Bird migration patterns contain clues to bird flu risks

Posted Oct 17, 2016 by Tim Sandle
Avian flu remains an ever-present risk. According to new research, monitoring the migration routes of wild birds should give an early warning of potential bird flu outbreaks.
The geese flying over the hills.
The geese flying over the hills.
Avian flu, according to the World Health Organization, is an infectious viral disease of birds. Most avian influenza viruses do not infect humans; however some, such as A(H5N1) and A(H7N9), have caused serious infections in people. Some types of avian flu are showing resistance to anti-viral medication.
The idea of tracking the migratory patterns of wild birds known to be potential carriers of avian influenza comes from a study that describes how one of the routes of viral transmission is from migratory birds (as opposed to domestic birds, such as chickens).
The new research, from the international scientific consortium Global Consortium for H5N8 and Related Influenza Viruses, has focused on a subtype of avian flu coded H5N8. This strain of avian influenza was transferred to different parts of the world during 2014, beginning with a point of origin in South Korea. From this starting point the virus was transferred to Japan, and then to North America and Europe. Cases of the virus continued until the spring 2015 and the level of risk of virus transfer was high for a six-month period.
One of the means of transmission was identified as wild birds, based on tests of different birds found to have the identical viral genetic code compared with the first cases in South Korea. Similar matches were found with birds in 16 different countries.
This enabled a research group to construct a map of the viral spread. It appears the virus was carried by long distance flights of infected migrating wild birds, beginning in Asia. Along the way, the infected birds spent time at their breeding grounds in the Arctic.
The lesson that arises from this research, University of Edinburgh scientists (who were involved with the study) argue, is the need to reinforce strict exclusion areas around poultry farms to keep wild birds out. Improved tracking and surveillance of wild birds is also required during times of heightened risk.
The research has been published in the journal Science. The study is titled “Role for migratory wild birds in the global spread of avian influenza H5N8.”