Without proper treatment, every person with bacillary TB form (producing bacilli) annually infects 10-15 on average. Therefore, TB spread can be reduced only if:
- People with TB symptoms get examined (sputum analysis, chest X-ray, and diagnosing)
- A person with TB undergoes a complete treatment course with ant-TB medicines
TB mostly disseminates in air in form of droplets (drop-shaped nuclei) produced by a person with bacillary TB form when couching, sneezing, or speaking. A healthy person can contract infection if inhales the air with these drop-shaped nuclei.
After a healthy person meets a TB source:
- He can remain healthy - neither infected, nor ill
- He can get infected but not ill with TB
- He can get infected and ill with TB
TB infection and TB disease are not similar
TB infection process
Some bacilli reach lungs alveoli (vesicles) with air. Immune system cells - macrophages - start fighting the bacilli by consuming them. When macrophages die, some bacilli spread with blood causing disease. If the immune system controls the process, a person remains TB-infected.
What is TB Infection?
One third of global population and 80% of Ukrainians are TB infected.
People with TB-infection:
- Are neither infectious nor disseminate TB bacillus.
- Are not ill with TB
- Feel healthy and don't have disease symptoms
- Normally have a positive tuberculin skin test (See TB Diagnosis)
- X-ray and sputum test are normal
- No treatment required
- Can get ill with TB if immune system weakens (see TB Disease Risk Groups)
- Are infected in childhood or youth