 Synonyms for PCP include pneumocystosis (pneumocystis + -osis), pneumocystiasis (pneumocystis + -iasis), and interstitial plasma cell pneumonia.The older species name "Pneumocystis carinii" (which now applies only to the "Pneumocystis" species that is found in rats) is still in common usage.As a result, "Pneumocystis" pneumonia (PCP) is also known as Pneumocystis jiroveci[i]" pneumonia and (incorrectly) as Pneumocystis carinii" pneumonia.