Cytomegalovirus (CMV) is a type of virus. It's related to the virus that causes herpes. Like many other viruses, CMV can invade human cells. It can then use those cells to reproduce and spread. If the virus makes many copies of itself, it may disrupt how cells normally work.
In people with a normal immune system, a new CMV infection can have no symptoms. Or it can cause an illness similar to the common cold or mononucleosis with sore throat, swollen lymph nodes, fatigue, and fever. But your immune system keeps the virus in check so it can’t do any serious harm and the infection goes away by itself. Very rarely, it can cause major problems in people with a normal immune system.
After infection, CMV stays inactive (dormant) in the body for life. That means that some of your cells stay infected with the virus. But the virus isn’t actively reproducing or causing symptoms. Sometimes the virus can become active again, especially in people who are sick or have a weak immune system. It then makes copies of itself and may harm cells in the body.
Infection with CMV is very common worldwide. Most people don’t even know they have it. In the U.S., infection rates are higher in women and older adults. It's also more common in people from lower socioeconomic backgrounds.
CMV infection is spread from one person to another. The virus is passed on when a person comes into direct contact with an infected person’s bodily fluids. These include blood, urine, saliva, semen, tears, and breastmilk. Many people are first infected with CMV during childhood. A pregnant mother can also pass CMV to her unborn child.
People who have organ transplants are more likely to get an active CMV infection. Transplants include a solid organ, bone marrow, or stem cell transplant. If you have had a transplant, you must take medicine for life to prevent your immune system from damaging the donated tissue. The cells of the immune system may attack the transplanted organ because your body thinks the new organ is a threat. This is called organ rejection.
The medicines you take after an organ, bone marrow, or stem cell transplant can help prevent damage to your donated organ. But they can have other effects on your immune system. They make it harder to fight off CMV and other infections. In the case of CMV infection, most transplant patients who develop problems from it have activated the CMV that has been dormant in their body for many years. Sometimes a transplant patient can get CMV from the transplanted organ, bone marrow, or stem cells, or from blood or white blood cell transfusions given when they are sick.
Certain types of transplants may have a higher risk for CMV. These include a lung or a small bowel transplant. You also have a higher risk for the disease if you didn’t previously have the infection but your donor organ came from someone who had it.
You may also have a greater risk of CMV disease if your immune system is not working as it should. Your specific risk may depend on a number of factors, such as:
Other health problems you have
Whether you have had symptoms of transplant rejection
Specific medicines you are taking to prevent rejection
An active CMV infection may cause a flu-like illness. Symptoms may include:
Swollen lymph nodes
When CMV invades certain tissues, it can cause serious problems and even death. CMV may also cause problems with a transplanted organ. Most of the time, these symptoms start between 1 and 4 months after the transplant. They may start later if you were taking antiviral medicine at that time. They may also start after you stop taking this medicine.
Before your transplant, your healthcare provider may want to know whether you have an inactive infection with CMV. Your organ donor will also undergo testing for CMV. This information will help make a treatment plan to lower your chances of a CMV infection. A number of different tests might give this information. Your healthcare provider can let you know at this time if you or your organ donor have an inactive CMV infection.
If you don’t have a CMV infection, you might become newly infected with it if the donated organ was carrying the virus. If you do have a CMV infection, there is a risk that the virus will reactivate after your transplant.
After your transplant, your healthcare provider may watch you for signs of active CMV infection. They will ask about any current symptoms and do a physical exam. You may also need other tests. These may include:
Basic blood work, to check your blood for signs of infection
Nucleic acid testing, to check for CMV infection
CMV pp65 antigen test, which quickly gives information about CMV infection status
Analysis of tissue samples under the microscope, to help confirm the disease
If you have an active CMV infection that's causing symptoms, you will need treatment. Antiviral medicines like ganciclovir or valganciclovir can help. These medicines can help control the virus. But they can't make you completely virus free.
Based on how serious your illness is, you might take an antiviral medicine by mouth or through an IV. Your healthcare provider will watch your symptoms and the amount of virus in your body to decide the extent of your treatment. Healthcare providers don’t want to give these medicines for a long time. They can cause other side effects and problems.
Many people with active CMV infections often recover quite well, but sometimes an active sickness can cause severe problems. That’s especially the case if not treated early.
An active CMV infection can cause major health problems. These include:
Liver disease (hepatitis)
Lung infection (pneumonia)
Infection of the pancreas (pancreatitis)
Digestive disease (colitis)
Infection of the brain or spinal cord (meningitis or encephalitis)
Heart infection (myocarditis)
Blood clots in a vein (venous thrombosis)
Bacterial infection of the blood (bacteremia)
These health problems may cause other symptoms. They may also require their own treatments. Sometimes that may involve supportive care in an intensive care unit (ICU). These complications can even result in death.
Active CMV infection can also raise your risk for organ rejection. You may need another transplant. Preventive treatments have greatly reduced the number of people who have serious problems from active CMV infection.
CMV may also raise your risk for certain chronic disorders after the transplant. These include atherosclerosis and diabetes.
Your healthcare team will do everything possible to help prevent active CMV infection. If your healthcare provider thinks you have a high risk for a new CMV infection or reactivation, they might start preventive antiviral medicines. You may take an antiviral medicine like valganciclovir right after your transplant. You may need to stay on it for some months. The medicine will greatly lower your chance of getting an active CMV infection. But sometimes people get an active CMV infection after stopping these medicines.
If you have never had CMV infection before, your healthcare providers will try to limit the possibility that you pick it up from transplant organs, bone marrow, or stem cells, or from blood or white blood cells that you receive. They will try, if possible, to give you transplants only from CMV negative donors. But sometimes this is not possible.
Other times, your healthcare provider might try to prevent you from having the symptoms of the infection using something called preemptive therapy. In this case, your healthcare provider might want you to have weekly lab tests to see if CMV has become active. In this way, they can find an active infection before you have any symptoms. It allows quicker treatment. That will cut your chance of complications.
Call your healthcare provider right away if you have any symptoms of a possible active CMV infection. These include:
Fever and chills
Nausea and vomiting
Shortness of breath
CMV is a virus. It rarely causes long-term problems in people with a normal immune system. In transplant patients, the virus can cause major problems.
After your transplant, the CMV virus may reactivate or you might get a new infection. Both of these can cause symptoms of active CMV disease.
An active CMV infection can raise the chance of organ rejection.
Your healthcare provider may try to prevent an active CMV infection by giving you antiviral medicines or avoiding exposing you to CMV.
Tips to help you get the most from a visit to your healthcare provider:
Know the reason for your visit and what you want to happen.
Before your visit, write down questions you want answered.
Bring someone with you to help you ask questions and remember what your provider tells you.
At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
Ask if your condition can be treated in other ways.
Know why a test or procedure is recommended and what the results could mean.
Know what to expect if you do not take the medicine or have the test or procedure.
If you have a follow-up appointment, write down the date, time, and purpose for that visit.
Know how you can contact your provider if you have questions.