Pneumonia is a lung infection caused by bacteria, viruses, or fungi. It occurs due to inflammation in the air sacs (alveoli) of one or both lungs, causing them to fill with fluid or pus, which makes ...

Mycoplasma pneumoniae is a common cause of mild respiratory illness, sometimes referred to as "walking pneumonia." Symptom onset is "typically gradual," the CDC says. It can include fever, a cough, ...

A bacterial infection known as walking pneumonia is on the rise in the United States, the U.S. Centers for Disease Control and Prevention has warned. Cases are particularly high among young children.

Small cell lung cancer (SCLC) may increase the risk of pneumonia due to a weakened immune system or structural changes to the lungs. SCLC is one of the two main types of lung cancer. Pneumonia is an ...