Pneumocystis jiroveci

Pneumocystis jiroveci, sometimes called by its former name Pneumocystis carinii, is a fungus (earlier classified as a protozoa) that causes pneumocystis jiroveci pneumonia (PCP). It affects those with weakened immune systems such as children and the elderly, but is especially common in patients with AIDS. Jiroveci is pronounced "yee row vet zee".

Pneumocystis infection is diagnosed by silver staining of the sputum.

In immunocompromised patients (e.g. those on chemotherapy or AIDS with a low CD4+ count; below 200/mm³), prophylaxis with regular pentamidine inhalations or sulfamethoxazole/trimethoprim (co-trimoxazole or TMP-SMX) may be necessary.

It is distributed worldwide.

A new name

In the 1990s, DNA evidence showed that Pneumocystis organisms in different mammals were actually quite different, and in 1999 the binomial name for the species affecting humans was officially changed to Pneumocystis jiroveci. The old name Pneumocystis carinii is now used for the related organism that affects cats.

References

• A New Name (Pneumocystis jiroveci) for Pneumocystis from Humans - from the Centers for Disease Control. Stringer JR, Beard CB, Miller RF, Wakefield AE. A new name (Pneumocystis jiroveci) for pneumocystis from humans. Emerg Infect Dis [serial online] 2002 Sep [date cited];8.