One-third of the world's population is infected with M. tuberculosis. It is
from this vast pool of infected people where the new cases of active disease originate.
Most of these cases of latent infection are found in low-income countries where
national tuberculosis programs concentrate practically all their efforts on the diagnosis
and treatment of tuberculosis disease, neglecting the diagnosis and treatment of latent
tuberculosis in contacts of an active case. Each case of pulmonary tuberculosis infects
an average of 20 contacts, and of these, 10% of immunocompetent subjects will
develop the active disease if the latent infection is not detected and treated, which
means that each case of active TB will generate two new cases of TB; this explains, at
least in part, the difficulty that high burden countries have in controlling the epidemic.
These figures are even higher for subjects with some state of immunosuppression (for
example, people living with HIV, patients receiving immunosuppressive treatment,
malnourished, etc.).
For the diagnosis of latent TB, we currently have in vitro tests to determine the release
of interferon-γ (IGRA´s), with higher specificity than the traditional tuberculin test, an
essential point in subjects vaccinated with BCG.
Also, now there is a regimen (isoniazid and rifapentine) that requires only 12 doses of
medication instead of 180-270 doses of isoniazid, which facilitates adherence to the
regimen, with the same effectiveness and less toxicity.
The WHO has recommended the treatment of infected cases of MDR-TB (specifically
children and people living with HIV) with a fluoroquinolone.
Keywords: HIV, IGRA, Infection, Isoniazid, Latent, Rifapentine, Treatment,
Tuberculin, Tuberculosis.HIV, IGRA, Infection, Isoniazid, Latent, Rifapentine, Treatment,
Tuberculin, Tuberculosis.
