Pneumocystis jirovecii infection
- 1Centre for Sexual Health and HIV Research, Department of Primary Care and Population Sciences, Royal Free and University College Medical School, University College London, London WC1E 6AU, UK
- 2Positive Health Programme and Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, Department of Medicine, University of California San Francisco, San Francisco, CA 94110, USA
- Correspondence to:
Dr R Miller
Centre for Sexual Health and HIV Research, Department of Primary Care and Population Sciences, Royal Free and University College Medical School, University College London, London WC1E 6AU, UK; rmillergum.ucl.ac.uk
A review of Pneumocystis and the rationale for renaming it
The organism Pneumocystis causes severe pneumonia in individuals with immune systems impaired by HIV, transplantation, malignancy, connective tissue disease, and the treatment thereof. In HIV infected patients it remains a major pathogen in those who are unaware of their HIV serostatus, or who decline to take or are intolerant of highly active antiretroviral therapy. Pneumocystis also infects a wide variety of mammals and causes pneumonia in those that are immunosuppressed or immunodeficient. Originally Pneumocystis was thought to be a single species of protozoa. Study of the organism has been severely hampered by the fact that it cannot be cultured in vitro. Over the last 20 years, using molecular biological, immunological and other techniques, Pneumocystis has been shown to be a fungus, to be genetically diverse, host species specific, transmissible from animal to animal, to colonise individuals with minor degrees of immunosuppression, and to cause clinical disease by “new” infection in addition to reactivation of latent childhood acquired infection. More recently the organism causing disease in humans has been renamed Pneumocystis jirovecii. This article highlights some of these recent developments and provides a rationale for the renaming of the organism.
WHAT IS PNEUMOCYSTIS?
Chagas first identified Pneumocystis organisms in humans in 1909, but they were mistaken for a new stage of the life cycle of the protozoan Trypanosoma cruzi.1 Within a very short time it became apparent that the organism infected other host species, was not a trypanosome, and was named Pneumocystis carinii in honour of Carini, a colleague of Chagas.2 For many years the organism continued to …
