Description
Tuberculosis infections are caused by the Mycobacterium tuberculosis complex family consisting of many members, out of which the ones most commonly affecting humans include:
- M. tuberculosis
- M. bovis
- M. africanum
Route of infection and progression
Person-to-person infections are spread through respiratory air droplets through coughing and sneezing.
Once the bacteria enters the body, most patients (75%) will be unaffected, but the remainder (25%) will become infected. This is known as the primary infection.
Once infected, they can go through several phases:
- Progressive primary tuberculosis
- Latent phase (dormant)
- Secondary infection (reactivation/reinfection)
- Healing
- Progressive secondary tuberculosis
Most primary infections are asymptomatic and typically occur during childhood. In immune-competent patients, the primary infection will be followed by a latent (dormant) phase. Patients are not infectious during the primary and latent phases.
Secondary infection can appear