The main characteristic of the pathogen of influenza
The causative agent of influenza in accordance with these biological classification belongs to the family Orthomyxoviridae, genus Influenzavirus. Virologists are three serotypes of viral particles - A, b, C.
Etiology the causative agent of influenza A
The development of influenza is carried out under the influence of viral particles related to RNA-containing viruses, which the outside is covered with a protein shell.
The most dangerous for the human body in respect of an epidemic on the severity of provoked disease virus serotype A. the serotype of this Virus has a high degree of genetic variability and has the ability to multiply rapidly in the body temperatures of medium up to 38 degrees Celsius. Other serotypes of the virus are less volatile, and termination of playback of viral particles occurs even at temperatures of the body of the carrier in the range 37-37,5 Celsius.
The composition of the protein coating of the viral particle consists of two antigens:
- the hemagglutinin, which can be in the form of 3 antigenic types;
- the neuraminidase - the protein component with two antigenic type.
The process of partial modification of the hemagglutinin and neuraminidase, which occurs without changes antigenic rooms, is called antigenic drift. The development of such a process have viral particles that are able to provoke the emergence of new epidemics. The emergence of radical changes in the hemagglutinin and neuraminidase, which are changes in the antigenic rooms, leads to the appearance of viral particles capable of causing pandemic spread of infectious disease. Formula flu includes in its composition:
- designation of serotypes of influenza;
- the name of the place of isolation;
- the number of the isolate;
- year detection of insulation;
- identification of the structure of hemagglutinin and neuraminidase.
After the occurrence of the drift of antigenic changes in the numbers of hemagglutinin and neuraminidase occurs. If you experience a radical mutation, the formula changes dramatically, changing the numbers of hemagglutinin and neuraminidase.
Brief characteristics of viral particles of influenza of different serotypes
At the present stage of development of Virology revealed 13 possible variations of hemagglutinin and 9 possible variations of the neuraminidase, which in theory can form 117 theoretically possible combinations of xeropotamou this serotype. All currently known variants of hemagglutinin and neuraminidase were detected in viral particles,highlighted in birds of various kinds. Some of these options are found in the structure of viral particles isolated from infected mammals. The man identified only three possible combinations of proteins in the virus particles And incorporated into the structure surface, which are causative agents. Such protein combinations are:
In the first hand of the medical specialists-virologists are three seropositive:
- Hsw 1N1;
- HON 1;
Only known to virologists five xeropotamou of influenza virus And human. Virologists believe that these caropodium limited set of varieties of influenza A which are of particular epidemiological importance to the human body.
General characteristics of virus particles serotypes b and C
Influenza viruses b and C are not found antigenic radical changes. The flu virus serotype changes In the type of drift and influenza virus type C vary very little. Very high variability of the virus-specific And serotype, and the ability of microorganisms serotype In substantial changes are the essential elements that provide the specific features of epidemic prevalence. Each new version of virus And or has the ability in some measure to overcome the protective properties of the immune system of the human body that are acquired as a result of effects on the body earlier forms of xeropotamou pathogens.
The flu virus in the air can survive for several hours. The variants of the virus belonging to the serotype A, are the most resistant to influence of adverse factors of the external environment. In the deposited and dried drops of virus particles able to retain signs of life on the surface of linen for two weeks in room dust particles of the virus retain the ability to infect for five weeks.
Wet cleaning with the use of any disinfectants almost completely disinfect the room. Disinfection of linen and clothes is carried out by boiling and washing. Sanation of air in the room is carried out using ultraviolet radiation and ventilation.
A simple mechanism of transmission of influenza
Viral aerosol emitted a sick person, contains in its composition vysokodispersnye and ed particles. In addition, the aerosol contains small and large drops. The amount of virus in the aerosol particle is determined by its volume. The basic amount is localized in the globular phase. The assessment of the probability of infection is required to take into account the kinetics of particle,available in aerosol, which depends entirely on the size of the particles. The radius of dispersion of aerosol particles by coughing is approximately one meter.
At hit in respiratory ways of the person selected aerosol particles are fixed, and some are excreted into the environment upon exhalation of air. Aerosol particles can settle in the upper respiratory tract or the mucous membrane of the lungs. Falling on the surface of the mucosa, the virus attaches to the membrane of the cells lining and then enters the cell. The probability of human infection with influenza and development of disease is dependent on the susceptibility of a person to the disease. The flu contributes to the development of anti-influenza immunity, which is closely interacting and growing three subsystems. It is the local factors, General and cellular immunities.