But the virus, which remains dormant in the body, can cause complications during pregnancy and for people with a weakened immune system.
The virus spreads through bodily fluids, and it can be passed on from a pregnant mother to her unborn baby.
Also known as HCMV, CMV, or Human Herpes virus 5 (HHV-5), cytomegalovirus is the virus most commonly transmitted to a developing fetus.
The Centers for Disease Control and Prevention (CDC) estimates that over 50 percent of adults in the United States are infected by the age of 40 years. It affects males and females equally, at any age, and regardless of ethnicity.
Fever is a symptom of acquired and recurring CMV.
The symptoms will depend on the type of CMV.
Most people with acquired CMV have no noticeable symptoms, but if symptoms do occur, they may include:
- night sweats
- tiredness and uneasiness
- sore throat
- swollen glands
- joint and muscle pain
- low appetite and weight loss
Symptoms will generally go away after two weeks.
Symptoms of recurring CMV vary, depending on which organs are affected. Areas likely to be affected are the eyes, lungs, or digestive system.
Symptoms may include:
- diarrhea, gastrointestinal ulcerations, and gastrointestinal bleeding
- shortness of breath
- pneumonia with hypoxemia, or low blood oxygen
- mouth ulcers that can be large
- problems with vision, including floaters, blind spots, and blurred vision
- hepatitis, or inflamed liver, with prolonged fever
- encephalitis, or inflammation of the brain, leading to behavioral changes, seizures, and even coma.
A person with a weakened immune system who experiences any of these symptoms should seek medical attention.
Around 90 percent of babies born with CMV have no symptoms, but 10 percent to 15 percent of them will develop hearing loss, normally during their first 6 months of life. The severity ranges from slight to total hearing loss.
In half of these children, just one ear will be affected, but the rest will have hearing loss in both ears. Hearing loss in both ears can lead to a higher risk of speech and communication problems later on.
If there are symptoms of congenital CMV at birth, they may include:
- red spots under the skin
- Purple skin splotches, a rash, or both
- enlarged liver
- enlarged spleen
- low birth weight
Some of these symptoms are treatable.
In about 75 percent of babies born with congenital CMV, there will be an impact on the brain. This may lead to challenges later in life.
Conditions that they may face include:
- central vision loss, scarring of the retina, and uveitis, or swelling and irritation of the eye
- cognitive and learning difficulties
- deafness or partial hearing loss
- impaired vision
- problems with physical coordination
- small head
Scientists have been searching for a CMV vaccine, but as yet there is no cure.
People with acquired CMV, who are infected for the first time, can use over-the-counter (OTC) painkillers such as Tylenol (acetaminophen), ibuprofen, or aspirin to relieve symptoms, and should drink plenty of fluids.
Patients with congenital or recurring CMV can use anti-viral medications such as ganciclovir to slow the spread of the virus.
These medications may have adverse effects. If there is extensive organ damage, hospitalization may be necessary.
Newborns may need to stay in the hospital until their organ functions return to normal.
The following precautions may help lower the risk of contracting CMV:
- Wash the hands regularly with soap and water.
- Avoid kissing a young child, including tear and saliva contact.
- Avoid sharing glasses and kitchen utensils, for example, passing round a drink.
- Dispose of diapers, paper handkerchiefs, and similar items carefully.
- Use a condom to prevent the spread of CMV via vaginal fluids and semen.
The CDC urges parents and caregivers of children with CMV to seek treatment as early as possible, whether it is medication or attending services such as hearing checks.
There are three main types of CMV infections: acquired, recurring, or congenital.
- Acquired, or primary, CMV is a first-time infection.
- Recurring CMV is when the patient is already infected. The virus is dormant and then becomes active due to a weak immune system.
- Congenital CMV is when infection occurs during pregnancy and affects the unborn child.
CMV is generally not a problem, except when it affects an unborn child or a person with a weak immune system, such as a recent transplant recipient or a person with human immunodeficiency virus, or HIV.
In people with HIV, CMV infection can lead to organ failure, eye damage, and blindness. Improvement in antiviral medication has reduced the risk in recent years.
Organ and bone marrow transplant recipients have to take immunosuppressants to lower their immune systems, so that their bodies do not reject the new organs. Dormant CMV can become active in these patients and lead to organ damage.
Transplant recipients may receive antiviral medicines as a precaution against CMV.
During pregnancy, CMV infection can pass from the mother to the fetus. This is called congenital CMV.
According to the CDC, around 1 in 150 newborns are already infected with CMV at birth.
Most of these infants will have no signs or symptoms, but around 20 percent of them will have symptoms or long-term health complications, including learning difficulties.
The symptoms may be severe, and they include vision and hearing loss, vision loss, small head size, weakness and difficulty using muscles, problems of coordination, and seizures.
Cytomegalovirus is a common herpes virus that affects 50 percent of people by the age of 40 years.
Acquired cytomegalovirus can spread between people through bodily fluids, such as saliva, semen, blood, urine, vaginal fluids, and breast milk.
Infection may also occur by touching a surface infected with saliva or urine, and then touching the inside of the nose or mouth.
Most humans become infected during childhood, at daycare centers, nurseries, and places where children are in close contact with each other. However, by this age, the child's immune system is normally able to deal with an infection.
Recurring CMV can occur in patients with a weakened immune system due to HIV, organ transplantation, chemotherapy or taking oral steroids for over 3 months.
Congenital CMV normally occurs when a woman is infected with CMV for the first time, either during her pregnancy or shortly before conceiving.
Occasionally, a dormant CMV infection may recur during pregnancy, especially if the mother has a weakened immune system.
A blood test can detect the antibodies which are created when the immune system responds to the presence of CMV.
A pregnant woman has a very small risk of reactivation infecting her developing baby. If infection is suspected, she may consider amniocentesis, which involves extracting a sample of amniotic fluid to find out whether the virus is present.
If congenital CMV is suspected, the baby must be tested within the first 3 weeks of life. Testing later than 3 weeks will not be conclusive for congenital CMV, because the infection could have happened after birth.
Any patient with a weakened immune system should be tested, even if there is no active CMV infection. Regular monitoring for CMV complications will include testing for vision and hearing problems.
Healthy people very rarely become significantly sick from CMV infection.
People with a weakened immune system, however, may develop CMV mononucleosis, a condition in which there are too many white blood cells with a single nucleus. Symptoms include sore throat, swollen glands, swollen tonsils, tiredness, and nausea. It can cause liver inflammation, or hepatitis, and spleen enlargement.
CMV mononucleosis is similar to classic mononucleosis, caused by the Epstein-Barr Virus. EBV mononucleosis is also known as glandular fever.
Other complications of CMV are:
- gastrointestinal problems, including diarrhea, fever, abdominal pain, colon inflammation, and blood the in feces
- liver function problems
- central nervous system (CNS) complications, such as encephalitis, or inflammation of the brain
- pneumonitis, or inflammation of lung tissue.