About CMV

Cytomegalovirus (CMV) is a common virus that infects people of all ages and is usually harmless to people with a healthy immune system. Most people have been exposed to CMV at some point in their lifetime without realizing it. It is estimated that 50-80% of adults in the United States have been infected with CMV by the time they reach 40 years old. Most infections with CMV are "silent" or asymptomatic, meaning most people who are infected with CMV have no signs or symptoms. Once CMV is in a person’s body, it stays there for life.

Congenital CMV infection occurs when a pregnant woman is exposed to CMV and the CMV passes from the pregnant woman to her unborn child, causing birth defects and developmental disabilities.

Acquired CMV infection is when a person is infected with CMV after birth, during childhood or adulthood.

Acquired CMV

Most healthy people with an acquired CMV infection will generally have few, if any, symptoms or complications from the infection. Because infections among healthy persons are common and typically asymptomatic, efforts to prevent transmission among healthy children and adults are not necessary.

At-Risk Populations

CMV can cause serious problems for people with weakened immune systems (immunocompromised) due to organ transplants, HIV/AIDS infection, chemotherapy, and medications such as glucocorticoids, cytostatics, antibodies, drugs acting on immunophilins, as well as other drugs.

In children and adults with organ transplants, CMV infections are linked with rejection or malfunction of the transplant.

In immunocompromised people, CMV can attack specific organs. Types and symptoms of CMV infections include, but are not exclusive/limited to:

• Esophagus (CMV esophagitis)
• Stomach or intestines (CMV gastroenteritis) - Diarrhea, swallowing difficulties or pain, and ulcerations with bleeding
• Eye (CMV retinitis) - Blindness, floaters in the eye, and visual impairment
• Lung (CMV pneumonia) - Pneumonia with impaired oxygen uptake (hypoxia)
• Brain - Coma, encephalitis with behavioral changes, and seizures

Testing

If you have symptoms of a CMV infection, blood tests can identify special proteins in your blood (antibodies) that are created by your immune system to fight off a CMV infection. The virus can also be detected by culturing or by a polymerase chain reaction (PCR) test from blood, other body fluids, or a tissue biopsy.

Treatments

CMV treatment includes both induction therapy and maintenance therapy. Induction therapy is meant to treat the disease and usually takes two or three weeks. Maintenance therapy is intended to prevent the virus from causing disease again in the future.

Current treatment options for acquired CMV include the following:

• Ganciclovir (Cytovene or Vitrasert) - can be given intravenously (into a vein), orally, or as a pellet implanted in the eye to treat an infection in the retina
• Valganciclovir - similar to ganciclovir, but with better oral absorption
• Cidofovir (Vistide) - approved for the treatment of CMV retinitis.
• Foscarnet (Foscavir) - given intravenously, usually reserved for those who have virus that is resistant to ganciclovir or those who have serious side effects from ganciclovir

NOTE: Side effects of ganciclovir and valganciclovir include the suppression of white blood cells (needed to fight infection), red blood cells (that carry oxygen), and platelets (that help the blood to clot). Additionally, cidofovir and foscarnet can cause kidney damage, so kidney function needs to be monitored carefully.

CMV Symptoms

Most people don't realize that they have been infected with CMV because, usually, CMV produces no obvious symptoms. Symptoms of CMV infection can be similar to those of mononucleosis. Symptoms of CMV infection may include the following:

• High fever
• Fatigue
• General discomfort, uneasiness, or ill feeling
• Joint stiffness
• Muscle aches or joint pain
• Night sweats
• Prolonged fever
• Sore throat
• Swelling of the lymph nodes
• Weakness
• Loss of appetite
• Weight loss

Infection Types

Primary

Primary CMV infection refers to the first time someone catches CMV. In other words, they have come into contact with the virus for the first time and have no pre-existing immunity to the virus.

Pregnant - Between 1-4% of healthy women will catch CMV for the first time while they are pregnant and are at risk of delivering a child born with congenital CMV. Primary CMV infection can cause more serious disease to babies born with congenital CMV than recurrent infection. There appears to be little risk of CMV-related complications, illness, or abnormalities in babies with mothers infected prior to pregnancy.

Recurrent

Recurrent CMV infection is when a previous CMV infection that has been considered dormant (or latent) becomes active like a new infection again. A recurrent infection will rarely cause visible symptoms because the body has pre-existing immunity to the virus. CMV reactivation rarely occurs unless the person's immune system is suppressed due to therapeutic drugs, disease, stress, hospitalizations, etc.

Pregnant - For healthy pregnant women, recurrent CMV infection does not pose the same risk for serious disease in a newborn as primary CMV infection. Therefore, babies contracting congenital CMV as the result of a recurrent infection are much less likely to suffer the severe effects associated with a primary infection. If you have already been exposed to CMV, your body has antibodies against CMV which, along with other immune factors, appears to protect the baby from serious illness due to CMV infection.

Reinfection

Reinfection is a new infection with a different strain of the CMV virus. This type of infection is very unusual and may only occur during special circumstances. Its consequences are unknown at this time.