Unlike Epstein-Barr virus, the chicken pox or shingles, you likely haven't heard of cytomegalovirus (CMV). However, as many as 80 percent of American adults have been infected with it by the age of 40 [source: CDC]. CMV is also known as human herpes virus 5 (HHV-5). Like Epstein-Barr, CMV resides in the h. It's also transmitted through bodily fluids such as saliva, although it's not considered highly contagious.
Most of the time, CMV doesn't cause any symptoms. Some people get mononucleosis, a fever or mild flulike symptoms that are often passed off as something else. It rarely returns after the initial infection, so most people who have it don't know about it. Sometimes CMV can cause other illnesses in people with weakened immune systems, such as liver failure, pneumonia, gastrointestinal disease or blindness.
CMV has the dubious distinction of being the most common congenital (present at birth) virus, which means that infected pregnant women pass CMV on to their unborn fetuses. Women who get CMV during pregnancy have about a 40 percent chance of passing it on to their baby [source: American Pregnancy Association]. Pregnant women in the United States can have their blood tested for the presence of CMV antibodies.
Most babies born with CMV don't have any symptoms. About 10 percent show temporary symptoms like liver or spleen problems that eventually resolve. A very small percentage of babies born do suffer severe complications: seizures, loss of hearing and vision, mental and physical disabilities, delayed development and even death. Some infected children don't demonstrate any of these symptoms for months or years after birth, or experience worse symptoms later in life after showing initially mild symptoms.
The spread of CMV can be prevented by engaging in good hand washing practices. Pregnant women need to avoid saliva and other lovely secretions from children. Some patients with weakened immune systems take antiviral drugs to suppress CMV and avoid some of its more dangerous complications, but these aren't usually used on pregnant women or babies with CMV.
Roseolovirus, another type of herpes, can also affect babies. We'll learn about it in the next section.