Sexually Transmitted Diseases

Though readily curable, these STDs (sometimes referred to as Sexually Transmitted Infections, or STIs) account for considerable morbidity, ranking among the most frequently reported communicable diseases. Chlamydia and gonorrhea pose threats to the reproductive health of women and are readily transmitted between sex partners. These and many other bacterial STDs influence adverse pregnancy outcomes, either during fetal development or during birth. No effective vaccines exist for these diseases.

Chlamydia. This disease is thought to be the most common of all STDs in the United States. Between 20 percent and 40 percent of sexually active women have been exposed; they have chlamydial antibodies. Since the 1970s, the pathogenesis (i.e., production and development) of and threats to reproductive health from chlamydia have become better understood; it has emerged as an STD with major consequences. It has been estimated that more than $2 billion is spent each year in the United States on treatment of chlamydia and its complications (Noegel et al. 1993). The most common clinical manifestations of chlamydial infections in women are salpingitis and mucccopurulent cervicitis, with the endocervix being the most common site of infection. Chlamydia is a particularly insidious STD because women with active infections usually have minimal or no symptoms. Most women are unlikely to be treated unless: (1) they undergo a screening test (a rapid, inexpensive diagnostic test has only recently become widely available in the United States, but is still unavailable in many parts of the world) that specifically cultures the pathogen; or (2) their male sex partner develops a symptomatic infection and the woman is informed. Seven-day oral antibiotic regimens of either doxycycline or azithromycin are effective treatment of chlamydia in men and women. A single dose azithromycin regimen is equally effective, and, though more expensive, is now available.

Gonorrhea. This disease is the second most commonly reported STD in the United States (approximately 350,000 cases per year are reported [approximately 260 cases per 100,000 U.S. population for men and women combined; many more are thought to occur]). The highest age-specific rates are for women ages fifteen to nineteen and for men ages twenty to twenty-four (Centers for Disease Control and Prevention 2000). For women, gonococcal infection occurs primarily in the cervix, although the pharynx, rectum, and urethra can also be infected. Approximately 40 percent to 60 percent of women with gonorrhea have symptoms, sometimes painful. Gonorrhea, which is less "silent" than chlamydia, can cause a purulent vaginal discharge, dysuria, and frequent urination. Cervical gonococcal infection is usually diagnosed via an endocervical culture. Most infected men have painful symptoms, usually pain and discharge upon urination, which cause them to seek treatment. Several antibiotic regimens (e.g., a single oral dose of cefixime) are safe and effective for most cases (Centers for Disease Control and Prevention 1993). Ominously, about one-third of all gonococcal isolates now manifest some degree of resistance to this conventional therapy, thus causing reliance on more expensive antibiotics and creating concern that some emerging gonococcal strains may soon be resistant to all known forms of antibiotics.

Comparison of chlamydia and gonorrhea. About 25 percent to 40 percent of women with gonorrhea also have a concurrent chlamydial infection. Yet the percentage of women with gonorrhea who also have a concurrent chlamydial infection varies dramatically by subpopulation (Holmes et al. 1999). (Since 1975, trends in reported U.S. gonorrhea rates have steadily declined.) Chlamydia is thought to be homogeneously distributed in the population, although focused in those who are younger, yet sexually active, whereas gonorrhea disproportionately affects minority populations. (In 2000, the ratio of U.S. gonorrhea cases reported in African Americans to whites was five to one; in Hispanics to whites, one to two; [Centers for Disease Control and Prevention 2000]). However, these differences should be viewed cautiously. Research analyzing population-based survey data suggests that the real differences may be less striking (Anderson, McCormick, and Fichtner 1994). Case reporting from publicly funded medical facilities tends to be more complete than that from private facilities, and minority populations disproportionately use publicly funded facilities. All states legally require the medical reporting of most STDs, but inconsistent adherence as well as frequent self-treatment of STDs prevent more accurate estimates of the incidence of STDs in the United States and thereby inhibit a better understanding of their respective epidemiologies.

Pelvic inflammatory disease (PID). PID broadly defines an array of inflammatory conditions, the most common of which are endometritis and salpingitis, which affect the upper reproductive tract of women. Symptoms are often pain with concurrent fever. (There are approximately 2.5 million symptomatic outpatient visits to medical facilities for PID annually in the United States. Nearly 300,000 women are hospitalized annually, and more than 100,000 associated surgical procedures need to be performed [Centers for Disease Control and Prevention 2000]). Most cases of PID are caused, directly or indirectly, by gonococcal and chlamydial infections. PID is frequently episodic, with initial acute episodes being directly caused by untreated or repeat infections of gonorrhea or chlamydia. Subsequent episodes can be caused by nonsexually transmitted pathogens or intrauterine contraceptive devices. Infertility caused by occlusion of the fallopian tubes, chronic pelvic pain, and ectopic pregnancy is the most frequent and serious complication of repeat episodes of PID. A diagnosis of PID is often difficult because there is a wide range of signs and symptoms—or none at all. Women and health care providers should be suspicious of symptoms, especially if there is a history numerous sex partners. A variety of antibiotic therapies (e.g., cefoxitin plus doxycycline) are available for PID; most require aggressive, extended regimens, usually up to fourteen days, for maximum effectiveness.

Syphilis. This disease has been central to the development of the practice of medicine and was the basis for venereology, an early medical subspecialty. Epidemic and a scourge in Europe in the fifteenth century, its symptoms, natural history, and transmission dynamics have fascinated students of medicine for years; its malevolence has caused great personal suffering; and it continues to be a prevention and treatment challenge. In the late 1970s and early 1980s, syphilis in the United States was at moderate levels and was primarily a disease that occurred in homosexual men (Fichtner et al. 1983). However, in the late 1980s, there was a surge in the reported incidence of syphilis in the United States, peaking at about 135,000 cases in 1990. About 50,000 of those cases in 1990, up from approximately 27,000 cases in 1985, represented occurrences of syphilis in primary or secondary stages, when the disease is infectious (i.e., transmissible). From 1990 to 2000, the rate of infectious syphilis declined by 89.2 percent. In 2000, only 5,979 cases were reported in the United States, the lowest since reporting began in 1941 (Centers for Disease Control and Prevention 2000).

About one-third of persons exposed to infectious syphilis acquire it. Within twenty-one days, primary, relatively painless lesions (ulcers or chancres) usually appear. Often these lesions disappear (after ten to ninety days) if the disease is untreated. The disease then reemerges in a secondary stage characterized by more disseminated symptoms, usually malaise, sore throat, and adenopathy (sore lymph glands). During this secondary stage, the classic rash of syphilis appears, often visible on the palms of the hands and soles of the feet. If the disease is still untreated in the secondary stage, a latent period of variable duration is entered by the patient. Subsequently, approximately 15 to 40 percent of the untreated patients develop tertiary syphilis, and small numbers of those (approximately 5–20%) develop serious neurological and/or cardiovascular manifestations that can become life-threatening (Holmes et al. 1999). These late manifestations are rarely seen in the United States.

Untreated pregnant women who are infected with syphilis have a 50 percent change of transmitting the disease to their newborns. About half of these women deliver a preterm baby or a still birth. Throughout the world, this is the most serious direct outcome of syphilis. (The rise of syphilis in U.S. women in the late 1980s, cresting in 1990, increased the concern for preventing cases of congenital syphilis. A peak in reported cases [approximately 4,400] of congenital syphilis occurred in 1991. [Centers for Disease Control and Prevention 2000]).

Syphilis is readily diagnosed by serologic (blood) testing; screening tests are inexpensive and routinely performed in a variety of settings. In the United States, premarital screening is required in nearly all states, a reminder of the history of the disease. One intramuscular injection of benzathine penicillin is the usual, effective treatment for syphilis during its early stages.