Random TB question

Tb is transmitted through droplets when an infected person coughs or sneezes and someone without immunity inhales the droplets. The body mounts an immune response and the macrophages that ingest the bacilli fuse and inside the lesion is caseous necrosis which the scar tissue forms tubercles around. Only if the tubercles and inflamed nodes rupture can the infection spread.

The tb skin test can reveal infection at some point but doesn't indicate active disease and a chesty X-ray will show turbercules in an inactive person.

After exposure, 5% of infected people will develop active tb within a year but in other infected people the microorganisms cause a latent infection. The immune system can destroy the bacillus or the encapsulated bacilli can live dormant in the tubercle for years.

Thank you.

remember, TB can occur in other parts of the body besides the lungs. Check that out.

Depends on the immune system of the person as well. IF a person is immuno-compromised such as with AIDS/or during chemotherapy etc. active TB infection will result since there is no immune system to keep the bacilli in check.

It also depends on the inflammatory response whether a strong response is mounted or none causing asymptomatic infection.

Testing positive on a Mantoux (TB skin Test) means you have Latent TB--that you have been exposed to the TB bacteria but have no symptoms and cannot spread the disease to others. The immune system prevents the bacteria from proliferating in 90% of cases. However weakened immune defiencies and other risk factors (HIV, malnutrition, other lung diseases etc) can cause the TB bacteria to grow and multiply, and you will become symptomatic and can make others sick, which means you have Active TB.

Don't forget that many countries use the TB "vaccine" so anyone that has had it will have a positive skin test but negative X-ray.