Book excerpt: "It is estimated that a million people acquire a sexually transmitted infection (STI) including human immunodeficiency virus (HIV) every day. Approximately 498.9 million estimated curable STIs, namely those due to Treponema pallidum (syphilis), Neisseria gonorrhoeae, Chlamydia trachomatis and Trichomonas vaginalis, occur each year throughout the world, with the largest proportion in sub-Saharan Africa and Latin America and the Caribbean, followed by the Western Pacific Region. In addition, millions of viral STI infections also occur annually, attributed mainly to HIV, herpes simplex viruses (HSVs), human papillomaviruses and hepatitis B virus. Although HIV surveillance has largely been institutionalized in almost all countries and data are more widely available, surveillance systems for STIs are generally weak, except for a few countries in western Europe and North America. The limited data available, however, suggest a huge burden of infection affecting people with high-risk sexual behaviours, as well as other vulnerable populations and the general population. The data that are available from developing countries relate mainly to bacterial STIs and there is a dearth of data on viral STIs, such as herpes simplex virus infections. Syphilis and chancroid are the common bacterial genital ulcer diseases but data on the prevalence and incidence of syphilis and chancroid are limited or unavailable. Similarly, surveillance data on gonococcal and chlamydial infections are also very limited in low- and middle-income countries. Much of the information on STIs from these countries is from either research studies or demographic health surveys. This document is intended to provide a framework for ministries of health and public health decision-makers at national and subnational level for implementation of STI surveillance systems that generate consistent and reliable data to facilitate disease-control efforts. The publication emphasizes the timely collection, analysis and use of data. Although data obtained through routine public health surveillance activities need to be interpreted carefully in view of their biases and limitations, they provide valuable information on disease burden and aspects of programme services. The strengthening of STI surveillance systems should be viewed as a central component of the effort to strengthen STI/HIV-prevention programmes globally."--Page 1.