Table 1.

Comparison of amino acid sequences of different H7N7/03 viruses

	Amino acid identity at indicated positiona
Virus	PB2					PA	HA			NA					NS
	79	297	355	563	627	666	13	143	416	164	308	346	442	458	126	137
A/ch/1/03	S	V	R	Q	E	F	I	A	K	T	N	A	T	P	K	V
chH7N7	.	.	.	.	.	.	.	.	.	N	.	.	.	.	.	.
maH7N7	.	.	.	.	K	.	.	.	.	N	.	.	.	.	.	.
A/33/03b	.	.	.	.	.	.	.	.	.	.	.	.	.	.	R	.
A/219/03c	I	I	K	R	K	L	S	T	R	.	S	V	A	S	.	I

^aAmino acids are indicated by single letters; dots represent amino acids identical to the A/ch/Netherlands/1/03 (A/ch/1/03) prototype [11].

^bInfluenza A/Netherlands/33/03, isolated from human conjunctivitis case [11].

^cInfluenza A/Netherlands/219/03, isolated from fatal human case [11].