Chlamydia

Chlamydia is a common sexually transmitted infection (STI) that affects both men and women. It is caused by the bacteria Chlamydia trachomatis. Chlamydia usually affects the sexual organs, but can also occur in the anus, mouth, and even eyes. Chlamydia is easily treatable when caught early. If left untreated, it may lead serious health problems such as Pelvic Inflammatory Disease (PID) and ectopic pregnancy in women.

Transmission

Chlamydia is a sexually transmitted disease. It can be transmitted during vaginal, anal, and oral sex. Genital infection can also be passed from an infected mother to the baby during vaginal childbirth.
Prevention:
The use of condoms and other protective measures may reduce the chance of infection but does not eliminate it completely. Using latex condoms consistently and correctly - from the very beginning of sexual contact until there is no longer skin contact - reduces the risk of transmission of chlamydia.

Symptoms

Most people with infection are unaware of it, particularly women. When symptoms do occur, it usually appears within 1 to 3 weeks after exposure.

Symptoms in Women include: 

Abnormal/ Increased vaginal discharge or bleeding
Bleeding between periods/ Heavier periods 
Burning sensation when urinating 
Pain (and/or bleeding) during sex
Bleeding after sex
Lower abdominal pain (pelvic pain) 

Symptoms in Men include: 

A white/cloudy or watery discharge from the penis 
Burning and itching around the opening of the penis. 
Pain with urination
Painful swelling of the testicles (epididymitis)
Anal pain and inflammation 

Persons who receive anal intercourse may contract chlamydial infection in the rectum, which can cause rectal pain, discharge, or bleeding. Chlamydia can also be found in the throats of women and men having oral sex with an infected partner.

Complications

If left untreated, Chlamydia can cause long term complications that may lead to infertility.
In women, this can include:
Pelvic Inflammatory Disease (PID)
Tubal Infertility
Ectopic pregnancy
In Men, this can include: 
Epididymitis (inflammation of the reproductive area near the testicles) characterized by pain and/or fever
Men may have reduced sperm quality, although often improves when infection is treated. 

Treatment 

Antibiotics is used to treat chlamydia. Persons with chlamydia should abstain from sexual activity for 7 days after single dose antibiotics or until completion of a 7-day course of antibiotics, to prevent spreading the infection to partners. It is important to take all the medication prescribed to cure chlamydia. Although medication will stop the infection, it will not repair any permanent damage done by the disease. If a person’s symptoms continue for more than a few days after receiving treatment, he or she should return to a health care provider to be reevaluated.
Men who have a thick or bloody discharge from the penis with soreness or inflammation and women with heavy offensive vaginal discharge or irregular bleeding and low abdominal pain should see their regular doctor.