Pathophysiology
It is one of the most common sexually transmitted diseases in the world, caused by the bacterium Chlamydia trachomatis. Infected individuals transmit the disease to their sexual partners via unprotected vaginal, oral or anal contact. It is also possible to spread the infection by sharing unwashed sex toys or those without a new condom. (2)
It is not always necessary to penetrate a person’s body for the infection to be contracted; simply contacting sexually bodily fluids from an infected individual can cause the infection. The most common cause of blindness in the world is trachoma, which occurs when the eyes come into contact with infected fluids. The infection can also be transmitted vertically from mother to baby when the baby passes through the vaginal canal of a mother infected with the disease.
By invading and infecting the host cells, Chlamydia bacteria receive nutrients, which are essential for their survival. Starved of these nutrients, the bacteria infected by the bacteria die off as well. The Chlamydia bacteria stop dividing once they are deprived of vitamins or iron, leading them to grow to abnormally large sizes. These aberrant cells can still be viable, as they can adopt a normal state when the host cell conditions return to normal.
According to studies, around half of infections disappear within a year, 80% disappear after two years, and 90% within three years after the initial infection. Some infections, however, persist and can cause serious problems, such as epididymitis in men and pelvic inflammatory disease in women. These infections can lead to infertility in both sexes.
The pathologic consequences of infection are well-established, but it is still not fully understood how chlamydia causes tissue damage. According to histological analysis of tissues from women with PID caused by Chlamydia trachomatis, they exhibit neutrophils in the endometrial surface epithelium and within the gland lumens, dense subepithelial lymphocytic infiltration, stromal plasma cells, and germinal centers containing transformed lymphocytes. In human female genital tract tissues infected with bacteria, neutrophils and chronic inflammatory cells are prominent but do not assist in determining specific responses responsible for the sequelae.