorrhea, vulvar itching and other symptoms. Men’s will appear urinary frequency, urinary urgency, painful urination and other symptoms. In short, chlamydia or prevention-oriented, usually strengthen physical exercise, increase body resistance, can reduce the chances of liquid infection, hygiene, to avoid cross-infection, and good hygiene habits.