P.jirovecii has a predilection to infect the lung alveoli of at-risk individuals. Extrapulmonary manifestations are rare. Asymptomatic lung colonization can occur in people with normal immune systems,

Pneumocystis is transmitted from person to person through an airborne route. Transmission requires a short period of exposure and low numbers of organisms. Patients presenting with PJP may show signs of fever, dyspnea, non-productive cough, weight loss and fatigue. The ideal sample type for the diagnosis of PJP is bronchoalveolar fluid or induced sputum samples. Patients with PJP infection may exhibit elevated levels of plasma 1-3-beta-D-glucan.