The Hindu : National : Swine flu can infect lungs deeper than seasonal flu

Online edition of India's National Newspaper
Thursday, Sep 10, 2009
ePaper | Mobile/PDA Version

National

National

Swine flu can infect lungs deeper than seasonal flu

Aarti Dhar

NEW DELHI: Pandemic swine flu infect cells deeper in the lungs than seasonal flu does, according to a new study published today in Nature Biotechnology.

The researchersfrom Imperial College London who conducted the research, say this may explain why people infected with the pandemic strain of swine-origin H1N1 influenza are more likely to showsevere symptoms than those infected with the seasonal strain of H1N1.

They also suggest that scientists should monitor the current pandemic H1N1 influenza virus for changes in the way it infects cells making infections more serious.

Receptors

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 virus cannot find its specific receptors, it cannot get into the cell.

Once inside the cell, the virus uses the cell’s machinery to multiply itself , which then burst out of the cell and infect neighbouring ones, establishing an infection.

Seasonal influenza viruses attach to receptors found on cells in the nose, throat and upper airway, enabling them to infect a person’s respiratory tract.

This research shows that pandemic H1N1 swine flu can also attach to a receptor found on cells deep inside the lungs, which can result in a much severe lung infection.

The pandemic influenza virus’s ability to stick to the additional receptors may explain why the virus replicates and spreads between cells more quickly.If a flu virus can bind to more than one type of receptor, it can attach itself to a larger area of the respiratory tract, infecting more cells.

Difference

Professor Ten Feizi, co-author of the paper, said: “Most people infected with swine-origin flu in the current pandemic have experienced relatively mild symptoms. However, some people have had more severe lung infections, which can be worse than those caused by seasonal flu. Our new research shows how the virus does this - by attaching to receptors mostly found on cells deep in the lungs. This is something seasonal flu cannot do.”

Mild symptoms

The researchers found that pandemic H1N1 influenza is bound more weakly to the receptors in the lungs than to those in the upper respiratory tract.

This is why most people infected with the virus have experienced mild symptoms. However, the researchers are concerned that the virus could mutate to bind more strongly to these receptors.

Printer friendly page
Send this article to Friends by E-Mail

National