<unk>  pneumonia (PCP) is a form of pneumonia caused by the yeast-like fungal<unk><unk> <unk>  is pronounced "yee row vet zee eye"). The causal agent was originally described as a protozoan and spelled P.<unk> and prior to then was classified as a form of<unk>  carinii, a name still in common usage. These names are discussed below. As a result,<unk>  pneumonia (PCP) has also been known as<unk> <unk> i] pneumonia and as<unk>  carinii pneumonia, as is also explained below.
It is relatively rare in people with normal immune systems but common among people with 
weakened immune systems, such as premature or severely malnourished children, the elderly, and especially AIDS patients, in whom it is most commonly observed today. PCP can also develop in patients who are taking immunosuppressant medications (e.g. patients who have undergone solid organ transplantation) and in patients who have undergone bone marrow transplantation.
The organism is distributed worldwide.
Pneumocystis jirovecii pneumonia
Tuberculosis
COVID-19-associated pneumonia
Invasive aspergillosis
Miliary tuberculosis
CMV pneumonitis
COVID-19-associated pulmonary hypertension
Histoplasmosis