An infection that usually produces no symptoms but can cause fatal illness in people with reduced immunity
- More common in males
- Age, genetics, and lifestyle are not significant factors
Infection with cytomegalovirus (CMV) is very common and affects most adults at some time in their lives. However, most people do not develop symptoms and are not aware that they have been infected with the virus, although they will carry CMV for life in an inactive form. CMV is a type of herpesvirus.
People with reduced immunity, such as those who have AIDS (see HIV infection and AIDS), are at risk of serious illness from a first infection, and CMV can also be reactivated in this group. In addition, the virus can seriously affect a fetus if a woman is first infected during pregnancy (see Congenital infections).
The virus can be passed in saliva, in minute droplets from the coughs or sneezes of infected people; during sexual intercourse; through a blood transfusion; during an organ transplant; and across the placenta to a fetus if the mother becomes infected during pregnancy. In developed countries, blood that is used for transfusion to high-risk groups is screened for CMV.
What are the symptoms?
CMV infection can produce widely differing symptoms, depending on the age and general health of the person affected. Most people have no symptoms from a first infection with the virus. If symptoms are present, they are often vague and may include:
Nausea, vomiting, and diarrhoea.
In teenagers and young adults, symptoms may resemble those of infectious mononucleosis.
The symptoms of CMV infection are more severe in people with reduced immunity. In such cases, first infection or reactivation of the virus can result in a fever lasting for 2–3 weeks, a nonitchy rash, and inflammation of the liver (see Acute hepatitis), which causes yellowing of the skin and whites of the eyes (see Jaundice). In addition, the virus can cause inflammation of the brain (see Viral encephalitis) and the lungs (see Pneumonia). In people with reduced immunity, CMV can also cause retinitis (inflammation of the light-sensitive cells at the back of the eye), which may result in blindness.
If a woman is first infected with the virus during pregnancy, there is a risk that the virus will infect the fetus and the baby may be born with jaundice, liver enlargement, and certain blood disorders. In other cases where the fetus is infected during pregnancy there are no symptoms present at birth but disorders such as hearing loss may develop later in life.
What might be done?
In a person who is otherwise healthy, CMV infection usually goes unnoticed, causes no problems, and is not treated. If your symptoms are severe and your doctor suspects CMV infection, he or she may arrange for a blood test to look for antibodies against the virus. The symptoms are often relieved by early treatment with antiviral drugs.
For people with reduced immunity, complications can be life-threatening. These people may be given antiviral drugs to protect against infection or, if a blood test shows that the virus is already present, to prevent symptoms from developing. Drugs may also be given to a pregnant woman who has the infection to help protect the fetus.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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