Several genetic mutations or human infection of bird flu

An international research team has recently discovered that several specific genetic mutations may lead to the ability of the H7N9 avian influenza virus to be transmitted from person to person. Monitoring these mutations will help prevent the spread of the epidemic in a timely manner.

Several genetic mutations or human infection of bird flu

  Avian influenza viruses usually only infect birds, but in recent years it has been found that multiple subtypes can be transmitted from poultry to humans. H7N9 is one of them. The ability of the avian influenza virus to obtain interpersonal infection has not yet been discovered, but if the virus acquires this ability through genetic mutations, it may lead to a pandemic.

  To this end, researchers at institutions such as the Scripps Research Institute have analyzed mutations that may occur in the H7N9 viral genome. They focused on genes encoding H7 hemagglutinin on the surface of the virus, a protein that binds the virus to host cells and causes infection.


  To complete the "binding", the host cell surface must have a structurally appropriate receptor protein that binds to H7 hemagglutinin, just like a key and a keyhole, the shape must match. There are no such receptors on the surface of human cells, but if genetic mutations make H7 hemagglutinin molecules suitable for human cells, it is possible to make the virus gain interpersonal transmission.

  The researchers mimicked the structure of multiple mutant forms of H7 hemagglutinin, which were then produced using harmless experimental cells to test their ability to bind to avian receptors and human receptors. It was found that several mutations in the hemagglutinin molecule with three amino acids allowed it to bind strongly to human receptors and successfully bind it to human tracheal tissue samples.

  For safety reasons, the researchers did not directly experiment with the H7N9 avian influenza virus, and thus could not test the actual effect of the variant virus on animals. But they believe that focusing on whether the H7N9 virus in nature has these mutations may win time to stop the spread of the epidemic.