Pneumonia due to pneumocystis

**Definition:** A disease of the pulmonary system, caused by an infection with the fungi Pneumocystis jirovecii. This disease is characterised by fever, dry cough, shortness of breath, or fatigue. Transmission is by opportunistic infection. Confirmation is by identification of Pneumocystis jirovecii in a lung fluid or tissue sample.

**Long definition:** Infection with Pneumocystis jirovecii (formerly Pneumocystis carinii) is an opportunistic infection that is frequently seen in the immunologically compromised, such as persons with HIV/AIDS, or steroid-treated individuals, the elderly, or premature or debilitated babies during their first three months. Patients may be only slightly febrile (or even afebrile), but are likely to be extremely weak, dyspnoeic, and cyanotic. This is a major cause of morbidity among patients with HIV/AIDS. It manifests principally as a pneumonia.