Highly pathogenic H5 avian influenza in 2016 and early 2017 : Observations and future perspectives

During 2016-2017 novel strains of highly pathogenic H5 avian influenza virus within the Goose/Guangdong/96 (Gs/GD/96)-lineage (mainly H5N8) caused multiple outbreaks of disease in poultry and wild birds across much of Europe, parts of Asia, the Middle East and West Africa, and have extended for the first time to affect poultry in Eastern and Southern Africa. The virus was reported first in the Tyva Republic in late May 2016 before being detected elsewhere. This was the fourth intercontinental wave of transmission by an H5 virus within this lineage and was by far the most severe in terms of the number of countries affected. This Focus On summarises observations from the fourth intercontinental wave associated with Gs/GD/96-lineage viruses as well as information on other related H5 viruses spreading in 2016-2017. It provides information on the genetics of these viruses, some discussion on the likely progress of the current intercontinental wave and guidance for forecasting future waves...