Which of the following conditions is characterized by interstitial infiltrates and is primarily a lung infection?

Pneumocystis pneumonia (PCP) is indeed characterized by interstitial infiltrates, primarily affecting the lungs. PCP is caused by the fungal organism Pneumocystis jirovecii, which typically causes opportunistic infections, particularly in immunocompromised individuals, such as those with HIV/AIDS or those on immunosuppressive therapy.

In the context of the lungs, the infection manifests as a pneumonia that presents with diffuse interstitial infiltrates on imaging studies, such as a chest X-ray or CT scan. These infiltrates represent inflammation and fluid in the lung interstitium, leading to symptoms like dyspnea, cough, and sometimes fever. The distinctive clinical and radiological features of PCP help differentiate it from other types of lung infections.

Community-acquired pneumonia, while also a lung infection, typically presents with alveolar infiltrates rather than interstitial infiltrates. Interstitial lung disease encompasses a range of conditions that can lead to inflammation and scarring in the lung interstitium but is not specifically classified as an infectious process primarily characterized by interstitial infiltrates. Bronchiectasis involves dilatation of the bronchi and is associated with chronic infection or inflammation but does not primarily feature interstitial infiltrates as a defining