What Causes Chlamydia Infection?

What Causes Chlamydia Infection? Chlamydia is a bacterial infection. The bacteria are usually spread through sex or contact with infected genital fluids (semen or vaginal fluid). You can get chlamydia through: unprotected vaginal, anal or oral sex. How does a person become infected with chlamydia? How is chlamydia spread? You can get chlamydia by having