gonorrhea, common infectious disease caused by a bacterium (Neisseria gonorrhoeae), involving chiefly the mucous membranes of the genitourinary tract. It may occasionally spread to membranes in other parts of the body, especially those of the joints and the eyes. Since the principal mode of transmission is sexual contact, gonorrhea is classified as a sexually transmitted disease. Gonorrheal conjunctivitis was once a prominent cause of blindness in the newborn, the infection being transmitted during delivery. Routine use of silver nitrate solution in the eyes of every infant at birth has largely overcome this problem.

The usual site of infection in women is the cervix. From there it can spread to the uterus and fallopian tubes and cause pelvic inflammatory disease, ectopic pregnancy, or infertility. Other complications, in both sexes, include infection of the joints, heart valves, and brain. Women are often asymptomatic, but may have a vaginal discharge or burning sensation on urination; men may have a discharge from the penis and pain on urination. Examination of the discharge reveals the presence of the bacteria. In most cases, the disease can be cured by adequate treatment with a fluoroquinolone or cephalosporin antibiotic such as ciprofloxacin or ceftriaxone. Failure of treatment is usually due to resistant strains (see drug resistance). Prior infection does not confer resistance and reinfection is common.

Sexually transmitted disease. It is characterized by genitourinary inflammation, caused by the bacterium Neisseria gonorrhoeae (gonococcus). Symptoms in men include burning on urination, discharge of pus, and, with deeper infection, frequent urination, sometimes with blood. Women may have mild vaginal discharge and burning, but there is usually no sign until a sex partner is infected or complications—sometimes serious—arise from its spread beyond the cervix. If spontaneous recovery does not occur, it may cause sterility in both sexes but is rarely fatal. Gonorrhea is common worldwide. Penicillin, generally a successful treatment, reduced its incidence, but resistant strains are increasingly found. Many cases are not reported. Penicillin may also mask coexisting syphilis (since the dose to cure gonorrhea does not cure syphilis).

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