Epstein-Barr virus (EBV), herpesvirus that is the major cause of infectious mononucleosis mononucleosis, infectious (mŏn'ən
..... Click the link for more information. and is associated with a number of cancers, particularly lymphomas lymphoma, non-Hodgkin's, any cancer of the lymphoid tissue (see lymphatic system ) in which the Reed-Sternberg cells characteristic of Hodgkin's disease (the other category of lymphoma) are not present.
..... Click the link for more information. in immunosuppressed persons, including persons with AIDS. Epstein-Barr is a ubiquitous virus, so common that it has been difficult to determine whether it is the cause of certain diseases or whether it is simply there as an artifact. In Third World nations, most children are infected with EBV; in most industrialized nations, about 50% of the people are infected. Research has found that all of the lymphomas associated with AIDS and most lymphomas in other immunocompromised persons are connected with latent EBV infection. EBV has been found in biopsy tissue of patients with Hodgkin's disease Hodgkin's disease, a type of cancer of the lymphatic system . First identified in 1832 in England by Thomas Hodgkin, it is a type of malignant lymphoma. Incidence peaks in young adults and the elderly.
..... Click the link for more information. , breast cancer, and some smooth muscle tumors. EBV also was formerly suspected as the cause of chronic fatigue syndrome chronic fatigue syndrome (CFS), collection of persistent, debilitating symptoms, the most notable of which is severe, lasting fatigue. In other countries it is known variously as myalgic encephalomyelitis, chronic fatigue and immune dysfunction syndrome, and
..... Click the link for more information. (originally named chronic EBV syndrome).

Epstein-Barr virus (EBV)

Virus of the Herpesviridae family that is the major cause of acute infectious mononucleosis. The virus, named for two of its discoverers, infects only salivary gland cells and one type of white blood cell. Saliva is the only bodily fluid that has been proved to contain infectious EBV particles. In less-developed nations, infection with EBV occurs in almost all children before the age of 5 and is not associated with recognizable symptoms. When EBV infection is delayed until the teen or early adult years, the body commonly responds differently, resulting in mononucleosis. Other, rarer disorders have also been linked with EBV, including certain cancers. There are no specific treatments for any form of EBV infection, and no vaccines have been developed.

Epstein-Barr virus

An antigenically distinct member of the herpesvirus group of viruses, whose genome is DNA. EB virus is the cause of one benign disease (infectious mononucleosis), and is associated with certain types of cancer; however, the great majority of EB virus infections are clinically inapparent. The virus was detected initially by electron microscopy in a small proportion of cells in continuous lymphoblastoid cell lines derived from Burkitt's lymphoma (but particles have not been seen in cells of the tumor itself). The virus also has been detected in cell lines derived from nasopharyngeal carcinomas, a type of cancer found with high frequency in persons from southern China. The virus is found in peripheral blood leukocytes from normal individuals and from patients with infectious mononucleosis. See Infectious mononucleosis, Lymphoma

If EB virus is indeed confirmed as having a role in the development of human malignancies, then one major question to be resolved is how a virus so ubiquitous can be involved in so wide a variety of responses. However, it should be recalled that many virus infections (for example, polio virus, hepatitis viruses, certain of the arboviral encephalitides) have a wide spectrum of outcomes, ranging from inapparent infection to severe syndromes. See Animal virus