LA JOLLA, Calif. – Scientists have identified several genetic mutations that could allow the H7N9 strain of avian influenza to spread among humans. An international team of scientists reported their findings in the journal PLOS Pathogens. The virus currently can’t spread from human to human, but scientists are concerned that the virus could mutate into a form that is transmissible among humans.
James Paulson, a scientist at The Scripps Research Institute, La Jolla, California, and colleagues examined mutations that could occur in the H7N9 genome. The team focused on the H7 hemagglutanin, which is a protein found on the surface of flu viruses that enables them to latch onto host cells. H7N9 has specific receptors on bird cells, but not receptors on human cells.
The team used molecular modeling and knowledge of hemagglutanin structures to identify mutations that could change the hemagglutanin amino acid sequence to target specific human cells. In lab experiments, mutant H7 hemagglutanin successfully latched onto cells in samples of human trachea tissue.
Safety regulations prohibit introducing the mutations to H7N9 cells, but scientists believe that monitoring the development of these mutations in humans infected with H7N9 could help promote a timely response and prevent an avian flu pandemic among humans.
“We suggest that understanding mutations that can confer human-type receptor binding will benefit risk assessment in worldwide surveillance of H7N9 in poultry and humans,” the researchers wrote.