Table 1. Molecular features of the human and related domestic avian H7N4 isolates compared to human H7N9 and H5N1 strains.

Virus	Subtype	PB2			PB1		PB1-F2		PA			HA		NA			M1		M2	NS1
		Virulence					del.					CS	RBS	Stalk	Resistance*		Virulence		Resistance§	del.
		89	627	701	99	368		66	100	356	409			del.	274	292	30	218	31		42
JS2018	H7N4	V	K	D	H	I	90aa	N	V	K	S	PELPKGR/GLF	QSG	No	H	R	D	T	S	230aa	S
Ck2018	H7N4	V	E	D	H	I	90aa	N	V	K	S	PELPKGR/GLF	QSG	No	H	R	D	T	S	230aa	S
A/Ck/103/2018	H7N4	V	E	D	H	I	90aa	N	V	K	S	PELPKGR/GLF	QSG	No	H	R	D	T	S	230aa	S
Dk2018	H7N4	V	E	D	H	I	90aa	N	V	K	S	PELPKGR/GLF	QSG	No	H	R	D	T	S	230aa	S
A/Dk/8/2018	H7N4	V	E	D	H	I	90aa	N	V	K	S	PELPKGR/GLF	QSG	No	H	R	D	T	S	230aa	S
A/Dk/12/2018	H7N4	V	E	D	H	I	90aa	N	V	K	S	PELPKGR/GLF	QSG	No	H	R	D	T	S	230aa	S
A/Dk/13/2018	H7N4	V	E	D	H	I	90aa	N	V	K	S	PELPKGR/GLF	QSG	No	H	R	D	T	S	230aa	S
A/Dk/16/2018	H7N4	V	E	D	H	I	90aa	N	V	K	S	PELPKGR/GLF	QSG	No	H	R	D	T	S	230aa	S
A/Anhui/1/2013	H7N9	V	K	D	H	V	90aa	N	A	R	N	PEIPKGR/GLF	LSG	Yes	H	R	D	T	N	217aa	S
A/SH/1/2013	H7N9	V	K	D	H	I	90aa	N	A	R	N	PEIPKGR/GLF	QSG	Yes	H	R/K#	D	T	N	217aa	S
A/SH/1/2006	H5N1	V	E	D	H	I	90aa	N	V	K	S	PLRERRRKRGLF	QSG	Yes	H	R	D	T	S	230aa	S

JS: Jiangsu; Ck: chicken; Dk: duck; SH: shanghai; del.: deletion; aa: amino acids; CS: cleavage site; RBS: receptor binding site

*: oseltamivir

§: amantadine. Bold character: mutated residues.

#Yen HL, et al. [14].