Cytomegalovirus (CMV) is a viral infection. CMV is a common virus in people of all ages. A healthy person's immune system usually keeps the virus from causing illness and does not need treatment. But in a person who has had an organ transplant, it can cause serious illness.

CMV is a virus related to the herpes virus. CMV is found in saliva, urine, semen, stool, tears, breast milk, and blood. The virus is easily spread in households. In a healthy person, CMV causes few or no symptoms. Because of this, most people don't know they have CMV. It's not curable and is a lifetime infection. Once you have CMV, you will always have the virus in your body.

If a person has symptoms of active CMV, they may include:

• A fever.
• A sore throat.
• Swollen glands.
• Fatigue and weakness.
• Flu-like symptoms.
• Muscle aches and joint stiffness.
• Diarrhea.

CMV can cause serious illness and even death in a person who has had an organ transplant. It can lead to serious infections from other causes as well. These may include infections from bacteria, viruses, or fungus. CMV can also lead to damage or failure of the new organ. And CMV can make it more likely that your body will reject the new organ.

An organ transplant is a surgery to replace a diseased organ with a healthy organ. The organ comes from an organ donor. A donor organ may be infected with CMV. Or the person who gets the organ may already have CMV. Either way, a CMV infection can turn serious after organ transplant. This is because of the antirejection medicines the person must take.

After a transplant, the new organ is at risk for rejection in a person's body. Rejection is a normal reaction of the body to foreign tissue. When a new organ is placed in a person's body, the immune system sees the new organ as foreign and tries to attack it. Medicines are given to prevent this. They act on the immune system, suppressing its response to the new organ.

But when the immune system is suppressed, it becomes weak and can't fight other infections as well. This includes CMV. A CMV infection may be severe when a person is taking antirejection medicine. This may happen several weeks, months, or even years after an organ transplant.

CMV infection can be diagnosed with tests. These include blood tests, biopsies, and tests of other body fluids and organs. You will be tested for CMV before having an organ transplant. This will help your healthcare team decide on the best transplant and treatment plan for you.

Antiviral medicine is used to treat CMV. You may also be given antibody medicine. These help your immune system fight the CMV virus better. You may need to take medicine for several months to control the infection. Your antirejection treatments may also need to be lowered to help treat CMV.