The organism was named thus in honor of Czech parasitologist Otto Jirovec, who described Pneumocystis pneumonia in humans in 1952. After DNA analysis showed significant differences in the human variant, the proposal was made again in 1999 and has come into common use.
The organism was named after Otto Jirovec, a Czech parasitologist who first described Pneumocystis pneumonia in humans in 1952.  DNA analysis later revealed significant differences between the human variant and others, leading to a renewed proposal for its name in 1999, which has now become common usage.