• Tuberculosis (TB) is an airborne bacterial infection caused by the organism Mycobacterium tuberculosis that primarily affects the lungs, although other organs and tissues may be involved. It is most commonly seen in people with weakened immune systems.
• TB is spread when a person with active, infectious TB disease coughs, sneezes, or spits, releasing droplets containing TB bacteria into the air, which are then inhaled by someone else. There are also forms of TB that are drug-resistant.

• Pneumonia is a common lung infection caused by germs, such as bacteria, viruses, and fungi. The infection causes the lung’s air sacs to become inflamed and fill up with fluid or pus making it hard for the oxygen to get into the bloodstream. The symptoms of pneumonia can range from mild to severe and include cough, fever, chills, and trouble breathing. Infants and Young children, adults 65 or older, smokers, and people who are ill are at higher risk.

• The flu is a respiratory infection caused by flu viruses. The viruses pass through the air and enter the body through the nose or mouth. The flu can also be acquired from contaminated surfaces. Symptoms of the flu are similar to those of the common cold, but they last longer and tend to be worse.

The different types of influenza virus families are:

Influenza Type A: There are different strains of influenza type A viruses, two of which circulate among humans, H1N1 and H3N2.
Influenza Type B: It can cause illness among humans but are associated with less severe infection than influenza A viruses.
Influenza Type C: It causes mild illness in humans and cases occur much less frequently than A and B.
Avian flu (H5N1): Also known as bird flu, is a subtype of influenza type A viruses. The virus is mainly transmitted to humans by direct contact with infected live, sick or dead poultry.

• Asthma is the most common chronic lung condition. Asthma attacks happen when the airways tighten and narrow, slowing down airflow. The lungs also become swollen and inflamed. Asthma can be triggered by an allergic reaction, pollution, exercise, other respiratory illness, and cold air. The symptoms of Asthma often present in periodic attacks or episodes of tightness in the chest, wheezing, breathlessness, and coughing.

COPD is an umbrella term used to describe progressive lung diseases including Chronic bronchitis, Emphysema, Refractory (non-reversible) Asthma. This disease is characterized by increasing breathlessness. The bronchial tubes become inflamed and scarred in Chronic bronchitis whereas the air sacs in the lungs are slowly destroyed in the case of Emphysema. It may be caused by smoking, air pollution, chemicals, or a genetic condition.

ARDS is a condition that causes fluid to leak into the lungs, blocking oxygen from getting to the organs. It occurs when there is trauma to the lungs e.g. sepsis, severe pneumonia. It is a serious condition and can be life-threatening.

Lung Cancer is the uncontrolled growth of malignant cells that originate in the lungs.

The two general types of lung cancer include:

• Small cell lung cancer: It occurs almost exclusively in heavy smokers and is less common than non-small cell lung cancer.
• Non-small cell lung cancer: It is an umbrella term for several types of lung cancers that behave similarly. Non-small cell lung cancers include squamous cell carcinoma, adenocarcinoma and large cell carcinoma.

Pulmonary hypertension occurs when there is abnormally high pressure in the blood vessels between the lungs and the heart. Pulmonary hypertension can be acquired as a result of other medical conditions such as heart disease, lung disease, or connective tissue disease. If no cause can be identified, the condition is called idiopathic pulmonary arterial hypertension.

This condition occurs when a blood clot gets caught in one of the arteries that go from the heart to the lungs and blocks the normal blood flow causing chest pain, acute shortness of breath, and coughing. It can be life-threatening and requires prompt medical attention.

Cystic fibrosis is an inherited and life threatening disease that causes thickened mucus to form in the lungs, pancreas and other organs. In the lungs, this mucus blocks the airways, causing lung damage and making it hard to breathe.

Pulmonary fibrosis is a lung disease characterized by damage and scarring to the tissues of the lungs, including those between and supporting the air sacs. Causes of Pulmonary Fibrosis can be

• Inhaling hazardous chemicals
• Chemicals and drugs that are toxic to the lungs
• Previous Radiation Treatment
• Certain medical conditions e.g. Sarcoidosis, Scleroderma
• Unknown (Idiopathic Pulmonary Fibrosis)