Pneumonia and Respiratory Infections

When Infections Attack the Lungs

Pneumonia is an infection that inflames the air sacs in one or both lungs. The air sacs may fill with fluid or pus, causing cough with phlegm, fever, chills, and difficulty breathing. Pneumonia can range from mild to life-threatening and is most serious for infants, older adults, and people with weakened immune systems.

Types of Pneumonia

Bacterial pneumonia is the most common type in adults. Streptococcus pneumoniae is the leading cause. Viral pneumonia can be caused by influenza viruses, respiratory syncytial virus (RSV), and coronaviruses. Fungal pneumonia is less common and typically affects people with compromised immune systems.

Other Common Respiratory Infections

Bronchitis involves inflammation of the bronchial tubes and causes coughing, mucus production, and chest discomfort. Acute bronchitis is usually viral and resolves within a few weeks. Influenza (flu) can cause severe respiratory symptoms and may lead to pneumonia as a complication. Tuberculosis (TB) is a bacterial infection that primarily affects the lungs and remains a significant global health concern.

Prevention

Vaccinations (pneumococcal vaccine, annual flu vaccine), good hand hygiene, avoiding close contact with sick individuals, and maintaining a strong immune system through healthy lifestyle habits are the most effective prevention strategies.