Chlamydia
Chlamydia is a common STI that can infect the vagina or urethra. Most people with chlamydia have no symptoms. Symptoms of chlamydia include an itching or burning sensation in the genitals and increased vaginal or penile discharge. Using a condom when having sex protects against the infection. Chlamydia is caused by a bacteria and can be cured with antibiotics.