Enteroviruses [3] ( Latin Enterovirus ) is a genus of viruses from the family of picornaviruses ( Picornaviridae ). The name of enteroviruses is associated with their reproduction in the gastrointestinal tract , but they rarely cause enteritis .
| Enteroviruses | |||||||||||
 Coxsackie viruses | |||||||||||
| Scientific classification | |||||||||||
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| International Scientific Name | |||||||||||
Enterovirus | |||||||||||
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| Baltimore Group | |||||||||||
IV: (+) ssRNA viruses | |||||||||||
Classification
The composition of the genus has gone through several revisions and for March 2019 it includes 15 species [4] :
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Previously, the genus included 71 serotypes pathogenic for humans: 3 types of poliomyelitis viruses , 23 types of Coxsackie A viruses , 6 types of Coxsack B viruses, 31 types of echoviruses and 4 types of enteroviruses (68-71).
Human Enteroviruses
Human enteroviruses contain single-stranded RNA encoding a polyprotein that is cleaved into 11 different proteins. RNA is surrounded by an icosahedral capsid containing 4 viral proteins (VP1 – VP4). VP1 is the main target of neutralizing antibodies.
Using X-ray analysis, a three-dimensional image of polio viruses was obtained. A recess ("canyon") on the surface of a virus is a region of connection with the cellular receptor. The polio virus binds to cell receptors belonging to the immunoglobulin superfamily; ECHO viruses of serotypes 1 and 8 - with alpha2beta1-integrin (VLA-2); serotype 7 enterovirus - with CD55 (decay acceleration factor).
Enteroviruses have no external lipid membrane.
For cultures chronically infected with enteroviruses, common features are [5] :
- low concentration of virus in the environment;
- slight infection of cells in the population;
- pronounced resistance to superinfection with a homologous virus;
- lack of formation of interferon;
- rapid release from carriage in the presence of specific antibodies.
Poliomyelitis virus is pathogenic only for primates, mainly due to the fact that only they have the appropriate receptors. They can not infect a culture of mouse cells, but in transgenic mice, the cells of which contain the corresponding receptor, polio develops with CNS damage.
The genomes of some enteroviruses have been cloned, copies of cDNA obtained can infect a cell culture.
The creation of recombinant viruses containing parts of both virulent and attenuated cDNAs allows the determination of nucleotide sequences responsible for the attenuation of a live polio vaccine.
Enteroviruses are resistant to acidic conditions, including gastric juice, as well as common disinfectants (ethanol, detergents) and remain viable at room temperature for several days.
Enteroviruses are ubiquitous. More than 90% of infections caused by the polio virus, and more than 50% of other enteroviral infections are covert. If symptoms appear, they are more often non-specific - fever, inflammation of the upper respiratory tract. The characteristic clinical picture develops only in a small part of cases.
Notes
- ↑ Taxonomy of viruses (English) on the website of the International Committee on Virus Taxonomy (ICTV) .
- ↑ Enterovirus (eng.) On the website of the National Center for Biotechnology Information (NCBI). (Checked April 19, 2019) .
- ↑ Sergeev V. A. , Nepoklonov E. A. , Aliper T. And . Viruses and viral vaccines. - M .: Biblonic, 2007. - P. 457. - ISBN 5-98685-012-2 .
- ↑ Taxonomy of viruses (English) on the website of the International Committee on Virus Taxonomy (ICTV) . (Checked April 19, 2019) .
- ↑ Andzhaparidze O. G., Bogomolov N. N. Modeling and study of chronic forms of viral infections in cell cultures. - M .: Medicine, 1974. - P. 164. - UDC .