any protozoan of the genus Pneumocystis, esp P. carinii, which is a cause of pneumonia in people whose immune defences have been lowered by drugs or a disease
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
A pneumonia caused by the parasitic protozoan Pneumocystis carinii and affecting primarily individuals with an immunodeficiency disease, such as AIDS.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.