Scientists have discovered how bird flu adapts in patients, offering a new way to monitor the disease and prevent a pandemic, according to research published in the August issue of the Journal of General Virology.
Highly pathogenic H5N1 avian influenza virus has spread through at least 45 countries in 3 continents. Despite its ability to spread, it cannot be transmitted efficiently from human to human. This indicates it is not fully adapted to its new host species, the human. However, this new research reveals mutations in the virus that may result in a pandemic.
"The mutations needed for the emergence of a potential pandemic virus are likely to originate and be selected within infected human tissues," said Professor Dr Prasert Auewarakul from Mahidol University, Thailand. "We analyzed specific molecules called haemagglutinin on viruses derived from fatal human cases. Our results suggest new candidate mutations that may allow bird flu to adapt to humans."
Viruses with a high mutation rate such as influenza virus usually exist as a swarm of variants, each slightly different from the others. These are called H5N1 bird flu quasispecies. Professor Dr Auewarakul and his colleagues found that some mutations in the quasispecies were more frequent than others, which indicates they may be adaptive changes that make the virus more efficient at infecting humans. Most of these mutations were found in the area required for the virus to bind to the host cell.