Table 2.

Virulence determinants in polymerase subunits of the Egyptian H9N2 viruses.

Protein	Site	Virulent	A virulent	Egyptian H9N2 isolates	HK/G1/97	Reference
PB2	147	G	M	I	M	[47]
	250	G	V	V	V
	391	E	D	E	E
	504	V	I	V	V
	526	K	R	R	K
	627	K	E	V	E
	701	N	D	D	D
PB1	317	I	M/V	I	I	[47]
PB1-F2	66	S	N	S	N
PA	127	V	I	V	V	[48]
	328	R	K	R	K
	672	L	F	L	L
	550	L	I	L	L