O Epstein-Barr it is a virus of the family Herpesviridae known mainly for triggering the infectious mononucleosis, popularly known as the kissing disease. The virus, however, is not only related to this disease, being associated with other health problems, including some types of cancer, especially the lymphatic system and head and neck.
The Epstein-Barr virus stands out for having a genome formed by a molecule of DNA, which is found within a nucleocapsid, which is, in turn, surrounded by a viral envelope. The virus has the ability to remain latent in the body and is not responsible for epidemics.
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Summary about the Epstein-Barr virus
Epstein-Barr is a family virus Herpesviridae which is between 120 and 180 nanometers and has double-stranded DNA.
It is latent in the organism, remaining in the body even after the end of the symptoms of the disease.
It is known to cause infectious mononucleosis, but it is also linked to other health problems.
There are two types of Epstein-Barr virus which are classified as 1 and 2 or A and B.
What is the Epstein-Barr virus?
Epstein-Barr (EBV), discovered in 1964, it's a family virusHerpesviridae. Formally, this virus is called herpes virus 4 (HHV-4) and is primarily known to cause mononucleosis. infectious, despite being related to other health problems, such as the rare Alice in Wonderland syndrome, encephalitis and sGuillain-Barré syndrome.
It is important to highlight that EBV also presents a strong relationship with the development of different types of cancer, especially those from the lymphatic system and head and neck. Furthermore, recently the virus has been associated with the development of multiple sclerosis.
The virus does not cause epidemics and it is estimated that it infects more than 90% of the world's population. Studies suggest that this virus is found latently in about 90% to 95% of adults and about 40% of children.
Characteristics of the Epstein-Barr virus
The Epstein-Barr virus is between 120 and 180 nanometers and stands out for having a hexagonal nucleocapsid that is surrounded by an envelope with a complex structure of proteins. O genetic material of this virus is a double-stranded DNA molecule, which has about 184,000 base pairs.
The virus, as well as other viruses in the family Herpesviridae, stands out for remaining in the body even after the disappearance of the clinical picture caused by it. The virus therefore remains latent in our body.
There are two types of Epstein-Barr virus, which are classified into 1 and 2 or A and B. These viruses differ in some alleles.
EBV-1 stands out for being the most common and having a worldwide distribution. When analyzing how to infect B lymphocytes in vitro, this virus manages to affect them more quickly. EBV-2, in turn, occurs mainly in Equatorial Africa and in individuals with HIV infection. This type of EBV affects B lymphocytes more slowly and less efficiently than type 1 EBV.
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infectious mononucleosis
Infectious mononucleosis is a contagious disease caused by EBV. It is a febrile, low-lethal disease that can affect people of any age, although it mainly affects young people and adults aged between 15 and 25 years. It is characterized by the occurrence of the triad: fever, pharyngitis and lymphadenopathy (increased lymph nodes).
A Transmission of infectious mononucleosis occurs via oral-oral route, through intimate contact with the saliva of the sick individual. For this reason, mononucleosis is also known as the kissing disease. In the case of children, transmission is associated with the fact that they often put objects in their mouths, which may be contaminated with saliva. Rarely, transmission of mononucleosis occurs through sexual contact or blood transfusion.
Epstein-Barr and multiple sclerosis
A multiple sclerosis é one chronic diseasethe and autoimmunehuh that affects the central nervous system. In this disease, the defense cells attack a layer of fat that covers the axons of the neurons, the so-called myelin sheath. Among the symptoms of the disease, we can highlight fatigue, muscle weakness, coordination and balance problems, urinary and intestinal tract problems.
A cause of multiple sclerosis is not known at this time, however, it is believed that the disease is triggered by a combination of genetic and environmental factors. Some studies suggest that infectious agents may be associated with the development of multiple sclerosis, EVB being one of them.
In an article published in the journal Science, in January 2022, entitled "Longitudinal analysis reveals high prevalence of Epstein-Barr virus associated with multiple sclerosis”, researchers claim that the risk of multiple sclerosis “increased 32-fold after EBV infection, but did not increase after infection with other viruses, including cytomegalovirus, transmitted in a similar way”. Also according to the authors, the findings after the analyzes cannot be explained by any known risk factor for multiple sclerosis (MS) and suggest EBV as the main cause of MS.
It is important to point out, however, that, as pointed out by Robinson and Steinman in a commentary article accompanying the study, “almost everyone is infected with EBV, but only a small fraction develops MS. Thus, other factors, such as genetic susceptibility, are important in the pathogenesis of MS.” This means that a person who has been infected with EBV will not necessarily develop multiple sclerosis, and it is critical to understand why not everyone develops the problem.
By Vanessa Sardinha dos Santos
Biology teacher
Source: Brazil School - https://brasilescola.uol.com.br/biologia/virus-epstein-barr.htm
