Definition Cytomegalovirus is a virus that causes different illnesses in different groups of people.
What is going on in the body? Cytomegalovirus is a common life-long infection. It is spread from one person to another. The virus usually remains quiet the tissues of the body after the initial infection. It can, however, be shed in the mouth, urine, and genital tract, serving as a source of infection for other people. CMV can cause a second, more severe infection if the immune system becomes weak for any reason.
What are the signs and symptoms of the disease? Symptoms primarily depend on the age of the person and how strong their immune system is.
CMV may infect a healthy unborn baby while it is still in the womb. Roughly 5% of infants who get CMV this way have serious birth defects. These can include brain damage, growth failure, blindness, and other defects. This problem usually occurs when a pregnant mother gets a CMV infection for the first time during pregnancy.
When CMV causes infection in early childhood, it usually causes no symptoms at all. This is thought to be the most common form of CMV infection.
During the teenage and young adult years, infection with CMV can cause a syndrome similar to infectious mononucleosis or glandular fever. Glandular fever generally causes symptoms of sore throat, fatigue, fevers, and swollen "glands." These symptoms can last for weeks or even months. Full recovery generally occurs without treatment.
CMV can cause serious problems in people with weakened immune systems. This is most commonly a problem in people with AIDS or those taking drugs to suppress the immune system. People with widespread cancer or people who receive an organ transplant are commonly affected. Infection may be due to a first time infection or more often, reactivated infection. People with AIDS often get an infection of the back of the eye, or retina, called retinitis. This may cause problems with vision. In transplant and cancer patients, CMV usually causes pneumonia or a gastrointestinal infection that causes diarrhoea.
What are the causes and risks of the disease? Most people have been infected with CMV by the time they are adults. People with weakened immune systems and unborn children are at risk for severe disease. Anyone who receives a blood transfusion or an organ transplant is at risk for a CMV infection.
What can be done to prevent the disease? Good hand washing and good hygiene should limit a few of the new cases spread from a person shedding CMV. Because CMV is so common, however, prevention is quite difficult. Special blood filters and testing of donated organs may prevent a few cases.
How is the disease diagnosed? The virus can be detected in various human tissues and even grown from these tissues in the laboratory. Because most people have CMV in their bodies, the significance of finding CMV depends on the situation. For example, CMV found in a baby in the first two weeks of life usually means the baby was infected inside the womb. A positive CMV result at any other time in life could mean a new infection or a reactivation of old CMV. Special tests may be useful in some cases to determine whether or not a CMV infection is new or old. A CMV infection of the eye can often be diagnosed by its appearance in people with AIDS.
What are the long-term effects of the disease? For most healthy people, a CMV infection has no long-term effects. An unborn baby that is infected in the womb may have permanent brain damage, behaviour problems, blindness, and other effects. An eye infection in a person with AIDS may result in blindness. CMV pneumonia or gastrointestinal disease in transplant patients may cause death.
What are the risks to others? People who shed CMV can pass it to others. For most people who get CMV, however, the infection is not serious.
What are the treatments for the disease? CMV in healthy people usually does not need therapy. For people with severely swollen tonsils, a medication, such as prednisone, can be used to reduce the swelling and inflammation.
Treating active CMV in people with weakened immune systems is done with antibiotics, such as ganciclovir and foscarnet. These drugs are designed to stop the virus from multiplying, rather than killing the virus that is present.
What are the side effects of the treatments? All medications may have side effects. These may include allergic reactions, stomach upset and other problems. A low white blood cell count is the most common side effect of ganciclovir. Other side effects depend on the drugs used.
What happens after treatment for the disease? People who are healthy and got treatment can return to normal activities after recovery. No further monitoring is generally needed. People who have weakened immune systems will need careful monitoring for long periods of time, possibly life.
How is the disease monitored? For a CMV infection of the eye in people with AIDS, repeated examinations of the eyes and vision testing are needed. Affected people should report any change in their vision. For people with pneumonia or gastrointestinal disease, symptoms, physical examination, and other blood and x-ray tests are commonly used for monitoring.
Author: Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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