Epstein Barr Virus (EBV)

EB virus is a gamma herpesvirus with a double stranded DNA genome of about 172 kb that remains in the nucleus in a stable episomal form.

Member of herpes family.

Infects more than 90% of humans and persists throughout their lives.

EBV, a type of herpes virus, causes mononucleosis as well as certain types of lymphoma and cancers of the nose and throat. 

EBV is most commonly transmitted by contact with saliva, such as through kissing or by sharing toothbrushes or drinking glasses. 

EBV can also be spread by sexual contact, blood transfusions, and organ transplantation. 

More than 90% of people worldwide will be infected with EBV during their lifetime, and most are asymptomatic.

There is no vaccine to prevent EBV infection and no specific treatment for EBV infection. 

EBV may lead to cancer by causing breaks in human DNA.

Over 95% of adults worldwide have serologic evidence of infection with EB virus.

Infection occurs only in humans.

Primary infection often occurs during early childhood with a second peak during late adolescence.

In industrialized nations and higher socioeconomic groups half the population has a primary EB infection by 1-5 years, with another large percentage becoming infected in the second decade.

In developing countries and in lower socioeconomic groups EBV most infections occur in early childhood.

Primary infections rare in first year of life due to maternal antibody protection.

Primary infection in young children is usually nonspecific.

EBV infections in early childhood has decreased in frequency because of improved sanitation and has caused increase in susceptibility in adolescence.

Within B cell the linear genome circulates and forms an episome in the lymphocyte nucleus.

Infection of B cells is latent without viral replication and the lymphocyte are not killed but acquire the ability to propagate indefinitely in vitro.

Able to immortalize B cells.

Remains continuously active in immunocompetent individuals even at low levels.

Transmission most commonly via oral secretions and can occur via sexual transmission, blood transfusions and transplantation.

Viral shedding from the oropharynx for months after the infection but persists intermittently throughout life.

Individuals may be infected by more than 1 strain of virus.

Establishes latency in B lymphocytes.

The normal proliferative and survival signals are deregulated in latently infected cells.

Gains entry into B cell lymphocytes via CD21 molecule expressed on all B cells.

Childhood infections are usually asymptomatic or associated with mild pharyngitis with or without tonsillitis.

In the elderly patients have nonspecific symptoms of fever, fatigue, myalgias and malaise.

The major disease associated with primary infection is infectious mononucleosis.

EBV infection may rarely trigger the hematophagocytic lymphohistiocytosis syndrome with hepatosplenomegaly, lymphadenopathy, prolonged fever, rash, pancytopenia, and liver function impairment.

Serum antibodies to EBV may be found years before the diagnosis of Burkitt’s lymphoma, nasopharyngeal cancer, Hodgkin’s disease, B cell lymphoma in immunosuppressed patients and multiple sclerosis.

Part of the Epstein-Barr virus mimics a protein made in the brain and spinal cord, leading the immune system to mistakenly attack the body’s nerve cells.

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