Table 2.

Amino acid differences between Norway3487 and Norway3568 viruses^a

Virus	Amino acid
	PB1 720b	PB2				HA		NA 257	NS1
		4	191	340	410	126	222		103	127
Norway3487	S	I	E	N	M	D	G	R	L	N
Norway3568	Y	T	K	K	V	N	D	K	F	D

^aComparison of the amino acid sequences of Norway3487 and Norway3568 viruses. There were no differences in the sequences of the PA, NP, M1, M2, NS2, and PB1-F2 proteins between these viruses.

^bNumbers represent amino acid positions.