Book excerpt: BACKGROUND: Latent tuberculosis infection (LTBI), defined as a state of persistent immune response to prior-acquired Mycobacterium tuberculosis antigens without evidence of clinically manifested active TB, affects about one-third of the world's population. Approximately 10% of people with LTBI will develop active TB disease in their lifetime, with the majority developing it within the first five years after initial infection. Currently available treatments have an efficacy ranging from 60% to 90%. Systematic testing and treatment of LTBI in at-risk populations is a critical component of WHO's eight-point framework adapted from the End TB Strategy to target pre-elimination and, ultimately, elimination in low incidence countries. OVERVIEW: Recognizing the importance of expanding the response to LTBI, in 2014 WHO developed Guidelines on the Management of Latent Tuberculosis Infection. The guidelines are primarily targeted at high-income or upper middle-income countries with an estimated TB incidence rate of less than 100 per 100 000 population, because they are most likely to benefit from it due to their current TB epidemiology and resource availability. The overall objective of the guidelines is to provide public health approach guidance on evidence-based practices for testing, treating and managing LTBI in individuals with the highest risk of progression to active disease. Specific objectives include identifying and prioritizing at-risk population groups for targeted intervention of LTBI testing and treatment, including defining an algorithm, and recommending specific treatment options. The guidelines are expected to provide the basis and rationale for the development of national guidelines for LTBI management based on available resources, epidemiology of TB including intensity of transmission, the health-care delivery system of the country, and other national and local determinants.