Cytomegalovirus Symptoms Can Look a Lot Like the Flu—Here's What to Know

Cytomegalovius is the virus that you've probably already had without even knowing it. The virus—commonly known as CMV—is estimated to have infected over half of American adults by the time they hit 40, according to the Centers for Disease Control and Prevention (CDC). A large number of those infections occur in childhood: The CDC estimates that one in three US children are already infected CMV by 5 years old.

For the most part, CMV affects people silently—the majority of people with CMV will show no symptoms, and won't be aware of the infection. But once it's entered your body, CMV will stay there for life, with the chance of reactivating.

Still, just because CMV can go unnoticed in many people, it won't be that way for everyone—there are some populations (people with weakened immune systems, infants born with CMV) who can suffer some more serious manifestations of the virus that can lead to long-term health issues.

Here, infectious disease experts explain the most common symptoms associated with CMV infections in otherwise healthy people, in those with weakened immune systems, and in infants who contracted CMV in utero.

What are the symptoms of cytomegalovirus?

Like many viruses, CMV affects different people in different ways. If you're otherwise healthy, there's a chance you won't even notice a you've contracted CMV, Donald Dumford, MD, director of infection prevention at Cleveland Clinic Akron General, tells Health. However, the CDC says some individuals may experience the following flu-like symptoms from a CMV infection:

• Sore throat
• Fever
• Fatigue
• Swollen glands

The US National Library of Medicine (MedlinePlus) adds a few more symptoms to that list, including:

• Loss of appetite
• Muscle ache
• Rash
• General feeling of unwell (malaise)

According to the CDC, a cytomegalovirus infection can cause more serious health problems, including mononucleosis (also known as mono) or hepatitis, which is inflammation of the liver, though these occurrences are rare.

Immunocompromised individuals—or those whose immune systems don't function properly and can't properly defend the body against illnesses—might experience other complications due to a cytomegalovirus infection. Specifically, their eyes, liver, lungs, esophagus, intestines, and stomach can be affected, according to the CDC. In addition to severe illness, a cytomegalovirus infection could result in death for an immunocompromised individual, Martin Hirsch, MD, a professor of medicine at Harvard University and editor in chief of The Journal of Infectious Diseases, tells Health.

CMV infections can also affect babies, who can be born with the condition—known as congenital CMV—when they're exposed to the virus in utero. The CDC says most babies born with congenital CMV don't show signs of the illness or go on to develop health issues from it. However, some infants will present with signs of an infection, per the CDC, that include:

• Rash
• Jaundice
• Microcephaly (small head)
• Low birth weight
• Hepatosplenomegaly (enlarged liver and spleen)
• Seizures
• Retinitis

Some children who present with signs of CMV at birth may also develop future health problems, like hearing loss, developmental delays, vision loss, microcephaly, and seizures—and, in some rare cases, CMV can result in pregnancy loss before the infant is delivered.

If you believe you are showing symptoms of CMV—or you think a family member or child is—you can discuss the possibility of being tested by your local health provider or pharmacist. The CDC says blood tests specifically can test adults showing CMV symptoms; in babies, experts recommend testing their saliva and urine.

And while otherwise healthy individuals infected with CMV aren't likely to require any medical treatment, there are therapies available to treat an infection in immunocompromised people, or babies with signs of congenital CMV, like antiviral treatments, that may help out with hearing or developmental issues that come as a result from a congenital CMV infection.