H10N8 bird flu unlikely to threaten public health

H10N8, the most recent avian influenza virus to infect humans, is unlikely to cause a threat to public health without further changes say the Medical Research Council (MRC). In order to determine whether H10 viruses had pandemic-causing potential, researchers at the MRC National Institute for Medical Research (MRC-NIMR) uncovered its molecular structure and studied its receptor binding properties, since strength of the interaction between virus and host is a major factor in determining the likelihood of an animal influenza virus causing a pandemic. Although the H10 influenza virus bound strongly to human receptors, it bound more tightly to avian receptors, and researchers believe it id were to pose a threat to human health it would need to lose some of its binding capacity for avian receptors. Dr John McCauley, Director of the WHO Influenza Centre at the MRC-NIMR said: “We pay special attention to viruses that show changes in receptor binding preference because it is likely to be a requirement for more efficient transmission to humans. A change in receptor binding is the essential first step in generating a pandemic virus. These results are the output of the NIMR/WHO Influenza Centre collaboration that illustrates the sophisticated scientific basis of monitoring influenza viruses and the importance of the WHO global influenza surveillance for public health.” Professor Paul Moss, Chair of the MRC Infection and Immunity Board, said: “Outbreaks and epidemics can strike quickly with a substantial impact on society. It is essential that we respond swiftly to potential pandemic strains. The team at the MRC-NIMR has been at the forefront of this endeavour and their work here shows exactly how the latest influenza virus identified from birds is able to bind to human cells. The work will be very important in allowing us to monitor for mutations that could lead to the virus gaining the ability to spread between humans". More information

• The first human H10N8 infection was detected in December 2013; there have been two further cases of infection and one death since.
• The binding characteristics of H10 are shared with other pandemic strains such as H1 and H7, but these have a clear preference for human receptors where they bind up to 100 times more tightly than to avian receptors.
• The H10 interaction with the avian receptor 150 times stronger than with the human receptor.