The incidence and correlates of symptomatic and asymptomatic Chlamydia trachomatis and Neisseria gonorrhoeae infections in selected populations in five countries.

Sexually transmitted infections (STIs) are a major health problem in most countries of the world, but especially in developing countries where the resources and technology to diagnose and treat them are limited.1 Currently, many countries, including China, are experiencing a resurgence of STIs, because of limited control efforts.2,3 In many of these countries, the major strategy for control of STIs has been through sexually transmitted disease clinics for the management of symptomatic genitourinary infections for individuals seeking treatment. However, an emphasis on this strategy has several limitations. First, because of the stigma associated with STIs, a high proportion (often 60 + %) of individuals with symptomatic STIs are reluctant to seek treatment from government clinics.4 Second, these symptomatic individuals often seek treatment in pharmacies and from indigenous providers, where treatment is often inadequate, partner treatment is not offered, and no record of their treatment is kept.5,6 Third, this strategy relies on individuals seeking treatment. Those who are asymptomatic are unlikely to seek any kind of treatment, and may have a long duration of infection, repeatedly exposing their regular partners and/or new partners to infection. For these reasons, studies of asymptomatic STIs require investigation of populations who do not seek care on the basis of symptoms. Several studies have reported high proportions of laboratory-confirmed Chlamydia trachomatis- and Neisseria gonorrhoeae-infected individuals who are asymptomatic, especially in women.7–13 However, the proportions of asymptomatic C. trachomatis and N. gonorrhoeae infections may differ between different countries and groups. The National Institute of Mental Health sponsored a trial of a community-level intervention based on the “popular opinion leader model” to prevent HIV/STIs among selected populations in 5 countries, China, India, Peru, Russia, and Zimbabwe.14,15 The populations in this study were selected on the basis of reported sexual risk behaviors and/or prevalence of STIs in their respective countries, and therefore, the ages are not comparable. In some countries, the individuals at highest risk for STIs were young, whereas in other country settings, were older and had more discretionary income. As part of the assessment of the trial, a baseline and 2 follow-up surveys at 12 and 24 months were conducted, in which symptoms of STIs were solicited, and participants were tested for the presence of several STIs, including C. trachomatis and N. gonorrhoeae, using sensitive nucleic acid amplification tests. Because of the large sample size, this study provided an excellent opportunity to study the prevalence and incidence of both symptomatic and asymptomatic infections in community settings among individuals not selected on the basis of symptoms or high-risk activities. We report herein the prevalence and incidence of laboratory-confirmed C. trachomatis and N. gonorrhoeae in these 5 diverse populations, the proportions of those reporting symptoms by several demographic characteristics, and predictors of symptomatic and asymptomatic infection. This information should be useful for decision makers in these countries attempting to control the epidemics of STIs in their populations. The study was approved by the institutional review boards of the institutions in each of the 5 countries, and by those at each of the American academic institutions.