Natural History of Tuberculosis in the Human Host: Infection, Latency and Active Disease. Are these Treatable?
Pp. 11-18 (8)
Dilvani O. Santos, Selma M.A. Sias and Paulo R.Z. Antas
Tuberculosis in children should be confronted as a seminal event in public health, as it refers
to recent infections supported by direct contact with infected people, mostly adults. However, due to
children seldom constituting an important source of infectiousness thanks to the small ratio of bacilli
released or spread, they have a limited epidemiology impact at a global perspective. Furthermore only
those cases with larynx commitment plus those ones with lung cavity are at risk for contagiousness.
There are three pathways that lead to illness: the progression of the primary infection, the exogenous reinfection,
and the endogenous reactivation, (which is usually the basis for the post-primary or secondary
tuberculosis in adults). Indeed, the possibility that persons previously infected with Mycobacterium
tuberculosis can be exogenously re-infected has been debated for decades. Frequently, children can
present both the primary form and the typical post-primary tuberculosis form of the adult. Primary
Tuberculosis predominates early in life, predominantly in highly endemic countries, since children are
constantly exposed to the infectious sources. In contrast, within developed countries, the risk of
infection is lower and individuals can expect to reach adolescence or adulthood without M. tuberculosis
Tuberculosis, Childhood, Infection, Latency, Active Disease.
Laboratorio de Biopatogenos e Ativacao Celular, Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Av. Barros-Terra s/n Valonguinho, zip: 24001-970, Niteroi, Rio de Janeiro, Brazil.