Table 1. Information for the 12 H9N2 subtype AIVs in this study.

H9N2 strains	Production type	location	co-infection	HA Accession number	NA Accession number
A/chicken/Sichuan/LB/2013	Broiler	Sichuan (Ya’an)	Single	KX768851	KX768863
A/chicken/Sichuan/XJ/2014	Broiler	Sichuan (Xinjin)	Single	KX768852	KX768864
A/chicken/Sichuan/YX/2014	Broiler	Sichuan (Ya’an)	Single	KX768853	KX768865
A/chicken/Chongqing/LP/2015	Broiler	Chongqing(Liangping)	IB	KX768854	KX768866
A/chicken/Guizhou/QZ/2015	Broiler	Guizhou(Guiyang)	Single	KX768855	KX768867
A/chicken/Sichuan/SZQ60/2015	Broiler	Sichuan (Meishan)	Bacteria	KX768856	KX768868
A/chicken/Yunnan/A615/2015	Broiler	Yunnan(Kunming)	Bacteria	KX768857	KX768869
A/chicken/Yunnan/YNKM/2015	Broiler	Yunnan(Kunming)	Single	KX768858	KX768870
A/chicken/Chongqing/CQ/2016	Broiler	Chongqing	Bacteria	KX768859	KX768871
A/chicken/Sichuan/LFY/2016	Broiler	Sichuan(Yibin)	Single	KX768860	KX768872
A/chicken/Sichuan/LMC/2016	Broiler	Sichuan(Meishan)	Single	KX768861	KX768873
A/chicken/Sichuan/ZYL/2016	Broiler	Sichuan (Yibin)	Single	KX768862	KX768874