It's official: for the first time in 40 years, the World Health Organisation declared swine flu pandemic. The virus spread to 74 countries. This is the fourth pandemic in 100 years. It has been tagged with 'moderate' so far. What is, exactly, the swine flu? Why don’t we have a vaccine yet? How are the virus mutations achieved? Mihhnea Bostina from Harvard Medical School answers.
R: General WHO manager Margaret Chan declared swine flu world pandemic, after 41 years from the last world pandemic. How do you comment this news?
The time interval is interesting. The main flu pandemic Hilleman observed so far are 1889 (H2) - 1900 (H3) - 1918 (H1) - 1957 (H2) - 1968 (H3) - 1986 (H1).
What's interesting is the period f time between the flu caused by the same root: 68 years, meaning a medium life span of a generation.
R: What are viruses?
If we simplify things, we could say they're a form of archived information. The information is their genome, made of either DNA or RNA. It is protected by a molecular tissue or membrane, or both.
R: And how do they work?
Their main task is self-replication. They need to disguise several timed during their life to be able to do it. They need to be able to infect the type of cells they specialise in and where they can replicate.
The problem in this case is for hem to get pass the membrane, whose function is to block their access. Secondly, they not only have to cheat the protection system in-built in the cell and to get away unnoticed, but they also need to use part of the molecular machine to produce new viruses. Thirdly, these viruses need to be able to leave the cell and infect other cells from new organisms.
This is the first round. There isn't usually a clear winner. The virus manages to self-replicate to a certain extent, but the infection is era
