Cytomegalovirus (CMV)

A virus is a microscopic organism that needs to hijack a host cell in order to reproduce. Typically, a virus penetrates the cell membrane and re-programs its new host to make more viruses instead of more cells. This technique provides excellent protection from the host’s immune system, because the infected cell ‘looks’ normal to the patrolling immune cells.

Cytomegalovirus (CMV) is a member of the herpes family. Related viruses include Epstein-Barr (causes glandular fever), varicella-zoster (causes chicken pox) and herpes simplex (causes cold sores). This viral infection can be spread through coughing, contact with blood, urine or faeces, or via the mucous membranes such as those of the mouth and genitals.

In Australia, about 50 per cent of young adults have been infected. In healthy people, CMV infection causes nothing more than a flu-like illness that lasts a few days. In certain people, including transplant patients and pregnant women, the effects can be much more serious.

Many organs can be targeted
CMV can infect virtually any organ of the human body. The most common organs include the blood, brain, colon, eye, heart, kidney, liver, lung and stomach. In the case of an organ transplant patient, the symptoms of CMV can be easily confused with rejection.

The symptoms vary according to which organ is infected, but generally a person with CMV will experience lethargy, a high temperature and a drop in white blood cell levels. For most people a CMV infection poses no real health threat. The symptoms are generally mild and flu-like, although some may feel unwell for a few weeks, rather than a few days. A few people experience no symptoms.

CMV infection is permanent
Once you have contracted CMV, you carry it for life. This is because the virus lies dormant inside the body and may or may not reactivate itself at any time.

Pregnant women
CMV causes brain damage in the human foetus, particularly in the earlier stages of pregnancy when internal organs are forming. If a baby in utero is exposed to the virus via the infected mother, they can suffer from hearing loss and mental retardation. Some babies stop growing as quickly as they should and experience developmental problems in affected organs, such as the liver. There is no risk if a baby catches CMV after being born.

Women of childbearing age should take care when handling nappies and be sure to wash their hands afterwards to avoid an infection which may spread to their unborn baby.

Organ transplant patients
People with compromised immune systems, such as organ transplant patients and those receiving treatment for HIV/AIDS or cancer, are at increased risk of serious complications. The drugs that suppress transplant rejection also reduce the immune system’s ability to fight viruses, so a CMV infection is much more serious. For example, infection of the brain, called CMV encephalitis, can lead to convulsions and coma. Tracking down the virus can be very difficult and diagnosis may take weeks. Organ donors can be tested and where possible donations from CMV seropositive donors avoided when the recipient is CMV seronegative.

Treatment options
Treatment depends on the severity of the condition. In a healthy person, bed rest, drinking plenty of fluids and medical supervision are all that is needed. Pregnant women and patients with suppressed immunity need careful medical monitoring and frequent testing, including blood, sputum and urine tests. Antiviral medication may be prescribed.

Where to get help

• Your doctor
• Immunologist (your doctor will refer you).

• Cytomegalovirus (CMV) is a member of the herpes family.
• In healthy people, it causes a mild flu-like illness that passes harmlessly within a few days or weeks. In susceptible people, such as those with suppressed immunity or unborn babies, CMV can be a dangerous infection.

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