Understanding latent tuberculosis: the key to improved diagnostic and novel treatment strategies

Treatment of latent tuberculosis (LTBI) is a vital component of tuberculosis (TB) elimination but is not efficiently implemented with currently available diagnostics and therapeutics. The tuberculin skin test and interferon-γ release assays can inform that infection has occurred, but do not prove that it persists. Treatment of LTBI with isoniazid targets actively replicating bacilli but not non-replicating populations, prolonging treatment duration. Developing more predictive diagnostic tests and treatments of shorter duration requires a greater understanding of the biology of LTBI, from both host and bacillary perspectives. In this article, we discuss the basis of current diagnosis and treatment of LTBI and review recent developments in understanding the biology of latency that might enable future improved diagnostic and treatment strategies.