Epstein Barr virus causes mononucleosis

2021-08-16 06:52 PM

Epstein Barr virus replicates in cultured human B lymphocytes and B lymphocytes of several other primates, and recent studies have shown that this virus is present in nasopharyngeal epithelial cells (nasopharynx)

The properties of the virus

Epstein Barr virus particles purified from cultured B lymphocytes are structurally similar to those of other herpes viruses. The viral particle has a cubic symmetric nucleocapsid surrounded on the outside by a complex shell, inside the nucleocapsid contains a double-stranded DNA with a molecular weight of about 101 x 106 daltons containing genes coding for at least 30 polypeptides.

Epstein Barr virus replicates in cultured human B lymphocytes and B lymphocytes of several other primates, and recent studies have shown that this virus is present in nasopharyngeal epithelial cells (nasopharynx). This virus is difficult to harvest in acellular form for mass culture. In the laboratory, B lymphocytes are evaluated by the transformation of B lymphocytes.

Various antigens of the Epstein Barr virus have been identified in infected cells by immunofluorescence.

VCA antigen: This is the Epstein Barr virus capsid antigen composed of at least three (3) proteins. Patients with infection by Epstein Barr virus in serum-containing anti-VCA class IgM and IgG

MA membrane antigen: This is a component of the membrane antigen induced by the Epstein Barr virus, which is also present in the envelope of the virus. This antigen stimulates the production of neutralizing antibodies.

EA Early Antigen Complex: Consists of two components.

* EA-D: Is a diffuse antigenic component identified in plasma and in the nucleus of infected cells.

* EA-R: A limited antigenic component found only in the cytoplasm of cells.

Epstein Barr Virus Antigen (EBNA): This antigen is found in the nucleus of infected cells. Antibodies to EBNA appear 6 to 8 weeks after illness and persist for life.

Possibility to cause disease

Epidemiology

The virus is shed from the nasal passages for up to 18 months after primary infection. Patients and healthy people carry viruses that can cause infection. Transmission is mainly through saliva when kissing, not through breathing air, the disease can be transmitted through blood transfusion.

Diseases in humans

Epstein Barr virus causes infectious mononucleosis that is common in adolescents and young adults. Manifestations of fatigue, anorexia, fever, sore throat, and enlarged lymph nodes. The disease usually goes away after 3 to 4 weeks and takes many months to regain health.

Complications are rare, once present, are often severe and involve multiple organs including the blood, nervous system, liver, heart, and lungs.

Epstein Barr virus also causes malignancies including Burkitt lymphoma, oropharyngeal cancer, and many B-cell lymphomas.

Laboratory diagnostics

Infectious mononucleosis

Tested for antibodies to sheep erythrocytes, this antibody can be removed by adsorption to the calf, sheep, and equine erythrocytes but is not adsorbed to rat kidneys. It's called a heterophil antibody. This antibody is seen in 50% of children and 90 to 95% of adolescents and adults with infectious mononucleosis. This antibody decreases in titers but remains positive for up to 9 months after acute illness.

IgM and IgG antibodies to VCA were determined by immunofluorescence and enzyme-linked immunosorbent assays using monoclonal antibodies. Antibodies to the EBNA antigen can be found.

Some laboratories are equipped with antibodies that correspond to early antigens (EA) and to EBNA.

In malignant diseases

Determination of antibodies to EBNA antigen, IgA antibody of VCA antigen by immunofluorescence, and enzyme immunoassay.

In both cases, viral DNA detection by DNA hybridization or PCR is used in equipped laboratories.

Prevention and treatment

Prevention

There is no effective vaccine to prevent the disease.

Treatment

Acyclovir, interferon, and bpropiolactone are inhibitors of Epstein Barr virus replication in the laboratory. The role of these drugs in the treatment of Epstein Barr virus infections has not been evaluated.