Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Phylogenetic tree of H7N9 strains based on HA gene. The chosen LPAIV and HPAIV strains were confirmed based on their law of basic amino acid motif located at the HA cleavage site. A/Chicken/Guangxi/SD098/2017 strain is the HA gene donor virus of H7-Re2.
