Pharmaceutical form

The main properties of the pathogen and the methods of its identification.

The causative agent of influenza, belonging to the family of orthomixoviruses, was first isolated in 1933 by the English researchers WS Smith, SN Andrewes, PP Laidlaw by the intranasal administration to African white ferrets of filtered material obtained from influenza patients.

In 1940, T. Fransis and T. P. Maqill independently isolated the influenza virus, which for a number of biological properties differed from that isolated in 1933, and in 1947, R. M. Taylor discovered a hemagglutinating agent-a "strain 1233 », identified as an influenza virus, but different from the viruses isolated in 1933 and 1940. These viruses were designated by the corresponding letters of the Latin alphabet: A, B, C, and each was qualified as an independent serotype.

The family of orthomixoviruses includes only influenza viruses, characterized by the presence of an outer shell and the content of RNA in a spherical nucleocapsid. The outer envelope of the virus consists of glycoprotein structures (hemagglutinin-H and neuraminidase-N), which determine the antigenic and infectious properties of the virus. The genome of the influenza virus is constructed from 8 single-stranded segments, the diameter of the inner spherical ribonucleoprotein (RNP) is within 9 nm. The viruses A, B, C differ in the antigen of the RNP, which does not give cross-type intertip reactions.

It is now recognized that the family of orthomixoviruses consists of two genera: the influenza virus, where the viruses A and B refer, and the conditionally influenza virus C (S. Ya. Gaidamovich, 1982).

The virus A is represented by several serotypes and antigenic variants, which differ in the composition of haemagglutinin and neuraminidase. This virus affects both humans and animals. According to the new classification (1980), the types of hemagglutinin of virus A are given numerical designations: from 1 to I, and neuraminidases from 1 to 8. Hemagglutinins 1, 2, 3, neuraminidases 1, 2 are inherent mainly in human A virus, and the remaining types of surface antigens H and N1) are detected in viruses that attack animals (horses, pigs, cattle, monkeys, dogs and different kinds of birds).

At present, when describing influenza A viruses, the type of hemagglutinin and neuraminidase is necessarily indicated, and their designations do not always correspond to the nomenclature of 1971. 1 presents new designations of hemagglutinins and neuraminidases of influenza viruses, adopted in 1980, in comparison with previous ones. The human HA, H1 hemagglutinin and Hsw1 pig hemagglutinin are combined into hemagglutinin H1, human HA hemagglutinin and horse and bird virus hemagglutinin (Heq 2 and HaV 7) into hemagglutinin H3. AA Smorodintsev and co-authors (1981) consider it illegal to combine human and animal glycoproteins into one serotype.

Another virus of the genus Influenza is virus B, which until 1979 was isolated in a separate genus B, there are no serotypes for this virus . There are antigenic variants inside the serotype.

The genus influenza virus G is represented by the virus C. Viruses of this genus are least studied from the whole family of orthomixoviruses. The WHO expert group (W. Dowdle, F. Davenport, N. Fukum, 1975) included this virus as a "conditional genus" in this family. A characteristic feature of virus C is the presence of one glycoprotein in the outer shell. There is no neuraminidase enzyme in the virus, although there is a receptor-destroying enzyme (RRE), completely different from known viral neuraminidases. The virus has a low adaptive capacity for chicken embryo cells and various cell cultures. In the amnion of the chick embryo, it develops at a temperature of 33 ° C for 3-4 days of incubation, does not agglutinate the erythrocytes of the guinea pig, and is poorly adsorbed on the surface of the chicken erythrocyte. To avoid rapid elution of the virus from the surface of the erythrocyte, serological hemagglutination should be set at low temperature.

If the viruses A and B are characterized by a change in the antigenic structure when circulating in vivo, then for the C virus, antigenic changes have not yet been noted. Dedicated in 1947, 1974, 1977 years. Viruses are identical to each other.

Properly chosen dosage form (lexform) will help you cope with various pathogens of influenza. The chosen dosage form will help you if only it is chosen by the doctor, and not by you alone.