Pneumocystis jirovecii

Pneumocystis jirovecii is a type of fungus that can cause pneumonia, especially in people with weakened immune systems like those with HIV/AIDS or cancer. It is commonly found in the environment and can be inhaled into the lungs. In healthy individuals, it usually doesn't cause problems, but in immunocompromised people, it can lead to serious lung infections characterized by cough, difficulty breathing, and low oxygen levels. Treatment involves specific antibiotics, and preventing infection with medication is important for at-risk populations.