+1 to HA and NA numbering-new fruity bat flu

Now I need to remake this tree!

Thanks to a new study in PLoS Pathogens by Tong and colleagues (they who brought us the last new influenza numbers from bats), we have a new haemagglutinin (HA) and a new neuraminidase (NA) to add to the list. These are also from a fruit bat (flat faced (Artibeus planirostris) in fact.

That makes 18 HAs and 11 NAs to play mix-and-match with. I wonder if we'll one day see the avian and bat genes mix up?

Read More

Haemagglutinin cleavage site graphic.

I've added a new graphic to the H7N9 page that compares the important cleavage site in the immature HA protein among influenza A viruses, including H7N9. 

This shows that H7N9 is more similar to seasonal influenza viruses in this area-low-pathogenic viruses rather than high pathogenic viruses. 

The latter have a multiple basic amino acids at the cleavage site making them a target for proteases located throughout the body rather than just in the human respiratory system and bird gut.

Read More

Four reassortment events led to H7N9 emergence.

With thanks to Prof. Ross Barnard, University of Queensland for helpful contributions.

A new article just published at the Lancet describes a detailed genetic analysis of four H7N9 virus sequences, in the context of all likely contributing influenza virus sequence. The resultant virus' HA and NA genes may have been contributed by migratory birds a year prior to acquisition of internal genes from poultry influenza viruses. 

Since its emergence "several months ago", H7N9 has divided into at least two different groups (lineages). One strain (Shanghai/1) has signs of oseltamivir resistance.

Read More