Disease History, Characteristics, and Transmission
Gonorrhea is one of the most common sexually transmitted diseases. It is caused by the bacterium Neisseria gonorrhoeae which infects parts of the reproductive tract such as the cervix, uterus, and Fallopian tubes in women and the urethra in both men and women.
N. gonorrhoeae, sometimes known as gonococcus, is one of two pathogenic species in the Neisseria genus. The other, N. meningitides, is a leading cause of acute bacterial meningitis, an inflammation of the membranes covering the brain and spinal cord. Gonorrhea is curable and treatment is important as the disease can cause serious complications that may lead to both female and male infertility. Treatment must extend to the sexual partners of those who are diagnosed with the disease in order to help control its spread. Strains of gonorrhea that are resistant to antibiotics appear to be increasing in importance; for this reason, researchers need to develop new antibiotics that can carry on fighting the disease.
Disease History, Characteristics, and Transmission
The word gonorrhea comes from the Greek words gono for seed and rhoea, meaning flow. The disease was first described in AD 170 by the Greek physician and philosopher Galen (c.129–216). It was thought that the characteristic discharge of gonorrhea in men consisted of semen. The causative agent, N. gonorrhoeae, was discovered in 1879 by Albert Neisser (1855–1916) who gave the bacterium its name. This was just one of many important advances during late nineteenth and early twentieth centuries in the understanding of the causes of venereal diseases (now know as sexually transmitted diseases, or STDs). N. gonorrhoeae is a coccus, a roundshaped bacterium that is Gram negative (a term referring to the way it is stained for microscopic examination). The N. gonorrhoeae bacteria tend to associate in pairs, a feature that aids identification.
Infection with N. gonorrhoeae causes urethritis (inflammation of the lining of the urethra) among men and cervicitis (inflammation of the cervix) in women. The time of onset of symptoms following infection varies from one day to 30 days. In men, the first symptom of gonorrhea is usually painful urination, followed by a thick purulent (pus-containing) discharge from the urethra. The presence of pus makes the discharge yellow, white, or green, and it may be flecked with blood. In some cases, there is swelling in the testicles. However, many men have no symptoms. In women, painful urination is also the first symptom of gonorrhea—this may be followed by a vaginal discharge and possible bleeding. Sometimes the symptoms in women are so minor that they are mistaken for a vaginal or urinary infection. Most women with gonorrhea have no symptoms at all.
Untreated, gonorrhea tends to resolve after several weeks. However, during this time complications may set in and the person remains infectious. In men, the epididymis (the coiled tube leading sperm from the testicles) may become inflamed, which can lead to infertility. Gonorrhea in women can lead to salpingitis, which is inflammation of the Fallopian tubes. It is also a leading cause of pelvic inflammatory disease (PID), which affects around one million women a year in the United States. Symptoms of PID can include severe abdominal pain and fever, and the condition may lead to the development of pus-filled abscesses, long-lasting pelvic pain, and infertility. PID can also scar the Fallopian tubes, increasing the risk of ectopic pregnancy. (An ectopic pregnancy occurs when a fertilized egg starts to develop inside a Fallopian tube instead of within the uterus; it requires immediate medical attention.) In around one percent of cases, gon- orrhea spreads throughout the body and causes severe arthritis—inflammation of the joints—and skin lesions. Neonatal gonorrhea contracted during childbirth causes very severe conjunctivitis, an inflammation of the conjunctiva (the mucus membrane that lines the inner surface of the eyelid) covering the cornea, and may lead to blindness.
Gonorrhea is spread through contact with the anus, mouth, penis, or vagina—typically from various forms of unprotected sexual intercourse. Ejaculation is not necessary for infection to occur. The chance of a man contracting gonorrhea from an infected woman is 20%. The corresponding risk for a woman is 50%. A few ‘core transmitters’ spread the disease through having unprotected sex with many different partners. Those without symptoms are more likely to spread the disease than those who do have symptoms. As the infection affects the cervix in women, an infected woman can transmit the disease to the fetus during childbirth.
WORDS TO KNOW
GRAM-NEGATIVE BACTERIA: All types of bacteria identified and classified as a group that does not retain crystal-violet dye during Gram's method of staining.
PURULENT: Any part of the body that contains or releases pus is said to be purulent. Pus is a fluid produced by inflamed, infected tissues and is made up of white blood cells, fragments of dead cells, and a liquid containing various proteins.
SEXUALLY TRANSMITTED DISEASE (STD): Sexually transmitted diseases (STDs) vary in their susceptibility to treatment, their signs and symptoms, and the consequences if they are left untreated. Some are caused by bacteria. These usually can be treated and cured. Others are caused by viruses and can typically be treated but not cured. More than 15 million new cases of STD are diagnosed annually in the United States.
Scope and Distribution
After chlamydia, gonorrhea is the most common sexually-transmitted disease in the United States. In 2004, the Centers for Disease Control and Prevention (CDC) recorded 330,132 new cases and the true figure is probably nearer to 700,000 because of under-reporting. Worldwide, there are around 62 million new cases of gonorrhea every year. Teenagers, young adults, and African-Americans appear to be most at risk of gonorrhea. It is also more common within lower socio-economic groups.
IN CONTEXT: A TOP SECRET WEAPON AGAINST GONORRHEA
The Unites States Army made immediate use of penicillin in World War II (1941–1945). In hospitals near the front, the new therapeutic agent saved thousands of soldiers from post-battle-field wound infections, and also proved an effective agent in treating many cases of syphilis and gonorrhea among the troops. Penicillin was initially considered a war asset and war secret in the United States and Britain but by the end of 1945, commercial manufacturing plants were capable of producing enough penicillin so that physicians also could prescribe it to their civilian patients.
Treatment and Prevention
Penicillin was the first treatment for gonorrhea. Many other antibiotics, including ceftriaxone and ciprofloxacin, are used, but they can only treat the primary infection, not the complications. It is important that any sexual partners of the infected person are traced and treated to stop spreading the infection. Nearly half of those infected with N. gonorrhoeae are infected with C. trachomatis as well. Antibiotic resistance can be a problem, as strains of N. gonorrhoeae resistant to penicillin and the fluoroquinolone antibiotics have emerged in recent years. Pregnant women should be tested for gonorrhea and treated to prevent the infection passing to their babies. Newborn's are routinely treated with silver nitrate drops or other drugs to prevent conjunctivitis and reduce the risk of blindness.
Sexual abstinence or a monogamous sexual relationship with an uninfected partner are the most effective means of preventing the spread of gonorrhea. Condoms, used correctly and consistently, can also help prevent infection. Vaccines and microbiocides against N. gonorrhoeae are under development.
Impacts and Issues
Gonorrhea is a serious public health problem because it can inflict long-term damage upon the female—and, to a lesser extent—male reproductive systems without an individual being aware that he or she is infected. There may be no symptoms associated with either the primary infection or the complications. According to the CDC, after a two-decade decline in the number of cases of gonorrhea in the United States, reported cases began rising again in the 1990s. The CDC estimates that about five percent of people in the United States ages 18–35 are unknowingly infected with gonorrhea. Meanwhile, the antibiotic drugs used to control N. gonorrhoeae could be losing their effectiveness, as resistance spreads from Southeast Asia through Hawaii to the west coast of the United States.
IN CONTEXT: TRENDS AND STATISTICS
Researchers are increasingly concerned about antimicrobial resistance shown by N. gonorrhoeae. The problem presents an important global public health challenge in the struggle to control gonorrhea.
Gonococcal strains have been demonstrated that are resistant to fluoroquinolones, penicillins, spectinomycin, and tetracyclines. Moreover, strains that resist treatment doses of the antibiotics ciprofloxacin and ofloxacin that exceed the CDC recommended treatment doses have been discovered. According to World Health Organization (WHO) data and reports such resistant strains may be encountered in more than 40% of cases treated in some Asian countries.
SOURCE: Centers for Disease Control and Prevention, Division of Sexually Transmitted Disease (STD)
Gonorrhea and HIV infection areclosely related; those with both conditions are more likely to transmit HIV. People with gonorrhea who are HIV negative are also more likely to be infected with HIV than someone without gonorrhea. Without a vaccine against N. gonorrhoeae, prevention efforts focused on safer sex practices, regular STD testing, and routine gynecological examination remain essential to controlling the spread of gonorrhea.
See AlsoAntibiotic Resistance; Bacterial Disease; Sexually Transmitted Diseases.
Wilson, Walter R., and Merle A. Sande. Current Diagnosis & Treatment in Infectious Diseases. New York: McGraw Hill, 2001.
Centers for Disease Control and Prevention (CDC). “Gonorrhea.” April 2006 <http://www.cdc.gov/std/Gonorrhea/STDFact-gonorrhea.htm> (accessed April 9, 2007).
National Institute of Allergy and Infectious Diseases. “Gonorrhea.” August 2006 <http://www.niaid.nih.gov/factsheets/stdgon.htm> (accessed February 23, 2007).