**3. Etiology**

*C. trachomatis* transmission occurs with direct contact, this includes the vaginal, anal, or oral sexual routes and vertical transmission to the newborn from an infected mother during vaginal birth.

Specific risk factors for the chlamydial infection are 15–24 years of age, poor socioeconomic conditions, multiple sexual partners, exchange of sex for money, intercourse without a barrier contraceptive, current coinfection with another STD, or a history of previous STD, certain cytokine polymorphisms that are related to severe disease and the risk of tubal factor infertility [27], specific variants in Toll-like receptor 1 and 4 genes creating infection predisposition [28].
