Pneumocystis carinii (NEW-mo-SIS-tis CA-RIN- nee-eye) pneumonia, or PCP, is a severe illness found in people with HIV. It is caused by a germ called Pneumocystis carinii. Most people infected with this germ don’t get pneumonia because their immune systems are normal. People whose immune systems are badly damaged by HIV can get PCP. People with HIV are less likely to get PCP today than in earlier years.

If you have PCP, you probably will have fever, cough, or trouble breathing. People with PCP may die if the infection is not treated quickly. See your doctor immediately if you have these symptoms. PCP can be diagnosed only by laboratory tests of fluid or tissue from the lungs

Most scientists believe PCP is spread in the air, but they don’t know if it lives in the soil or some- place else. The PCP germ is very common. Since it is difficult to prevent exposure to PCP, you should get medical care to prevent PCP.

PCP can be prevented. The best drug for prevent- ing PCP is trimethoprim- sulfamethoxazole (try- METH-o-prim - sul-fa- meth-OX-uh-sole), or TMP-SMX. TMP-SMX is a combination of two medicines. It has many different brand names, such as Bactrim, Septra, and Cotrim*. Adults and older children can take TMP-SMX as a tablet. You can also get TMP- SMX as a liquid.

No. The pneumonia vaccine protects you against another kind of pneumonia, but not against PCP. There is no vaccine for PCP.

You should have your blood tested regularly to check the strength of your immune system. Your doctor should prescribe TMP-SMX to prevent PCP if your CD4 cell count falls below 200. Your doctor may also put you on TMP-SMX if you show certain symptoms, such as having a tem- perature above 100°F that lasts for 2 weeks or longer, or if you get a fungal infection in the mouth or throat (commonly called “thrush”). Having thrush is believed to raise your risk for getting PCP.

TMP-SMX can make some people have a rash or feel sick. If the drug reaction is not severe, TMP-SMX should be continued because it works so much better than any other medicine to prevent PCP.

Yes. Check with your doctor about the possibility of other treatments. Take all of your medicines as prescribed by your doctor. Don’t change how many pills you are taking without speaking with your doctor.

Yes. If you have already had PCP you can get it again. TMP-SMX can prevent second infections with PCP. Therefore, you should take TMP-SMX even after you have had PCP to prevent getting it again.