Men between the ages of 15 and 30 who have multiple sex partners are most at risk for nongonococcal urethritis (NGU), which is believed to be the most common sexually transmitted disease in the United States.

NGU is spread almost exclusively via sexual contact, and appears most often in men because a woman's urethra is less easily infected during sex. The infection is most often due to Chlamydia trachomatis, the organism that causes chlamydia. Those that aren't caused by Chlamydia trachomatis are usually due to another bacterium, Ureaplasma urealyticum. In 10% to 20% of NGU cases, the cause is unknown.

Symptoms appear within one to five weeks after infection, and include a slight clear discharge (the color of the discharge can vary from one patient to the next), and itching or burning during or after urination.

However, some men never develop symptoms, and women almost never show signs of infection. However, it's possible that symptoms of burning or itching in or around the vagina may be due to NGU.

The disease is communicable from the time of first infection until the patient is cured. Past infection doesn't make a person immune.

Nongonococcal urethritis is diagnosed by excluding other causes, since inflammation that is not caused by gonorrhea is classified as NGU. A microscopic and/or culture test of the discharge or urine can reveal the infection.

Since many people are infected with both NGU and syphilis at the same time, infected patients also should have a test for syphilis before treatment for NGU begins, and three months after treatment ends.

Antibiotics such as tetracycline or azithromycin will cure NGU; both sexual partners should be treated at the same time.

Patients taking tetracycline should avoid milk or milk products and take the medication at least one hour before or two hours after meals. On the last day of treatment, a male should have a urine test to make sure the infection has cleared. If it hasn't, he should take a second course of therapy. Men should use a condom during treatment and for several months after treatment is completed.

If urine tests indicate the infection is gone but symptoms persist, the doctor will check for signs of prostate inflammation.

NGU is completely curable with proper antibiotic treatment. Untreated, NGU can lead to sterility in both men and women, inflammation of the mouth of the uterus, and infections of the woman's internal sexual organs. An infection during pregnancy may lead to pneumonia or eye infections in the newborn child. Untreated men may develop swelling of the testicles and an infected prostate gland.

People can prevent the spread of NGU by:

• using a condom
• limiting the number of sex partners
• washing the genital area after sex
• if infected, avoid sexual contact; take antibiotics, notify all partners