In what area of the body does Pneumocystis cause disease?

Pneumocystis, specifically Pneumocystis jirovecii, is a type of fungus that primarily affects the respiratory system, leading to a form of pneumonia known as Pneumocystis pneumonia (PCP). This organism is particularly opportunistic and commonly affects individuals with compromised immune systems, such as those with HIV/AIDS or other immunodeficiency conditions. In healthy individuals, Pneumocystis jirovecii generally does not cause significant disease.

The respiratory tract serves as the main site of infection, where the organism can cause inflammation and considerable difficulty in breathing, often presenting with symptoms such as cough, fever, and chest discomfort. The importance of recognizing Pneumocystis as a cause of pneumonia highlights the need for vigilance in immunocompromised patients.

Other body systems, such as the digestive tract, nervous system, or urinary tract, do not have a direct association with Pneumocystis infections in the same manner, making the respiratory tract the correct answer for this particular question.