Sexually Transmitted Diseases Health Article

Definition

Sexually transmitted diseases (STDs) are viral and bacterial infections passed from one person to another through sexual contact.

Description

Adolescence is a time of opportunities and risk when many health behaviors are established. Although many of these behaviors are health-promoting, some are health-compromising, resulting in increasingly high rates of adolescent morbidity and mortality. For example, initiation of sexual intercourse and experimentation with alcohol and drugs are normative adolescent behaviors. However, these behaviors often result in negative health outcomes such as the acquisition of STDs. As a consequence of STDs, many adolescents experience serious health problems that often alter the course of their adult lives, including infertility, difficult pregnancy, genital and cervical cancer, neonatal transmission of infections, and AIDS (acquired immunodeficiency syndrome).

Examples of STDs with high prevalence among sexually-active adolescents include:

• Gonorrhea: Caused by the bacteria Neisseria gonorrhoeae, gonorrhea infects the reproductive tract of women, causing pelvic inflammatory disease (PID), a major cause of infertility. The bacteria are found in vaginal secretions and semen.
• Chlamydia: The bacteria that causes chlamydia, Chlamydia trachomatis, trigger inflammation of the reproductive tract, leading to PID in women and epididymitis (inflammation of the epididymis) in men.
• Syphilis: Treponema pallidum is the bacteria that causes syphilis. The course of syphilis is broken down into four distinct segments: primary syphilis, occurring within a few weeks or months of initial exposure; secondary syphilis, occurring generally between six weeks and six months of initial exposure; latent syphilis, an asymptomatic period which may stretch for years; and late syphilis, the most serious stage. If left untreated, syphilis can infect a number of organ systems and cause serious complications.
• Herpes simplex virus: Two different types of HSV (HSV-1 and HSV-2) cause lesions on the genitals, although HSV-2 is associated with the majority of cases. (HSV-1 is most commonly associated with oral lesions, or "cold sores.")
• Human papillomavirus (HPV): HPV causes condylomata acuminata, more commonly known as venereal warts or genital warts. The warts may affect any of the external and internal genital organs in men and women.
• Human immunodeficiency virus (HIV). HIV is the causative agent of acquired immune deficiency syndrome (AIDS), a potentially fatal condition in which the immune system fails and the individual becomes prone to frequent and unusual infections.

Transmission

The mode of transmission varies among the different sexually transmitted diseases. Some bacteria or virus are found in vaginal secretions or semen (e.g. HIV and gonorrhea), while others are shed from the skin of and around the genitals (e.g. HSV and HPV). Infection typically occurs during sexual intercourse or when the genitals come into close contact. Infection may also occur during oral sex, such as transmission of HSV from an oral lesion to the genitals or vice versa, or transmission of HIV from genital secretions through a cut in the mouth. STDs may be transmitted during nonconsensual sex acts such as rape or molestation.

The transmission of many STDs is more efficient from men to women than from women to men. For example, with just one unprotected sexual encounter with an infected partner, a woman is twice as likely as a man to acquire gonorrhea or chlamydia. In addition, different STDs have different rates of transmissibility. For example, with one exposure of unprotected sexual intercourse, a woman has a 1 percent chance of acquiring HIV, a 30 percent chance of acquiring herpes, and 50 percent chance of contracting gonorrhea if her partner is infected.

Demographics

STDs among sexually experienced adolescents occur at alarmingly high rates. One-fourth of the estimated 12 million new cases reported annually occur among adolescents between 15 and 19 years of age. Moreover, since many STDs are asymptomatic, they are often undiagnosed and untreated, thus increasing their potential for proliferation among adolescents.

Gonorrhea and chlamydia, the most prevalent bacterial STDs, disproportionately affect adolescents. The rates of gonorrhea in adolescents ages 15 to 19 years declined between 1990 and 2004, but in the early 2000s they continue to be higher than rates for any five-year age group between 20 and 44 years, particularly among women and African Americans.

Numerous prevalence studies for chlamydia have shown rates to be highest among adolescents and young adults under 25 years of age, many of whom are minorities. Rates of chlamydia reported by gender indicate that women, overall, have higher rates than men due in large part to increased efforts in screening women for asymptomatic chlamydial infections. The low rates of chlamydia for men suggest that the sexual partners of women diagnosed with chlamydia are not being diagnosed or treated. Chlamydia has been detected in more than 10 percent of sexually experienced women during screening.

While rates of syphilis declined between 1990 and 2004, the disease continues to be an important cause of sexually transmitted infection. The rate of syphilis infection among adolescents ages 15 to 19 is 1.3 per 100,000 population for males and 2.2 per 100,000 population for females. For comparison, the syphilis rates among males 20 to 24 is 5.5 per 100,000, and among females of the same age, 3.3 per 100,000.

HSV and HPS occur at alarming rates among sexually experienced adolescents. Studies indicate that one in six Americans is infected with HSV-2, reflecting a ninefold increase between 1975 and 2005. Prevalence of HSV-2 in adolescents and young adults varies by the demographic and behavioral characteristics of the populations studied as well as the diagnostic methods used. As of the early 2000s approximately 4 percent of Caucasians and 17 percent of African Americans are infected with HSV-2 by the end of their teenage years. One study of young pregnant women of low income status found an HSV-2 infection rate of 11 percent in women 15 to 19 years of age and 22 percent in women 25 to 29 years of age.

In 2002, there were 4,785 reported cases of AIDS among teenagers between the ages of 13 and 19, more than double the 1994 figures. Most adolescents with AIDS were infected as a result of high risk sexual and substance use behaviors. Among adolescents ages 13 to 19 years infected with HIV, 49 percent are male and 51 percent are female. Studies also indicate that African-American and Latino teens are overrepresented among persons with AIDS relative to their proportion in the population. Although these epidemiological statistics on AIDS in the United States provide a descriptive overview of the prevalence and patterns of HIV exposure in adolescents, the extent of asymptomatic HIV infection remains largely unknown.