The first stage of tuberculosis (TB) is called the primary TB infection.
Primary TB Infection Explained
During this initial phase, Mycobacterium tuberculosis bacteria enter the body, typically through the lungs. Here's a breakdown of what happens:
- Entry: The bacteria are inhaled, often as airborne droplets expelled when someone with active TB coughs, speaks, or sings.
- Immune Response: The body's immune system immediately recognizes these foreign invaders. Immune cells, like macrophages, engulf the bacteria.
- Potential Outcomes:
- Elimination: In many cases, the immune system effectively destroys the bacteria completely, preventing any further development of the disease.
- Latent TB Infection: If the immune system cannot completely eradicate the bacteria, it may be able to contain them. This leads to a state called latent TB infection. In this stage, the bacteria remain alive but inactive within the body. People with latent TB do not feel sick, do not have symptoms, and cannot spread TB to others. However, the infection can become active later if the immune system weakens.
- Active TB Disease (Rare): In some cases, particularly in individuals with weakened immune systems (e.g., those with HIV, infants, or the elderly), the initial infection can progress directly to active TB disease. This means the bacteria are actively multiplying and causing damage to the body. People with active TB disease typically experience symptoms such as a persistent cough, fever, night sweats, weight loss, and fatigue. They are also infectious and can spread TB to others.
It's important to note that not everyone infected with Mycobacterium tuberculosis develops active TB disease. Many individuals will only develop latent TB infection and may never experience symptoms.
