H5N8 is a subtype of influenza that nobody cared about or studied until a big outbreak in 2014. This outbreak was important for two reasons.
- It showed that all the papers about wild birds not being able to spread highly pathogenic flu virus were wrong (Sorry Gaidet at al.)
- It allowed the Guangdong Goose H5 hemagglutinin to spread to North America.
That is it. No more interest. It actually reassorted to H5N2 pretty quickly in the US as H5N8 does not often occur because it is not a preferred packaging of the virus. H5N1 is much more frequent and H5N2 also seems to be a better alternative.