The World Health Organisation (WHO) noticed it first. Now, Scientists from Imperial College, London, know why.
A study of the H1N1 swine flu virus isolated in US and Europe by British scientists found that the pandemic strain had the advanced ability to infect cells deep in the lungs which the seasonal flu didn’t have.
Influenza viruses infect cells by attaching to bead-like molecules on the outside of the cell, called receptors. Different viruses attach to different receptors, and if a avirus cannot find its specific re-ceptor, it cannot get into the cell and spread infection.
Once inside the cell, the virus replicates into thousands of copies, which then burst out of the cell to infect neighbouring ones, establishing an infection.
Scientists at Imperial College found that while seasonal influenza viruses attached to receptors found on cells in the nose, throat and upper airway, enabling them to infect a person’s respiratory tract, the pandemic H1N1 swine flu attached to receptors found on cells deep inside the lungs, which resulted in a more severe lung infection like viral pneumonia.
The finding explains why people infected with the pandemic strain of H1N1 have exhibited severe symptoms than those infected with the seasonal influenza strain.
Professor Ten Feizi, from the division of medicine at imperial college London, said pneumonia during a seasonal influenza infection was caused by a bacteria which was much milder.
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