Monday, October 22, 2007

Epstein-Barr virus/Alice in Wonderland syndrome

Epstein-Barr virus - Wikipedia, the free encyclopedia

Epstein-Barr virus

From Wikipedia, the free encyclopedia

Epstein-Barr virus
Leukemia cells containing Epstein Barr virus (in green) by Fluorescent antibody staining technique.
Leukemia cells containing Epstein Barr virus (in green) by Fluorescent antibody staining technique.
Virus classification
Group: Group I (dsDNA)
Family: Herpesviridae
Genus: Lymphocryptovirus
Species: Human herpesvirus 4 (HHV-4)

The 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.

EBV is named after Michael Epstein and Yvonne Barr, who together with Bert Achong, discovered the virus in 1964.[1]


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. Though once deemed "The Kissing Disease," recent research has shown that transmission of Mono not only occurs from exchanging saliva, but also from contact with the airborne virus. It is predominantly found in the developed world, and most children in the developing world are found to have already been infected by around 18 months of age. EBV antibody tests turn up almost universally positive. In the United States up to 95% of adults between 35 and 40 years of age have been infected.[9]

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[10] as well as multiple sclerosis and other autoimmune diseases.[11]

Burkitt's lymphoma is a type of Non-Hodgkin's lymphoma [2] 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 malignant 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).[12]

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

Alice in Wonderland syndrome

From Wikipedia, the free encyclopedia

Alice in Wonderland syndrome (AIWS), or micropsia, is a disorienting neurological condition which affects human visual perception.

An illustration by John Tenniel ofAn illustration by John Tenniel of Alice rapidly growing. Alice rapidly growing.

Subjects perceive humans, parts of humans, animals, and inanimate objects as substantially smaller than in reality. Generally, the object perceived appears far away or extremely close at the same time. For example, a family pet, such as a dog, may appear the size of a mouse, or a normal car may look shrunk to scale. This leads to another name for the condition, Lilliput sight or Lilliputian hallucinations, named after the small people in Jonathan Swift's Gulliver's Travels. The condition is in terms of perception only; the mechanics of the eye are not affected, only the brain's interpretation of information passed from the eyes.

The syndrome is associated with, and perhaps in part caused by, the classical migraine headache. Occasionally, Alice in Wonderland syndrome is named as one of the first symptoms of mononucleosis. Micropsia can also be caused by complex partial epilepsy, and the actions of various psychoactive drugs (notably dextromethorphan).


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