Pneumocystis jirovecii pneumonia risk factors

Overview
This type of pneumonia is caused by the fungus Pneumocystis jiroveci. This fungus is common in the environment and does not cause illness in healthy people. However, it can cause a lung infection in people with a weakened immune system due to:
 * Cancer
 * Chronic use of corticosteroids or other medications that weaken the immune system
 * HIV/AIDS
 * Organ or bone marrow transplant