Chlamydia is a gram-negative pathogen, which can pass through bacterial filters and parasitize in cells, and has a unique development cycle. Chlamydia is a creature smaller than bacteria, but larger than virus. It is an obligate intracellular parasitic pathogen, similar to bacteria and viruses, and has a two-stage life cycle. It has no ability to synthesize high-energy compounds ATP and GTP, and must be provided by host cells, so it becomes an energy parasite, mostly spherical and piled, with cell walls and cell membranes. It belongs to prokaryotic cells and is generally parasitic in animal cells. At present, there are four kinds of chlamydia: trachoma, pneumonia, parrots and domestic animals.
Chlamydia pneumoniae is considered as a common cause of pneumonia, bronchitis and other respiratory infections. Chlamydia bovis only exists in cattle and sheep; Chlamydia psittacosis can cause psittacosis, which is caused by human inhaling dry dust particles from the feces of infected birds. The onset is often manifested as high fever, headache, muscle pain, chills and upper and lower respiratory discomfort, and some patients may be complicated with encephalitis, myocarditis or thrombophlebitis. Chlamydia trachomatis can not only cause trachoma, but also be recognized as one of the sources of sexually transmitted diseases. Almost half of nongonococcal urethritis is caused by chlamydia trachomatis infection. It can also cause urethral syndrome and venereal lymphogranuloma, male urethritis, epididymitis, female infertility, cervicitis, pelvic inflammatory disease and so on. Neonatal infection through the birth canal can lead to neonatal ophthalmia or