New research carried out at The Pirbright Institute indicates that the genes of some chickens makes them almost resistant to bird flu. The findings, which are published in the journal Scientific Reports, show that genetics play a key part in whether the birds are susceptible or resistant to the potentially deadly virus. Until now, scientists around the world have not paid enough attention to the role the genetics of birds play in the transmission of flu, focusing instead on how the virus itself evolves and infects.
Dr Colin Butter, Reader in Bioveterinary Science at the University of Lincoln, UK, carried out the research while at The Pirbright Institute and the findings could prove valuable in developing our understanding of the mechanisms of influenza transmission within and between birds.
Influenza virus is the cause of influenza, or ‘flu’ – a contagious respiratory viral disease common in many birds and mammals. The viruses circulating in wild birds and domesticated poultry are of particular interest to scientists because they may mutate into forms that are capable of infecting humans, and represent a major threat to human health as potential sources of the next flu pandemic. This potential danger has led the World Health Organisation to highlight effective control measures, as well as an in-depth assessment of factors surrounding the infection of host animals, as part of their research priorities. Pirbright’s research takes an important step towards meeting these needs.
Dr Butter said: “It is important for us to understand how different genetic lines of birds react to influenza viruses, so that we can begin to understand the spread of the disease. Our results are valuable in emphasising the important role a ‘host’ plays in the spread of avian flu, and also in highlighting a number of factors relating to the chain of infection and control mechanisms which are affected by the route of infection.”
The research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and included scientists from the University of Oxford and The Francis Crick Institute in London. The researchers examined two genetically distinct lines of chickens to determine whether genetics played a part in the susceptibility or resistance to infection. They found that birds that carried the virus but were genetically resistant to the disease only shed the virus through their respiratory tract and for a limited period of time, whereas birds, which were susceptible to the disease, also shed virus in faeces and over a longer time. The researchers discovered that this was the only relevant means of spreading the virus and that resistant birds were therefore unable to initiate or sustain the chain of transmission. Further results in the study suggest that this could be due to a genetic restriction within the animal which stops the virus spreading when inside the body.
Professor Venugopal Nair, the Head of the Avian Viral Diseases programme at The Pirbright Institute, said: “The findings of this study emphasise the importance of examining the intricate nature of the virus-host interactions and the potential role of the host genetic factors influencing the transmission dynamics and outcomes of important diseases such as avian flu.”
These findings now lead the way for further investigation and work is being planned to discover and examine the precise biological mechanisms behind genetic resistance. This could have major implications for poultry breeding, as well as human flu treatments, in the future.