Gonococcal and Chlamydial Genital Infections and Pelvic Inflammatory Disease

Epidemiology

While the annual incidence of gonococcal infections in the United States declined from the early 1980s to an all-time low in 2009, the rate began to creep up, and by 2013 it was 106.1 cases per 100,000. Notably, rates in men exceeded those in women for the first time in 2013, possibly representing either increased ascertainment or actual higher incidence among men who have sex with men . The highest reported rates of gonorrhea were in women 15-19 years of age and in men 20-24 years of age, with marked differences by race (higher in blacks). While gonorrhea typically infects the cervix or urethra, both rectal and pharyngeal infections occur and are an important reservoir of asymptomatic infection, which helps to promote sexual transmission.

An estimated 2 million new chlamydial infections occur annually in the United States, and 3 million in Europe. In contrast to gonorrhea, these infections are more widely geographically distributed, and peak in even younger age groups—at least in women, as the epidemiology in men has not been well defined. Biological and social factors (namely, cervical ectopy and choice of sex partners) likely play a role in placing adolescent females at highest risk for chlamydial infection. The incidence of this disease has declined dramatically in some areas, probably in response to widespread screening programs begun in the 1980s. However, these trends may be undergoing a reversal. Chlamydia prevalence also remains high in many areas of the country in which screening has not become routine, approaching or exceeding 15-25% in some adolescent populations.

The prevalence of gonorrhea and chlamydia infections, as well as other STIs, is higher in developing countries than in the United States, although surveillance data from many areas are not comprehensive. The impact of both of these diseases goes beyond the obvious clinical and economic concerns and their well-recognized sequelae for women (which include ectopic pregnancy, tubal infertility, and chronic pelvic pain). Both gonorrhea and chlamydia potentiate infectiousness for and susceptibility to HIV. Urethral infection with N. gonorrhoeae is associated with an eight-fold increase in the amount of HIV in semen. In a prospective study of commercial sex workers in Kenya, acquisition of cervical chlamydial infection was associated with a 2.5-fold increase in the likelihood of acquiring HIV. Thus, these infections further fuel the HIV epidemic throughout Africa, Asia, and Latin America, along with other factors such as migration of refugees, population shifts from rural to urban environments, and persistence of commercial sex and illicit drug use. The spread of HIV in developing countries is discussed in more detail in Chapter 14 .