Tuberculosis (TB) is a severe infectious disease that primarily targets the lungs.
Causes:
TB is caused by the bacterium Mycobacterium tuberculosis. It spreads when an infected person coughs, sneezes, or sings, releasing tiny germ-containing droplets into the air. Others can inhale these droplets, allowing the bacteria to enter their lungs.
The disease spreads more easily in crowded places or living conditions. Individuals with weakened immune systems, such as those with HIV/AIDS, are at higher risk of contracting TB compared to those with normal immunity.
Symptoms:
TB infection occurs when the bacteria survive and multiply in the lungs. It progresses through three stages, each with distinct symptoms:
- Primary TB Infection –
This is the initial stage, where immune cells detect and trap the bacteria. While some germs may be destroyed, others can survive and multiply. Many people show no symptoms, but some may experience flu-like signs, such as:- Mild fever
- Fatigue
- Cough
- Latent TB Infection –
After the primary infection, the immune system walls off the bacteria in the lungs, preventing further harm. No symptoms appear during this stage, but the germs remain alive. - Active TB Disease –
This occurs when the immune system fails to control the infection, allowing the bacteria to spread in the lungs or other body parts. It can develop soon after primary infection or years later.
Symptoms of active TB in the lungs include:
- Persistent cough
- Coughing up blood or mucus
- Chest pain
- Pain while breathing or coughing
- Fever and chills
- Night sweats
- Weight loss
- Loss of appetite
- Fatigue
- General discomfort
Active TB outside the lungs (extrapulmonary TB):
TB can spread from the lungs to other organs, causing varied symptoms depending on the affected area. Common signs include:
- Fever and chills
- Night sweats
- Weight loss
- Loss of appetite
- Fatigue
- Pain near the infection site
Common sites of extrapulmonary TB:
- Liver
- Kidneys
- Brain and spinal cord lining
- Heart muscles
- Genitals
- Lymph nodes
- Bones and joints
- Skin
- Larynx (voice box)
- Blood vessel walls
Risk Factors for TB Infection:
Certain conditions increase the risk of TB transmission:
- Living with an active TB patient
- Residing or working in crowded places (prisons, nursing homes, homeless shelters)
- Belonging to a high-risk community
- Working in healthcare with TB-prone populations
Diagnosis:
Doctors diagnose TB using:
- Skin or blood tests
- Lab tests on sputum and lung fluid
- Chest X-rays
- CT scans
Preventing Spread:
If you have active TB, take these steps to protect others:
- Medication: Complete the full course (4, 6, or 9 months).
- Isolation: Stay home for the first 2–3 weeks.
- Limit contact: Minimize time with household members; sleep separately.
- Ventilation: Keep windows open or use fans to improve airflow.
- Masks: Wear one around others; household members should too.
- Cover coughs/sneezes: Use tissues and dispose of them properly.
Vaccinations:
In high-TB countries, infants often receive the Bacille Calmette-Guérin (BCG) vaccine, which helps prevent severe forms like TB meningitis. However, it may not protect against lung TB, which is more common in the U.S. Multiple new TB vaccines are currently in development.
