What Are Risk Factors and Causes of Epstein-Barr Virus Infections?
EBV is a contagious virus that is transmitted from person to person and occurs throughout the world. The cause of infection is generally close person-to-person contact through bodily fluids, especially saliva. It may also be transmitted during sexual contact through semen, and can also be spread by blood transfusions or organ transplants.
The virus contains double-stranded DNA and multiplies in white blood cells (a certain type of lymphocyte called a B cell) and other cells, such as those lining the mouth, tongue, and nose. The human immune system usually contains the virus effectively, reducing but not eliminating the viruses. A few living viruses will persist in a line of lymphocytes for the rest of the person's life. This is known as "latent" infection (inactive stage). Occasionally, the virus may multiply (reactivate), but this does not cause symptoms unless the person's immune response system is not working properly.
Most people in the U.S. have been infected with EBV, mononucleosis is more common in whites than in the African-American populations.
Some risk factors associated with acquiring EBV include being female, living in tropical countries, having immunodeficiency, and being sexually active.
What Are Epstein-Barr Virus Infection Symptoms and Signs?
Once the Epstein-Barr virus is acquired, it takes about four to six weeks for symptoms to appear. Children usually have nonspecific symptoms or no symptoms at all. Rarely, young children may have rashes, pneumonia, or low white blood counts.
Many teenagers and young adults develop symptoms of mononucleosis. Acute mononucleosis causes sore throat, fever, fatigue, and swollen lymph nodes. The sore throat is very painful and is the usual reason for infected people to seek medical attention. Tonsils may become very swollen. Loss of appetite, fatigue, chills, headache, bloating, sore muscles, body aches, weakness, and sweats are common. Dizziness is reported in some patients. Although the symptoms fade in days to weeks, some patients complain of fatigue that lasts for weeks after infection, though most people eventually recover completely.
A small percentage of people develop a rash due to the infection. A rash can also develop in people with mononucleosis who are given ampicillin or amoxicillin. This common reaction does not necessarily mean the patient is allergic to penicillin or related antibiotics. Appearance of the rash in conjunction with the above symptoms and signs can also lead to misdiagnosis of the condition.
The spleen becomes swollen in up to half of people with mononucleosis. The spleen is always engorged with blood, and if it ruptures, it can cause a patient to bleed to death. Blunt trauma to the abdomen, even mild trauma, may result in splenic rupture if swollen. Patients with mono are usually advised not play sports, especially any contact sports. The spleen may also rupture spontaneously.
A very small number of infected people have neurological complications. These include inflammation of the brain (encephalitis), of the lining of the brain (meningitis), or of individual nerves. Less commonly, infection of the spinal cord may occur. The majority of patients with neurological complications recover completely. Rarely, other organs may be involved, including the lungs or heart.
Rarely, boys may develop overwhelming infection with EBV known as X-linked lymphoproliferative syndrome. In X-linked lymphoproliferative syndrome, the number of immune cells or lymphocytes (B cells) in the body increases substantially. The lymphocytes infiltrate major organs, often causing severe liver disease or death. Lymphoproliferative syndrome is probably a result of a subtle genetic defect that makes it difficult for the immune system to contain the virus. Organ transplants or bone marrow transplants are also risk factors for developing lymphoproliferative syndrome.
In addition to lymphoproliferative syndrome, EBV is considered a risk factor for some cancers. One such cancer is lymphoma of the brain. Lymphoma of the brain is most common in people with advanced AIDS but also occurs in other immunosuppressed states. Nasopharyngeal cancer, Burkitt lymphoma (a type of non-Hodgkin lymphoma), and some types of Hodgkin's lymphoma are also associated with EBV. The exact mechanism by which EBV helps to transform normal lymphocytes into cancer cells is not fully understood.
EBV is associated with a condition called oral hairy leukoplakia. This is a white plaque on the side of the tongue that cannot be removed by gentle scraping. It is most common in people with AIDS or other immunosuppressive states.
Mononucleosis causes fatigue, which can sometimes last for weeks or even longer. Therefore, chronic infection with EBV (CEBV) has been investigated as a cause of chronic fatigue syndrome (CFS), also called systemic exertion intolerance disease (SEID). Studies to date have not been able to find a causal link between EBV and CFS. In CFS, there is a chronic lack of energy often associated with difficulty concentrating or generalized pain. CFS is more common among women than men and occurs in early to middle adulthood. Blood tests are usually normal. There is no specific diagnostic test for CFS, and the cause remains unknown.
During pregnancy, it is rare for a fetus to become infected with EBV even if the mother is infected. Even among women who do become infected while pregnant, there are no documented birth defects that have resulted.
EBV is also associated with several autoimmune diseases, including multiple sclerosis, autoimmune thyroiditis, systemic lupus erythematosus, oral lichen planus (OLP), rheumatoid arthritis (RA), autoimmune hepatitis, Sjögren's syndrome, and Kawasaki disease.