Pneum ID

Background
Pneumocystis jirovecii pneumonia (PCP) is a life-threatening opportunistic disease caused by Pneumocystis jirovecii, formerly known as Pneumocystis carinii species, a unicellular eukaryotic and ubiquitous yeast-like fungus. Conservative approximations calculate around 400,000 cases of PCP annually worldwide, but this is likely to be an underestimate of the true burden. It is estimated that up to 20% of adults might carry this fungus at any given time, without any symptoms, resulting in continuous interindividual circulation responsible for transmission to immunocompromised individuals who are at high risk of developing PCP. Amongst them, around 30-40% of PCP infections occur in individuals with human immunodeficiency virus (HIV) infection/acquired immune deficiency syndrome (AIDS). In addition to HIV coinfection, other risk factors include chronic lung diseases, cancer, inflammatory or autoimmune diseases and solid organ or stem cell transplant. Once PCP is clinically suspected, the diagnosis should be time-sensitive, and treatment should be initiated as soon as possible to avoid further complications.