Epstein-Barr Virus, (EBV), also called Human herpesvirus 4 (HHV-4), is a virus of the herpes family (which includes Herpes simplex virus and Cytomegalovirus), and is one of the most common viruses in humans.
Most people become infected with EBV, which is often asymptomatic but commonly causes infectious mononucleosis.
It is named after Michael Epstein and Yvonne Barr, who together with Bert Achong discovered the virus in 1964
Pathology
Infectious mononucleosis
Epstein-Barr can cause infectious mononucleosis, also known as 'glandular fever', 'Mono' and 'Pfeiffer's disease'. Infectious mononucleosis is caused when a person is first exposed to the virus during or after adolescence. It is therefore predominantly found in the developed world, as most children in the developing world are found to be already infected by around 18 months of age. EBV antibody tests turn up almost universally positive in developing nations, but only 70-80% positive in the United States.
EBV-associated malignancies
The strongest evidence linking EBV and cancer formation is found in Burkitt's lymphoma and nasopharyngeal carcinoma. It has been postulated to be a trigger for a subset of Chronic Fatigue Syndrome patients as well as Multiple Sclerosis and other autoimmune diseases.
Burkitt's lymphoma is a type of Non-Hodgkin's lymphoma and is most common in equatorial Africa and is co-existent with the presence of malaria. Malaria infection causes reduced immune surveillance of EBV immortalised B cells, so allowing their proliferation. This proliferation increases the chance of a mutation to occur. Repeated mutations can lead to the B cells escaping the body's cell-cycle control, so allowing the cells to proliferate unchecked, resulting in the formation of Burkitt's lymphoma. Burkitt's lymphoma commonly affects the jaw bone, forming a huge tumour mass. It responds quickly to chemotherapy treatment, namely cyclophosphamide, but recurrence is common.
Other B cell lymphomas arise in immunocompromised patients such as those with AIDS or who have undergone organ transplantation with associated immunosuppression (Post-Transplant Lymphoproliferative Disorder (PTLPD)). Smooth muscle tumors are also associated with the virus in malignent patients.
Nasopharyngeal carcinoma is a cancer found in the upper respiratory tract, most commonly in the nasopharynx, and is linked to the EBV virus. It is found predominantly in Southern China and Africa, due to both genetic and environmental factors. It is much more common in people of Chinese ancestry (genetic), but is also linked to the Chinese diet of a high amount of smoked fish, which contain nitrosamines, well known carcinogens (environmental).
Chronic fatigue syndrome
In the late 1980s and early 1990s, EBV became the favored explanation for chronic fatigue syndrome. It was noted that people with chronic exhaustion had EBV, although it was also noted EBV was present in almost everyone. In a four year study, the Centers for Disease Control and Prevention found no definitive association between CFS and EBV but it is still being studied by researchers.
Other diseases associated with EBV
* Stevens-Johnson syndrome
* Hepatitis
* Herpes
* Alice in Wonderland syndrome
* Several Non-Hodgkin's lymphomas, including primary cerebral lymphoma
* Hodgkin's disease
* Post-transplant lymphoproliferative disorder
* Herpangina
* Multiple Sclerosis
* Hairy leukoplakia
* Common variable immunodeficiency (CVID)
* Kikuchi's disease