Human Nose too Cold for Bird Flu

A recent study conducted by the Imperial College of London found that the avian flu would need to undergo several mutations before it was a threat to humans. As it cannot function in the human nose environment because it is too cold.

The virus is suited to the warmer environment of the gut of birds, which is at 40 degrees, opposed to the 32 degrees of the human nose. The avian influenza viruses and a human virus where both able to grow normally at 37 degrees, the temperature inside the human lung. However it was found that only the human viruses was able to grow at 32 degrees. The low temperature made the avian virus unable to replicate and grow.

The researchers also tried to simulate a mutation of the human flu with the avian strain, by adding a protein from the surface of the avian flu to the human flu. However when cultured the new mutated virus did not grow at 32 degrees.

The study leader Professor Wendy Barclay suggested that the avian influenza virus would have to undergo a number of mutations, and possibly mix with the human strain, before it could become a threat to humans. She goes on to explain how viruses which are transmitted between animals at low temperatures are more likely to cause pandemics. Swine flu appears to be an example of a virus which has adapted to the cooler environment of the human nose.

Professor Ian Jones, a virologist at the University of Reading, has said that this study has shown that the proteins on the outside of the virus are likely to determine how well a virus will function at different temperatures.

Reference:
14/05/09, Human Nose too Cold for Bird Flu, BBC, [Online], 18/5/09, http://news.bbc.co.uk/2/hi/health/8050523.stm