Gonorrhea

Gonorrhea is the most reported STI in the United States.* The infection is caused by the bacterium Neisseria gonorrhoeae, a gram-negative diplococcus, and humans are the only known natural host. Once thought to be rather fragile and fastidious, not surviving for long periods of time outside of the host, research has recently discovered strains that are capable of surviving in dried pus on a bed sheet for 6 weeks. The organism can be transmitted through vaginal, anal, and oral sexual activity. The typical incubation time for the infection is between 2 and 7 days. Gonorrhea can be transmitted by individuals who are asymptomatic. Up to 40% of males and between 60% and 80% of females may be infected without any symptoms, but they can act as carriers for up to 5 to 15 years. A small number of organisms, in some cases only about 1000, is required to cause an infection. The symptoms of gonorrhea vary between males and females (Box 17.1). Besides infections of the genitals, oral and anal sexual activity can also lead to gonorrheal infections in the pharynx and the rectum, leading to general systemic bacteremia. Symptoms of systemic gonorrheal infections include the following:

• Fever

• Endocarditis

• Skin lesions (Figure 17.1) that can move to the joints, causing arthritis

Gonorrhea increases the risks of other infections, including HIV and chlamydia. Men with prolonged infections may also develop an inflammation of the testicles called epididymitis, a condition often leading to infertility. Prolonged infections in women can result in pelvic inflammatory disease (see Chapter 16, Infections of the Reproductive System), which may include the uterus and fallopian tubes. Scar tissue in the fallopian tubes can prevent fertilization, and damage to the uterine wall can stop implantation of a fertilized ovum (zygote). Pelvic inflammatory disease also increases the risk of ectopic pregnancy.

During delivery gonorrhea can be passed from the infected mother to the baby as it moves through the birth canal (see Chapter 23, Human Age and Microorganisms). Infection of the newborn often leads to infection of the joints, blood infection (bacteremia), and/or blindness.

Diagnosis of gonorrhea is accomplished by identifying the organism by microscopic examination of discharge samples or in laboratory cultures of swabs from infected tissue. Treatment of gonorrhea originally involved sulfonamides and/or penicillin, but the organism has developed resistance to these antibiotics. Antibiotics currently used include ciprofloxacin, cefixime, ofloxacin, and levofloxacin.

Although treatment with antibiotics has a high success rate in eliminating the infection, any damage done to the organs during the infection is permanent.

At the present time there is no vaccine for gonorrhea but research is underway. Preventive measures to avoid contracting an infection include the following:

Syphilis

Syphilis has been in the human population for many years and is documented in many historical writings. Because it causes symptoms that can be associated with numerous other diseases, syphilis is sometimes referred to as the “great imitator.” It is caused by Treponema pallidum, a gram-negative spirochete. Humans are the organism’s only natural reservoir and transmission occurs through direct contact with sores of an infected person. Although the bacterium can be passed on through body fluids such as saliva, the primary means of transmission is through any sexual activity—vaginal, anal, or oral. A pregnant woman can also pass the infection on to her child during pregnancy. This infection is known as congenital syphilis (see Chapter 23, Human Age and Microorganisms).

Syphilis takes place in three stages, with an incubation time between 10 and 90 days after the initial infection. The initial symptoms may be mild and are sometimes difficult to diagnose because they resemble symptoms of other diseases such as gonorrhea. Many infected persons in the early stages do not realize that they are infected. If treated early, syphilis can be cured without any resulting serious or long-term health problems. Untreated, syphilis manifests itself in three stages: primary, secondary, and tertiary syphilis (Table 17.1).

• Primary syphilis represents itself as small, red sores (chancres) that appear on the body at the site of infection within 10 to 90 days after initial contact. These sores will eventually disappear, leaving a scar on the skin. if untreated, the symptoms will move to the secondary stage.

• Secondary syphilis occurs within 2 to 10 weeks of the primary stage (Figure 17.2). During this stage the organism enters the bloodstream and travels to other organ systems, causing a wide variety of symptoms including the following:

• A red-brown rash on the palms of the hands and soles of the feet

• Fever

• Swollen lymph nodes

• Sore throat

• Muscle and joint pain

Without treatment at this point the disease will move into the tertiary stage:

Patients with syphilis in the later stages are also at increased risk for HIV infection.

Pregnant women run the risk of passing the infection on to their unborn child and they have an increased risk for miscarriage, premature delivery, and stillbirth (see Chapter 23, Human Age and Microorganisms). Diagnosis of syphilis can be done by a number of different methods. Observing a sample from a lesion for the organism itself, using a dark-field microscope, is typically one of the first methods used for early detection. Along with microscopic examination, a number of blood-screening tests are available to confirm an infection. These include the following:

Because of the possibility that a single test may result in a false positive or negative reading during the different stages of the disease or under different circumstances, at least two blood tests are done to determine and confirm an infection. For example, the tests based on detection of antibodies are not useful in diagnosing the infection in a person who has had the disease previously, as the antibodies remain in the body for years.

Treatment for syphilis in the primary and secondary stages is fairly simple and can often be achieved with a single intramuscular dose of penicillin. In a more advanced stage of the infection hospitalization and a daily antibiotic regimen may be required. Tetracycline and erythromycin have proven to be effective for persons allergic to penicillin. At the present time there is no vaccine available; however, research is ongoing. Preventive measures to avoid contracting syphilis include the following:

Chlamydia

Although usually referred to simply as chlamydia, the organism Chlamydia trachomatis, a gram-negative coccus and an intracellular obligate parasite, is responsible for a number of different infections of the reproductive system. These include nongonococcal urethritis (NGU), pelvic inflammatory disease (PID), and lymphogranuloma venereum (LGV). Chlamydial infections are now the most prevalent STIs in the United States (Box 17.2). Female carriers of the infection are often asymptomatic, thus increasing the transmission of chlamydial infections. Transmission occurs through exchange of semen or vaginal fluid during vaginal, oral, or anal sexual activity. Pregnant women can also pass the infection on to their child during labor and delivery. The incubation period is between 1 and 3 weeks before symptoms appear. The symptoms of a chlamydial infection tend to be very mild or virtually nonexistent. According to research data, up to 75% to 80% of infected women and up to 50% of infected men show no symptoms at all.