ToRCH & Childhood Diseases

Epstein-Barr Virus (EBV) The Epstein–Barr virus (EBV), also called human herpesvirus 4 (HHV-4), is a virus of the herpes family and infects more than 95% of the world’s population. The most common manifestation of primary infection with this organism is acute infectious mononucleosis, a self-limited disease that frequently affects adolescents and young adults.

Primary EBV infections are typically asymptomatic and it is perhaps the most common reason for fever of unknown origin in young children. It does not occur in epidemics and has relatively low transmissibility, spreading mainly through bodily fluids (saliva). Approximately 90% of the US population is infected with EBV by the age of 25 and this infection rate is similar in other developed countries worldwide. EBV during pregnancy and transplacental transmission is rare. When infection with EBV occurs during adolescence or young adulthood, it causes infectious mononucleosis 35% to 50% of the time. EBV is the first human virus to be directly implicated in carcinogenesis. Infection is associated with particular forms of cancer, such as Hodgkin’s lymphoma, Burkitt’s lymphoma, nasopharyngeal carcinoma, and conditions associated with AIDS including hairy leukoplakia and central nervous system lymphomas. In particular in Africa, the virus is associated with endemic Burkitt lymphoma in DIAGNOSIS Diagnosing an EBV infection can be challenging since the symptoms are similar to other illnesses. However, different proteins are expressed during the various stages the EBV life cycle and the detection of these antigens can help distinguish whether an infection is a primary acute, convalescent, latent, or reactivation infection. Diagnostic methods for EBV include IFA, ELISA, blot techniques, IgG avidity, PCR and virus isolation. About 90% of adults have antibodies that show that they have a current or past EBV infection. In most cases, the antibody response occurs rapidly during primary EBV infection. Tests are available for detecting antibodies to the following EBV-associated antigens: Viral capsid antigen (VCA) • Elevated anti-VCA IgM indicates acute infection: appears early in infection and usually disappears within 4- 6 weeks

EBV INFECTION KINETICS

Source: katkars.com

the setting of co-infection with Plasmodium falciparum. Specifically, it has been found that a malaria infection can impair the T-cell response to EBV and directly contribute to tumor pathogenesis.

• Elevated anti-VCA IgG indicates prior infection: appears in the acute phase, peaks 2-4 weeks after onset, declines slightly, then persists for the rest of a person’s life • Common VCA proteins are gp125 and p19 Early antigen (EA) • Anti-EA IgG appears in the acute phase of illness and generally falls to undetectable levels after 3-6 months • In many people, detection of antibody to EA is a sign of an active infection • 20% of healthy people may have antibodies against EA for several years EBV nuclear antigen (EBNA) • Antibody to EBNA is not seen in the acute phase of EBV infection but slowly appears 2-4 months after onset of symptoms • Persists for the rest of a person’s life

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ToRCH & Childhood Diseases- Reagents for Assay Development

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