Tuberculosis (TB) is an infectious disease that continues to be a significant public health concern worldwide, particularly in developing countries, including Thailand. Many people wonder why tuberculosis most commonly affects the lungsrather than other parts of the body. The answer lies in the route of infection.

Tuberculosis Spreads Through the Air

Tuberculosis is caused by the bacterium Mycobacterium tuberculosis, which spreads through airborne droplets. When a person with pulmonary tuberculosis coughs, sneezes, speaks, or expels respiratory secretions, tiny droplets containing the bacteria are released into the air.

These droplets can remain suspended in the air for extended periods. When another person inhales them, the bacteria enter the respiratory tract and travel directly to the lungs. As a result, the lungs become the first organ exposed to the infection and the most common site where TB develops.

What Happens After the Bacteria Enter the Lungs?

Once TB bacteria reach the lungs, the body’s immune system attempts to eliminate them.

• If the immune system is strong, it may successfully control or destroy the bacteria, preventing active disease.
• If the immune system is weakened, the bacteria can multiply, causing inflammation and damage to lung tissue, eventually leading to pulmonary tuberculosis.

People at higher risk of developing active TB include:

• Individuals living with HIV/AIDS
• Cancer patients
• People undergoing chemotherapy
• Older adults
• Individuals with weakened immune systems

Symptoms of Pulmonary Tuberculosis

Tuberculosis often develops gradually, making it easy to overlook the early signs. Common symptoms include:

• A persistent cough lasting more than 2 weeks
• Coughing up sputum or blood
• Fatigue and weakness
• Unexplained weight loss
• Loss of appetite
• Low-grade fever
• Night sweats

Anyone experiencing these symptoms should seek medical evaluation promptly for proper diagnosis and treatment.

How Can Tuberculosis Be Prevented?

Although TB is an airborne disease, the risk of infection can be reduced by:

• Wearing a face mask in crowded or poorly ventilated areas
• Washing hands regularly
• Avoiding close contact with individuals who have untreated active TB
• Maintaining a healthy immune system through proper nutrition and adequate rest

Conclusion

Tuberculosis most commonly affects the lungs because the bacteria enter the body through inhalation, making the lungs the first and primary site of infection. Early diagnosis and appropriate treatment can effectively cure tuberculosis and help prevent its spread. If you experience a persistent cough or have risk factors for TB, consult a healthcare professional for further evaluation as early as possible.