IsMycobacterium tuberculosisinfection life long?

Abstract

People with immunoreactivity to tuberculosis are thought to have lifelong asymptomatic infection and remain at risk for active tuberculosis. Marcel A Behr and colleagues argue that most of these people are no longer infected

Host transcriptional response to TB preventive therapy differentiates two sub-groups of IGRA-positive individuals

“…We believe that the observation that 90% of individuals with positive testing by IGRA/TST do not develop TB disease is more likely to reflect low frequency of persistent viable ("reactivate-able") infection than low frequency of breakout of Mtb replication from long-term immunological control. The empirical evidence that we present in support of this contention is consistent with recent re-evaluations of epidemiological data which suggest that (1) duration of Mtb infection viability is likely to be much shorter than previously believed [20] and that (2) reactivation rates in IGRA or TST positive individuals unprotected by PT undergoing immunosuppressive therapy are much lower than would be expected if such testing represented infection truly capable of reactivation [21]. Emerging mathematical modelling outputs add weight to this paradigm shift, suggesting that a significant proportion of Mtb-infected individuals achieve self-clearance, leaving a much smaller population with persisting viable Mtb infection than previously assumed [22].…”

Ending tuberculosis by 2030—Pipe dream or reality?

“…Diagnosis is based on a positive tuberculin skin test (TST) or positive interferon-gamma release assay (IGRA), both of which are challenging to use in resource-limited settings. The notion that a positive TST or IGRA means life-long Mtb infection has recently been challenged with the suggestion that only 10% of individuals with TB immunoreactivity harbour viable organisms (Behr et al, 2019). This highlights the urgent need to develop and deploy highly sensitive and specific biomarkers that can distinguish true persistent infection from immunological memory of a past infection and predict who will progress from latent infection to active disease.…”

Mycobacterium tuberculosis Dissemination Plays a Critical Role in Pathogenesis

“…At least a quarter of the world's population is currently infected with active or latent tuberculosis, with over 10 million new infections and 1.2 million deaths from tuberculosis occurring every year. Over 15% of tuberculosis cases occur in the form of extrapulmonary infections that can affect any tissue in the body and are particularly difficult to diagnose and treat (Behr et al, 2018(Behr et al, , 2019WHO, 2019). The challenges facing patients with extrapulmonary infections are indicative of how little we understand this deadly disease, in spite of the long history of research that has been undertaken on the subject.…”