Chlamydia is a sexually transmitted disease, or STD, caused by the organism Chlamydia trachomatis. Sexually transmitted disease refers to any contagious disease transmitted from one person to another during sexual contact. In men, the infection normally involves the urethra. The urethra is the tube that carries urine from the bladder to the outside of the body.

What is going on in the body?

The organism Chlamydia trachomatis causes chlamydia infection. It infects the cells and causes a number of changes. The organism is usually passed from one partner to another during sexual intercourse. Irritation and inflammation of the man's urethra from the infection often causes symptoms. Other areas of the body, including the rectum and the throat, can also become infected with chlamydia.

What are the causes and risks of the infection?

The organism that causes a chlamydia infection is usually passed from one partner to another during sexual intercourse. Any other intimate contact of the genitals, mouth, rectal area, or the sharing of sexual toys can transmit the organism from one individual to another.

A man's risk of chlamydia infection is increased if he has more than one sexual partner.