Orthomyxoviruses
Posted by bhavin | Posted on 7:33 AM
Orthomyxoviruses are the influenza viruses which belong to the Orthomyxoviradae family. This virus is further classified in 3 types A,B and C and it is composed of one genus. Influenza, a acute respiratory disease which is caused due to the Orthomyxoviruses. The types A and B are responsible for regional epidemics during the winter season, the A type is also responsible for periodic worldwide epidemics.
The influenza viruses is found very often and recurring as it has a special ability to exhibit variation in the surface antigens. There are 2 phenomenon which is responsible for variations:
The influenza viruses is found very often and recurring as it has a special ability to exhibit variation in the surface antigens. There are 2 phenomenon which is responsible for variations:
- Antigenic drift- It is caused due to the mutations in the RNA which eventually leads to changes in antigen character of N and H molecules. The changes in the antigen drift involves subtle changes that may cause the epidemics. However it does not involve pandemics.
- Antigen shift- It is caused due to the rearrangement of various segments of viral genome which in turn is responsible production of the major changes in the character of antigen of N and H molecules.
Since 1173 AD, the influenza epidemics have been documented. Over 20 million deaths world wide in the year 1918 took place due to pandemic.
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